scholarly journals Delineation of Stratigraphic Units in Xyz Field of Niger Delta Using Geophysical Logs

2019 ◽  
Vol 3 (1) ◽  
pp. 38-49
Author(s):  
Charles C. Ekeh ◽  
Etim D. Uko ◽  
Ejiro F. Eleluwor ◽  
Friday B. Sigalo
Keyword(s):  
Niger Delta ◽  
Well Logs ◽  
Surface Porosity ◽  
Depositional Sequences ◽  
Petrophysical Parameters ◽  
Geophysical Logs ◽  
Net To Gross ◽  
Geophysical Well Logs ◽  
System Tracts ◽  
Optimum Recovery

AbstractGeophysical well logs were used to delineate the stratigraphic units and system tracks in the XYZ Field of the Niger Delta. The gross percentages for sand levels range from 93-96% in the shallow levels to 60-66% in the deeper levels. Porosity values ranged between 27% at shallower sections and 9% at deeper depths. Six depositional sequences were identified and categorized into their associated system tracts. Porosity decreases with depth in normal compacted formation for both sandstone and shale units. Surface porosity for sandstone is 42%, and for shale it is 38.7% from extrapolation of sub-surface porosity values to the surface. The depth to the base of Benin Formation is highly variable ranging between 1300 and 2600m. This study reveals the possibility to correlate sand levels over long distances which enables inferring porosity values laterally. The knowledge of the existent stratigraphic units, the Benin, Agbada and Akata Formations and their petrophysical parameters such as porosity, lateral continuity of the sands and shales, the variation of the net-to-gross of sands with depth, enables the reservoir engineer to develop a plan for the number and location of the wells to be drilled into the reservoir, the rates of production that can be sustained for optimum recovery. The reservoir engineer can also estimate the productivity and ultimate recovery (reserves) using the results on this work.

scholarly journals Analysis of shaly sand reservoir rocks in the eastern Niger Delta Basin using geophysical well logs

2019 ◽  
Vol 10 (1) ◽  
pp. 1-13
Author(s):  
K. F. Fozao ◽  
Lordon A. E. Djieto ◽  
E. A. A. Ali ◽  
C. M. Agying ◽  
D. M. Ndeh ◽  
...  
Keyword(s):  
Niger Delta ◽  
Well Logs ◽  
Reservoir Rocks ◽  
Shaly Sand ◽  
Geophysical Well Logs ◽  
Niger Delta Basin

scholarly journals Geoscience Assessment of Declined Production Rate and Recovery from a Reservoir in “ANDA” Field, Onshore Southwestern Niger Delta

2021 ◽  
pp. 17-29
Author(s):  
Udoinyang, I. E. ◽  
Ekere, Udo Akpan ◽  
George, N. J.
Keyword(s):  
Niger Delta ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Production Performance ◽  
Well Logs ◽  
Production Plan ◽  
Formation Evaluation ◽  
Factors Associated ◽  
Well Production ◽  
Optimum Recovery

Declined production rates in wells producing from common reservoirs are enigmatic and generally viewed as phenomenal in some fields worldwide. The challenge posed by such discordant production trends forecloses the preponderance of totally and partially abandoned production, especially in aging fields. This study assesses possible factors associated with varying well production trends from a common reservoir in a field in the onshore western Niger Delta, by integrating multi-geoscience parameters including formation evaluation, 3D quantitative seismic analyses, paleoenvironmental diagnoses, paleobathymetric studies, and reservoir petrophysics to unravel the complexity of the reservoir. Composite well logs were collected from five wells selected for the study. Gamma-ray and SP logs were combined to delineate the depositional environment of "Heri sand" based on Schlumberger's (1985) log motif classification. The results were applied and found useful to develop an optimum recovery production plan for the study field.  It has been revealed from this study that declined production performances of the Heri sand reservoir are attributed to the deposition of the reservoir in three distinct paleoenvironments under different bathymetric settings within a coeval period. These factors constitute strong influences on the petrophysics of the reservoir which invariably influences’ the production performance of the reservoir.   Having realized the cause of the declined rate of the reservoir in the Anda field, the reservoir can be revitalized by well injection and fracturing.

scholarly journals Sequence Stratigraphic Interpretation of FX-1 and FX-2 wells, Onshore Western Niger Delta, Nigeria

2020 ◽  
Vol 24 (2) ◽  
pp. 303-311
Author(s):  
F.O. Amiewalan ◽  
F.A. Lucas
Keyword(s):  
Sequence Stratigraphy ◽  
Niger Delta ◽  
Gamma Ray ◽  
Computer Software ◽  
Well Logs ◽  
Data Simulation ◽  
Candidate Sequence ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Sequence Boundaries

The area of study is a portion of the Greater Ughelli Depobelt in Niger Delta Basin. The main aim of the paper is to interpret the sequence  stratigraphy of FX-1 and FX-2 wells by employing data sets from biostratigraphic data and well logs. Standard laboratory techniques were used for  data treatment while computer software such as Petrel and StrataBugs were used for data simulation, processing, integration and interpretation. Sedimentology, interpreted gamma ray and resistivity well logs integrated with biostratigraphic data were utilized to define the candidate maximum flooding surfaces and sequence boundaries. The wells have the following distributions of sequences: FX-1 well have five depositional sequences with eight candidate maximum flooding surfaces at depths 10011 ft., 9509 ft., 9437 ft., 6362 ft., 5752 ft., 5507 ft., 5161 ft. and 4816 ft. dated 34.0 Ma, 33.0 Ma, 31.3 Ma, 28.1 Ma, 26.2 Ma, 24.3 Ma, 23.2 Ma and 22.0 Ma and seven candidate sequence boundaries at 9616 ft., 6656 ft., 6116 ft., 5639 ft., 5424 ft., 4859 ft. and 4581 ft. dated 33.3 Ma, 29.3 Ma, 27.3 Ma, 24.9 Ma, 23.7 Ma, 22.2 Ma and 21.8 Ma, respectively. FX-2 well have four depositional sequences, five candidate MFSs were identified at 7764 ft., 7196 ft., 6721 ft., 5862 ft. and 5571 ft. dated 34.0 Ma, 33.0 Ma, 31.3 Ma, 28.1 Ma and 24.3  Ma and five candidate SBs at 6941 ft., 6029 ft., 5688 ft., 5653 ft. and 5542 ft. dated 32.4 Ma, 29.3 Ma, 27.3 Ma, 24.9 Ma and 23.7 Ma respectively. The correlation of the two wells and sequence stratigraphic interpretation is a supplementary understanding of the subsurface geology of the Onshore, western Niger Delta area of Nigeria. Keywords: Bio-stratigraphic data, Well logs, Sequence stratigraphy, Well correlation.

scholarly journals NMR AND WELL LOGS PETROPHYSICAL CHARACTERIZATION OF SANDSTONE FROM THE MARACANGALHA FORMATION, BAHIA, BRAZIL

2021 ◽  
pp. 239-252
Author(s):  
Nathália De Souza Penna ◽  
Joelson Da Conceição Batista ◽  
Suzan Sousa de Vasconcelos
Keyword(s):  
Gamma Ray ◽  
Production Capacity ◽  
Clay Content ◽  
Well Logs ◽  
Depth Interval ◽  
Porous Space ◽  
Petrophysical Parameters ◽  
Porosity And Permeability ◽  
Using Data ◽  
Geophysical Well Logs

The storage and production capacity of reservoir rocks can be estimated through some petrophysics characteristics involving the lithological identification of the constitute rocks, fluids nature in the porous space, porosity, permeability, saturation and clay content. The most popular tools for obtaining these petrophysical parameters are the conventional geophysical well logs. However, the determination of petrophysical parameters from tools based on the phenomenon of nuclear magnetic resonance (NMR) has gained prominence in recent decades. In this work, we analyzed rock samples from outcrops in Frades Island region, Bahia, Brazil, through laboratory NMR measurements, to estimate and evaluate the petrophysical properties of the Maracangalha Formation, one of the main hydrocarbons reservoirs in the Recôncavo Basin. The Sandstone samples were characterized in terms of porosity, permeability, saturation, and petrofacies. Finally, we calculated porosity, permeability, and clay content using data from gamma-ray, electrical and density logs, measured in a depth interval interpreted for Maracangalha Formation. These results corroborate with the obtained by NMR since, despite the effects of weathering and erosion on the samples used, the values of porosity and permeability obtained in NMR are in the range of values calculated from these profiles.

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