Hydrocarbon reservoir characterization of “Keke” field, Niger Delta using 3D seismic and petrophysical data (original) (raw)
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Hydrocarbon trapping mechanism and petrophysical analysis of Afam field, offshore Nigeria
The structural trapping mechanism and petrophysical attributes of Afam field, offshore Niger Delta was evaluated using 3D seismic reflection data and composite well logs data. The structure maps and seismic sections show that the anticlinal structure at the centre of the field, which is tied to the crest of the rollover structure assisted by faults, is the principal structure responsible for the hydrocarbon entrapment in the field. Distinctive fault closures are the dominant structural plays in the field. Structural highs, fault assisted closures comprising two-way closure and four-way dip closed structures are evident on the depth structure maps. Petrophysical analysis of four (4) mapped reservoir sand horizons quantitatively revealed water saturation ranging from 3.07 to 12.02% in Well1 and 7.25 to 19.32% in Well 5; hydrocarbon saturation with range 87.98 to 96.93% (well 1), 80.68 to 92.75% (well 5). The porosity and permeability values of the reservoirs within the field proved them to be quite prolific with the porosity ranging from 24.5 to 31% (well 1), 21.25 to 28.25% (well 5) and permeability range of 2606.91 to 11,777.71 mD (well 1), 1050 to 6502.20 mD (well 5).
Journal of Geosciences and Geomatics, 2018
This paper presents the results of the reservoir characterization of Baze field, Niger Delta, Nigeria, using seismic and well log data. The area of the field is bounded with longitudes 3.00 0 E and 7.00 0 E, and latitudes 4.00 0 N and 8.00 0 N. Analysis of the structural maps of five horizons showed the structural geometry of the subsurface and the presence of possible trapping mechanism, which control the accumulation of hydrocarbons in the Baze field. Interpretations of faults that described the structural setting of the field showed two major faults trends from East to West whiles dipping southward with other minor (synthetic and antithetic) faults. Petrophysical parameters are estimated to determine reservoir properties, while the hydrocarbon volumetric reserves are calculated with total oil and gas recoverable estimates of 6.115 MMbbls and 8.456 Bscf respectively. From the reservoir characterizations done in this research work, the Baze field located onshore of the Niger Delta has been identified as suitable for hydrocarbon production.
Reservoir characterization is a process that involves the integration of various qualities and quantities of data in a consistent way to describe the reservoir properties of interest in each well locations. Characterizing the reservoir is a process which describes various properties in reservoirs using all the available data to provide reliable reservoir models for accurate prediction of the performance of a reservoir. Reservoir characterization is of high importance because it plays an important role in the exploration and exploitation processes of the oil and gas industry and also gives room for optimum recovery of hydrocarbon at a minimized cost. A play is one or more prospects that may define a profitable accumulation of undiscovered petroleum. Traditionally, a play is developed and evaluated without any particular petroleum system in mind. Wireline log data and 3D seismic data were analyzed to characterize the reservoir with respect to its porosity, water saturation, the volume of shale and permeability in “HARK” field. Reservoir “A” was delineated across four (4) wells-HARK_5, HARK_7, HARK_10 and HARK_11. The average permeabilities observed across the wells range from 1108.945mD to 1767.393mD, while the effective porosity ranges from 21.4% to 23.9%. The Hydrocarbon saturation ranges from 69.1% to 90.5% signifying the presence of a commercial quantity of hydrocarbon accumulation. Oil-Water Contact has been encountered by the well at 3814 m TVD. The volumetric analysis carried out revealed that the volume of hydrocarbon in place for reservoir “A” was estimated at 308 bb/STB. The outcome of this project is a notable approach in characterizing reservoirs and hydrocarbon producibility of the reservoir.
Hydrocarbon Reservoir Characterization of 'Khume' Field, Offshore Niger Delta, Nigeria
Journal of Geography, Environment and Earth Science International, 2021
The integrative approach of well log correlation and seismic interpretation was adopted in this study to adequately characterize and evaluate the hydrocarbon potentials of Khume field, offshore Niger Delta, Nigeria. 3-D seismic data and well logs data from ten (10) wells were utilized to delineate the geometry of the reservoirs in Khume field, and as well as to estimate the hydrocarbon reserves. Three hydrocarbon-bearing reservoirs of interest (D-04, D-06, and E-09A) were delineated using an array of gamma-ray logs, resistivity log, and neutron/density log suites. Stratigraphic interpretation of the lithologies in Khume field showed considerable uniform gross thickness across all three sand bodies. Results of petrophysical evaluations conducted on the three reservoirs correlated across the field showed that; shale volume ranged from 7-14%, total and effective porosity ranged from 1926% and 17-23% respectively, NTG from 42 to 100%, water saturation from 40%-100% and permeability from 1265-2102 mD. Seismic interpretation established the presence of both synthetic and antithetic faults. A total of six synthetic and four antithetic faults were interpreted from the study area. Horizons interpretation was done both in the strike and dip directions. Time and depth structure maps revealed reservoir closures to be anticlinal and fault supported in the field. Hydrocarbon volumes were calculated using the deterministic (map-based) approach. Stock tank oil initially in place (STOIIP) for the proven oil column estimated for the D-04 reservoir was 11.13 MMSTB, 0.54 MMSTB for D-06, and 2.16 MMSTB for E-09A reservoir. For the possible oil reserves, a STOIIP value of 7.28 MMSTB was estimated for D-06 and 6.30 MMSTB for E-09A reservoir, while a hydrocarbon initially in place (HIIP) of 4.13 MMSTB of oil equivalents was derived for the undefined fluid (oil/gas) in D-06 reservoir. A proven gas reserve of 1.07 MMSCF was derived for the D-06 reservoir. This study demonstrated the effectiveness of 3-D seismic and well logs data in delineating reservoir structural architecture and in estimating hydrocarbon volumes
Journal of Petroleum Exploration and Production Technology
Seismic interpretation and petrophysical assessment of borehole logs from seven wells were integrated with the aim of establishing the hydrocarbon reserves prior to field development which will involve huge monetary obligation. Four hydrocarbonbearing sands, namely Pennay 1, 2, 3 and 4 were delineated from borehole log data. Four horizons corresponding to near top of mapped hydrocarbon-bearing sands were used to produce time maps and then depth structural maps using checkshot data. Three major structure-building faults (F2, F3 and F5 which are normal, listric concave in nature) and two antithetic (F1 and F4) were identified. Structural closures identified as rollover anticlines and displayed on the time/depth structure maps suggest probable hydrocarbon accumulation at the upthrown side of the fault F4. Petrophysical analysis of the mapped reservoirs showed that the reservoirs are of good quality and are characterized with hydrocarbon saturation ranging from 56 to 72%, volume of shale between 7 and 20% and porosity between 25 and 31%. Pennay 2 and 3 have a better relative petrophysical ranking compared to other mapped reservoirs in the study area. Dissimilarity in the petrophysical parameters and the uncertainty in the reservoir properties of the four reservoirs were considered in calculating range of values of gross rock volume (GRV) and oil in place volume. This research study revealed that the discovered hydrocarbon reserve resource accumulations in the Pennay field for the four-mapped reservoir sand bodies have a total proven (1P) reserve resource estimate of 53.005MMBO at P90, 59.013MMBO at 2P/P50 and 65.898MMBO at 3P/P10. Reservoir C, the only interval with a gas cap, has a volume of 7737MMscf of free gas at 1P, 8893.2MMscf at 2P and 10185.2MMscf at 3P. These oil and gas volumetric values yield at 1P/ P90 total of 137.30MMBOE, 154.9MMBOE at 2P and 171.515MMBOE at 3P. Reservoirs B and D have the highest recoverable oil at 1P, 2P, and 3P values of 5.265MMBO and 10.70MMBO, 12.053MMBO and 5.783MMBO, 13.557MMBO and 6.244MMBO, respectively.
Integration of Seismic and Petrophysics to Characterize Reservoirs in “ALA” Oil Field, Niger Delta
The Scientific World Journal, 2013
In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential) reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on "ALA" field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of −2,453 to −3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments.
In the exploration and production business, by far the largest component of geophysical spending is driven by the need to characterize (potential) reservoirs. The simple reason is that better reservoir characterization means higher success rates and fewer wells for reservoir exploitation. In this research work, seismic and well log data were integrated in characterizing the reservoirs on "ALA" field in Niger Delta. Three-dimensional seismic data was used to identify the faults and map the horizons. Petrophysical parameters and time-depth structure maps were obtained. Seismic attributes was also employed in characterizing the reservoirs. Seven hydrocarbon-bearing reservoirs with thickness ranging from 9.9 to 71.6 m were delineated. Structural maps of horizons in six wells containing hydrocarbon-bearing zones with tops and bottoms at range of −2,453 to −3,950 m were generated; this portrayed the trapping mechanism to be mainly fault-assisted anticlinal closures. The identified prospective zones have good porosity, permeability, and hydrocarbon saturation. The environments of deposition were identified from log shapes which indicate a transitional-to-deltaic depositional environment. In this research work, new prospects have been recommended for drilling and further research work. Geochemical and biostratigraphic studies should be done to better characterize the reservoirs and reliably interpret the depositional environments.
Hydrocarbon reservoir characterization of “Otan-Ile” field, Niger Delta
Journal of Petroleum Exploration and Production, 2021
Otan-Ile field, located in the transition zone Niger Delta, is characterized by complex structural deformation and faulting which lead to high uncertainties of reservoir properties. These high uncertainties greatly affect the exploration and development of the Otan-Ile field, and thus require proper characterization. Reservoir characterization requires integration of different data such as seismic and well log data, which are used to develop proper reservoir model. Therefore, the objective of this study is to characterize the reservoir sand bodies across the Otan-Ile field and to evaluate the petrophysical parameters using 3-dimension seismic and well log data from four wells. Reservoir sands were delineated using combination of resistivity and gamma ray logs. The estimation of reservoir properties, such as gross thickness, net thickness, volume of shale, porosity, water saturation and hydrocarbon saturation, were done using standard equations. Two horizons ( T and U ) as well as ma...
Hydrocarbon Prospect Re-Evaluation of Nko Field, Onshore Niger Delta Basin, Nigeria
International Network Organization for Scientific Research , 2022
Integrated 3-D seismic and well-log interpretation was employed to re-evaluate the hydrocarbon prospects of NKO Field in Onshore Northern Depobelt of Niger Delta Basin, Nigeria. The objectives of this research are to map and interpret the structural framework of the field, identify the reservoirs present and access their continuity across the studied area and obtain petrophysical parameters of the reservoirs. Four reservoirs (A1, A2, A3, and A4) were identified, correlated and mapped using available well-log suites. The sand units were further mapped on seismic section with the aid of synthetic seismogram. Seven faults were mapped to constitute the structural framework of the field. Time and depth structural maps of the interpreted reservoirs shows the distribution of the fault networks with the major faults trending northwest-southeast. Petrophysical analysis for reservoirs A1 and A3 showed good reservoir potential and quality with average porosity of 0.27 & 0.21; Net-to-Gross of 0.765 & 0.79; and hydrocarbon saturation of 0.55 & 0.31 respectively. Two prospects were identified from depth structural maps of A1 and A3 reservoirs at the central fault block sandwiched between two major faults which are responsible for possible hydrocarbon accumulation. The trapping mechanisms are 2-way and 3-way fault dependent closures.. The results of this research show that NKO Field has potentials for further development drilling.
Seismic interpretation and petrophysical evaluation of SH field, Niger Delta
Journal of Petroleum Exploration and Production Technology
Three out of the 14 hydrocarbon-bearing sands (A, B and I) in the 'SH' field onshore Niger Delta which contain bulk of the hydrocarbon reserves in the field were considered as development candidates. Seismic interpretation and petrophysical evaluation of logs of 13 wells were integrated with the aim of verifying and ascertaining the hydrocarbon reserves prior to field development which involves enormous financial commitment. Results show that the field is structurally controlled by sets of northwestsoutheast-trending synthetic faults which dip southwest. Hydrocarbon traps at the three sand levels are rollover anticlinal closures that are generally sealed by a major listric fault that demarcated the field into northwest and southeast blocks. The southern fault block is hydrocarbon bearing; wells drilled in the field targeted these closures and encountered a number of stacked hydrocarbon-bearing sand levels. Reservoir-A developed a hanging-wall rollover anticlinal structure sealed by a major listric fault forming a trap with oil-water contact (OWC) of 1222 m TVDSS. Reservoir-B also shows similar structure as reservoir-A, but it is partitioned into two hydrocarbon compartments by a sealing fault; these two compartments have different OWCs. Reservoir-I exhibits similar structure to reservoir-A. The evaluation of the petrophysical characteristics revealed that the reservoirs are of good quality with average net to gross, porosities, water saturation and hydrocarbon saturation ranging from 0.774 to 0.980, 0.220-0.339, 0.133-0.367 and 0.633-0.867, respectively. Variation in the petrophysical parameters and the uncertainty in the reservoir structure of the three reservoirs were considered in calculating range of values of gross rock volume and in-place volume. The study shows oil-in-place volume in the range of 243.83-357.90 MMstb in reservoir-I, whereas reservoir-A contains 148.98-241.14 MMstb, reservoir-B1 31.31-50.36 MMstb and reservoir-B2 67.79-108.98 MMstb of oil. Conclusively, this study has further confirmed the high productivity and commercial viability of the wells within the field of study to be able to adequately compensate for the cost of development.