Origin of overpressure and pore-pressure prediction in the Baram province, Brunei

Tingay, Mark; Hillis, Richard R.; Swarbrick, Richard E.; Morley, C.K.; Damit, Abdul Razak

doi:10.1306/08080808016

Cited by 254 publications

(117 citation statements)

References 62 publications

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“…The NE-SW maximum horizontal stress in the outer shelf most likely reflects this active deltaic gravity spreading tectonics and is decoupled from the far-field NW-SE maximum horizontal stress by overpressured basal shales (Tingay et al, 2005b;Tingay et al, 2007;Tingay et al, 2009b). Furthermore, gravity spreading tectonics is typically linked to margin-perpendicular compression in the delta toe, and has been suggested to further contribute towards the NW-SE maximum horizontal stress orientation observed in the Baram Deepwater stress province ).…”

Section: Accepted M Manuscriptmentioning

confidence: 97%

Present-day stress field of Southeast Asia

et al. 2010

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It is now well established that ridge push forces provide a major control on the plate-scale stress field in most of the Earth's tectonic plates. However, the Sunda plate that comprises much of Southeast Asia is one of only two plates not bounded by a major spreading centre and thus provides an opportunity to evaluate other forces that control the intraplate stress field. The Cenozoic tectonic evolution of the Sunda plate is usually considered to be controlled by escape tectonics associated with India-Eurasia collision. However, the Sunda plate is bounded by a poorly understood and complex range of convergent and strike-slip zones and little is known about the effect of these other plate boundaries on the intraplate stress field in the region. We compile the first extensive stress dataset for Southeast Asia, A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTthe radiating stress patterns arising from the eastern Himalayan syntaxis. However, the present-day maximum horizontal stress is primarily oriented NW-SE in Borneo, a direction that may reflect plate-boundary forces or topographic stresses exerted by the central Borneo highlands. Furthermore, the South and Central Sumatra Basins exhibit a NE-SW maximum horizontal stress direction that is perpendicular to the Indo-Australian subduction front. Hence, the plate-scale stress field in Southeast Asia appears to be controlled by a combination of Himalayan orogeny-related deformation, forces related to subduction (primarily trench suction and collision) and intraplate sources of stress such as topography and basin geometry.

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Section: Accepted M Manuscriptmentioning

confidence: 97%

Present-day stress field of Southeast Asia

et al. 2010

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“…Another important potential application of the modeling is for the detection and prediction of overpressure in shales due to their extremely low permeability that makes the pore pressure less able to equilibrate to hydrostatic pressure. Accurate overpressure detection and prediction play an important role in understanding the depositional and evolutional history of a sedimentary basin, hydrocarbon migration, and trapping in the reservoir, as well as in reducing the risks of drilling hazards during hydrocarbon exploitation [42][43][44][45]. Overpressure results in lower than expected electrical resistivity (reciprocal of conductivity) through the enlarged porosity associated with the high pore pressure, and conventional overpressure prediction models based on electrical properties evaluate the difference between the measured electrical properties and those of the normally compacted shales at the same depth to estimate the abnormal pore pressure [46,47].…”

Section: Discussionmentioning

confidence: 99%

Theoretical Modeling of Dielectric Properties of Artificial Shales

et al. 2018

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Accurately modeling the anisotropic dielectric properties of shales is important for the interpretation of dielectric data acquired from shales as source rocks and unconventional reservoirs. We have developed a multiphase incremental model for the frequency dependent anisotropic dielectric properties of sedimentary rocks and presented an approach based on the developed model to simulate the measured anisotropic dielectric behaviors of artificial shales. The new model was built based on the theoretical basis of differential effective medium models for any number of mineral grain components aligned in any direction and was shown to be independent of the mixing order. The model incorporates the measured orientation distribution function of the clay particles to determine the shale dielectric anisotropy, and the frequency dependent dielectric behaviors of the wet clay minerals are obtained by inverting the dielectric properties of the artificial sample composed of clay and the same brine as in other artificial shales. The modeling technique combined important polarization mechanisms in the intermediate frequency range and was shown to give satisfactory fit to the measured frequency dependent anisotropic relative permittivity and conductivity of the artificial shales with varying silt contents by using a reasonable aspect ratio and constant dielectric parameters for the silt grains.

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“…For example, Tingay et al (2009) used exponent of 6.5 in vertically transferred overpressures in Brunei. In central swamp (Middle Miocene) Onshore Niger Delta, Nwozor et al (2012) used exponent of 6.5, while Chukwuma et al (2013) raised the exponent to 5 or 6 using data set from Oligocene to Lower Miocene depobelt.…”

Section: Discussionmentioning

confidence: 99%

A method to reduce the uncertainty of pressure prediction in HPHT prospects: a case study of Onshore Niger Delta depobelt, Nigeria

Asedegbega

Oladunjoye

Nwozor

2017

J Petrol Explor Prod Technol

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The search for hydrocarbons has gone beyond shallow hydrostatic reservoirs, necessitating deep drilling beyond known depths in the mature Onshore Niger Delta fields. Often times, the challenge has been the ambiguity in pore pressure prediction beyond the shallow depths where disequilibrium compaction is no longer the active overpressure contributor. This leads to underbalanced drilling with the implication that well drilling is terminated at the occurrence of the first kick, before reaching the target depth. Thus, in this study, the dominant overpressure mechanism is determined by the analyses of velocity, density versus depth cross-plots. The Eaton empirical approach, equivalent depth method (EDM), a deterministic approach, and Bowers velocity-vertical effective stress (Vp-VES) relationship were applied to Vp-sonic log to compare prediction profiles. Pressure data were used to infer geologically consistent Eaton's exponents and Vp-VES curve for loading and unloading scenarios. The results show that deeper than the approximately 11,000 ft where unloading began, EDM and Eaton's exponent of 3.0 would fail. However, higher exponents can be adopted for the area at onset of unloading temperatures ranging from 98 to 100°C. The estimated shale pressure profile from the EDM, Eaton's exponents and Vp-VES models accurately fit the measured pressure data. In that way, the uncertainty in the prediction can be quantified. Hence, predrill estimates of shale pressures can be generated beyond known depths since the model can be used to transform seismic velocity to formation pressure, thereby ensuring better anticipation of potential risks and cost-effective drilling.

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Origin of overpressure and pore-pressure prediction in the Baram province, Brunei

Cited by 254 publications

References 62 publications

Present-day stress field of Southeast Asia

Present-day stress field of Southeast Asia

Theoretical Modeling of Dielectric Properties of Artificial Shales

A method to reduce the uncertainty of pressure prediction in HPHT prospects: a case study of Onshore Niger Delta depobelt, Nigeria

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