What's New in IMEX 2012

What's New in IMEX

Version 2012

By Computer Modelling Group Ltd.

What's New in IMEX 2

Important Changes in IMEX 2012

SIMULATOR CHANGES

Gas Adsorption

The new keywords *ADGMAXV, *ADGCSTV, *ROCKDEN) *ADGPCRIT (Rock-

Fluid Section) and *ADS_WATERZONE (Component Properties section) allow the user

to specify the Langmuir Isotherm parameters used to model the adsorption/desorption of

gas to/from rock. This feature can be used to model simple adsorption effects in shale

gas and CBM problems.

Multiple Solvent PVT Tables

IMEX now optionally allows the PVTS table, the *OMEGASG keyword and the

*DENSITY *SOLVENT keywords to be entered for each PVT region. This allows the solvent properties and mixing parameters between solvent and oil and solvent and gas to

vary from PVT region to PVT region. This option is backwards compatible; no data

modification is required for earlier solvent models to run.

Solver Technology

Improved Cache, Adaptive Implicit and Fully Implicit Alignment

For both fully implicit and adaptive implicit models this will improve parallel efficiency.

These options are enabled by default. They are not described in the IMEX 2012.10

manual but are described in the doc directory.

Automatic Parallel Partitioning in 2 Dimensions (Any Two of the x, y, and z Directions)

Two dimensional partitioning now can be set up automatically using *PPATTERN

*AUTOP2D

Improved Parallel Performance

Improvements to the implementation of parallelization in IMEX have allowed the

Simulator to run more efficiently on larger number of threads on Shared Memory

Processors.

Improved Initialization of skewed corner point grids

A very fine scale (optional) horizontal integration option has been introduced into the

DEPTH_AVE integration option to be used with skewed corner point grids. Sub-

keyword *FINE_INTG enables this option for corner point grids.

Additional *MOD Keyword Feature (*ARRAY)

The *MOD *ARRAY option lets you replace values in a rectangular region of the grid,

using an array of values. For example: *MOD *ARRAY value_array replaces the

existing property values in the region by the corresponding values from value_array.

The number of values in value_array must be (i2-i1+1) (j2-j1+1) (k2-k1+1) and repeat

counts are allowed. A value must be specified for each block in the I-J-K range, even if

the block is null.


Other New Keywords

Three Point Endpoint Scanning (*3PTSCALING)

When *3PTSCALING is enabled an interior scaling point is added to the saturation

endpoint scaling procedure.

For each of Krw, Krow, Krg, and Krog, a different interior scaling point is used depending on

the value of block water saturation (oil-water table) and block liquid saturation (gas-

liquid table).

Krw Scaled between Swcrit and (1-Sorw), if block Sw is less than or equal to (1-Sorw),

or between (1-Sorw) and (1-Soirw), if Sw is greater than (1-Sorw).

Krow Scaled between Swcon and Swcrit, if block Sw is less than or equal to Swcrit, or

between Swcrit and (1-Sorw), if Sw is greater than Swcrit.

Krg Scaled between Slcon and Slrg, if block Sl is less than or equal to Slrg, or

between Slrg and (1-Sgcrit), if Sl is greater than Slrg.

Krog Scaled between Slrg and (1-Sgcrit), if block Sl is less than or equal to (1-Sgcrit)

or between (1-Sgcrit) and (1-Sgcon), if Sl is greater than (1-Sgcrit)

Extrapolate Krw from Krw (Sorw) to Krw=1.0 at Sw = 1.0 (*KRWEXTRAP)

This keyword enables the linear extrapolation of water relative permeability from the last

water saturation in the oil-water table to a saturation of 1.0 and a value of Krw of 1.0.

The command line argument -restart_sr2 can be used to indicate if the SR2 files are combined or separated. If restart_sr2 main is assigned, sr2 will be considered to have restart and results information combined in one sr2 file set. Otherwise if restart_sr2 separate is used, restart and results will be treated separately in two different sr2 file sets. Combined or separated sr2 files should keep consist between initial and restart run. No

mixed uses of sr2 files are supported. Currently, IMEX default is to use the combined sr2.

This option is not described in the IMEX 2012.10 manual (see outboard documentation).

Enhancements to Existing Keywords

*WATER_FIX 4

The WATER_FIX keyword has been used in the past to improve performance in water

filled blocks when small amounts of oil or gas re-enter the block. Without this option,

numerical issues could occur.

The *WATER_FIX 4 option has been implemented to improve its performance.

*WATER_FIX 4 is recommended for models where the complete disappearance of water

leads to numerical issues. Water_fix 4 includes all of the enhancements included in

water_fix 2 and 3.

Template Data Set Changes

Added mxgro024.dat to demonstrate the *IRCONNECT keyword

Added mxspr009.dat to demonstrate multiple solvent PVT regions

Added mxsmo054.dat to demonstrate *PPARTITION *AUTOP2D (two dimensional

partitioning)


Added mxsmo055.dat to demonstrate a shale gas model using with desorption

Added mxsmo056.dat to demonstrate a coal bed methane model using gas desorption

Added mxsmo057.dat to demonstrate three point scaling (*3PTSCALING)

Added mxsmo058.dat to demonstrate Krw extrapolation (*KRWEXTRAP)

Added mxwwm054.dat to demonstrate on-time average layerlump rate output

(*LAYERLUMP_ACTR)

Added mxwwm055.dat to demonstrate the specification of the minimum time interval

between the opening of auto-drill wells in a dill queue (*DRILLT) *DRILLT not in 2012

manual, outboard documentation only

Data Incompatibilities with Previous Versions of IMEX

Keywords *SECTOR, *SECTORARRAY and *SECTORNAMES may not be used

together.

The *LAYERXYZ calculation method has been improved, producing different results, in

some cases, from the previous calculation method.

Use of variable *PB and* PDW and *API initialization arrays may result in slightly

different initialization. A problem, which occurred when inconsistent data was entered,

has been corrected. This does not affect the *PBT, *PDWT or *APIT table vs. depth

initialization options.

WELL MANAGEMENT CHANGES

*LAYERXYZ-METHOD *DIRECT

The original method for calculating well bore radius and well permeability for directional

wells has been improved. The New default method, directional weighting (*DIRECT)

replaces the previous method (*OLD) which used cardinal weighting. Please see the

keyword *LAYERXYZ-METHOD for a detailed description of the differences.

*MONITOR *SHUTLAYER1

Plug the most offending layer (which, when shut, causes the well to have the

lowest/highest value of the monitored variable) and continue the simulation.

*SHUTLAYER1 has the same effect as *SHUTLAYER for a rate type monitor (e.g.

STO), but will be different for a ratio type monitor (e.g. GOR).

*MONITOR *AUTOLAYER1

Similar to *AUTOLAYER but corresponding to *SHUTLAYER1.

*GCONP *TARGET *NONE

Remove any production target specified previously (including *VREP, *RECYCLE and

*PMAINT). Existing maximum / minimum constraints are not affected.

*GCONI stream *TARGET *NONE

Remove any previously specified injection target (including *VREF, *VREFP,

*RECYCLE and *PMAINT) for the indicated stream (gas, water or solvent). Existing

maximum constraints are not affected.


*LAYERLUMP_ACTR

Use on-time averaged rates for calculation of rates and rate based quantities when using LAYERLUMPS. The default is to use instantaneous rates.

*DRILLT

*DRILLT is a keyword to allow the specification of minimum time intervals between the

auto-drilling of injectors and producers (keyword not in 2012 manual, outboard

documentation only).

GRID CHANGES

*IRCONNECT Keyword

A new irregular connection keyword (*IRCONNECT) has been added to the grid

module. It is more flexible than the existing *SCONNECT keyword in that it is direction

aware and so may be used with compaction and dilation models. It will use

permeabilities in the blocks specified to be connected as well as input lengths, input

interblock area and input connection direction to calculate block transmissibility.

*SECTOR, *SECTORARRAY and *SECTORNAMES

Keywords *SECTOR, *SECTORARRAY and *SECTORNAMES may not be used

together. In a single data set all sectors need to be defined using the same method.

BUILDER can be used in the conversion of one format to another.

*MOD *ARRAY Input option Added

The *MOD *ARRAY input option has been implemented for Grid Module variables (see

Simulator Changes).

Corner Point Node Location Entry

Specify the location and usage of each corner point node of a fundamental grid. The

keywords *NNODES, *NODEX, *NODEY, *NODEZ, *NODES, and *BLOCKS are

used. This option reduces the size of the grid data and speeds up grid reading.

LGR Grid Definition Enhancement (Ratio Method)

For a locally refined grid, the default action is to divide the parent block into child blocks

of uniform size. To over-ride this default, use sub-keyword *RG to specify the ratios of

child block sizes. This ratio method makes it easy to specify child block sizes when

parent block size is odd or unknown.

Improved Grid Module Efficiency

Command-line argument -crncon_node causes the simulator to convert internally incoming block-based corner-point data (e.g., *CORNERS) to the node-based

representation. This option may speed up significantly the grid-building part of the run,

at the price of additional memory requirement. This option does not change how corner-

point data is written to the SR2 file set and is not limited by the restrictions of the node-

based input data (e.g., *CORNERS *RG is allowed). This command-line argument is

considered temporary and may not be available after the 2012 version year. This option is

not described in the IMEX 2012.10 manual (see outboard documentation).


Transmissibility Multiplier Action

The TRANSMULT keyword changes the default action for transmissibility multipliers in

IMEX. Currently in IMEX new transmissibility multipliers defined in recurrent data

replace previous values. This keyword allows the action to be changed to accumulate. This option is not described in the IMEX 2012.10 manual (see outboard documentation).

Documents

What's New in IMEX 2012