Direct evidence of high pore pressure at the toe of the Nankai accretionary prism

Pwavodi, Joshua; Doan, Mai‐Linh

doi:10.1002/essoar.10510789.1

Cited by 1 publication

(3 citation statements)

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“…Based on the variable onset of pore pressure in the Offshore Niger Delta, the recommended mud pressure should be slightly higher than the pore pressure in order to maintain pressure balance between wellbore mud pressure and formation pressure. As discussed by Pwavodi and Doan (2022), we recommend that downhole annular mud pressure sensors should be attached to the bottom hole assembly to provide realtime mud pressure while drilling.…”

Section: Implication On Reservoir Quality and Drilling Activitiesmentioning

confidence: 99%

“…Zhang & Yin, 2017;Baouche et al, 2020;. Therefore successful drilling campaigns are achieved when the pore pressure regime within an oil basin or other geological settings is properly understood (Pwavodi & Doan, 2022). Several methods have been used to understand and characterised the pore pressure regime in the Niger Delta, yet several drilling incidences (Opara et al, 2009;Nwaufa W.A., 2006;Asedegbega et al, 2018) and overpressures have been identified within this hydrocarbon basin (Dosunmu, 2002;Opara et al, 2013;Ugwu & Nwankwo, 2014;Ichara & Avbovbo, 1985;Opara et al, 2009;Nwaufa W.A., 2006;Alabere & Akangbe, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, underestimating the actual consolidation history of sediments. Pwavodi and Doan (2022) showed that the normal compaction trend is affected by structural control and fluid flow within a geological setting.…”

Section: Introductionmentioning

confidence: 99%

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Pore Pressure Prediction in Offshore Niger Delta: Implications on Drilling and Reservoir Quality

Pwavodi

Kelechi

Angalabiri

et al. 2022

Preprint

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Despite exploration and production success in Niger Delta, several failed wells have been encountered due to overpressures.Hence, it is very essential to understand the spatial distribution of pore pressure and the generating mechanism in order to mitigate the pitfalls that might arise during drilling. This research provides estimates of pore pressure along three offshore wells using the Eaton's transit time method. An accurate normal compaction trend was estimated using the Eaton's exponent (m=3). Our results show that there are three pressure magnitude regimes: normal pressure zone (hydrostatic pressure), Transition pressure zone (slightly above hydrostatic pressure), and over pressured zone (significantly above hydrostatic pressure). The top of the geopressured zone (2873 mbRT or 9425.853 ft) averagely marks the onset of overpressurization with the excess pore pressure ratios above hydrostatic pressure varying averagely along the three wells between P * = 1.06 -24.75 MPa and the lithostatic load range is λ = 0.46 -0.97 and λ * = 0.2 -0.9. The parametric study shows that the value of Eaton's exponent (m = 3-6) need to be applied with caution based on the dominant pore pressure generating mechanism in the Niger Delta. The generating mechanisms responsible for high pore pressure in the Offshore Niger Delta are disequilibrium compaction, unloading (fluid expansion) and shale diagenesis.

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Section: Implication On Reservoir Quality and Drilling Activitiesmentioning

confidence: 99%