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Geonaft
Software Manual
Geosteering Technologies
1
Table of contents
1 Introduction ...................................................................................................................................... 3
2 Glossary ............................................................................................................................................ 3
3 Installation overview ......................................................................................................................... 4
3.1 Software and Computer Requirements ....................................................................................... 4
3.2 «GEONAFT» Software installation ............................................................................................... 5
4 Geosteering method ......................................................................................................................... 5
4.1 General principles ....................................................................................................................... 6
4.2 Geosteering methods implementation in «GEONAFT» software ................................................. 7
5 «GEONAFT»....................................................................................................................................... 8
5.1 Initial settings ............................................................................................................................. 8
5.1.1 Product activation ................................................................................................................ 8
5.1.2 Language menu .................................................................................................................. 10
5.1.3 Creating a project ............................................................................................................... 10
5.1.4 Opening and closing the existing project ............................................................................ 12
5.2 Uploading the data ................................................................................................................... 13
5.2.1 General information ........................................................................................................... 13
5.2.2 Data quality requirements .................................................................................................. 14
5.2.3 Reference well data input................................................................................................... 14
5.2.3.1 Adding/Removing reference wells ................................................................................... 15
5.2.3.2 Markers ........................................................................................................................... 16
5.2.3.3 Logging data .................................................................................................................... 17
5.2.3.4 Trajectory inclination ....................................................................................................... 22
5.2.3.5 Fluid contacts .................................................................................................................. 23
5.2.3.6 Formation structure dip................................................................................................... 24
5.2.4 Uploading the actual well data ........................................................................................... 24
5.2.4.1 Trajectory ........................................................................................................................ 25
5.2.4.2 Logging data .................................................................................................................... 25
5.2.5 Planned trajectory data uploading ...................................................................................... 25
5.2.5.1 Adding/Removing planned trajectories ........................................................................... 25
5.2.5.2 Planned trajectory inclination data .................................................................................. 26
5.3 Data display settings ................................................................................................................. 27
5.3.1 Reference well logs display ................................................................................................. 27
5.3.1.1 Reference well logs display pane ..................................................................................... 28
5.3.1.2 Changing the log data scale display ................................................................................. 29
5.3.2 Cross-section display pane ................................................................................................. 29
5.3.2.1 Cross-section display settings .......................................................................................... 30
5.3.2.2 Trajectory display ............................................................................................................ 32
5.3.2.3 Contacts display .............................................................................................................. 32
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5.3.2.4 Markers display ............................................................................................................... 33
5.3.3 Color scale .......................................................................................................................... 34
5.3.3.1 Default color scale ........................................................................................................... 34
5.3.3.2 Custom color scales ......................................................................................................... 34
5.3.4 Synthetic and actual logs display ........................................................................................ 35
5.3.4.1 Display settings ............................................................................................................... 35
5.3.4.2 Adding/Removing synthetic logs...................................................................................... 36
5.3.4.3 Adding/Removing actual logs .......................................................................................... 37
5.3.4.4 Curve display settings ...................................................................................................... 38
5.4 Navigation within the cross-section .......................................................................................... 38
5.4.1 Using the navigation arrows ............................................................................................... 38
5.4.2 Mouse navigation ............................................................................................................... 38
5.4.3 «Set view» and «Home view»............................................................................................. 39
5.5 Matching the synthetic logs to the actual logs .......................................................................... 39
5.5.1 Changing the structure dips ................................................................................................ 39
5.5.2 Vertical reservoir position fitting ........................................................................................ 40
5.6 Additional functions .................................................................................................................. 41
5.6.1 Depth/distance display ....................................................................................................... 41
5.6.2 Distance measurement....................................................................................................... 42
5.6.3 Copying the image .............................................................................................................. 43
5.6.4 Printing .............................................................................................................................. 43
5.7 Help .......................................................................................................................................... 43
5.7.1 Tooltip mode ...................................................................................................................... 43
5.7.2 Documantation .................................................................................................................. 44
5.7.3 Online help and software FAQ ............................................................................................ 44
6 Example of using the «GEONAFT» software .................................................................................... 44
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1 Introduction
«GEONAFT» enables detailed geological analysis for improved well planning and optimal tra-
jectory design based on the actual well data and adjusted according to the data collected during drilling.
«GEONAFT» is unique among similar software products by its intuitive interface and a broad set of
required user functions.
The software allows to perform the following tasks:
1) creates a geosteering model with synthetic logs;
2) creates geosteering progress reports and further drilling recommendations;
3) makes decisions about the trajectory of the well based on the comparison of synthetic and ac-
tual logs;
4) optimizes and adjusts the well trajectory;
5) creates of the final report and geosteering models after drilling.
2 Glossary
Well trajectory (well path) – spatial position, either actual or planned, that defines the actual or
preferred existence of a well bore.
Planned well path defines the preferred spatial existence of a well bore. The planned well path
can change abruptly, typically as the result of new information acquired while drilling.
Actual well - well, the trajectory of which is necessary to optimize during the drilling process.
Reference well - well adjacent to the actual borehole. Reference well logs are considered as a
reference for the calculation of synthetic logs.
Actual logs – Logs of the actual well in the drilling process.
Synthetic logs – calculated logs for the actual well trajectory, based on the reference well logs
and formation dips.
Logging curve - one curve recorded during logging.
Markers - mark stratigraphic boundaries of the strata section.
Fluid contact - The interface that separates fluids of different densities in a reservoir. A mixed-
fluid reservoir will stratify according to fluid density, with gas at the top, oil in the middle, and water
below. (GOC – gas-oil contact, OWC – oil-water contact, GWC – gas-water contact, FWL – free water
level).
Formation dip - The angle between a planar feature, such as a sedimentary bed and a horizon-
tal plane (in the GEONAFT the angle is calculated along the trajectory of the actual well – apparent
dip).
Dipping bed - a layer with several different dips.
The marks on the trajectory of the well measure the depth of the well path in the cross section
pane.
Project - a GEONAFT project with the uploaded data used to optimize the trajectory of the well
during drilling.
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Project file - All data and the project settings are saved in the project folder containing project
file ( the_project_file_name.gnproj) and the folders containing all project data.
Project data – data that needs to be loaded into the project - trajectories, logs, markers and fluid
contacts.
Application window typically contains Title Bar, Menu Bar, Toolbar, Application Status Bar,
Log Panes and the Section Cut Pane.
Menu bar is located just under the Title Bar. Clicking on a menu item displays a drop down list
of commands that can be used to access different features and screen functions.
Toolbar contains icons that are used for a quick access to the functions and various data.
General data includes general data related to the actual well. It includes information about the
well location and does not affect the application run.
Reference well logs pane displays the log curves of the reference well. Recorded strata charac-
teristics are translated into differentially colored fragments displayed on the cross section pane.
Actual and synthetic logs pane displays one or more curves of the actual or synthetic logs.
Cross section pane displays the cross section along the trajectory of the actual well.
Color scale is located on the left side of the cross section pane.
Status bar is located at the bottom of the application window. It contains messages about the
status of application processes.
3 Installation overview
«GEONAFT» installation package distribution is a subject to the terms and conditions of the
License Agreement between customers and the copyright holder "Geosteering Technologies Inc”. The
trial version of the software is available on the company's website http://www.geosteertech.ru/. The
installation process is simple and not time-consuming.
3.1 Software and Computer Requirements
«GEONAFT» software has comparatively low system requirements for an effective perfor-
mance.
Minimum System Requirements:
Windows XP/Windows Vista/Windows 7
1.0 GHz Pentium III or equivalent processor
100 MB available HD space
256 MB RAM
800x600 minimum display resolution
Recommended Specifications:
1.5 GHz Pentium IV or equivalent processor
512 MB RAM
1024х768 display resolution
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3.2 «GEONAFT» Software installation
To start the installation of the «GEONAFT» Software application, double-lunch the installation
package downloaded from the Geosteering Technologies internet site. To exit the process of installa-
tion click “Cancel”. When the installation is launched, the “Select Installation Folder” window is dis-
played. Choose the installation location, then click “Next”. Follow the instructions displayed in the in-
stallation window to complete the installation process.
To open installed «GEONAFT» application select «GEONAFT» in the menu Start/All pro-
grams/GEONAFT/ or double-click the GEONAFT icon from the computer desktop.
After software installation, selected «GEONAFT» folder will contain the following files and
folders:
There is an Example folder which supplied as a part of the installation package. It contains an example
project which can be loaded into GEONAFT and worked with.
4 Geosteering method
Increasing demand in developing new reservoirs, which require complex geological drilling
conditions, creates a demand in real-time information on a wide range of parameters of the developed
geological section. Successful well placement both on the way to the reservoir and in the reservoir is
the combination of the right technology and expert log analysis. This combination leads to maximum
hydrocarbon recovery, reduces the drilling risks and extends well life. Accurate well placement im-
proves the long-term and short-term performance of wells.
For a long time new geological-petrophysical methods of planning and on site maintenance of
drilling wells are put into practice in oil and gas reservoir development. The growing experience in
monitoring and adjustment of well trajectory as well as the test results of the currently developed de-
posits allow creation of a model that can be continuously updated with the data from reservoir logs. In
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this case, the key point of the modern well design is the speed of obtaining and integrating information
to make timely decisions and ensure that your well objectives are met.
4.1 General principles
Geosteering method is based on comparison of the horizontal well logs with the logs of the ref-
erence well. Reference well may be vertical or deviated. Prior to drilling a horizontal well, reservoir
model is created. This model reflects the regional formation dip obtained from the geological model of
the field. Reference well logs are used to calculate synthetic logs along the trajectory of horizontal
well. The actual well logs compared with the synthetic logs created by the model, and results are used
to update current model. New model should produce synthetic logs that match previously obtained ac-
tual logs and the reference log data. Thus the stratigraphic position of the wellbore in the reservoir is
determined, as well as the prediction of the formation structure dip and behavior. These predictions are
based on the regional formation dip and combination of actual and synthetic logs. If necessary, the well
trajectory is corrected during drilling.
Method limitations
There are two requirements for using described geosteering method:
1) reference well logs are used in creating an model assuming the reservoir model with proper-
ties equal or very similar in reference and actual well locations;
2) formation layer thickness is equal or very similar for the reference and actual well locations.
The first limitation can be reduced by using the correlation of actual well logging and logging
of the reference wells. It’s important to achieve the identity of stratigraphic reference markers of syn-
thetic and actual logs. If the correlation is impossible, the geosteering techniques hardly can be used.
The second limitation is minor. It does not limit the possibility to define the stratigraphic posi-
tion of the borehole, but due to different thicknesses of the layer, formation dips along the well trajec-
tory cannot be determined correctly. Similar errors can occur when using the reference well with small
angle between well path and formation bed layers (highly deviated reference well or large formation
dip in the reference well location). In this case the calculated thickness of the layer in the reference
well will be larger or smaller than the actual thickness depending on the way reference well crosses the
target layer.
In some cases fitted dips based on several reference wells logging are incompatible with expec-
tations. This, apart from the reasons mentioned above, can be due to local changes in the angle of the
layer bed, caused by the sedimentological characteristics of the field. In these conditions synthetic and
the actual logging should be fitted into a model. However, the actual layer structure prediction should
be determined by the information on the regional formation dips.
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4.2 Geosteering methods implementation in «GEONAFT» software
To build the reservoir model for geosteering well trajectory, reference well is chosen. Reference
well can be vertical or deviated. It is chosen from the wells drilled close to the target area; the proper-
ties of the reservoir are assumed to be similar in those wells locations and in the target area. Pilot hole
for a horizontal well can also serve as a reference well. The purpose of a reference well is to determine
the petrophysical properties of each layer of the formation and create an initial prediction of properties
along the planned horizontal well.
To reduce risks and to improve the geosteering precision we recommend using several refer-
ence wells. Each reference well can be used to build individual 1D reservoir model. 1D model is repre-
sented as a cross section of the formation along the horizontal well. Stratigraphic thickness of the cross
section is equal to the stratigraphic thickness in the reference well (figure 2).
Figure 2 – 1D reservoir model
Properties of each layer of 1D model reflect the properties of the corresponding layer in the ref-
erence well calculated from, for example, resistivity log (in the resistivity model). Other logging curves
from the reference well - a model of gamma ray, neutron log, density log, spontaneous potential (SP)
log – can be used to build 1D model as well. Reference well log is transformed into a synthetic logs
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along the trajectory of horizontal wells according to its actual trajectory and formation layers bends.
Model synthetic logs are compared with the actual horizontal well logs, obtained in the drilling process
in real time. By fitting the model structure of the reservoir the best match is selected. In the drilling
mode, new data is integrated into the reservoirs model, step by step, matching of the synthetic and ac-
tual logs. The result of matching is a reservoir with a number of dips in the structure that allows to de-
termine the position of the actual well in the reservoir. The use of different curves and several refer-
ence wells is the best way to define the current stratigraphic position of the wellbore, and predict the
behavior of reservoir structure.
5 «GEONAFT»
5.1 Initial settings
5.1.1 Product activation
Product activation helps protect the company from unauthorized copying of software. Activa-
tion is mandatory.
Standard software package contains the trial version of the software. The user can run the pro-
gram up to 30 times to get acquainted with its functions. After that, product activation is required for
further use of the software.
To open the product activation dialogue, select "Help/Activate ..." as shown in Figure 3
Figure 3 – Product activation
The following dialog box (Figure 4) will appear. It contains general information on how to ac-
tivate the product, as well as option to view the license agreement, which was accepted during the in-
stallation of the software.
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Figure 4 – Product activation dialogue
To continue the activation process click "Activate". The activation process can be interrupted
by pressing "Cancel" button.
In the next step you are prompted to the Licence code dialog box (Figure 5). During the product
installation your computer will generate a number which you must provide to the Company. This can
be done by contacting product support services by phone or email. This number does not contain any
personal information or information about your computer.
Figure 5 – Licence code dialogue
Shortly after receiving your activation number Company will provide you with the Licence
code which you can enter in the dialog box in order to complete the activation process.
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This software can make changes to the configuration of your computer. A slight reconfiguration
of the hardware after activation does not require additional activation. After replacing the hard disk or
transferring the product from one licensed computer to another, you may need to reactivate the product.
More information about product activation is available at //www.geosteertech.ru/activation
5.1.2 Language menu
After starting the «GEONAFT» software the interface language can be changed. «GEONAFT
1.1» supports two languages: English and Russian. To change the language, go to the menu
"View/Language” (Figure 6). The language settings will be saved for subsequent application runs.
Figure 6 – Language menu
5.1.3 Creating a project
To create a new project, select "File/New Project” or press «Ctrl + N» (Figure 7). Enter the region
name, field name, code/name of the actual well, etc., select the location of your new project on the disc,
then click OK. (Figure 8).
To save a project select "File/Save” press «Ctrl+S» (Figure 9). The project file has the extension *.
gnproj. Saving a project « GEONAFT » creates a folder with a name that includes the name of the actual
well. This folder is used to store internal files of the project and users must not remove, add or make any
changes to the data files in order to avoid software malfunction.
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Figure 7 – Creating a project
Figure 8 – Creating a project
Saved project also contains file that stores information about configuration of the project, in-
cluding information about the current reference well, the used color scale, vertical and horizontal ends
of the cross-section, etc. (for more information about data display settings, see Chapter 5.3 Data dis-
play)
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Figure 9 – Saving a project
To save the project in the different location select “File/Save as” in the main menu.
5.1.4 Opening and closing the existing project
To view and edit existing projects, click File/Open in the main menu or press «Ctrl + O» (Figure
10). Select the desired project and click Open. Opened project retains all the configuration parameters
(scales, log curves, color scale and the main cross-section), saved before.
Close the project by selecting "File/Close All" or "File/Exit" (Figure 11).
Figure 10 – Opening an existing project
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Figure 11 – Project exit
5.2 Uploading the data
«GEONAFT» needs a set of data including log data for the actual and reference wells, devia-
tion survey data for both wells, the position of the fluid contacts and geological markers, etc. This sec-
tion describes how to upload the data, and the requirements of data quality.
All raw data can be downloaded via "Data" in the main menu or the using corresponding
toolbar buttons (Figure 12).
Figure 12 – Uploading the data
5.2.1 General information
General information includes the name of the region, field, and the actual well. These data are
not required for the software use. To enter General information data select “Data -> General infor-
mation" (Figure 13)
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Figure 13 – Common data
5.2.2 Data quality requirements
«GEONAFT» performs initial quality control of the input data, however, the user must visually
control the quality and sufficiency of the data from deviation surveys, logs, markers, fluid contacts.
Input data quality control is required both at the initial setup and during drilling, while loading
the updated data. Specific requirements for the input data will be discussed in the following sections.
5.2.3 Reference well data input
As mentioned above, the reference well (see Section 4.2) is used to build synthetic logs along
the path of the actual borehole. Reservoir properties in the area of new horizontal or deviated wells
are assumed to be similar to properties in the reference well (i.e., if the vertical well was drilled in the
place of the new wells, logging would be similar to logging in the reference well). By changing the
formation dips the most appropriate correlation between the actual and synthetic logs is chosen. As a
result, a set of reservoir bends with calculated structure dips defines the position of the actual well in
the reservoir. The name of the current reference well appears in the info window on the left (Figure
14).
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Figure 14 – Current reference well
5.2.3.1 Adding/Removing reference wells
To add or remove a reference well, select “Data -> Wells -> Reference wells "(Figure 15).
Figure 15 – Reference wells
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Figure 16 – Adding/Removing reference wells
In the Reference well dialog box current reference well is at the top of the drop-down list, con-
taining all the currently available reference wells. The user can create new or remove existing wells
using the buttons Add and Delete respectively. Adding a new reference well requires reference well
“Name" and "Altitude" In this case, the " Altitude" denotes the height of the rotary table above mean
sea level.
There are five types of data sets used in the «GEONAFT»:
1) information about the geological markers ("Markers", see Section 5.2.3.2);
2) reference well logs ("Logging", see Section 5.2.3.3);
3) reference well deviation survey data ("Trajectory", see Section 5.2.3.4);
4) the depth of the fluid contacts ("Contacts", see Section 5.2.3.5);
5) the formation dips ("Dips”, see Section 5.2.3.6).
Critical data here are the reference well inclination data and logging data. Without this infor-
mation it is impossible to build a main cross-section (see Section 5.3.2). Each data set button has a col-
or indicator, which turns green if the corresponding set of data has been uploaded.
5.2.3.2 Markers
Reference well markers are necessary to specify the key borders of the reservoir. Loaded geo-
logical markers can significantly facilitate the correlation of the synthetic and the actual logging, at the
same time, this information is not critical for the «GEONAFT». Loading markers is carried out by
pressing the "markers" on the Reference well dialog box (Figure 16). Depth markers are indicated in
the absolute depths relative to mean sea level and they vary in the cross-section according to the for-
mation dips (Figure 17). Number of markers per well is not limited.
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Figure 17 – Geological markers data entry
5.2.3.3 Logging data
Log data together with inclination data are critical to the operation of the «GEONAFT». To
download log data press "Logs" in the Reference well dialog box. Example of Logs data form is shown
in Figure 18.
The header row showing the logging data types and units, as well as the last column containing
the vertical depth from the rotary kelly bushing cannot be modified. These row and column are in gray.
The vertical depth is introduced for user convenience, since the log data (see Section 5.5.3) are dis-
played on the graphs versus the vertical depth values. The true vertical depth (TVD) of the well is re-
calculated using the borehole deviation data (see 5.4.3.4). Important to note, that the values of depth
should be in increasing order, otherwise the program will display an error message indicating the num-
ber of the first line, for which the subsequent value of depth of the shaft is less than or equal to the pre-
vious value. Column "MD" - depth, measured along the shaft should always be first.
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Figure 18 – Logging data
Data input menu includes following commands (рисунок 19):
1) «Cut»;
2) «Copy»;
3) «Paste».
Figure 19 – Data input commands
«GEONAFT» has a function of data search by the value of depth. To use this option, select
"Search" in the menu and enter the value of the desired depth in the dialog box (Figure 20). For a se-
lected reference well there are two search options: search for the data by the depth along the borehole
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and the search by the true vertical depth. For the actual well search could be made by the depth along
the borehole, and by the horizontal distance from the wellhead.
Figure 20 – Log data search by the value of depth
«GEONAFT » can import log data from the *.las data files, special file format used for storing
log data. To import data from the *.las file select “LAS file -> Import". Chose the desired *.las file,
and click Import, this command opens the LAS file dialog box (Figure 21).
The upper part of the form contains the data read from the LAS file header. It includes start and
end logging points, and the target depth, the name of the reservoir and other information. Bottom part
of the form contains four columns, the first three of them are read from the LAS file: the name of log
data in the original file, an example curve value and its measurement units. The fourth column is filled
by the user by selecting the appropriate curve from the dropdown menu (Figure 22).
Figure 21 – Import logs from the *.las data files
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Figure 22 – Assigning the LAS file curves
Prerequisite is the selection of the appropriate curve for each column of the LAS file. The
dropdown list contains a fairly wide set of curves, but in the absence of the required curve, the user can
choose a «Custom» curve. The maximum number of «Custom» curves is five. Importantly,
«GEONAFT» does not allow duplicate curves (curves with the same name), for example, if having two
GR curves only one of them can be assigned the «GR» type, the second one have to be assigned as
«Custom1». If your selected type has already been reserved for one of the curves, LAS file line will be
highlighted in red. After assigning the correct type for every curve in the LAS file click Apply to up-
load all the data into the main form, shown in Figure 18.
In addition, it is possible to export / import data between «GEONAFT» software and Microsoft
Excel. To use this option, select «Excel -> Export (Figure 23). Because the input logging data dialog
box has limited editing functions, we recommend to export the data into Excel, perform all necessary
manipulations (such as filtering values, increment of depth, etc.), and then import this modified data
using the menu item «Excel - > Import. The data can also be pasted directly into the Logging data form
21
Figure 23 – Export of log data into Microsoft Excel
In the case «GEONAFT» has already a set of the uploaded log data; to upload an additional
curve, use the option "Add/Remove curve" in the Logging data form (Figure 18). The "Add/Remove
curve” dialog box will appear (Figure 24).
Figure 24 – "Add/Remove curve” dialog box
Click Add to add a new curve in the list. To remove a curve, select the curve and click "Re-
move". In the column "Curve type" select the type of the loaded curve. List of included curve types
presented in Table 1.
Table 1 - List of curves that can be added
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Curve name Units Log curve
AZIM degree azimuth
INCL degree inclination
COND mS/m conductivity
PERMH mD horizontal permeability
PERMV mD vertical permeability
DEN g/cm3. density
BITSIZE inch Bit size
CALI inch caliper
GR API units gamma ray log
GR_rus mR/h gamma ray log
ROP Rpm rate of penetration
TGAS Per cent total gas
MUDWEIGHT g/cm3. mud weight
SP mV spontaneous potential log
PEF eV photoelectric factor
POR Per cent porosity
TVD m true vertical depth
TVDSS m absolute vertical depth below mean sea level
MD m measured depth
RES_DEP Ω m deep resistivity log
RES_MED Ω m medium resistivity log
RES_SLW Ω m shallow resistivity log
RES_MIC Ω m microlog survey with a cylindrical focusing
TEMP Degree Celsius temperature
NEU Per cent neutron porosity log
DT msec/ft acoustic log
It is also possible to download four other types of log curves as «Custom» curves.
5.2.3.4 Trajectory inclination
Second, critical to the reference well, data are inclination (trajectory) data. Reference well in-
clination data is necessary to calculate the stratigraphic thickness of the reservoir (in case of the reser-
voir horizontal position or low angles of reservoir crossing by the reference wells).
To download data, click on "Trajectory" in the reference well data input form. After that, an in-
clination data entry dialog box appears, shown in Figure 25. Header row of the table includes the depth
of the borehole, the angle and azimuth of the well, as well as units of these variables. These rows are
gray and cannot be modified.
To upload the inclination data either import data from MS Excel “Excel -> Import”, or copy
and paste the data directly into a data entry form. The order of the data is strictly fixed!
Column 1 - MD - the measured depth of the borehole in meters.
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Column 2 - INCL - inclination, degree.
Column 3 - AZIM - azimuth, degree.
Figure 25 – Inclination data entry
It is important to note that depths values should be in increasing order, otherwise the program
will display an error message indicating the number of the first row, which depth value is less than or
equal to the previous value. When inclination data is loaded not from the starting point (well head) of
the reference well (depth of the borehole - 0 m), there is ambiguity in the TVD calculations (due to
lack of information about changes in the angles in the upper ranges of depth). In order to avoid such
situations, the inclination data must be uploaded from 0 m MD! In addition, since a horizontal
well cannot be a reference well, all values of column 2 (inclination) should be ≤ 89 degrees!
5.2.3.5 Contacts
«GEONAFT» has a possibility to display fluids contacts. To upload data on fluid contacts,
press "Contacts" on the reference well data entry form. After that, Fluid contacts data entry dialog box
appears, shown in Figure 26.
Figure 26 – Fluid contact data
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You cannot import the contacts data from LAS file or MS Excel file. To upload the data paste
the values into the form directly. Use absolute vertical depth below mean sea level.
5.2.3.6 Reservoir dip
If regional data, geological models, etc. are available «GEONAFT» can construct a reservoir
model with number of dips that allows determining the position of wells in the reservoir. In this case,
upload the data to «GEONAFT» using "Dips” button on the reference well data entry form. In the fol-
lowing dialog box, shown in Figure 27, the first column «L» is a horizontal distance from the wellhead,
the second one («Dip») - the angle (dip) for a given L.
Figure 27 - The dip data entry form
You cannot import the contacts data from LAS file or MS Excel file. To upload the data paste
the values into the form directly. In the absence of the data, this table will be filled in the process of
fitting of synthetic logs to the actual logging (see Section 5.5).
5.2.4 Entering the actual well data
Actual well is a currently drilled horizontal (or deviated) borehole, and the trajectory of which
must be optimized in the process of obtaining new geological and geophysical data on the reservoir.
The project can create only one actual hole. It is upload with trajectory data and logs obtained during
drilling. The trajectory of the actual well and adjusted position of the reservoir will be used to calculate
synthetic logs.
To create an actual well or edit the actual well data, select "Data -> Actual Wells” in the main
menu. This opens a window "Actual well data entry”, shown in Figure 28.
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Figure 28 – Actual well data entry
5.2.4.1 Trajectory
Pressing the "trajectory" in the Actual well data entry form opens a window for input / editing
of the trajectory (Figure 28). Color indicator next to this button shows the presence / absence of the
uploaded data (red - no data, green - the trajectory data is uploaded).
Trajectory data entry form and all data entry instructions are similar to the trajectory inclination
data entry for the reference well described above (see Section 5.2.3.4). Also, all data restrictions speci-
fied in Section 5.2.3.4 are valid for the actual wells inclination data, with one important exception - the
value of the data in column 2 (zenith angle) can exceed 89 degrees (e.g. horizontal well).
5.2.4.2 Log data
To enter or edit the log data for the actual well, press “Logs” in the Actual well data entry form.
The data entry instructions are the same as for Log data entry for the reference well, described above
(see Section 5.2.3.3). Also, all data restrictions specified in Section 5.2.3.3 are valid for the actual wells
logging data.
5.2.5 Planned trajectory data entry
Planned trajectory is a trajectory uploaded to design the trajectory of actual wells. Number of
planned trajectories is not limited, but the maximum number of well paths that can be displayed simul-
taneously on the main cross-section (Section 5.3.2) is three. The only data required for the "planned
trajectories" are the inclination data.
5.2.5.1 Adding/Removing planned trajectories
To create a new planned trajectory or edit the existing one select “Data -> Wells -> Planned tra-
jectories”. The following dialog box will appear (Figure 29):
26
Рисунок 29 – Planned trajectory data entry
Click "Add" or "Delete" to add new or delete existing planned trajectory respectively. When
adding a new trajectory, fill in the name of the planned trajectory in the "New planned trajectory” form
(Figure 30).
Figure 30 - Adding new planned trajectory
By selecting a trajectory in the list of "planned trajectories" you can edit its name in the lower
panel of the Planned trajectories data form (Figure 29).
5.2.5.2 Planned trajectory inclination data
Pressing the "trajectory" in Planned trajectories data form opens a window for input / editing of
the trajectory. Color indicator next to this button shows the presence / absence of the uploaded data
(red - no data, green - the trajectory data is uploaded).
Trajectory data entry form and all data entry instructions are similar to the trajectory inclination
data entry for the reference wells described above (see Section 5.2.3.4). Also, all data restrictions spec-
ified in Section 5.2.3.4 are valid for the actual wells inclination data, with one important exception -
the value of the data in column 2 (zenith angle) can exceed 89 degrees (e.g. horizontal well).
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5.3 Data display settings
5.3.1 Reference well log display
Figure 31 shows the main window of «GEONAFT» software. The main elements and their
function is described below.
Figure 31 - «GEONAFT» 1.1 main window
1 - Main menu - the main options available at the current stage.
2 - Toolbar - contains icons for quick access to main functions.
3 - General reservoir data, pad / platform name.
4 - The names of the actual well; selected reference well; planned trajectory, the reference well
curve which is used for coloring of the main cross-section.
5 – Reference well logging data, which is which is used for coloring of the main cross-section.
6 – Cross-section pane - visualization of the cross-section cut along the trajectory of the actual
well, with the trajectory of the actual well and planned trajectories.
7 - Color scale - user-selected range of colors for coloring the main cross-section.
8 - Visualization of the actual and synthetic logs.
9 - Navigation toolbar for the main cross-section and layer bend adjustment tools.
10 - Status bar - displays information about current processes.
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5.3.1.1 Reference well log display pane
«GEONAFT» displays the reference well log graphs versus to the vertical depth from the rotary
kelly bushing. Displayed graph is the graph of the log curve used for coloring of the main cross-section
(see Section 5.3.2). The graph is presented in the panel 5 (Figure 32). This area has three components
with custom settings:
1) The depth axis;
2) The log data axis;
3) Reference well log.
To adjust the depth axis scale left click on the depth axis. In the resulting window, adjust the
number and distance between the tick marks, the font, color and number of digits in the depth values
(Figure 33). Extreme values on this scale are dependent on the values chosen on the scale of the verti-
cal depth from the rotor table of the main cross-section (see Section 5.3.2).
Figure 32 – Reference well logging display
Figure 33 - Depth axis scale configuration
29
5.3.1.2 Changing the log data scale display
To change the log data display limits, left click on the axis. In the resulting window, adjust the
number and distance between the tick marks, the font, color and number of digits in the log data values
(Figure 34). In addition, to set maximum and minimum values of the log data scale, enter the desired
values in the dialog box. To use the reverse order of log data values, check the corresponding box.
"Fixed” (auto) maximum and minimum values will be determined by the log curve.
Figure 34 - Log data scale properties
To adjust the thickness and color of the curve, click on the logging curve display area. This will
bring up a dialog shown in Figure 35.
Figure 35 – Log data curve properties
5.3.2 Cross-section display pane
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The main cross-section of the well is a graphical representation of 1D reservoir model. More
detailed description of the basic principles that are used in creating this model is given in section 4.2.
This section deals with basic function of the cross-section pane. The main elements of the cross-section
pane and their functions are as follows (Figure 36):
Figure 36 - The cross-section pane
1) Vertical depth from the rotary kelly bushing axis;
2) Distance along the horizontal profile of the well;
3) Reservoir cross-section, colored according to the the selected curve of the reference well log
data according to the color scale (see Section 5.3.3);
4) Absolute vertical depth axis;
5) Actual well trajectory;
6) Horizon markers identified in the reference well;
7) Planned trajectory included in display (maximum of three planned trajectories);
8) Dips, made to adjust the synthetic logs to the actual logs;
9) Fluid contacts.
5.3.2.1 Cross-section display settings
To change the current limits of the cross-section display:
1) Use axis scales of vertical depth and horizontal distance from the wellhead;
2) Use the navigation arrows (see Section 5.4.3);
3) Scroll with the mouse wheel (see Section 5.4.4).
To change the limits of the cross-section display left click on the axis of vertical depth (Area 1
on Figure 36). This will bring up the dialogue box, shown in Figure 37. Adjust the maximum and min-
imum values of the depth scale, number and distance between the tick marks, the font, color and num-
31
ber of digits in the depth values (Figure 34). Font of the values and font of the axis title can be set in-
dependently of each other.
Figure 37 - "Vertical" and "Horizontal" axis settings
The axis of the horizontal distance from the wellhead is configured similarly. To change, left
click the axis and set the properties using the same dialog box (Figure 37).
True Vertical Depth Sub Sea (TVDSS) values are calculated using the minimum and maximum
vertical depth from the rotary kelly bushing, and the actual well altitude. Absolute elevation axis set-
ting can be adjusted by left clicking on the axis, using the dialog box shown in Figure 38.
Figure 38 – TVDSS axis settings
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5.3.2.2 Trajectory display
The trajectory of the actual hole is displayed automatically in the cross-section pane after im-
porting the trajectory data.
To display planned trajectories choose the required trajectory in the current settings display
pane (area 4, Figure 31).
To customize the trajectory display, go to the tab "Trajectories" (Figure 39) in the Display set-
tings dialog box (to open the display settings, left click on the cross-section pane area) and select the
desired trajectory. The current trajectory color and line thickness will be displayed in the corresponding
fields. Change the settings if necessary. The actual trajectory has an option to display the measured
depth (MD) along the trajectory in the form of tags. To do this, tick "Display marks on the trajectory”,
choose distance between the tick marks and the font of the depth values.
Figure 39 - Trajectory display settings
5.3.2.3 Contacts display
To customize the display of fluid contacts, left click on the main area of the cross-section (re-
gion 3, Figure 36) and select the Contacts tab (Figure 40). Select required fluid contact, adjust color
and line thickness of selected contact, if necessary.
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Figure 40– Contacts display settings
5.3.2.4 Markers display
To customize the display of geological markers, left click on the main area of the cross-section
(region 3, Figure 36) and select the tab "Markers" (Figure 41). Adjust color and line thickness, if nec-
essary. All markers will have the same color.
Figure 41– Markers display settings
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5.3.3 Color scale
The color scale displayed on the left of the main cross-section is used to correlate the values of
the curve at a particular depth interval with a certain color. It allows visually separation of the cross-
section into the interlayers with particular geophysical properties (eg, to differentiate the reservoir and
non-reservoir) and to determine the actual position of the well relative to these layers.
5.3.3.1 Default color scale
«GEONAFT» contains several default color scales. Color scales are defined for the GR, density
and neutron logs, as well as resistance logs. Since the selection of a common template, which covers all
possible logging values for large number of deposits is difficult, «GEONAFT» allows to create, edit
and save custom color scale templates.
5.3.3.2 Custom color scales
To create or edit a custom color scheme the user must either select "Settings -> Fill” in the
main menu, or double-click the area 7 of the main window (see Figure 31). Afterwards, Custom color
scale dialog box will appear, containing all the parameters of the current color scale (Figure 42). The
most important ones:
1) the number of value ranges - the maximum number is limited to 7;
2) the number of shades - the number of color gradations in each range of values;
3) minimum and maximum values in the range
Figure 42 - Color scale settings
The first color corresponds to the minimum value in the range, the second - to the maximum.
The range limits have the same units as the curve values on the reference well logging graph (see Sec-
tion 5.3.1). Interlayers, that have values of the synthetic curve beyond the minimum and maximum
values, are colored in white. This setting cannot be changed.
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5.3.4 Synthetic and actual logs display
Synthetic and actual logs display pane contains three charts with curves (region 8 of the main
window in Figure 31). Each chart can display up to four curves of the actual and/or synthetic logging.
On the left of each diagram is the pane used to change the color of the curves and axis scale settings for
each curve, the curves display area is also used to add or delete curves (Figure - 43).
Рисунок 43 – Synthetic and actual logs display pane
5.3.4.1 Display settings
Graphs of actual and synthetic logging represent the actual or synthetic logs data plotted versus
horizontal distance from the wellhead. The horizontal scale is changed according to the horizontal scale
of the main cross-section. Vertical scales are independent of each other, but the greed is based on the
right-most of them. To change the scale, left click on the axis. The following dialog box will appear
(Figure 44).
First tab contains the curve settings, such as color and thickness of the line on the graph, the se-
cond tab contains the axis scale settings of the corresponding curve. Choose the minimum and maxi-
mum values (fixed or user-defined), number and distance between the tick marks, the font, color and
number of digits in the value numbers. Values can be displayed in reverse order.
36
Рисунок 44 – Actual and synthetic logging display settings
5.3.4.2 Adding/Removing synthetic logging
To add or remove the synthetic curve, double-click on the synthetic and actual logging display
area (Figure 43). All reference well curves, except the depth of the along the borehole are synthetic. To
move the curve from the “Available curves” list to the "The curves on the chart” list or vice versa, use
or accordingly. Click OK to close the "Add/Remove curves” dialog box (Figure 45) and
save the changes.
37
Figure 45 – Adding/Removing synthetic logs
5.3.4.3 Adding/Removing actual logging
To add or remove actual logging curves, chose the Actual logging curves tab in the dialog box
(Figure 46) and add/remove curves according to instructions for the reference well logging curves de-
scribed above (Section 5.3.4.2).
Figure 46 – Adding/Removing actual logs
38
5.3.4.4 Curve display settings
To change the color or the thickness of the curves, use the instructions from the Section 5.3.4.1
5.4 Navigation within the cross-section
Navigation (changing the display limits) within the main cross-section can be done in three
ways:
1) Use axis scales of vertical depth and horizontal distance from the wellhead (see Section
5.3.2.1);
2) Use the navigation arrows;
3) Scroll with the mouse wheel.
5.4.1 Using the navigation arrows
Figure 47 – Navigation arrows
Arrow navigation occurs as follows:
1. - Vertical displacement of 10% of the displayed depth range.
2. - Horizontal displacement of 10% of the displayed interval of distances from the well-
head, movement occurs if the left limit is greater than zero. If the left limit is zero, the image does not
move left but stretches instead - i.e. the left boundary is fixed at zero and the maximum horizontal dis-
tance begins to decrease.
5.4.2 Mouse navigation
To use a mouse scroll wheel to zoom the main cross-section, activate zooming by clicking
in the «GEONAFT» toolbar or by selecting "Mouse -> Zoom" in the main menu. Values on the hori-
zontal axis cannot decrease below zero during scrolling, while changing vertical depths is not limited.
39
5.4.3 «Set view» and «Home view»
«GEONAFT» can remember previously specified settings of the main cross-section vertical
and horizontal limits, for this purpose click . After that, all the following navigation within the
cross-section can be cancelled and the border can be set back to the original ones by clicking .
Default vertical borders are determined by the first and the last points of the synthetic log
curve, used for coloring the main section. Default horizontal borders are from zero distance from the
wellhead to the last point of the actual logging data.
5.5 Matching the synthetic logs to the actual logs
Basic principles of the method of setting a synthetic log to the actual described in Section 4.
This section focuses on the method of this adjustment implemented in «GEONAFT» software.
Setting up a synthetic log to the actual logging is a selection of an optimal structure of the res-
ervoir so that the synthetic logs well coincided with the actual logging.
The first step is a selection of the optimum vertical position of the reservoir, which provides the
greatest match of synthetic and actual logging in the starting point (see Section 5.5.1).
The second step is to select the first marker of synthetic logs corresponding to the appropriate
marker in the actual logs. This may be the structural roof of the reservoir or any marker above the layer
that clearly stands out.
Further steps are to fit formation dips to match synthetic and actual log. During matching,
cross-section in the main window is redrawn and synthetic logs are recalculated.
5.5.1 Vertical reservoir position fitting
As mentioned above, the first step in setting up synthetic logs to the actual logs is a selection of
the optimum vertical position of the reservoir, which provides the greatest match of synthetic and actu-
al logging in the starting point of adjustment. For this purpose, use Vertical reservoir position reservoir
inclination editing dialog box and the button «Delta TVD» (Figure 48).
Figure 48 - Vertical reservoir position and reservoir inclination editing dialog box
40
Vertical shift («Delta TVD») is saved together with the project. It is recommended to edit it on-
ly during the initial correlation of synthetic and actual logging. Further logging adjustment is carried
out by changing the reservoir inclination, adding dips.
5.5.2 Changing the reservoir inclination, adding dips
Changing the angle of the reservoir can be done in two ways.
1. Changing inclination angles in the table. To do that, select “Data -> Wells -> Reference wells
-> The reservoir inclination”, or click on the toolbar (Figure 27). In the column "Distance, L, m"
enter a number that indicates a distance from the wellhead displayed on the horizontal scale of the
cross-section when the change the angle of the layer as well as the inclination of the layer needs to be
made. This option is preferable in case there is a geological reservoir model with the estimated angles,
enter this information when you enter the initial data. Fine-tuning is better made using the option num-
ber 2.
2. Changing the angle of the reservoir by adding the dips lines on the main cross-section. To
switch to the adding dips mode select "Settings -> Display dips lines”, or press on the «
GEONAFT » toolbar. Blue vertical lines indicating the dips at the defined distance from the wellhead
will appear on the main section (Figure 49).
Figure 49 – Main cross-section with dips lines
To create a new dip left click on the main area of the section. Vertical dotted line appears in
red, indicating an active location for the new dip (Figure 50). In the Dips editing dialog box (Figure 48)
enter the angle of the formation in degrees relatively to the horizon, which gives the best correlation
between synthetic log and actual logging, and click “Apply”.
41
Figure 50 - The main cross-section with visualization of the new dip
The newly created dip formation appears as a vertical blue line. To correct the previous dip
formations, activate the desired fold formation by moving the mouse cursor over it and then change the
angle in the Dips editing dialog box.
After changing the angles, «GEONAFT» automatically recalculates all synthetic curves. The
user can compare the correlation between synthetic and actual logging at various angles of dips. Thus
obtained set of reservoir dips allows determining the position of the actual borehole in the reservoir.
5.6 Additional functions
«GEONAFT» has a set of additional functions designed to facilitate the export of the results of
adjustment of the synthetic logs to the actual logs and making drilling recommendations.
5.6.1 Depth/distance display
This mode allows you to display information in a pop-up hints on three main panes of
«GEONAFT» (Figure 51).
42
Figure 51 - Pop-up tips in the main section
1. The actual and synthetic logging pane – pop-up hints display the horizontal distance from the
wellhead in meters.
2. Logging data graph, used for coloring of the main section - shows depth adjusted to the ver-
tical shift of the reservoir layer and layer inclinations, as well as the unadjusted vertical depth from ro-
tary kelly bushing.
3. The main section – hints contain information about the TVD and the horizontal distance from
the wellhead in meters.
To activate this mode, use “Mouse -> Display Depth/Distance” menu item, or toolbar but-
ton.
5.6.2 Distance measurement
To measure the distance between two points, select, "Mouse -> Measure distance" in the main
menu or click . Select with left mouse click two points in the cross-section pane, the measurement
results will be displayed in the status bar - the vertical distance (TVD), the horizontal distance (L) and
the physical distance between two points (Fig. 52). All distance measurements are in meters.
43
Рисунок 52 – Distance measurement
5.6.3 Copying the image
To copy the entire graphical information from the «GEONAFT» main window, select "Report -
> Copy to clipboard" in the main menu or click .
5.6.4 Printing
To print the entire graphical information from the «GEONAFT» main window, select "Report -
> Print" in the main menu or click .
5.7 Help
For additional information go to:
1) Menu Help;
2) «GEONAFT» documentation;
3) Company's website "Geosteering Technologies";
4) Geosteering Technologies support services.
5.7.1 Tooltip mode
Select "Help -> Tooltip” in the main menu. In this mode, putting the mouse cursor over any el-
ement of your application brings a tooltip with a brief description of the basic functions and purpose of
this element.
44
5.7.2 Documantation
Includes this User's Guide, a detailed description of the program's interface, its features and
functions. This manual is provided in MS WORD and PDF formats, in English and Russian. This
manual can be downloaded from our official website http://www.geosteertech.ru.
To go to the «GEONAFT» Help menu press «F1», or select "Help -> Manual" or on the
toolbar.
To view the content of the help menu, select the tab "Content". Desired section can be found
using the index by selecting the tab "Index".
5.7.3 Online help and software FAQ
If you have any questions about how to activate, install and use «GEONAFT» software, use the
Help menu. In addition, consult the "Frequently Asked Questions” section on the official website of
“Geosteering Technologies” http://www.geosteertech.ru.
If you need additional help, please contact «GEONAFT» technical support via sup-
6 Example of using the «GEONAFT» software
This section shows the example of using the «GEONAFT» software. The program has to be ac-
tivated and ready to work, otherwise consult Section 5.1. All necessary data are in the «EXAMPLE»
folder, or can be downloaded from the official website of "Geo Technologies»
(http://www.geosteertech.ru/example). «EXAMPLE» folder contains three sub-folders (Figure 53):
1) RAW DATA - raw data in MS EXCEL and LAS format;
2) INITIAL PROJECT - a project uploaded with raw data, but without adjustment of the syn-
thetic logs to the actual logs;
3) FINAL PROJECT - final version of the project, containing the set of synthetic logs fitted to
the actual logs, final table of the dips, the drilling recommendations.
Figure 53 - EXAMPLE folder contents
«RAW DATA» folder includes three sub-folders presented in figure 54:
1) ACTUAL WELL with files:
• INCLINOMETRY_ACTUAL.xls - actual borehole inclination survey data in MS EXCEL
format;
• LOGS_ACTUAL.las - logging data for the actual wells in LAS digital format,;
2) PLANNED TRAJECTORY contains:
45
• LOGS_ACTUAL. xls – inclination of the planned trajectory in MS EXCEL format;
3) REFERENCE WELL contains:
• LOGS_REFERENCE.las - logging data for the reference wells in LAS format;
• CONTACTS_REFERENCE.xls - details about fluid contacts in MS EXCEL format;
• DIPS_REFERENCE.xls - original table of dips in MS EXCEL format;
• INCLINOMETRY_REFERENCE.xls - inclination survey data of the reference well in MS
EXCEL format;
• MARKERS_REFERENCE.xls – Geological markers data in MS EXCEL format.
Figure 54 –«RAW DATA» folder contents
Copy the «EXAMPLE» folder to the hard disk and start by creating the new project. Fill out all
required information about the deposit, wells and the planned trajectory (for a detailed description see
section 5.1.3).
After creating the project, upload the reference and actual wells logging data, inclination sur-
vey, contacts data, and so on. The data for the actual wells are located in the «ACTUAL WELL» fold-
er, the data for the reference wells - in the folder «REFERENCE WELL», as described above. The in-
clination data for a planned trajectory is in the «REFERENCE WELL» folder. The description of data
loading can be found in chapter 5.2.
Alternatively, open a project that already contains all the necessary input data. This project is
located in the folder «INITIAL PROJECT». The process of opening of a previously saved project is
described in Section 5.1.4 of this manual.
After uploading all the necessary data, or after opening the file INITIAL_PROJECT.gnproj
project will have a following view, shown in Figure 55.
46
Figure 55 - General view of the project prior to fitting the synthetic curve
The formation dip in the planned drilling area calculated from the geological model is 3 de-
grees. Pre-built model of the structure behaviour, as well as the planned trajectory (black trajectory) is
shown in Figure 55. Section color fill is made based on the GR curve of the reference well; optionally
select any of the existing curves in the project for this purpose. During drilling project is uploaded with
data of the actual trajectory (red trajectory) and the actual logging. The program calculates the synthet-
ic curve for the actual trajectory.
At this point, the synthetic and actual curves differ very much - synthetic logs need to be fitted
to the actual logs. Adjustment is made for all selected curves. The setup process begins with a vertical
shift of the layer (see Section 5.5.2). Then, when the vertical shift is defined and fixed, change the dips
for further adjustment (see Section 5.5.1). General view of the project during this process is shown in
Figure 56.
47
Figure 56 – General view of the project during adjustment of the synthetic and actual curves
The process of adding and changing the dips of the reservoir should be repeated until the best
match (correlation) between the synthetic and the actual logging is achieved. We do not recommend to
changed the vertical shift of the reservoir the initial settings; all necessary improvements can be made
by changing the dips. During further drilling, detect changes in the behaviour of structure formation by
comparing the actual and synthetic logging. Dips should be added with regard to the regional inclina-
tion data. As seen in Figure 57 the actual well was coming nearer to the base of the reservoir and then
went to the roof. At this stage it is recommended to reset the trajectory of the actual well to avoid going
beyond the roof of the reservoir. New data and adjustment confirm the statement (Figure 57).
48
Figure 57 - General view of the project in the process of adjustment of the synthetic curve -
coming to the roof of the reservoir
At the stage of approaching the bottom of the reservoir, which was marked on the actual log-
ging by comparing it to the synthetic curves, recommendations were made to increase the angle of the
actual well to stay in the reservoir - Figure 58.
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Figure 58 - General view of the project in the process of adjustment of the synthetic curve -
changing the well trajectory during drilling
The project view after the final adjustment of the synthetic logging to the actual logs is shown
in Figure 59.
There is a correlation between the synthetic and the actual curves, so we can conclude that the
correct set of dips was chosen and the location of wells relative to the reservoir was determined cor-
rectly.
Thus, using the synthetic logging adjustment and based on the resulting reservoir structure data,
the timely decisions on the optimal well path can be made to minimize the loss of the borehole to drill-
ing in the non-reservoir areas.
50
Figure 59 - General view of the project after the synthetic curve adjustment
