Overpressures Induced by Compaction Disequilibrium Within Structural Compartments of Murree Formation, Eastern Potwar, Pakistan

Amjad, Muhammad Raiees; Zafar, Muhammad Usman; Ahmad, Tausif; Hussain, Muyyassar; Shakir, Urooj

doi:10.3389/feart.2022.903405

Cited by 4 publications

(10 citation statements)

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“…54 If the sedimentation rate is slow, rocks are compacted in the normal compaction trend, with maintaining the equilibrium between the increasing overburden and fluid expulsion. 53 Sakesar is a proven reservoir in the Potwar Basin, 44 but the formation is mostly water-saturated and has poor reservoir capability in terms of fluid accommodation. Porosity is one of the most important factors that determine whether or not a petroleum accumulation may be economically viable.…”

Section: Discussionmentioning

confidence: 99%

“…This suggests that the overburden pressure increased, resulting in porosity reduction and fluid expulsion, as the deposition continues . If the sedimentation rate is slow, rocks are compacted in the normal compaction trend, with maintaining the equilibrium between the increasing overburden and fluid expulsion …”

Section: Discussionmentioning

confidence: 99%

“…Both events are marked by the Indian and Eurasian post-collisional depositional changes during the Miocene times. Uplifting of the Indian plate was followed by the high sedimentation influx of the molasse sediment, which resulted in an increase of lithostatic pressure . A high subsidence rate in response of the increased sediment influx could possibly cause the overpressuring in the Eocene carbonates.…”

Section: Discussionmentioning

confidence: 99%

“…A line group is manually drawn on the GR log curve, which is taken to be around 70 API to separate the clay points from the non-clay ones. Overburden pressure or the lithostatic pressure is the major reason for the fluid expulsion form the pores. , Overburden pressure (OB) can be calculated using the density data. To predict the pore pressures, OB is required, which is a crucial step in this process since the pore pressure and fracture pressure are often calculated directly from the OB.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…Geohistory analysis is used for determining the burial history (subsidence and uplift) and its related processes controlling the compaction of sediments . Burial history represents all the changes with respect to the compaction and heat flow.…”

Section: Materials and Methodsmentioning

confidence: 99%

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Carbonate Reservoir Quality Variations in Basins with a Variable Sediment Influx: A Case Study from the Balkassar Oil Field, Potwar, Pakistan

Amjad

Ehsan

Hussain³

et al. 2023

ACS Omega

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The carbonate reservoir quality is strongly reliant on the compaction process during sediment burial and other processes such as cementation and dissolution. Porosity and pore pressure are the two main factors directly affected by mechanical and chemical compactions. Porosity reduction in these carbonates is critically dependent on the overburden stress and subsidence rate. A variable sediment influx in younger basins may lead to changes in the reservoir quality in response to increasing lithostatic pressure. Deposition of molasse sediments as a result of the Himalayan orogeny caused variations in the sedimentation influx in the Potwar Basin of Pakistan throughout the Neogene times. The basic idea of this study is to analyze the carbonate reservoir quality variations induced by the compaction and variable sediment influx. The Sakesar Limestone of the Eocene age, one of the proven carbonate reservoirs in the Potwar Basin, shows significant changes in the reservoir quality, specifically in terms of porosity and pressure. A 3D seismic cube (10 km2) and three wells of the Balkassar field are used for this analysis. To determine the vertical and lateral changes of porosity in the Balkassar area, porosity is computed from both the log and seismic data. The results of both the data sets indicate 2–4% porosities in the Sakesar Limestone. The porosity reduction rate with respect to the lithostatic pressure computed with the help of geohistory analysis represents a sharp decrease in porosity values during the Miocene times. Pore pressure predictions in the Balkassar OXY 01 well indicate underpressure conditions in the Sakesar Limestone. The Eocene limestones deposited before the collision of the Indian plate had enough time for fluid expulsion and show underpressure conditions with high porosities.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Materials and Methodsmentioning

confidence: 99%

Section: Materials and Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Carbonate Reservoir Quality Variations in Basins with a Variable Sediment Influx: A Case Study from the Balkassar Oil Field, Potwar, Pakistan

Amjad

Ehsan

Hussain³

et al. 2023

ACS Omega

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An Integrated Approach for the Assessment of Hydrocarbon Potential in Carbonate Reservoirs: Potwar Plateau, Pakistan

Ehsan,

Munir,

Latif

2024

Journal of GeoEnergy

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The Potwar Plateau region of the Upper Indus Basin in Pakistan is known for its complex carbonate reservoirs, which pose significant challenges for hydrocarbon exploration and production. The integrated reservoir simulation study can help mitigate these challenges by better understanding the reservoir behavior and optimizing production strategies. The reservoir characterization of this region has essential importance in Pakistan because tight limestone and fractures (with vugs and leached features) may provide a zone of high porosity, permeability, and reservoir properties with isolated distribution in tight carbonates. The seismic and well log data were integrated to get the reservoir characterization and mark targeted reservoirs (Chorgali and Sakesar Formations) in Balkassar Oil Field. The study utilized 3D seismic interpretation, petrophysics analysis, rock physics analysis, and seismic inversion techniques to evaluate the subsurface properties of the carbonate reservoir. The time grid and depth contour map generation for Chorgali and Sakesar Formations show less time, about 1.2–1.3 s for Chorgali and 1.32–1.488 s for Sakesar which reveal clearly that the central part between the two faults is a shallow portion which is the crest of Balkassar anticline forming the suitable structural trap for hydrocarbon accumulation. Three reservoir zones with certain depths are marked based on petrophysics and rock physics analysis. The cross‐plot between mu–rho versus lambda–rho value indicates a high porosity value at 2,460–2,580 m. From seismic inversion, low impedance values are observed in that reservoir zone (2,400–2,500 m).

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Features of forecasting abnormally high reservoir pressures when drilling wells in areas of south-western Turkmenistan

Deryaev

2023

Innovaciencia

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Introduction: The study is essential because predicting areas with high formation pressures in geophysical research is complex. It requires new technologies to accurately locate them and minimize unforeseen emergencies. The purpose of this study is to analyse and identify the peculiarities of predicting anomalously high formation pressures during well drilling in the territory of south-western Turkmenistan in order to provide more effective and reliable pressure management during drilling and operation. Materials and Methods: Methods such as analysis and prediction were used in this study. Results and Discussion: The paper presents valuable research data highlighting the changes in reservoir pressure gradients in the unique stratigraphic section of reservoirs in the oil and gas fields of the Pribalkan and Gogerendag-Ekerem zones. The analysis of the studies reveals the dynamism with which the properties of reservoir rock change with increasing depth of occurrence. Special attention is paid to the processes associated with the formation of anomalously high formation pressures, which is an important aspect for understanding complex geological processes. Conclusions: The study provides a detailed classification of formation pressures, considering the anomaly coefficient, enhancing our understanding of this phenomenon. Predicting formation pressures for specific horizons relies on analyzing deep well drilling results.

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Overpressures Induced by Compaction Disequilibrium Within Structural Compartments of Murree Formation, Eastern Potwar, Pakistan

Cited by 4 publications

References 54 publications

Carbonate Reservoir Quality Variations in Basins with a Variable Sediment Influx: A Case Study from the Balkassar Oil Field, Potwar, Pakistan

Carbonate Reservoir Quality Variations in Basins with a Variable Sediment Influx: A Case Study from the Balkassar Oil Field, Potwar, Pakistan

An Integrated Approach for the Assessment of Hydrocarbon Potential in Carbonate Reservoirs: Potwar Plateau, Pakistan

Features of forecasting abnormally high reservoir pressures when drilling wells in areas of south-western Turkmenistan

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