Pore Pressure Evaluation and Prediction in Esenam Field Northern Depobelt, Niger Delta Nigeria

2013 ◽  
Vol 1 (1) ◽  
pp. 8
Author(s):  
G. E. Omolaiye ◽  
E. A. Ayolabi ◽  
C. S. Ugwuagbo
Keyword(s):  
Pore Pressure ◽  
Niger Delta

scholarly journals Disequilibrium Compaction, Fluid expansion and unloading effects: Analysis from well log and its pore pressure implication in Jay Field, Niger Delta

2020 ◽  
pp. 389-400 ◽  
Author(s):  
Chukwuemeka Patrick Abbey ◽  
Meludu Chukwudi Osita ◽  
Oniku Adetola Sunday ◽  
Mamman Yusuf Dabari
Keyword(s):  
Acoustic Wave ◽  
Pore Pressure ◽  
Niger Delta ◽  
Sedimentary Basins ◽  
Burial Depth ◽  
Well Log ◽  
Major Mechanism ◽  
Porosity And Permeability ◽  
Well Log Analysis ◽  
Pressure Regime

     Disequilibrium compaction, sometimes referred to as under compaction, has been identified as a major mechanism of abnormal pore pressure buildup in sedimentary basins. This is attributed to the interplay between the rate at which sediments are deposited and the rate at which fluids associated with the sediments are expelled with respect to burial depth. The purpose of this research is to analyze the mechanisms associated with abnormal pore pressure regime in the sedimentary formation. The study area “Jay field” is an offshore Niger Delta susceptible to abnormal pore pressure regime in the Agbada –Akata formations of the basin. Well log analysis and cross plots were applied to determine the under compacted zone in the formation since compaction increases with burial depth. It was observed that porosity and permeability of the deeper depth (3700 m to end of Well) are higher than those of the shallow part (3000 – 3700 m). This is against what is expected from normal compacted sediment, demonstrating disequilibrium compaction in deposition. Furthermore, it reveals that sedimentation rate was high, making it unable for the sediments to expunge its fluid as expected. Density and acoustic wave increase with depth in normal compaction trend. However, the reverse that was identified in the mapped interval is attributed to disequilibrium compaction, unloading, clay diagenesis, and fluid expansion. The cross plot divulges sediments at the deeper depth had lower density and acoustic wave value with increased porosity when compared to those at shallow depth. This forms the basis that the sediments from this mapped interval experienced disequilibrium and unloading traceable to clay diagenesis during and after deposition, respectively.

Seismic and petrophysical evidence of abnormal pore pressure in western Niger delta

2014 ◽  
Vol 8 (2) ◽  
pp. 1003-1016
Author(s):  
Lukumon Adeoti ◽  
Olawale B. Olatinsu ◽  
Kehinde S. Ishola ◽  
Matthew Ogofa
Keyword(s):  
Pore Pressure ◽  
Niger Delta

scholarly journals Pore pressure prediction in Niger Delta high pressure, high temperature (HP/HT) domains using well logs and 3D seismic data: a case study of X-field, onshore Niger Delta

2021 ◽  
Vol 11 (10) ◽  
pp. 3747-3758
Author(s):  
Abdulquadri O. Alabere ◽  
Olayemi K. Akangbe
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Pore Pressure ◽  
Niger Delta ◽  
Seismic Velocity ◽  
Sedimentary Basins ◽  
Geothermal Gradient ◽  
Pore Pressure Prediction ◽  
Fracture Gradient ◽  
High Temperature High Pressure

AbstractFew wells targeting high temperature, high pressure intervals in most tertiary sedimentary basins have achieved their objective in terms of technicalities and cost. Since most shallow targets have been drilled, exploration focus is drifting into deeper plays both onshore and in deep offshore areas. To ensure safe and economic drilling campaigns, pore pressure prediction methodologies used in the region needs to be improved. The research aims at generating and testing a modification of Eaton’s equation fit for high temperature, high pressure intervals on a field. The evolution of pore pressure in the field was established from offset well data by making several crossplots, and fracture gradient was computed using Mathew and Kelly’s equation. Eaton’s equation parameters were then calibrated using several wells until a desired field scale result was achieved when compared with information from already drilled intervals i.e., kicks and RFT data. Seismic velocity data resulting from high density, high resolution velocity analysis done to target deep overpressured intervals were then used to predict 1D pore pressure models at six selected prospect locations. Analyses reveal depths shallower than 3800 m TVD/MSL with geothermal gradient 3.0 °C/100 m and pressure gradient less than 1.50sg EMW are affected mainly by undercompaction; depths greater than 3800 m TVD/MSL with geothermal gradient of 4.1 °C/10 m and pressure gradients reaching 1.82–2.12sg EMW are affected by unloading with a narrow drilling margin for the deep highly pressured prospect intervals. Eaton’s n-exponent was modified to 6, and it proved accurate in predicting high overpressure in the first prospect wells drilled.

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