Journal of Science Research Facies model building of integrated multiscale data in Dn-Field, Onshore, Niger Delta, Nigeria Nton, M. E. and Arigbe, O. D. Department of Geology, University of Ibadan, Nigeria Correponding author: ntonme@yahoo.com Abstract This study employs 3D Post-Stack Time-Migrated seismic data from the DN-Field, within the Coastal Swamp depobelt of the Niger Delta in predicting lithofacies and fluvial facies of OVK-1 sand bodies in the Agbada Formation, as a tool to identify new drillable prospects. A lithofacies model for OVK-1 reservoir sand body was generated after upscaling using Most Of, as the averaging method. Calibrated by fluvio-facies at the well locations, channel sands were identified in OVK- 1 reservoir interval using Stochastic Sequential Indication Simulation (SSIS) algorithm. Based on lithofacies, fluvial facies and biofacies analyses, a terrigenous and shallow fluvio-deltaic fill within a lowstand system tract was evident. Petrophysical properties including porosity, volume of shale and effective porosity were upscaled, guided by facies model and then Stochastic Gaussian Simulation (SGS) algorithm was used to produce the model. Porosity model predicted sand layers having maximum porosity of 27.5% which implied very good reservoir potential. However, the volume of shale model with values from 0.45 to 0.50 incorporates silt and clay and indicates marginal reservoir potential. The study identifies four potential reservoir intervals with thickness ranging from 9.1 to 38.5 m. The effective porosity in OVK-1 ranges from 0.10 to 0.30 and identified fluvial facies such as floodplain, channel sand, levee and crevasse splay sand. Facies model show a good sand distribution with minor shale localized in the western part of the Field. The central part of the model has good reservoir qualities, evident by low volume of shale values and high porosities. This study helps to identify a potential unexplored drillable prospect on OVK-1 sand body south-west of DN-2 well. Successful drilling of the identified prospect could increase the reserve of the Field. Keywords: Facies modeling; stochastic sequential indicator simulation; sequential gaussian simulation; Niger Delta; Nigeria. Introduction known accumulation of recoverable hydrocarbons, with The Niger Delta is an active sedimentary basin [1] reserves exceeding 34 billion barrels of oil and 93 trillion which is situated in the Gulf of Guinea (Figure 1a). It cubic feet of natural gas [7]. There is renewed lies between Latitudes 3o and 6o N and Longitudes 5o exploration interest currently in the deepwater and 80 E, and extends throughout the Niger Delta depositional systems, as about 50% of global oil province as defined by Klett et al [2]. From the Eocene production is currently from shallow marine, paralic to the present, the delta has prograded south- and fluvial strata [8]. This necessitated the application westwards, forming depobelts that represent the most of improved approaches for facies modelling in order active portion of the delta at each stage of its to properly integrate multi-scale data in the exploration development [3]. These depobelts form one of the and field development of the vast hydrocarbon largest regressive deltas in the world, with an area of resources locked in these areas of the Niger Delta 300,000 km2 [4], sediment volume of 500,000 km3 [5], basin. and thickness of over 10 km in the basin’s depocentre Facies modelling is a critical step in the life cycle of [6]. a reservoir characterization process. All petro-physical The Niger Delta is the most prolific sedimentary modelling is based on facies; geometric distributions basin in sub-Saharan Africa, containing the 12th largest are determined by geologic knowledge of facies Volume 14, 2015, pp. 107-116. Journal of Science Research, 2015 UNIVERSITY OF IBADAN LIBRARY 108 Journal of Science Research Vol. 14 S t u d y a r e a Study area Figure 1a. Map of Nigeria showing the location of Niger Delta and associated tectonic features. Inset is the Map of Africa showing southern Nigeria (Corredor et al 2005). deposition and the flow units controlling the production found the reservoir lithology to be grossly of a reservoir are generated directly from facies, or heterogeneous. Afuye et al [13] developed 3D representation of the facies distributions [9]. As rightly depositional and lithofacies models using Truncated remarked, a common challenge of facies modelling is Gaussian with Trends (TGT) and Truncated Gaussian the integration of multiple scale data to create a reliable Simulation (TGS) algorithms. With the available data facies model [9]. set for this work, Sequential Indicator Simulation The sequential indicatior simulation (SIS) technique algorithm was found appropriate and ideal for producing is a statistical tool that can be used to simulate a large the reservoir facies model with the limited well control. number of equiprobable realizations of a particular This study attempts to predict reservoir facies of property or attribute. It is a cell- (pixel) based modelling OVK-1 sand bodies using stochastic sequential algorithm that uses the upscaled well observation as indicator simulation, facies architecture and petro- the basis to segregate the facies types to be modelled physical properties to identify potential unexplored and also honour semivariogram (commonly referred drillable prospects. This no doubt if drilled, will help to as variogram) and trends to constrain the distribution boast additional reserves in the Niger Delta Basic. and connection of each facies as well as the histogram. Journel [10] states that the differences between the Study area and geology realizations themselves should provide a measure of The study area, DN Field, lies within the coastal swamp spatial uncertainty about the input. This method is depobelt (Figure 1a) of Niger Delta and it is operated particularly useful as it produces geologically by Shell Petroleum Development Company of Nigeria reasonable results in data-challenged areas with few Limited. The in-lines and cross-lines are in the ranges well controls [11]. of 11,228 to 12,028 and 2,673 to 3,373 respectively Ataei [12] applied the principle in the modelling of a with a spacing of 100 m between lines (Figure 1b). turbidite reservoir in the Gulf of Mexico, where he The onshore portion of the Niger Delta Province is UNIVERSITY OF IBADAN LIBRARY Nton and Arigbe: Multiscale data in Dn-Field onshore 109 M a p C o u n t r y S c a l e1 . 6 2 5 0 0 B l o c k C o n t o u r i n c S y m b o l l e g e n d L i c e n s e U s e r n a m e F D E R O L T + U n d e f i n e d M o d e l n a m e D a t e 0 4 / 1 8 / 2 0 1 3 H o r i z o n n a m e S i g n a t u r e Figure 1b. Base map of DN Field showing the positions of the three Wells within the Field available for this study. delineated by the geology of southern Nigeria and oldest to youngest; the marine shales of the Akata south-western Cameroon. The northern boundary is Formation, middle paralic Agbada Formation and the the Benin Flank, an east-north-east trending hinge line topmost Benin Formation [1, 14]. south of the West Africa basement massif. The north- eastern boundary is defined by outcrops of the Akata Formation Cretaceous on the Abakaliki High and further east- The Akata Formation, the oldest formation in the Niger south-east by the Calabar Flank, a hinge line bordering Delta, is of Paleocene age to the present. It comprised the adjacent Precambrian Basement Complex [1]. The pro-delta marine shales with local sandy and silty beds offshore boundary of the Niger Delta Province is which have been transported to deep water areas. The defined by the Cameroon volcanic line to the east, the sediments are characterized by low energy conditions eastern boundary of the Dahomey Basin to the west, and oxygen deficiency [15] laid down as turbidites and and the 2 km sediment thickness contour or the 4,000 continental slope channel fills. It is estimated that the m bathymetric contour in areas where sediment formation is up to 7,000 meters thick [3]. The formation thickness is greater than 2 km to the south and south- underlies the entire delta, and is typically overpressured. west. The province covers an area of approximately Turbidity currents likely deposited deep sea fan sands 300,000 km2 and includes the geologic extent of the within the upper Akata Formation during development Tertiary Niger Delta (Akata-Agbada) Petroleum of the delta [16]. This formation constitutes the System. effective source rocks in the Niger Delta. Stratigraphy Agbada Formation The sedimentary sequences of the Niger Delta are This formation overlies the Akata Formation in the Niger made up of three stratigraphic units which are from Delta and is made up of paralic sands and shales. The UNIVERSITY OF IBADAN LIBRARY 110 Journal of Science Research Vol. 14 sands constitute themain petroleum-bearing unit in the some loading steps for the data already in the industrial Niger Delta while the shales provide lateral and vertical format acceptable to the software. The header seals [17]. Deposition of the Agbada Formation, began information and mapping coordinates were carefully in the Eocene and continues into the Recent. The inputted during the loading exercise. To effectively formation is over 3,700 meters thick and represents cover the study area, the seismic data was interpreted the actual deltaic portion of the sequence. The clastics at a scroll increment of 10 lines on both in-lines and accumulated in delta-front, delta-topset, and fluvio- cross-lines. The well data was in the ASCII format deltaic environments. In the lower Agbada Formation, and was also imported into the Petrel 2009.1™ shale and sandstone beds were deposited in equal software. The methodology involved making additional proportions, however, the upper portion is mostly sand well logs like volume of shale, seismic attribute with only minor shale interbeds. generation, facies modeling, petrophysical modeling, determination of the environment of deposition using Benin Formation well logs and biofacies. The Benin Formation is the youngest stratigraphic The work flow for the different aspects of the study sequence in the Niger Delta. It is about 2,000 m thick is shown in Figure 2. , and consists mainly of fresh-water fluvial sands and D a t a S e t gravels which are occasionally interspersed with shale beds towards the base of the unit. The sands are 3 D S e i s m i c W e l l l o g s C h e c k s h o tV o l u m e D a t a generally fine to coarse-grained and very poorly sorted. F a u l t V o l u m e E s t i m a t e d F a c i e s Occasional streaks of lignite and thin scattered grayish I n t e r p r e t a t i o n A t t r i b u t e s C o r r e l a t i o n L o g s I n t e r p r e t a t i o n brown shale beds are intercalated with the sands and gravels. The grains are subangular to well rounded S y n t h e t i cS e i s m o g r a m and varies in colour from clear white to yellowish brown quartz with subordinate hematite and feldspar grains [14]. It ranges in age from Oligocene to Recent. H o r i z o nI n t e r p r e t a t i o n Structures T i m e a n d The Niger Delta is subtly disturbed at the surface but D e p t h M a p s the subsurface is affected by large scale synsedimentary features such as growth faults, rollover G e o l o g i c a lG r i d s anticlines and diapirs [3,15]. The structural style, both on regional and on the field scale, can be explained on S c a l e u p the basis of influence of the ratio of sedimentation to W e l l l o g s subsidence rates. The different types of structures are namely, simple non-faulted anticline rollover anticline D a t aA n a l y s i s with multiple growth faults, or anticline faults and complicated collapse crest structures [18]. Other F a c i e s structures are sub-parallel growth fault (k-block M o d e l l i n g structures) and structural closures along the back of growth faults. P e t r o p h y s i c a lM o d e l l i n g Materials and methods Figure 2. Workflow of study. Dataset The dataset used for this study includes 3-D seismic, Deductions from well logs composite logs of three wells, biofacies data of the Well log data (GR, Vshale, Porosity, FDC well log suite) three wells and checkshot data containing velocity were used to train a seismic classification. This is based information. The three wells used for this study are on the fact that these logs provide first hand information namely; DN-1, DN-2 and DN-3 with respective total about the properties of a Formation before using seismic depths; 7,700 ft (2,333.3m), 7,500 ft (2,272.7 m) and attributes as a follow-up. Seismic volume attribute 10,000 ft (3,030.3 m). The dataset were obtained from cubes (Figure 3) notably; acoustic impedance, iso- the Shell Petroleum Development Company of Nigeria. frequency and envelope, capable of recognizing the The 3-D seismic data, which was in ZGY bricked properties of interest such as porosity, volume of shale format was imported into the Petrel 2009.1™, following and effective porosity respectively were generated. UNIVERSITY OF IBADAN LIBRARY Nton and Arigbe: Multiscale data in Dn-Field onshore 111 distribution were used to create local variations even away from input data. Fluvial facies interpretations from well logs were upscaled and stochastic object modeling algorithm was used to produce a fluvial facies model. Palaeodepositional environment Palaeodepositional environment was determined based on gamma ray log shapes as reported by Morris and Biggs [21] and biofacies analysis result. According to Emery and Myers [22], clean-up, dirtying-up and boxcar trends can be recognised when examining well log curves. Selley [23] opined that the environments of shallowing-upward and coarsening successions is divided into three categories namely; regressive barrier bars, prograding marine shelf fans and prograding delta or crevasse splays. Boxcar trend could indicate a slope channel and inner fan channel environments [24]. According to Emery and Myers [22], the greater range of thickness indicates turbidites sands and lesser thicknesses indicate inner fan channel environments. In a non-marine setting, dirtying-upward is predominant within meandering or tidal channel deposits with an upward decrease in fluid velocity within a channel [22]. The irregular shape has no character, representing aggradation of shales or silts and in the analysis classifies the log facies as belonging to a flood plain environment. Biofacies analysis was based on a checklist constructed by occurrence, abundance and diversity Figure 3. Seismic volume attributes showing acoustic of planktonic and benthonic foraminifera, and pollens impedance, iso-frequency and envelope respectively. [25]. Maximum abundance and diversity values generally reflect transgressive conditions and minimum In this study, a Principal Component Analysis (PCA) values reflect regressive conditions. was first run on all the properties to be modeled and the correlation coefficient ascertained. Principal Results and discussions Component Analysis (PCA) is a technique for Based on well logs and seismic interpretation, a number simplifying any dataset by reducing the multidimensional of models and cross plots were generated. Four dataset to lower dimensions for analysis. As reported reservoir sands were identified namely; OVK-1, by Jungmann et al [19], principal component analysis OVK2, OVK-3 and OVK-4 with intervals from 4,645 and stepwise discriminant analysis are two major to 4,700 ft [ 1407.6 to 1,424.2 m]; 4,773 to 4,864 ft methods used for feature extraction; they help to [1,446.4 to 1,473.9 m], 5,748 to 5,778 ft [1,741.8 to emphasize variation and bring out strong patterns in 1,750.9m] and 5,889 to 6,016 ft [1,784.5 to 1,823.0 m] the dataset which can improve the accuracy and respectively. In this study, OVK-1 reservoir sand being stability of classifiers by removing unwanted, non- the reservoir of interest has an interval of 4,529-4,584 distinctive and interrelated features. The already ft [1,372.4 to 1,389.1 m] in DN-1 well and 4,562-4,617 generated lithofacies model was used to constrain the ft [1,382.4 to 1,399.1 m] in DN-2 well and 4,645-4,700 petrophysical models generated. The properties to be ft [1,407.6 to 1,424.2 m] in DN-3 well (all depths are modeled such as volume of shale and effective porosity in SSTVD) (Figure 4). were first upscaled and Stochastic Gaussian Simulation (SGS) algorithm was utilized to produce the model. It Lithofacies’ model should be noted that Sequential Gaussian Simulation Stochastic sequential indicator simulation algorithm (stochastic) uses well data, input distributions, approach was used to generate a lithofacies model for variograms and trends [20]. The variograms and OVK-1 reservoir sand body. This was achieved by UNIVERSITY OF IBADAN LIBRARY 112 Journal of Science Research Vol. 14 Figure 4. Well log correlation and biofacies information of DN-Field Wells showing the potential reservoir intervals, the seals and continuity across the wells. assigning discrete values to each point to show sand deposits (Figure 6). Clean reservoir sands and marginal and shale. Sand was assigned a value of ‘0’ and colour shaly sands are superimposed on top of the background coded as yellow, fine sand was assigned a value of ‘1’ facies. The flanks of the reservoir area have more and colour coded as orange while shale was assigned a value ‘2’ and given a grey colour (Figure 5); this is as opposed to property modeling, that is continuous, which was able to show the gradual lateral change of petrophysical properties towards the flanks of the reservoir unit. In the lithofacies model, the central part of the OVK-I reservoir sand body shows cleaner sands (Figure 5) with minor shale development in the western part of the Field. In the fluvial facies model, majority of the channels are concentrated there with attendance highest values of porosity and hydrocarbon saturation recorded. Modelled channels show geometry and N-S orientation within the Agbada Formation across the field as shown by the compass direction (Figure 6). It could also be seen that all the wells fall Figure 5. Facies model of OVK-1 reservoir showing good within the channel sand area, having the highest porosity. sand distribution and minor shale in western part with The fluvial facies model indicates areas covered by positions of existing wells. Enclosed loop shows the channel sands, back ground flood plains, and levee identified drillable prospect. UNIVERSITY OF IBADAN LIBRARY Nton and Arigbe: Multiscale data in Dn-Field onshore 113 Figure 6. Fluvial facies model of OVK-1 reservoir with Figure 8. Effective porosity model of OVK-1 reservoir with positions of existing wells showing distribution of ranging between 0.2 and 0.4. background flood plains, channel sand , levee and crevasse splay sands. Figure 7. Volume of shale model of OVK-1 reservoir; areas Figure 9. Porosity model of OVK-1 reservoir following with blue colour have the best reservoir qualities, followed the distribution of volume of shale; central portion of the by areas with yellow/green while areas in red are highest model has the highest porosity values. volume of shale. flood plain materials such as shales and silts, hence upscaled using ‘Arithmetic Mean’ as the averaging the very high volume of shale (Figure 7) and low method as they are continous variables as opposed to effective porosity (Figure 8). facies which is discrete. The grid was calibrated into fractions which define the 3D model into various Petrophysical properties depositional environments; the part which captures Petrophysical properties which include porosity, volume values of 0.15-0.23, signifies potential reservoir rocks of shale and effective porosity were modeled. The while areas with high volume of shale are poor distribution of petrophysical properties gives clues to reservoirs. Bamidele and Ehinola [27], reported the the petroleum potential of the DN-Field. The areas volume of shale as ranging from 0 to 0.65 for offshore with high porosity values having shades of yellow and Niger Delta. The effective porosity model gives the red, ranges from 19 to 27.5% and are potential areas degree of interconnectivity of the reservoir. In this study, for hydrocarbon prospecting (Figure 9). The areas with areas with blue colour which capture 0.20-0.40, show low values of effective porosity allow little or no flow high effective porosity while those with purple colour of hydrocarbon (Figure 8). As reported by Ajibola and in the model indicate regions in the DN-Field with low Brian [26], the porosity values of the Agbada Reservoir effective porosity values. Sands range from 10 to 30 %, with formation thickness in the order of between 9,600 to 14,000 feet. Lithological identification The volume of shale (Figure 7) represents the The different cross plots show overlay of points with distribution of properties from the upscaled version of common lithology. As reported by Schlumberger [20], the well logs. The volume of shale as well as other responses of the logging tools used in any particular petrophysical properties modelled in this work was interval, will plot as a point on a crossplot. These UNIVERSITY OF IBADAN LIBRARY 114 Journal of Science Research Vol. 14 crossplots give a quick view of the lithology in qualitative 1,749 m), and 6,504-6,456 ft ( 1,971-1,956 m) (DN-1); and quantitative ways. The gamma ray/density and 5,516-5,550 ft (1,672-1,682 M) (DN-2) and 5,444-5,461 gamma ray/neutron crossplots for DN-3 well (Figure ft (1,650-1,655 m)(DN-3) (Figure 3). Blocky trend, 10) show that the reservoir sand (shades of red) and characterised by sharp upper and lower boundaries shaly facies (shades of purple) plot in same zone, occur at intervals; 6,071-6,143 ft (DN-1), 7,133-7,200 implying the reservoir facies to be dominantly sand ft (DN-2), 5,894-5,952 and 6,200-6,234 ft (DN-3). It is with some silt. observed that the sands here are not as thick as 25 m, hence they are in inner fan channel environment as Palaeodepositional environment reported by [22]. The irregular trend in DN-1 well, The log shapes of OVK-1 reservoir at interval between showing from a depth of 6,200-6,510 ft and 6,250-6,525 4,678 (1,417 m) and 4,700 ft (1,424 m) in DN well 3 ft in DN-2 well, classifies the log facies as flood plain (Figure 3) can be inferred to indicate a crevasse splay. [22]. The environment is characterised by a blanket of This 28 ft (6.7 m) thick reservoir unit according to clays and silts, deposited from suspension, with high Chow et al[28], is comparatively thin to be a prograding lateral continuity and low lithologic variation related to delta. Crevasse splay deposits also occur at intervals a gradual upward change in the clay mineral content 5,368-5,414 ft (1,627-1,641 m), 5,741-5,771 ft (1,740- or an upward thinning of sand beds in a thinly Figure 10. Lithological identification from GR/FDC and GR/CNL crossplots of DN-3 well areas with red and blue signifying coarse and fine sand facies respectively while grey represents the shale facies. UNIVERSITY OF IBADAN LIBRARY Nton and Arigbe: Multiscale data in Dn-Field onshore 115 interbedded sand-shale unit, both of which imply a (SSTVD), having high foraminifera diversity, all decrease in depositional energy. correlate with the shales and silts of both the flood From the biofacies data of DN-3 well (Table 1), plain and levee which are low energy depositional depths 4,700-4,782 ft ( 1,424-1,449 m), 4,816-4,834 ft environments. There are very little benthic foraminifera (1,459-1,465 m), 4,864-4,993 ft (1,474-1,513 m), 5,027- in the study-area but an abundance of planktonic and 5,056 ft (1,523-1,532 m) , 5093-5,230 ft (1,543-1,585 shallow marine forams, validating the environment of m), 5,269-5,382 ft (1,597-1,631 m), 5,467-5,623 ft deposition as fluvio-marine. (1,657-1,703 m), 9,200-9,818 ft (2,788-2,975 m) Table 1. Biofacies interpretation for DN-3 well showing the environment of deposition and population of both benthic and planktonic foraminifera. S/N Depth Type Environ- Foram Foram Plankton Plankton ment diversity population diversity population 1 5000 3 B 0 0 0 0 2 5030 3 B 0 0 0 0 3 5060 3 B 0 0 0 0 4 5090 3 B 0 0 0 0 5 5120 3 SH.IN 2 5 0 0 6 5150 3 SH.IN 1 2 0 0 7 5180 3 SH.IN 1 8 0 0 8 5210 3 B 0 0 0 0 9 5240 3 B 1 1 0 0 10 5270 3 B 0 0 0 0 11 5300 3 SH.IN 2 7 0 0 12 5330 3 IN-MN 8 14 2 2 13 5360 3 IN 5 12 0 0 14 5390 3 IN 3 11 0 0 15 5420 3 IN 1 4 0 0 16 5450 3 SH.IN 1 4 0 0 17 5480 3 MN 10 14 2 2 18 5510 3 IN-MN 8 21 2 3 19 5540 3 SH.IN 2 2 0 0 20 5570 3 IN 5 8 1 1 Conclusions new drillable prospect, located on clean sand, with high Facies model building of integrated data in Dn-Field, porosity and good effective porosity has been onshore Niger Delta was undertaken to predict identified. The identified drillable prospect is southwest lithofacies and fluvial facies of OVK-1 sandbodies in of DN-2 well, coinciding with 3,500 m contour line on the Agbada Formation, as a tool in identifying new the structure map. However to better ascertain drillable prospects. A stochastic sequential indicator lithofacies both horizontally and vertically, it is simulation method which uses a nonlinear function with imperative that core data be provided. A chronology better connectivity, higher repeatability and shorter turn- of depositional episodes can be established from careful around time, was used to generate a lithofacies model analysis of cross-cutting relationships observed on core for OVK-1 reservoir sand body in the Niger Delta. pictures and seismic time slices at different times. Calibrated by fluvio-facies at the well locations, channel sands were identified in OVK-1 reservoir sands with Acknowledgments the channels concentrated in the central part, where The authors are grateful to the Shell Petroleum Development there are more sands in the lithofacies model. Based Company Limited, Nigeria, for provision of dataset for this on lithofacies, fluvial facies and biofacies analysis, a study. We are grateful to the Department of Geology, terrigenous and shallow fluvio-deltaic fill, within a University of Ibadan, for accessibility to the workstation lowstand system tract is evident. for the data interpretation. Porosity model predicts sand layers to have maximum References porosity of 27.5% while silt and clay have porosity below 20%. Porosity values of 0.15-0.23 for areas [1] Reijers, T. J. A., Petters, S. W. and Nwajide, C. S. 1997. around the central portion were interpreted as channels. The Niger Delta Basin, In:. Selley, R.C (Ed) AfricanBasins – Sedimentary Basins of the World 3, Integrating structural, petrophysical properties’ Amsterdam, Elsevier Science, pp. 151-172. distribution and seismic volume attribute analysis; a [2] Klett, T. R., Ahlbrandt, T. S., Schmoker, J. W. and Dolton, UNIVERSITY OF IBADAN LIBRARY 116 Journal of Science Research Vol. 14 J. L. 1997. Ranking of the world’s oil and gas provinces [15] Stacher, P. 1995. Present understanding of the Niger by known petroleum volumes: U.S. Geological Survey Delta Hydrocarbon habitat. In: Oti, M.N. and Postuma, Open-file Report-97-463, CD-ROM. G. (Eds.), Geology of Deltas, Rotterdam Balkema, pp. [3] Doust, H. and Omatsola, M. E. 1990. Niger Delta. In: 257-267. J.D. Edwards and Santogrossi (Eds.), Divergent/ [16] Burke, K.C. 1972. Longshore drift submarine canyons Passive Margins basin. American Association of and submarine fans in the development of the Niger Petroleum Geologist Memoir 48, pp. 201-238. Delta. American Association of Petroleum Geologists [4] Kulke, H. 1995. Nigeria. In: Kulke, H. (Ed.), Regional Bulletin 56: 1975-1983. Petroleum Geology of the World. Part II: Africa, [17] Krusi, H.R., and Idiagbor, C. 1994, Stratigraphic traps America, Australia and Antarctica: Berlin, Gebrüder in Eastern Niger Delta: Inventory and concepts. NAPE Borntraeger, pp. 143-172. Bulletin, Vol. 9, No. 1, pp. 76-85. [5] Hospers, J.,1965. Gravity field and structure of the Niger [18] Evamy, B. D., Hareboure, J., Kamerling, P., Knaap, W. Delta, Nigeria. West Africa: Geological Society of A., Molloy, F.A. and Rowland, P. H. 1978. Hydrocarbon American Bulletin, Vol. 76, pp. 407-422. habitat of Tertiary Niger Delta. American Association [6] Kaplan, A., Lusser, C. U. and Norton, I. O. 1994. of Petroleum Geologists Bulletin Vol. 62, pp. 277-298. Tectonic map of the world, Panel 10: Tulsa, American [19] Jungmann, R., Scheibie, M., Kuzyk, A., Pardatscher, Association of Petroleum Geologists, Scale 1: G., Castro, C.E. and Simmel, F.C. 2011. DNA origami- 10,000,000. based nanoribbons: Assembly, length distribution and [7] Tuttle, L.W., Charpentier, R. R. and Brownfield, M. E. twist. Nanotechnology 22: 275301. 1999. The Niger Delta Petroleum System: Niger Delta [20] Schlumberger. 1995. Log Interpretation Charts. province, Nigeria, Cameroon and Equatorial Guinea, Houston: Schlumberger Wireline and Testing. Africa.Denver: USGS, Open-File Report. 99-50-H. [21] Morris, R. L. and Biggs, W. P. 1990. Using log-derived [8] Steele, D., Ejedawe, J., Adeogba, T., Grant, C., Filbrandt, values of water saturation and porosity. SPWLA 8th J. and Ganz, H. 2009. Geological framework of Nigerian- Annual Logging Symposium, 1-26. linked shelf extension and deepwater thrust belts. [22] Emery, D. and Myers, K. J. 1996. Sequence American Assosiation of Petroleum Geologists, Stratigraphy. Blackwell Science Ltd. Hedberg Conference , Oct 4-9, 2009, Tirrenia, Italy. [23] Selley, R.C. 1998. Element of Petroleum Geology, [9] Benzaoui, K. and Cox, T. 2009. Integration of Multi Second Edition. Academic Press, New York, 470pp. Scale Data in Facies Modelling using Neural Network. [24] Shell. 1982. Well log interpretation: Chapters 11-13, Journal of Canadian Society of Exploration Shell Houston. Geophysicist, pp. 798-801. [25] Lawton, M. A. and Lamb, C. J. 1987. Transcriptional [10] Journel, A.G. 1988. Conditional geostatistical activation of plant defense genes by fungal elicitor, operations to non-linear volume averages. Stanford wounding and infection. Mol Cell Biol 7:pp. 335-341. Center for Reservoir Forecasting, Vol. 11, Stanford, [26] Ajibola, O. O. and Brian, W. J. 2006. Depositional USA. patterns across syndepositional normal faults, Niger [11] Afuye, T.J., 2013. 3D Static Reservoir Modeling of X- Delta, Nigeria, Journal of Sedimentary Research, Vol. Field, Offshore Niger Delta: AJ-1 Reservoir Case Study: 76, pp. 346-363. Unpublished MSc thesis, University of Ibadan. [27] Bamidele, O. F. and Ehinola, O. A. 2010. Fault analysis, [12] Ataei, M. 2012. Log facies evaluation and property stratigraphic discontinuities and 3D structural modeling of a turbidite reservoir, the Gulf of Mexico: modeling of Tb-field, offshore Niger Delta. American Unpublished M.Sc Thesis, Norwegian University of Association of Petroleum Geologist, Proceedings , Science and Technology. pp. 68-83. [13] Afuye, T., Osezele, I., Feyisola, B., Olusola, O. and [28] Chow, J.J., Ming-Ching Li and Fuh, S. 2005. Emmanuel, E. 2015. Building 3D Facies Model Utilising Geophysical well log study on the palaeoenvironment Sequence Stratigraphic Driven Approaches and of the hydrocarbon-producing zones in the Erchungchi Simulations for Miocene Reservoirs, ‘Rhode’ Field, Formation, Hsinyin, SW Taiwan. TAO Vol. 16 No. 3, Coastal Swamp Depobelt, Niger Delta. 33rd Annual pp. 531-54. International Confernece of the Nigerian Association [29] Corredor, F., Shaw, J. H. and Bilotti, F. 2005. Structural of Petroleum Explorationists Book of Selected styles in the deep-water fold and thrust belts of the Extended Abstracts. Niger Delta. American Association of Petroleum [14] Short, K.C. and Stauble, A. J. 1967. Outline of the Geologist Bulletin, vol. 89, No. 6, pp 753-780. Geology of the Niger Delta. American Association of Petroleum Geologist Bulletin 51: 761-779. Journal of Science Research Volume 14, 2015, ISSN 1119 7333 Citation: Nton, M. E. and Arigbe, O. D. Facies model building of integrated multiscale data in Textflow Limited Dn-Field, Onshore, Niger Delta, Nigeria. Ibadan, Nigeria UNIVERSITY OF IBADAN LIBRARY