CHAPTER ONE

1.0 INTRODUCTION

1.1 BACKGROUND OF THE STUDY

The world’s demand for energy is continually growing. There are many reasons for this phenomenon

such as economic development, increased population and consumption of reserves (Jan et al 2001).

According to the American Agency for Energy Information Administration, the world’s energy

consumption in 2005 came to 462 quadrillion BTU (British thermal unit). One of the predictions by

this agency states that this consumption may rise by 50% by the year 2030. The increased energy

consumption has stimulated explorations aimed at new discoveries of viable oilfields. This search has

also taken the oil companies to the deep offshore of major oceans across the globe as witnessed since

the later part of the 90’s to this moment. This adventure has yielded positive results in terms of new oil

wells. Despite the fact that renewable resources such as wind, Solar power and more recently the bio-

fuel are getting more and more popular, 60% of world’s energy still comes from oil and gas

(Geofizyka et al 2009).

The search of hydrocarbon in the Chad Basin and other basins in northern part of the country is timely

and necessary due to the unrest in the oil rich region of the Niger-Delta as witnessed in the last decade.

The perpetual vandalism of oil facilities in the region and other parts of the country has caused the

refinery to shut down on several occasions. This menace necessitated the need for an alternative

provision of raw material for Kaduna refinery which serves the northern part of the country with

petroleum product. Also as calm begins to return to the Niger Delta region there is a need for an

alternative means of getting the economic enriching substance being the major source of revenue

generation in the country. The urgency is spelt out in the Federal Government’s effort in seeing to it

that this is achieved through the Nigerian National Petroleum Corporation (NNPC) in partnership with

the technologically endowed Chinese company Bureau for Geophysical Prospecting/China National

Petroleum Corporation (BGP/CNPC).

Geophysical methods are used to acquire information about the subsurface that can harbor commercial

accumulation of natural resources such as ground water, mineral resources and hydrocarbon. These

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methods include magnetic, gravity, electrical (spontaneous potential-SP and Induced Polarization-IP),

electromagnetic (Very Low Frequency), radiometry, ground penetrating radar, geothermal exploration

and Seismology to mention a few. The word seismic is obtained from the Greek word “seismos”

meaning earthquake or waves (Milton, 1998). The method is divided into two basic types: Seismic

Refraction and Reflection Methods. The former is proficient in engineering geophysics for foundation

studies of man-made structures such as dams, road and highway, buildings, tunnels etc while the later

is an effective method in hydrocarbon exploration. There are three (3) stages of seismic reflection

exploration; Data Acquisition, Data processing and Interpretation. It uses one of explosives, vibrators

or dropping of weights to generate wave energy (acoustic signal) transmitted into the earth subsurface

which is reflected off by a geological layer called events. This reflected wave is recorded using motion

vibrations sensitive receivers called seismometer (geophone for land survey and hydrophone for

marine survey) (Sherrif et al 2004). The choice of the source is a function of the terrain as many

swampy areas utilize the explosive and the vibroseis is good in desert region where the terrain is plain.

The systematic arrangement of source (shot) points and receiver (geophone) points to mirror a

particular structure in the earth subsurface is referred to as survey design (Geometry). There are two

(2) types of survey designing seismic exploration: 2D seismic survey and 3D seismic. The 2D seismic

survey places the source and receiver points along the same line; therefore it gathers data only along a

seismic profile and it is basically used for preliminary hydrocarbon exploration survey, unlike the 3D

seismic which acquires data of an area. It requires a dense and regular grid of source and receiver

points placed along separate lines used for detail exploration survey prior to drilling (Vermeer et al

2002).

There are three (3) major types of 3D acquisition geometry; Parallel Geometry: Source line parallel to

receiver lines, Orthogonal Geometry: Source line orthogonal to receiver lines. Aerial Geometry:

Sparse grids of receivers combine with dense grids of sources. Other geometry include: Brick Wall

geometry, slanted geometry and zigzag geometry (two families of source line making angles 45o and

135o with the receiver lines) (Vermeer et al 2002).

Seismic project for hydrocarbon exploration consists of several stages such as planning, scouting,

designing and execution. The use of spatial analysis and multi-criteria decision making is getting more

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popular and can have important role to play at each of the stages of seismic project (Smith et al 2008).

Space and location are key components of all kinds of geophysical exploration and seismic exploration

in particular. GIS is a tool for spatial data manipulation and processing that integrate different types of

data aimed at providing answers to spatial questions. In the case of seismic survey the decision of

source and receiver points are made with the choice of the survey geometry and purported target. It is

pertinent to note that the key parameter for defining optimum survey geometry is usually derived from

illumination studies that determine ideal source and receiver location. (Alvarez et al 2007). Accurate

positioning of a seismic line is as crucial as having the best possible data quality. Positioning is

important for three reasons;

Many data processing steps requires accurate relative source and receiver positions

Tying several seismic lines together requires knowledge of where they are relative to one another

When drilling sites are selected from seismic data they have to be reference back to an actual

location on the earth’s surface.

Accurate land positioning is not simple because survey terrains are not flat, so land positioning must

include accurate elevation measurements (Geofizyka et al 2009).

Spatial problems associated with seismic survey are numerous but fall into one of the following

categories;

Low signal to noise ratio where seismic trace have high amplitude at times that correspond to

reflection (geologic layer) and little or no amplitude at other times. This is caused by the presence of

noise which can either be generated by the source / shot adherence to the ground or coherent noise

(Bacon et al 2004).

Spatial aliasing which is a problem associated with processing centre of an ambiguity that arises

when a signal is sampled less than twice per cycle.

Offsetting: The term is the distance between the shot line and the first receiver line or the switch

dimension. However there will be an opponent change in this distance in cases where obstacles are

encountered (Vermeer et al 2002). Some of the obstacles encountered in seismic survey include

houses and structures, septic tanks, buried stream channel, tomb, wetland, swamp, railway, roads, and

rough terrain. Others include buried facilities such as tunnel, pipeline (gas, hydrocarbon product,

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crude oil and water), geologic features like outcrops and big boulders which requires offsetting from

the real survey design.

Land surveyors engage in the early stage of the seismic survey with the pre-plot schedule from the

seismologist and they cut traverses based on the schedule. The pre-plot schedule is the conventional

survey layout produced from acquisition software whose input is based on the regular spacing from the

client’s interest or targeted depth. The occurrence of the mention obstacle are not put into

consideration in the design of the pre-plot but are altered to post-plot when such obstacles are

encountered after a huge seismic time lost (Coulson et al 2008). Also soft sediment may attenuate the

acoustic signal strongly conversely at the other textual extreme, hard rock strew surface which may

not allow proper coupling because of the vibrator pad contacts in a situation where veibroseis is used

as source type (Stravastava et al 2006). Evaluating risk of poor source and receiver coupling to the

earth surface and of every lose surface related to seismic wave propagation in the near surface is

important for planning a seismic survey. These factors accounts for the majority of the degradation of

seismic energy loss (Mistra et al 2003 and Stravastava et al 2006).

Remote sensing provides digital image of the earth at specific wavelength within the electromagnetic

spectrum. Various features on the earth either natural or man-made give distinguishable signature of

the electromagnetic radiation (Mohammed et al 2006). This signature helps categorize the data into

different features for various geographic applications such as land cover, vegetation types, terrain

conditions, built-up areas etc. Geographic information System on the other hand is a computer based

tool for mapping and analyzing features geographically referenced to the earth surface and it stores

information of the earth on thematic layers. The efficacy of GIS is in its ability to store data from

sources with different format and analyzing them in single environment exhibited by Islas and London

(2003) of the American Southern Energy LLC. Data set from well logs and other related sources were

used in a systematic modeling technique to spatially create and analysis the subsurface horizons of the

Bertleville Ss and Mississippi Fm in Oklahoma with a 3D dataset and demonstrated spatial recognition

of structural and stratigraphic features related to the entrapment of hydrocarbon, the format also

correlated gravity, seismic, radiometric, and new relevant technology such as multiband hyper-spectral

imaging for satellite sources. All relevant spatial information were then overlaid in various

combinations using GIS technology which aided in identifying causal mechanism related to the

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structural deformation from initial and reactivated tectonic stress regimes relevant to hydrocarbon

entrapment in the subject area.

Similarly, Andrew (2009) used integrated landsat-7 enhanced Thematic Mapper plus (ETM+) imagery

calibrated by selected surface geology sampling to predict probable instance of wet Sabkha (the

commonly used Arabic name to describe a relatively flat saline area of sand or silt that typically forms

above water table). He investigated the correlation between the multi-spectral remote sensing data and

the vibrator (energizer) sweep performance data with the near surface. The integration was aided by

GIS data base. Steven (2008) focused on predicting wet land risk which poses a serious operational

risk both with respect to logistic and QHSE (Quality Health Safety and Environment). The risk of low

quality seismic data because of poor coupling between the ground and seismic source or receiver was

inferred from satellite imagery using a rock physic model of the interpreted lithology. The ability to

locate dangerous terrain is essential for protection of Health and Safety of survey personnel and

equipment. This information alone with interpretation of terrain stability obtained from overlay of

DEM and attribute map determined safe deployment of seismic acquisition vehicles and associated

equipment. It also identified environmentally sensitive areas and through the use of survey planning

minimized the negative impact of acquisition on these areas.

1.2 STATEMENT OF THE RESEARCH PROBLEM

The Nigerian Chad Basin is the largest inland basin in Northern Nigeria and it attracted explorationists

due to the rift origin, nature, structure and thickness of sediment of the basin ranging from 2000m to

6500m (Nkemjika et al 2003). Despite this fact, all exploration activities in the region over the last

few decades have proved abortive while other parts of the basin in other countries such as Niger, Chad

Republic and Cameroun have recorded commercial accumulation hitherto production of hydrocarbon

in the basin with almost the same geologic setting with Nigerian side of the basin. According to

Ajakaiye (2010) the major discoveries within the Lake Chad basin include Doba, Doseo Logorne Birni

in the Republic of Chad has a combined capacity of 1,900 Bbbo (Recoverable) and 100Bbls of oil, gas

and condensate – (Speculative) (the Logorne Birni (extends to Northern Cameroun). Also Termi

Agadem of the Niger Republic has proven to have 1Bbls oil, 10mbbls condensate & 100 Bcf gas).

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Exploration project began in the Chad Basin (Nigeria) in 1976 with the acquisition of 33,643km of 2D

seismic data and lasted to 1996. During this period international oil companies such Shell, Elf &

Chevron explores in the basin by processing and interpreting the 2D Seismic data. 3 wells were

drilled namely Kolmani River 1 well (drilled to a depth of 300m), Nasara I well (drilled to depth of

1700m) and Kuzari I located in Gombe State (drilled to a depth of 1666m) by Shell, Chevron and Elf

respectively. These 3 wells were recorded to have non commercial gas discoveries of the 23 dry wells

(Matori et al 2010).

In 2002 the Federal Government of Nigeria directed that data generated should be re-evaluated to

further ascertain the prospect of the basin. This led to the deploring of 3D seismic prospecting method

and invitation extended to the Chinese National Petroleum Corporation (CNPC) responsible for the

exploration in the countries with contiguous geologic formation of Chad Basin to work in the same

might in Nigeria in October 2009 (NNPC Bulletin www.nnpcgroup.com). Over the last two years

slowly but steadily the fact has come to be widely acknowledged that the north east region of Nigeria

has a high propensity to harbor considerable oil and gas reserves. The issue is not whether there is oil

and gas in the region but how soon it will be stock in commercial quantity.

Nkemjika (2003) reviewed some of the challenges encountered in the study area in the era of 2D

seismic data acquisition before the abandonment of the project. The terrain is undulating with

vestigial sand dunes. Thorny scrubs, dense overgrowths and subterranean and surface flooding in

parts all combined to create difficult accessibility He pointed out that the use of airboats and canoes

is imperative in the seasonally flooded regions of the Chad. He attributed the loss of time and energy

to inadequate knowledge on the types of formation which contributed to while loss of circulation is

recorded in weakness porous layers during shot hole drilling. These issues are spatial in nature and

they have to do with the vegetation cover and terrain features which can be adequately addressed in

the functionality of remote sensing & GIS. The problem of unsuccessful nature of the basin to

hydrocarbon exploration might not be farfetched from quality of the 2D seismic data acquired in the

past and the circumstances surrounding it as itemized by Nkemjika. He suggested a more robust

prospecting method for a better quality of data to harness the unyielding nature of the basin to

hydrocarbon exploration. This led to the birth of 3D seismic prospecting in the area.

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As 3D seismic prospecting is being deployed in the area, there is an imminent need to preserve the

quality of data which can be compromised due to nature of terrain, natural features (such as

vegetation, wetland, geologic outcropping terrain with slope etc) and manmade feature such as

telecom mast, road networking, petroleum pipeline, water pipeline, built up, cultivated land, livestock

husbandry etc) and more importantly elevation variation of the survey area which according to Gravy

(2004) has a processing constrains and an adverse effect on the quality of data requiring a lengthen

static correlation procedure during data processing. The conventional 3D Seismic prospecting requires

the seismologist to prepare a preplot schedule for the land surveyors who by means of either GPS or

the total station cut lines (transverses) of both source and receiver points. Graig (2003) pointed out that

once nominal geometry has been decided upon it may not be easy to realize the geometry without

modification especially in heavy built up and cultivated areas due to obstacles and terrain difficulties.

He reiterated the facts that sticking to the nominal geometry would be impossible however spatial

continuity of the grid of acquisition lines is of great importance. Similarly Vermeer itemized the

factors governing the design of survey geometry as thus;

Requirement Parameters

Special continuity resolution Symmetric sampling

Resolution Shot & receiver stations intervals

Shallowest horizon Line interval

Deepest horizon to be mapped Maximum offset, speed lengths

Noise suppression Fold and Offset Distribution

Table 1: Factor Governing Survey Geometry

(Source: Gravy Publication 2004)

All these factors are indeed important but can only work in an ideal environment where

topography and features constitute no impediment whatsoever. Such environments are practically

difficult to get in a real situation hence inclusion of terrain suitability and elevation variation is

evident as proposed by Grary (2004).

The land surveyors while on the field may encounter obstacles that require offsetting. In such

situation, report will be made known to the seismologist who then redesigns the geometry by

factoring in the obstacles and other factors. The output design is regarded as the post-plot which

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will be the eventual recording geometry. Due to the nature of natural and manmade features,

many might be encountered along various seismic lines hence generate post plots. The time taken

to address the issue of obstacle contributes immensely but adversely to the entire project time

therefore increasing the overhead expenditure of the prospect. These obstacles are spatially

referenced to the seismic lines, which can be adequately addressed using Remote Sensing and

GIS. The resultant effect will be to reduce time line for seismic project thereby increasing the

opportunity of surveying larger prospect area for oil and gas at a reduce cost with the better

quality of data having eliminated the terrain effects and topographic variation.

A couple of geophysical and geologic investigations have been made in the region over a few

decades with respect to natural resources management. Li Jihanying of the CNPC/BGP attempted

3D sequence stratigraphy and reservoir delineation in Block H of the Chad Basin using the 2D

seismic prospecting and a further exploration using 3D seismic surveys. He applied 3D seismic

data and well log data to establish chronostratigraphic framework. The focused on the data

acquired in the past for the interpretation of the basin potential. Nkemjika faulted the quality of

this data set due to the circumstances surrounding the acquisition. Meanwhile Ajakaiye and Louis

(2006) applied different geophysical methods to examine the geodynamic models proposed for

the Chad Basin and Benue trough. They focused more on the geologic interpretation and pointed

out that Precambrian origin for the major anomaly of Haraz where the Benue trough was

interpreted as a failed arm of the triple junction created during the opening of the Atlantic.

Gamba (2005) applied space technology for integrated water resources management of the Lake

Chad Basin by utilizing the hydrometeorological data and GIS (mean monthly records of

climatological data between 1970 and 2005) and satellite imagery. Parameters such as

precipitation, temperature, run off and evaporation maps were generated using software packages

such as Ilwis, Erdas, Imagine and Arcview. The hydrological modeling of the Lake Chad Basin

was used to solve the water scarcity problem of the area inhabiting 30 million people.

In the same vein Marc Le blanc (2003) applied remote sensing and GIS for groundwater modeling

of large semiarid areas of Lake Chad Basin due to the large extent and extremes of climatic and

environmental conditions of the region where it was difficult to collect hydrogeological field

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observations. He used maps and low cost satellite data such as AVHRR and meteostat of the

fluctuations of Lake Chad extent over a period of three decades which was used for estimating

transient groundwater model with a MODFLOW program through GIS. In a similar research

geoscientists led by Selvam (2012) applied high resolution satellite imagery and GIS in the

integration and analysis of multi thematic layers in delineating ground water prospect and deficit

zones by adopting a multi-criteria evaluation (MCE) method. They produced a final thematic

map using ArcGIS and classified the areas into five categories of groundwater prospect zones as

very good, good, fairly good, moderately poor and poor.

All these research works in the study area addressed issues that are based on 2D seismic data

acquired in the past or the functionality of remote sensing and GIS in hydrology and more

relevantly is the ground water modeling using GIS. Groundwater and hydrocarbon are both

naturally occurring substances with the depth of occurrence as the only variance. This technique

can work for seismic planning for oil & gas exploration if it can work for ground water. In the

world beyond GIS has been applied to hydrocarbon exploration from seismic data acquisition to

well completion as observed from literature within and outside of the scope of this research work.

However the best Remote Sensing and GIS was used for in the study area is reconnaissance

survey in 2002 when exploration work resumed by CNP/BGP & NNPC/IDSL joint Venture.

There is disconnect between the trend of things in the development of seismic work in the

developed world and what is obtainable in the study area. The research work intends to fill this

gap and create a template of geographic model for seismic data acquisition.

RESEARCH QUESTIONS

i. What role do spatial features play in planning and execution of activities at different stages of

seismic projects in the prospect area?

ii. Is there a relationship between dampness and the quality of shot?

iii. What effect does topography/elevation variations have on survey design?

iv. What terrain features contribute to change in continuity of survey pattern?

v. What contribution will RS & GIS make to better exploration in the basin?

1.3 AIM AND OBJECTIVES

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The aim of the research is to apply RS & GIS for optimization designed of 3D seismic survey in

view of reducing survey time and cost with a better data quality. The following objectives are set

towards achieving the stated aim.

i. Identify the various spatial problems that can hinder survey trend.

ii. Estimate the extent of the survey area that is wetland and dryland in view of deciding the type

and quality of source to apply.

iii. Determine the variation in elevation as it affects the survey pattern

iv. Generate a seismic quality map to ascertain areas that requires advance logistics

v. Assess the contribution of RS & GIS to seismic exploration in the basin.

1.4 SCOPE OF THE STUDY

The prospects fall in Kukawa L.G.A of Borno State in the administrative map. The scheduled

hydrocarbon exploration in the basin is progression of acquisition of 3D seismic data for a 12

phase project covering a total area of 3,550km2 within the basin. Phase 1-4 have been completed

with varying degrees of challenges due to terrain difficulty. The research will utilize the seismic

data schedule acquired within the first quarter of 2009 to last quarter of 2011. Phase 1 and 3 are

100% dry land, while phase 2 is about 95% dry land and 5% wetland. Phase 4 is about 40% dry

land and 60% wet land. The research will focus on phases 3 & 4 where variables that affect the

time of execution of seismic project and the quality of data will be determined and used for

planning of the remaining phases. The choice of phase 3 & 4 is due to the fact that they both have

diverse representation of terrain features. The variables include wetness, geologic features,

manmade features and variation in topography which have effect on the choice of survey layout.

The research will examine the process of seismic data acquisition and will not look into seismic

data processing but the resultant effect would provide processing specialist a starting model for

elevation static correction with Digital Elevation Model (DEM) and MOD- Model Offset

Dependent Statics (MODS).

1.5 JUSTIFICATION OF THE STUDY

The choice of survey geometry in 3D seismic exploration has been carefully chosen by

explorationists to include spatial continuity, resolution, shallowest & deepest horizon to be

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mapped and noise suppression. These factors are input to determining the full fold and spread

spacing in the seismology survey software which generates the pre-plot layout. However Craig

J.Beasley (2003) acknowledge the fact that such nominal geometry are difficult to maintain

without modification as a result of terrain challenges and obstacles which then increases the time

line of the project. There is therefore an apparent need to examine the effect of these on the

design of geometry and it inclusion as a factor.

The unyielding nature of the study area to successful exploration despite the discovery of

commercial deposit of hydrocarbon in the other side of the basin and the advancement in

technology from the international community on hydrocarbon exploration in the application of

space technology has drawn attention to the study area. The mandate by the FGN to NNPC to find

oil in the basin will be made achievable if the quality of the 3D seismic data to be acquired is

checked of any form of error due to terrain challenges and topographic variation. It will also be a

starting point for future research in seismic data acquisition in the northern part of the country. In

addition to that, the creation of geodatabase and harmonizing same with seismic metadata which

is the trend in exploration as established in seismic companies will have the model in this research

as an input.

The application of RS & GIS to seismic exploration is becoming a global trend for the robust

nature of the technology in addressing exploration issues from data acquisition to well

completion. However, in Nigeria and Nigerian indigenous companies its use is limited to

reconnaissance survey which is just having a synoptic view of the area/coverage extent. High

resolution imagery can harness some unforeseen challenges subtle in the reconnaissance survey.

This will place our indigenous oil and gas company in strategic position of standard and quality as

of their foreign counterparts in line with the Federal Government transformation agenda of vision

20 2020.

The research will help to incorporate RS & GIS into exploration process/procedure and for future plan

in the remaining phases of the ongoing project and the remaining frontier basins under consideration

for exploration. It will also be an eye opener for management of seismic data acquisition companies

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for effective way of planning any space related project to examine technical component very well not

just the commercial component, in bidding for seismic contracts and related item procurement. The

various challenges in the different stages of seismic project like scouting, planning, community affairs,

staging, surveying, drilling, recording, quality control and assessment & compensation should be

factored into the cost of the bid. The act of basing contracts on square kilometer is sometimes not

profitable in the face of difficult terrain.

CHAPTER TWO

LITERATURE REVIEW

2.0 HYDROCARBON EXPLORATION

GEOPHYSICAL METHODS OF HYDROCARBON EXPLORATION

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CHAPTER 3

THE STUDY AREA AND METHODOLOGY

1.6.1 LOCATION AND EXTENT

The study area is called kukawa in Kukawa local government area in the north eastern Nigerian state

of Borno close to lake chad with geographical coordinates 12055’33” North 13034’12”East . It has

average elevation/ altitude of 277meters. It was formally known as Kuka founded in 1814 as capital of

Kanem-Borno Empire by the Muslim scholar and warlord Muhammed Al-kanem after the fall of the

previous capital, Ngazargamu, conquered in 1808 in the Fulani war. With a population of over 16,077

people (according to the Geomane geographical database 2010) most inhabitants engage in farming,

fishing, and salt mining as a means of livelihood. The study area is flanked to the north by Bre, by

Tarari, Gubogumma and Kobuchi to the east, west and south respectively.

PHYSICAL SETTING

GEOLOGY AND LANDFORM OF THE STUDY AREA

It belongs to one of the seven Nigeria Frontier Inland Sedimentary Basins (NFSB) namely Anambra,

Bida, Chad, Dahomey, Gongola/Yola, Middle/Lower Benue Trough and Sokoto basin. The area lies in

the Chad formation, an area subjected to prolonged continental and lake sedimentation as a result of

the down warp of the Chad basin in the Pleistocene period. The Chad formation is separated by a 14

cretaceous Bima and kerri sand stones. The volcanic areas of the Biu Plateau and the basement

complex area of Mandra Mountains are found in the south and south east respectively. The area lies on

vast open plain which is gently undulating. The landscape developed on the young sedimentary rocks

on the Chad formation .This extensive plain contains no prominent hills and attains an average

elevation of 300m above sea level, sloping towards the lake and Chad level. The open nature of this

landscape especially it uniformity is striking during the rainy season when vast areas in the Lake Chad

are flooded. The Mandra mountains complex of the southeastern part of the region on the other hand is

predominantly granite suite, the most wide spread of which is a coarse granite composed of quartz and

feldspar with little biotite. The Bima sandstone is the oldest sedimentary deposit in the Chad Basin. A

Middle Cretaceous shale-limestone succession, subdivided into the Gongola Formation at the base and

the Fika Shale at the top. It constitutes the marine and transitional deposits which extend from the

Upper Benue into the Southern Chad Basin. The Tertiary Chad Formation is very thick. Marine Late

Cretaceous - Palaeocene beds in the SE lullemme- den Basin are well exposed into the Sokoto region,

in Niger and extending into Mali. The Rima cycle of Late Cretaceous age comprises the Taloka

Formation (50m of brown, laminated, parallel, bedded, carbonaceous, fine-grained sandstone,

siltstones and mudstones), overlain by the Dukamaje Formation (10m of basal bone bed, gypsiferous,

fissile, gray lower and upper shales and middle marl) (Brownfield et al 2007).

1.6.3 CLIMATE

Three seasons have been identified: the cool dry (harmattan) season (October-March), hot dry season

(April-June) and rainy season (July-September). Temperatures are high all the year round, with hot

season temperatures ranging between 39°C and 40°C under the shade. In the southern part of the state,

the weather is relatively mild. The rainy season lasts for less than eighty days in the extreme north, but

is as high as 140days in the extreme south. The mean annual rainfall is over 800mm on the Biu Plateau

but less than 500mm the extreme north around Lake Chad. Rainfall variability is over 100 per cent.

Droughts endemic tends to have been in decline since the 1960s (Department of Meteorological

Services, 2004). Relative humidity is generally low throughout the state, ranging from as low as 13 per

cent in the driest months of February and March to the highest values of seventy to eighty per cent in

the rainy season months of July and August (www.onlinenigeria.com)

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1.6.4 HYDROLOGY

The Borno region is drained by two groups of rivers; one is bound towards the south draining to the

Benue system, while the other is towards Lake Chad. The region is generally drained by seasonally

flowing rivers, whose peak flows are recorded during the rainy season in the months of July and

August. The Biu Plateau to the south is largely drained by the Hawul River, which flows southwards

and discharges its waters into the Gongola River (Olorunniwo et al 2010)

1.6.5 SOIL AND VEGETATION

Two vegetation zones are identified in the state: Sudan savannah and southern Sahel. The semiarid

nature of the Sahel and northern Sudan savannah makes the vegetation consist mainly of open acacia

tree savannah. In the wetter south scrub vegetation is interspersed with tall trees and woodland.

Vegetation has been greatly modified in most places as a result of over-cultivation and over-grazing.

Land degradation and desertification have been on the increase, causing the desert to advance

southwards.

The soils of Kukawa vary in colour, texture, structure, physio-chemical and other essential

characteristics from the hilly south to the northern dune landscape. Vertisols dominate the flat plains

close to Lake Chad; and also in the depressions. There are heavy dark clay soils (Firki) which develop

wide cracks during the dry season. On the dunes are regosols which are shallow with weakly

developed profiles. The volcanic and Basement Complex areas have fertile clayey loamy soils in the

valley bottoms, but skeletal soils and rock outcrops occur along the gentle and steep slopes

(www.onlinenigeria.com)

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FIGURE 1: Map of the Study Area with Well Locations

(Source: Integrated Data Services Limited)

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FIGURE 2: Geologic Map of Nigeria.

(Source: Nigerian Geologic Survey)

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FIGURE 3: Map showing the Greater Chad Basin spanning through Four Countries.

(Source: National Frontier Exploration Services)

3.3 HUMAN SETTING

3.3.1. PEOPLE AND POPULATION

3.3.2. AGRICULTURE

3.3.3. COMMERCE AND INDUSTRY

3.3.4. TOURISM

3.3.5. INFRASTRUCTURES

3.3.5.1. EDUCATION

3.3.5.2 HEALTH

3.3.5.3 ELECTRICITY SUPPLY

3.3.5.4 TRANSPORTATION AND COMMUNICATION

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3.3.5.5. WATER SUPPLY

3.4. METHODOLOGY

1.7.1 TYPES AND SOURCES OF DATA REQUIRED

1.7.1.1 TYPES OF DATA REQUIRED

The types of data required for the research work are;

i. LandSat 7 Enhanced Thematic Mapper Plus (ETM 7+) Satellite Imagery (30m

resolution) over the study area.

ii. Spot 5 Imagery (high resolution -5m).

iii. Geologic map/Aster data of the study area.

iv. The Topomap map/control map of the study

iv. Shuttle Radar Topography Mission (SRTM) imagery.

v. Transportation map of the study area.

vi. Google earth images (high resolution and updated).

vii. Facilities Maps.

viii. Pre-plot and Post plot maps of phases 3 and 4.

ix. Uphole Data and Shot Remark Report.

1.7.1.2 SOURCES OF DATA

i. LandSat 7(ETM 7+) will be downloaded from the websites of Global Landcover

Facility (www.glcf.umd.edu)

ii. Spot 5 Imagery will be obtained from National Centre for Remote Sensing in Jos,

Plateau State.

iii. Geologic map of the study area will be obtained from National Frontier Exploration

services (NFES) a subsidiary of NNPC

iv. The topomap/contour map of the study area will be obtained from Borno State

Ministry of Lands & Survey.

v. SRTM and Aster data will be downloaded from GLCF website

vi. Transportation of map will be obtained from Borno State Ministry of Transportation.

vii. Google Earth images will be downloaded from Google Earth using Google Earth Pro

12.

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viii. Facilities map are of 3 types

a. Water pipeline from the Borno State Water Corporation.

b. Petroleum product pipeline from pipeline & product marketing company.

c. Underground tunnels and drainages map from Ministry of Works Housing

Borno State.

1.7.2 TECHNIQUE OF DATA COLLECTION

1.7.2.1 SAMPLING TECHNIQUES

i. The total area extent of the prospect is 3550Km2 which is divided into (12) twelve

phases. The research will address each phase as an entity hence the sample population is

12.

ii. According to Arlosoroft (1987) and Hagget (1977) statistical argument, which stated

that for the validity of a research 20% of the total population should be selected. Also

Ader (2008) suggested that the sampling size should be small in order to improve quality

and accuracy of the research work. 20% of 12 phases gives 2.4

The research will focus on two of the phases. Four (4) of the 12 phases have been

completed i.e. phases 1 to 4. Phases 1 and 3 are 100% dry land; phase 2 is about 95% dry

land and 5% wetland while phase 4 is about 40% dry land and 60% wetland.

Considering the variation in the wetness & dryness of the phase, phase s 2 and 4 will be

examined for the purpose of the research.

1.7.2.2 DATA COLLECTION

The Global Land Cover Facility is an organization that supports satellite technology

research by developing and distributing remote sensing satellite data and products for

land use and land cover studies for local to global scales. The LandSat 7 ETM+ and the

SRTM will be downloaded from the website www.glcf.umd.edu by entering the

coordinates of the prospects area in the inquire data box. Spot 5 imagery of the prospect

area will be acquired from NCRS Jos. The Google Earth image will be downloaded via

Google Pro 12 for updated record and precision. The preplot, post-plot, shot remark

report and uphole maps will be acquired from JV 109 Crew of IDSL/BGP. The

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topomap, transportation map and facilities maps will be obtained from various ministries

responsible for it while the geologic map will be obtained from the Nigerian Geologic

Survey, Kaduna.

1.7.3 TECHNIQUE OF DATA ANALYSIS

The various data available in this research work will have varying application but two or more

will be combined to address the stated objectives. Thereafter the statistical analysis to project the

future exploration plans.

1.7.3.1 DATA GATHERING

Data obtained will be analyzed in different software such as Erdas Imagine 9.2, Iliwis

3.3, ArcGIS 9.3, Google Earth Pro 12 and AutoCAD Map.

I. All the data set (map and images) obtained will be moved to the C drive for ease of

accessibility by the various software packages. In cases where they need to be imported

into individual package, the data format will be maintained as either Tagged Image File

Format (TIFF), Image format (.img) or as a shape file (.shp).

II. The data set different from the given format will be converted through the windows

paint image viewer environment and “save as” tab on the image or any of the GIS

software which can read the data.

III. The LandSat 7 ETM+ comes in bands in a zipped folder. The folder will be extracted

and the bands will be layer stacked to give the colour composite of the imagery.

1.7.3.2 DATA PROCESSING

I. The different scenes covering the study area for spot5 Imagery will be mozaiced in the

Erdas 9.2 software. Also the layer stacked LandSat7 ETM+ and the SRTM images will

be imported into the same environment. All other maps will be imported into ArcGIS

environment. All maps and images will be unified on the same coordinate system of

projection [i.e. universal Transverse Mercator-UTM] for easy distance measurement.

The portion of the imagery and maps covering the study area will be subset for detailed

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analysis. The geologic map and the aster data will be analyzed for lineaments features.

This is to ascertain the orientation of the inline and crossline used in the design of the

geometry for the completed phases. The strike (angle) which is the orientation of most

fractures of bedding plane is usually considered as the crossline orientation which is the

source/shot line. Conversely dip (angle) is the perpendicular to the strike and it is

oriented as the inline; the receiver lines. The lineaments map will be generated at this

stage.

II. The topomap will be digitalized in the ArcGIS environment and various geographic

attributes such as roads, rivers, cultivated areas and built up areas will be mapped on it.

This environment will serve as a base map on which the transportation map and other

facility map will be added as layers. The reason for this is a quick identification various

developmental changes in the study area over the years from when the topomap was

produced

III. The SRTM and digitized topomap will be used to generate Digital Elevation Model

(DEM) and Digital Terrain Model (DTM) respectively using the triangulated Irregular

Network (TIN) to extrapolate missing contour range on the data.

IV. The ETM+ imagery will be used with the uphole for lithology classification by

utilizing the bands 3, 5, & 7 of the imagery within the Erdas environment the degree of

shaliness can be ascertain. The uphole map can be used to create uphole contour with the

concept of TIN. The two procedures will generate the lithology map.

V. The slope will be estimate from the topomap and DEM/DTM. This will help generate

the drainage map of the area.

VI. Supervised classification will be performed on the spot 5 image to generate the land

use, Land cover map of the area. This map will help identify obstacles that can hinder

the success of the survey at all the stages of the project. The GPS will be used here

during field visitation to take control points or different sections of the survey area. The

Google Earth Pro 12 will provide the missing update from the imagery from few years

after the data was acquired. The vegetation cover, wetland built up, geologic outcrops

will be identified in the LULC map.

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VII. The preplot 3D survey design as well as the post plot map of the two (2) phases of

the research will be exported from Mesa geophysical software in the TIFF format to be

imported into ArcGIS environment.

VIII. In estimating the percentage of the survey area that is wetland and dry land, the

preplot map will be overlay on LULC map and drainage/slope map to know areas that are

liable to flooding during rainy season. This will help determine the type of source to be

used

Vibroseis - Dryland

Explosive -Wetland

IX. The seismic quality map will be generated based on elevation variation and wetness

of the area with respect to the remark on shot on the datasheet. This seismic quality map

will help determine the type of Hole in the future seismic work. Hole can be pattern hole

[5m deep x 4] on single diphole (20m deep).

X. The preplot map will be superimposed on the LULC and DEM to identify obstacles.

Then the preplot is reconstructed in areas where obstacles are identified. The resultant

map will then be compared to the post-plot map used for the actual recording of the data.

The comparison will ascertain if the variation is due to some other factors like elevation

variation or underground obstacles which will be evident in the uphole map.

XI. The shot remark report will be used to generate a thematic map that will be overlaid

on the DEM to estimate the degree of degradation the topographic variation has on the

shot. This will then be swiped with the LULC/Preplot superposition.

1.7.3.3 STATISTICAL ANALYSIS

I. The various component involved in the formation of seismic quality map will be plot

on bar chart & for histogram using the GIS software as Multi-Criteria Evaluation (MCE)

II. The remark of the quality of shot will be rated from “very good” to “poor” (and

retake) and given weight of 5 to 0 respectively.

III. Both the component histogram and the remark can help in generating a model for

next set of phases to be explored in the study area. Also combination of two or more of

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the derived data set can help to generate Terrain Stability for deployment of vehicles and

equipment for the upcoming phases or projects in the prospect area.

REFERENCES

Abdullah M.A.H (2006) Sea Bed Topography Mapping Using LandSat TM Imagery, Remote Sensing Group, eMap Division Integrated Solutions Services Department (ISSD) Saudi Aramco, Dhahran, Saudi Arabia

Ader, H.J. Mellerbergh, G.J. and Hand D.J. (2008) Advising on research Methods. A consultant Companion. Huizen Therlands: Johannas .Van Kessel publishing. Wikepedia, the free encyclopedia.

Ajakaiye D. E., Cratchley C.R. (2000) Geophysical and geological evidence for the Benue-Chad BasinCretaceous rift valley system and its tectonic implications Journal of African Earth Sciences, Vol. 2, No.2. pp. 141to 150, 1984 Printed in Great Britain 0731-7247/84

Alvarez Gabriel (2004) Flexible 3-D seismic survey design. A paper presentation.

Andreas Laake , Gatwick, U.K. and Martin Insley (2004) Applications of satellite imagery to seismic survey design, The Leading Edgetle.geoscienceworld.org 10.1190/1.1813353 The Leading Edge October 2004 v. 23 no. 10 p. 1062-1064 2004 Society of Exploration Geophysicists.

Andrew Cutts (2009) The benefit of Remote Sensing” Schlumberger oilfield review middle East Issue. 2nd edition GIS world development 2009

Brian J. Evans (1997) A Handbook for Seismic Data Acquisition in Exploration

25

Brownfield, M. E. Assessment of undiscovered oil and gas resources of the chad basin province north central Africa

Burdziej, J. and Geofizyka, T. (2009) The Role of Spatial Analysis in Seismic Explorations, GIS Ostrava 2009

Cousins, M.G., Whiting P.M. and Allen T.J. (2007) Offset dependent static corrections on a continental shelf edge 3D seismic survey Exploration Geophysics Hand book 22(1) 75 – 8

Everett J. R., Jengo C. and Staskowski R. J., (2002) Remote sensing and GIS enable future exploration success. World Oil, vol.223/11, 59-65.

Garba, S. H. (2005) Space Technology for Integrated Water Resources Management of the Lake Chad Basin

Garg H.N. , Anoop Singh , G.B.Ramamurthy and C. Markandeyulu (2003), Cost Effective Land Seismic Data Acquisition by Geophysical Services of WON Basin, Gujarat, India international conference and exposition on petroleum geophysics. 7th

Proceedings of an international symposium held at Montpellier. April 2003. IAHS Publ. no. 278, 2003.

Gray S. H., Gary M., Amoco C., Kurt J (2004), Crooked line, rough topography: Advancing toward the correct seismic image , VeritasDGC Inc. Marfurt, Amoco Exploration The Leading Edge October 2004 v. 23 no. 10 p. 1062-1064

Hagget, P. A, D.C and Allay F. (1977), Principle of physical geology, 2nd edition . The English Language Book society and Nelson.

Harris, R. and Cooper,M. (2002). Structural analysis in eastern Yemen using remote sensing data. World Oil, vol.223/11, 52-57.

Islas, J.L. and London, J. ( 2007) Basin Analysis Using GIS Subsurface Modeling Techniques of Northeastern Oklahoma with Emphasis on Roger’s County, Oklahoma American Southern.

Leblanc M, Christian L. (2007) Applications of remote sensing and GIS for groundwater

modeling of large semiarid areas: example of the Lake Chad Basin, Africa, Africa Hydrogeology Journal, Volume 15, Number 1, February 2007 pp. 97-100 the original publication is available at www.springerlink.com

Leblanc M. (2008) Remote Sensing for groundwater Modelling in large semi arid areas lake Chad Basin Africa, Hydrology journal 15 (1) pp97- 10

26

Longley, A. Paul (2002). Geographical Information Systems and Science. John Wiley & sons, West Sussex, England.

Mark, W. (2006) Application of LIDAR in seismic Acquisition and Processing. Veritas VGC article. Energy LLC, Bowling Green, Kentucky

Milton, B. D. (1998) Introduction to Geophysical Prospecting. Mcgrawhill Publishing, USA.

Mishra, P., Patel K. B., Mehta S. N. and Nath K. K., (2002). Structural analysis in the Assam-Arakan fold-thrust belt using ArcGIS 8.1 3D-Analyst. Fifth ESRI India User Conference, 22-23 January 2002, New Delhi.

Mohammed, Z. (2008) Oil and Gas Exploration in Ethiopia using GIS, Map Asia 2008 conference.

Murali, M. Ramakrishna k, Saha U.K. and Sarvesam G. (2010). Application of Remote Sensing and GIS in Seismic Surveys in KG Basin, 8th Biennial International Conference and Exposition on Petroleum Geophysics, Hyderabad.

Nkereuwem, O. T., Mijinyawa, M. U. and Yusuf, S. N. (2010) Perspectives of GIS modeling in hydrology Continental J. Earth Sciences 5 (1): 1 - 7, 2010 ISSN: 2141 4076 Wilolud Journals, 2010 http://www.wiloludjournal.com

Olorunniwo, M.A. and Okpikoro, F.E. (2004) seismic sequence architecture and structural analysis of northeastern Nigeria Chad (Bornu) Basin Continental journal of Earth Sciences.

Premanan, Mishra and Sagar, N. M. (2005) Using Remote Sensing and GIS technologies as an aid for hydrocarbon exploration in the Assam-Arakan fold-thrust belt Hindustan Oil Exploration Company Limited,Tandalja Road, Vadodara, Gujarat-390020

Redekop, G. M. (2005) GIS Application in oil Exploration, Oil Quatar conference 2005

Ron M., Gehrig S., Andrew C., and Malcolm L. (2012) 3D Seismic Operational Optimization in the Lusitanian Basin, Portugal

Richard, H. (2003) Focusing oil and gas exploration in Eastern Yemen by using satellite Images and elevation Data alongside convectional 2D-seismic. Schlumberger oilfield review 2008/2009, NASA Maryland USA.

Saraf A. K., Mishra P., Mitra S., Sarma B. and Mukhopadhyay D. K., (2002). Remote sensing and GIS technologies for improvements in geological structures interpretation and mapping, International Journal of Remote Sensing, vol.23/13, 2527-2536.

Selvam.G1, K.Banukumar, Srinivasan.D, Selvakumar.R, P.Alaguraja (2012)

Identification of ground water potential zone in hard rock terrain A case study from parts of Manapparai block Tamilnadu using Remote Sensing and GIS techniques Hydrology

27

of the Mediterranean and Semiarid Regions , International Journal of Advances in Remote Sensing and GIS, Vol. 1, No. 1, 2012.

Smith G. and Jepps C. (2008). The Role of GIS in E&P Information Management, http://www.exprodat.com/papers/default.asp?pid=10

Srivastava, V.K., Ghosh R., and Chhualsingh B.B (2006), Satellite Based Seismic Technology, 6th International Conference & Exposition on Petroleum Geophysics

Stephen, C. (2008). Satellite Sensing; Risk mapping for Seismic Survey, Schlumberger oilfield review 2008/2009, NASA Maryland USA.

Vermeer, Gijs J.O., (2009) Geophysical Advice, the Netherlands A comparison of two different approaches to 3D seismic survey design

Vermeer Gijs J.O., Ali, M. Q. (2008) 3D seismic survey design optimization American-Eurasian Journal of Scientific Research 3 (1): 84-91, 2008 ISSN 1818-6785 IDOSI Publications.

Telford, A.M. (2003) Applied Geophysics Cambridge University Press, New York

Zolnai, A. (2002) The second revolution. ArcUser, vol.5/4, 10-11.

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