3D modeling of abnormal pore pressure in shallow offshore Niger delta: An application of seismic inversion
作者机构：Adetola Sunday Oniku a a Department of PhysicsModibbo Adama University of Technology YolaNigeria Department of Petroleum Chemistry&PhysicsAmerican University of NigeriaNigeria
出 版 物：《Petroleum Research》 (石油研究（英文）)
年 卷 期：2021年第6卷第2期
页 面：158-171页
核心收录：
学科分类：070801[理学-固体地球物理学] 0709[理学-地质学] 0819[工学-矿业工程] 0808[工学-电气工程] 07[理学] 0708[理学-地球物理学] 0807[工学-动力工程及工程热物理] 0818[工学-地质资源与地质工程] 0816[工学-测绘科学与技术]
主 题：Acoustic impedance Pressure Seismic inversion Formation Overpressure
摘 要：Pore pressure is the pressure associated with fluids in the pore spaces of sedimentary rocks. Thispressure varies from hydrostatic to severe overpressure. It is classified as abnormal pressure when itdeviates from hydrostatic pressure. Incorrect prediction or the absence of pore pressure evaluation canlead to severe damage of the drilling platform, loss of personnel, waste of resources and environmentalpollution. This study was carried out in an offshore field in Niger Delta with an objective of predicting theabnormal pressure regime from the seismic volume using seismic inversion technique. First, weemployed the Eaton’s and Bower’s model of predicting pore pressure from Well log. The predicted porepressure from the well was used to calibrate the P-impedance that was used in the inversion process. Apressure-based model for the seismic inversion process was developed. This was constrained by therelationship between the P-impedance and pore pressure in the study area. The predicted pore pressurefrom the Well logs aligned with the measured pore pressure in the formation. At about 3600 m to end ofthe Well, depicts a pressure regime that is a deviation from the hydrostatic pressure trend. The abnormalpressure regime is marked by the region where a change is observed in the normal compaction trendline. The cross plot of acoustic impedance against pore pressure reveals a linear relationship;with adirect relationship indicating a normal pressure interval and the indirect relationship at the abnormalpressure regime. The inverted 3D pressure result from the seismic volume validates the normalcompaction trend line and also the pressure values estimated from the Well logs. The abnormal pressureregime in the study area is predicted to be found towards the end of Agbada Formation and through theAkata Formation due to the un-compacted shales.
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