Article Open Access QUANTITATIVE PETROPHYSICAL EVALUATION AND RESERVOIR CHARACTERIZATION OF WELL LOGS FROM "DATOM" OIL FIELD, NIGER DELTA

This paper presents a detailed reservoir characterization of three wells in “Datom” Oil Field, Niger Delta using well logs data. The distributions and thicknesses of sand bodies were determined within each of the wells in the field using interactive petrophysical (IP) software. The quantitative and qualitative analysis were done for the three exploration wells with the depth ranges of 8700-9200ft for Datom North well , 8900-9400ft for Datom West well, and 9000-9500ft for Datom East well. Two distinctive porous sand bodies were identified across the field (A and B), Datom North has it reservoirs as 1A (8815- 8903ft) and 1B (9100-9157ft), Datom West has its reservoir as 2A (8996-9095ft) and 2B (9263- 9321ft) and Datom East as 3A (9101-9219ft) and 3B (9357-9418ft). Petrophysical evaluation was made from a suite of wire-line logs comprising of gamma ray, resistivity, neutron and density logs of the wells. The average porosity values obtained are in the range of 0.18-0.22 with average net pay permeability values ranging from 322.70mD to 733.20mD. The water saturation obtained for each reservoir unit in combination with the resistivity index was used to prove the presence of hydrocarbon in the sand units. The hydrocarbon saturation of the reservoirs are in the range of 0.6-0.7 across the prospect zones with gas effect of the combination logs of neutron and density indicating the hydrocarbon accumulation is predominantly gas. The average net to gross ratio across the reservoirs (0.7-0.9) is defined using an average porosity (∅) and volume of clay ( ) cut offs values of ≥ 0.1 ≤ 0.5 respectively. With a moveable hydrocarbon index (MHI= ⁄ ) less than 0.7 across the sand units, it shows favorable hydrocarbon moveability in the reservoirs. The results clearly revealed that the gas bearing sand units have good reservoir potentials favorable for hydrocarbon production

Research Article 3-D Seismic Attribute Analysis for Enhanced Prospect Definition of "Opu Field'', Coastal Swamp Depobelt Niger Delta, Nigeria

Background and Objective: Analysis of seismic attributes has been an integral part of reflection seismic interpretation for over two decades now. Seismic attributes facilitates structural and stratigraphic interpretation as well as offer hints to formation type and fluid content estimation with the potential benefit of detailed reservoir characterization. The current study evaluated the use of seismic attributes generated from 3D seismic and well log data for characterization of the reservoirs of ʻʼOpu Fieldʼʼ, Coastal Swamp Depobelt, Niger Delta. Materials and Methods: Root mean square (RMS) amplitude, instantaneous frequency and interval average maps were extracted on seismic events with pronounced bright and dim spots. These maps were used to establish the diagnostic ability of 3D seismic attribute analysis in enhancing seismic interpretation and volumetric estimation of the mid Miocene to Pliocene Agbada Formation reservoirs within the Coastal Swamp Depobelt, Niger Delta basin. The methodology involved a well-defined procedure which included the delineation of the various lithologies from the gamma ray log, identification of reservoirs from the resistivity log, regional well correlation, determination of petrophysical parameters, horizon and fault mapping, time to depth conversion, attribute analysis and reserve estimation. Results: Two main reservoirs identified as Sand-A and Sand-B were mapped in the study area using seismic data. Similarly, seven faults labelled F1-F7 and four horizons were mapped within the field. Depth structure maps generated revealed a massive Northeast-Southwest (NE-SW) trending anticlinal structure. Petrophysical analysis revealed a mean porosity value of 18% while the mean permeability values ranged from 63-540 md across the two reservoirs. Water saturation and volume of shale (Vsh) across the reservoirs ranged from 38-90 and 17-82%, respectively. Conclusion: This study revealed that the“Opu Field” has high hydrocarbon potentials and excellent petrophysical characteristics favourable for hydrocarbon accumulation and production. The benefits of integrating structural interpretation, petrophysical evaluation and seismic attributes analysis in prospect identification and reservoir prediction was therefore highlighted in this study

3D Geomechanical reservoir model for Appraisal and Development of Emi-003 field In Niger Delta, Nigeria

In this paper, geomechanical parameters were effectively integrated in 3-D geostatic model of Emi-003 reservoir in the Niger Delta basin, Nigeria for deformability and rock strength appraisal using well logs and 3D seismic volume. Unconsolidated sandstone and compacted shale were delineated and evaluated by determined elastic moduli (Poisson ratio, Young modulus, Bulk modulus, Shear modulus and Compressibility) and the Unconfined compressive strength (UCS) using sonic logs and petrophysical analysis, correlations and cross plots for comparison of the evaluated reservoir strength, physical properties (such as modulus, porosity, velocity) of the five mapped zones from five vertical wells in the studied reservoir for validation were done. Finally, incorporation of elastic properties, unconfined compressive strength in 3D static model of the studied reservoir was carried out to capture strong lateral variance of rock elastic moduli and strength into areas where well control may not exist. especially off the well points. The results show average parameters of the weakly cemented sand to have lower Poisson ratio, Young, Bulk, Shear modulus and Unconfined compressive strength (0.27, 2.3GPa, 10.8GPa, 6.91GPa, 14.21MPa respectively,) high compressibility and porosity (0.13 GPa-1, 0.26) conversely the compacted shale have higher Poisson ratio, Young, Bulk, Shear modulus and rock strength as (0.36, 8.91GPa, 18.05GPa, 21.09GPa, 56.44MPa respectively) lower compressibility and porosity (0.05 GPa-1, 0.05 respectively). There is a marked increase of rock strength and elastic moduli with relative decrease in porosity. The mechanical failure in the NNW direction of the reservoir will be relatively lower than other areas as analyse using the 3D earth model. The information gathered will help manage reservoir stress and strain induced during development and maximize reservoir performance, while mitigating risk

Geomechanical Characterization of a Reservoir in Part of Niger Delta, Nigeria

Geomechanical characterization of a reservoir in the Niger Delta basin, using geophysical well-logs was adequately evaluated. The deformability and strength of delineated unconsolidated sandstone and compacted shale were investigated by determined elastic moduli (Poisson ratio, Young modulus, Bulk modulus, Shear modulus and Compressibility) and the unconfined compressive strength (UCS), cross plots of the parameters were done for validation. Sand production prediction was used to adequately analyse sanding. The results show average parameters of weakly cemented sand to have lower Poisson ratio, Young, Bulk, Shear modulus and Unconfined compressive strength of magnitudes of 0.28, 2.4GPa, 10.5GPa, 6.83GPa, 14.44MPa respectively, high compressibility (0.1 GPa-1), and porosity (0.25) the compacted shale have higher Poisson ratio, Young, Bulk, Shear modulus and rock strength as (0.35, 8.93GPa, 18.08GPa, 21.01GPa, 56.17MPa respectively, lower compressibility (0.06 GPa-1) and porosity (0.06). The shale has maximum average rock strength value of 56.17MPa.These results can be useful in the planning of well drilling and sanding prediction in the study area

3-D Seismic Interpretation and Volumetric Estimation of “Osaja Field” Niger Delta, Nigeria

3-D seismic interpretation and petrophysical analysis of the Osaja Field, Niger Delta, was carried out with aim of carrying out a detailed structural interpretation, reservoir characterization and volumetric estimation of the field. Four wells were correlated across the field to delineate the lithology and establish the continuity of reservoir sand as well as the general stratigraphy of the area. The petrophysical analysis carried out, revealed two sand units that are hydrocarbon bearing reservoirs (Sand_A and Sand_B).The spatial variation of the reservoirs were studied on a field wide scale using seismic interpretation. Time and depth structural maps generated were used to establish the structural architecture/geometry of the prospect area of the field. The depth structure map revealed NE-SW trending anticlinal structures with F5 and F6 as faults assisted closures to the reservoir. Furthermore, reservoir parameters such as net pay, water saturation porosity, net-to-gross etc, were derived from the integration of seismic and well log data. The structural interpretation on the 3-D seismic data of the study area revealed a total of seven faults ranging from synthetic to antithetic faults. The petrophysical analysis gave the porosity values of the reservoir Sand_A ranging from 18.1 - 20.3% and reservoir Sand_B ranging from 13.1-14.9% across the reservoir. The permeability values of reservoir Sand_A ranging from 63-540md and reservoir Sand_B ranging from 18-80md hence there is decrease in porosity and permeability of the field with depth.The net-to-gross varies from 22.1% to 22.4% in Rerservoir Sand A to between 5.34- 12% for Rerservoir Sand _A while Sw values for the reservoirs ranges from 38-42% in well 2 to about 68.79-96.06% in well 11. The result of original oil in place for all the wells calculated revealed that well 2 has the highest value with 9.3mmbls. These results indicate that the reservoirs under consideration have a poor to fair hydrocarbon (oil) prospect

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to < 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of & GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P < 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo