Reservoir characterization of the middle Miocene Kareem sandstones, Southern Gulf of Suez Basin, Egypt

Abstract

In this study, we have assessed the petrographical and petrophysical characteristics of the progradational, syn-rift Middle Miocene Rahmi sandstone gas reservoir (Lower Kareem Formation) from the East Matr and Amal hydrocarbon fields, southern Gulf of Suez by integrating sidewall cores and wireline logs. We interpreted a reservoir gas gradient of around 0.09 psi/ft from the downhole pressure measurements. Based on well log-based petrophysical analyses, we interpreted that the Rahmi reservoir in the East Matr field has a 0.10–0.18 v/v total porosity, 0.08–0.14 v/v effective porosity, 0.08–0.17 v/v shale volume along with water saturation ranging between 0.09 and 0.32 v/v. The correlated reservoir in the Amal field is observed to have higher porosities (0.17–0.22 v/v total porosity and 0.15–0.19 v/v effective porosity), although it exhibits higher water saturation (0.38–0.54 v/v). The reservoir consists of very fine to coarse grained, poorly to moderately sorted, subangular to subrounded, poorly cemented and moderately compacted sublithic, subarkosic and arkosic arenites with moderate to good intergranular porosity. Abundant lithic fragments and poor textural maturity of the Rahimi sandstones imply a high energy shoreface depositional environment in close proximity to the hinterland. Porosity reduction is attributed to dolomite cementation, kaolinite, formation of pseudomatrix by mechanical compaction of argillaceous lithics, and quartz overgrowth. Long and concavo-convex intergranular contacts indicate that silica needed for quartz cementation was derived by moderate degree of chemical compaction of the quartz grains. Partial to near-complete dissolution of the labile grains (feldspar and lithics) and dolomite attributed to the reservoir quality improvement. Scattered dolomite cements prevented more severe mechanical and chemical compaction.

Evaluation of Recovery of Tight Sandstone Gas Reservoirs Based on a Seepage Steady-State Model

“…porosity, low permeability, and high water saturation [5,6], which makes it difficult to develop them, and there are many influencing factors and complex influencing mechanisms [7,8]. Therefore, the study of recovery evaluation for tight sandstone gas reservoirs is of great guiding significance for the efficient development of gas reservoirs, and it is helpful to understand and evaluate the recovery level of gas reservoirs.…”

“…Recovery is the most important comprehensive index to measure the development effect and level of oil and gas fields, and it is also one of the key issues in the dynamic analysis of oil and gas fields [1][2][3][4]. Tight sandstone gas reservoirs are characterized by low porosity, low permeability, and high water saturation [5,6], which makes it difficult to develop them, and there are many influencing factors and complex influencing mechanisms [7,8]. Therefore, the study of recovery evaluation for tight sandstone gas reservoirs 2 of 23 is of great guiding significance for the efficient development of gas reservoirs, and it is helpful to understand and evaluate the recovery level of gas reservoirs.…”

Hydrocarbon Reservoir Characterization in the Challenging Structural Setting of Southern Gulf of Suez: Synergistic Approach of Well Log Analyses and 2D Seismic Data Interpretation

“…Subsequent exploration wells (e.g., well GH 376-1) confirmed the subsurface stratigraphic and structural settings as well as hydrocarbon accumulations, marking both the Kareem and Rudeis formations as effective pay zones [32]. Since hydrocarbon exploration and production began in the southern Gulf of Suez, including the Ras Ghara oil field, local Miocene formations have represented the major hydrocarbon-producing reservoirs [2,3,5,7,[39][40][41][42][43][44]. However, geoscientific studies of the Miocene formations are insufficient to understand the subsurface setting, and lithologic and petrophysical characteristics, and published works leave ample room for further exploration.…”