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
| Autor: | Abdulquadri O. Alabere, Olayemi K. Akangbe |
|---|---|
| Přispěvatelé: | IFP Energies nouvelles (IFPEN), IFP School, University of Ibadan |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Well logging
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences 02 engineering and technology 010502 geochemistry & geophysics 01 natural sciences Eaton equation Pore water pressure 020401 chemical engineering Drilling window 0204 chemical engineering Petrology Geothermal gradient [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology Pressure gradient 0105 earth and related environmental sciences Fracture gradient Drilling Geotechnical Engineering and Engineering Geology Pore pressure Overpressure General Energy Offshore geotechnical engineering Overburden gradient [SDE]Environmental Sciences Submarine pipeline Geology |
| Zdroj: | Journal of Petroleum Exploration and Production Technology Journal of Petroleum Exploration and Production Technology, Springer, 2021, 11 (10), pp.3747-3758. ⟨10.1007/s13202-021-01264-5⟩ |
| DOI: | 10.1007/s13202-021-01264-5⟩ |
| Popis: | Few 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. |
| Databáze: | OpenAIRE |
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