Depositional Environment of Shallow-Marine Sandstones from Outcrop Gamma-Ray Logs, Belait Formation, Meragang Beach, Brunei Darussalam

Siddiqui, Numair Ahmed; El‐Ghali, Mohamed A.K.; Rahman, Abdul Hadi Bin Abd; Mijinyawa, Abubakar; Ben-Awuah, Joel

doi:10.19026/rjees.5.5705

Cited by 13 publications

(6 citation statements)

References 14 publications

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“…SGR have been used effectively by various researchers to characterize the mineralogy and sedimentology of outcrops (Svendsen and Hartley 2001). Log trends/patterns and electrofacies developed from the gamma ray log responses, which will allow the characterization of the depositional environment in different facies (Siddiqui et al 2013) of the various outcrops and provide information about minerals and clay types. Secondly, from the spectral gamma ray logs, gamma radiation was counted within specific energy ranges.…”

Section: Introductionmentioning

confidence: 99%

Mineralogical investigation of fine clastic rocks from Central Sarawak, Malaysia

Ibrahim

Salim

Sum

2019

J Petrol Explor Prod Technol

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The reduction in the conventional resources and insistent request for hydrocarbons and energy lead us to look forward for the increasing interest in unconventional resources by exploring new technologies for the national economy and local utilization in Malaysia. Upper Mesozoic-Cenozoic is considered the age of Central Sarawak Formations. This paper attempts to evaluate the clay mineralogy, depositional environment, gamma ray evaluation and the relationship between total organic carbon and uranium concentration of the Nyalau, Tatau, Begrih, Liang and Belaga Formation which eventually comprise black shales and mudstones using spectral gamma ray (SGR), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), XRD clay separation and total organic content (TOC%). The results from SGR indicate that the formations composed mainly of kaolinite, smectite and chlorite. These results are confirmed by XRD, XRD clay separation and FESEM with the presence of illite as a dominant clay mineral component. Based on Th/U ratios which vary between 0.42 and 3.95, the formations are expected to be deposited in the reduced marine environment. Results from calculated API (90.76-233.32 API) reveal the ability of the clay minerals to absorb uranium and thorium through cation exchange capacity. The relationship between TOC% and U cross plots also show a significant positive correlation. The presence of high U concentrations in the formations is possible because of their relatively higher clay contents and the existence of organic matter.

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Section: Introductionmentioning

confidence: 99%

Mineralogical investigation of fine clastic rocks from Central Sarawak, Malaysia

Ibrahim

Salim

Sum

2019

J Petrol Explor Prod Technol

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“…In the studied area, the blocky sandstones facies reflects regressive or shallowing upward sequence. Based on the GR trend, the depositional environment of the Sidri blocky sandstone lithofacies can be interpreted as a marine dominant environment, most likely tidal sands channels (Emery and Myers 1996;Siddiqui et al 2013;El-Tehiwy et al 2019) (Table 4, Fig. 9).…”

Section: Deduction Of Depositional Environment Of the Sidri Member And Sandstone Reservoirsmentioning

confidence: 99%

Modeling the Depositional Environment of the Sandstone Reservoir in the Middle Miocene Sidri Member, Badri Field, Gulf of Suez Basin, Egypt: Integration of Gamma-Ray Log Patterns and Petrographic Characteristics of Lithology

Radwan

2020

Nat Resour Res

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Understanding the depositional setting of siliciclastics reservoir is fundamental process to exploration and development of hydrocarbon reservoirs and to the multi-phase cycle of the oil and gas industry. Typically, core samples from existing or potential reservoirs can be used for interpretation of depositional environment. However, the lack of core samples in certain reservoirs represents a challenge for reservoir development plans and further exploration. To overcome the absence of core samples in the middle Miocene Sidri Member in the Badri field, Gulf of Suez, this study aimed to reconstruct its depositional settings by coupling well logging patterns and petrographic characterization of ditch cuttings. Consequently, 30 thin section samples representing the reservoir section of four wells were described in detail and standard petrographic characteristics were determined. Then, gamma-ray (GR) log patterns of the studied reservoir wells were used for interpretation of depositional environment. Petrographic analysis indicates that the sandstone reservoir is fine- to medium-grained arkose with dominant siliceous cement and composed mainly of quartz, feldspars, and lithic fragments. Pores reflecting primary and secondary porosity as well as inter-granular pores are dominant. The facies analysis indicates that the studied member has a heterogeneous nature and rapid facies change; its main lithofacies are blocky sandstones, intercalated sandstones and shales, and shales. Three electrofacies were interpreted in the studied section: (1) electrofacies-A (blocky sandstones), which is characterized by a cylindrical-shaped (right boxcar) GR trend; (2) electrofacies-B (intercalated sandstones and shales), which is characterized by an irregular log trend with serrated shape; and (3) electrofacies-C (shales), which is characterized by irregular GR trend and has no character. The interpreted results indicate a tidal channel depositional setting for electrofacies-A, mixed tidal flat depositional setting for electrofacies-B, and low relief offshore mudstone depositional setting for electrofacies-C. Finally, the results illustrate how the coupling of GR patterns with the analysis of petrographic characteristics can be used to understand the depositional setting of a hydrocarbon reservoir that lacks core samples. This work could be useful for assessment of reservoir distribution and quality, for reduction of uncertainty during field development, as well as for providing useful insight to similar hydrocarbon reservoirs elsewhere.

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“…The assessment of depositional environments is based on available GR wireline log data; however, core or sedimentological data is necessary for the accurate interpretation of a depositional environment because the defined gamma log trends are not indicative of a specific environment (Cant 1992;Siddiqui et al 2013). The sandstone package in Chanda-1 represents a boxcar trend (Fig.…”

Section: Log Interpretation Of Clastic Reservoirsmentioning

confidence: 99%

Petrophysical evaluation and fluid substitution modeling for reservoir depiction of Jurassic Datta Formation in the Chanda oil field, Khyber Pakhtunkhwa, northwest Pakistan

Khan

Rehman

2018

J Petrol Explor Prod Technol

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Petrophysics coupled with rock physics studies are significant in the evaluation of well and field potential, and to construct subsurface models based on rock properties. This case study combines petrophysics and fluid substitution modeling for reservoir characterization of the producing Datta Formation in the Chanda oil field of Kohat Basin. The Datta Formation interval of two wells, Chanda-1, and Chanda Deep-1, is analyzed to calculate petrophysical parameters including gross thickness, net thickness, net to gross ratio (NGR), porosity (PHA), permeability (K), and water saturation (S W ). The Datta Formation represents fair to good porosity in the range of 7-13%. Water saturation shows low values lying in the range of 31-36%. The formation is interpreted from gamma ray (GR) log trends, where sand packages dominantly represent a left box-car and irregular trend. Cross-plots, such as density porosity (RHOB-NPHI), gamma ray-density (GR-RHOB), gamma ray-porosity (GR-NPHI), and thorium-potassium (Th-K), were used for lithological identification in the studied wells, and indicated arkosic and micaceous sandstone as the dominant lithology with shale. Evaluation of petrophysical parameters shows that the Datta sands have high hydrocarbon saturation in the area. The fluid substitution modeling was applied to clastics of the Datta Formation for field development. One hydrocarbon-bearing zone (zone 1) was identified in Chanda-1, while four hydrocarbon-bearing zones (zones 1, 2, 3, and 4) were identified in Chanda Deep-1. Fluid substitution results at the Datta level showed that the P-wave velocity and density varied when the hydrocarbon phase was substituted completely with water. With the substitution of brine with oil, there was a change in compressional wave velocity (V p ) and a decrease in density (RHOB), while the shear wave velocity (V s ) was stable and unaffected by the change of fluid density and saturation. The results of this research could be used to predict saturation types of reservoir using seismic data and to identify pay-zones, and map reservoir saturation to drill for oil and gas.

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Depositional Environment of Shallow-Marine Sandstones from Outcrop Gamma-Ray Logs, Belait Formation, Meragang Beach, Brunei Darussalam

Cited by 13 publications

References 14 publications

Mineralogical investigation of fine clastic rocks from Central Sarawak, Malaysia

Mineralogical investigation of fine clastic rocks from Central Sarawak, Malaysia

Modeling the Depositional Environment of the Sandstone Reservoir in the Middle Miocene Sidri Member, Badri Field, Gulf of Suez Basin, Egypt: Integration of Gamma-Ray Log Patterns and Petrographic Characteristics of Lithology

Petrophysical evaluation and fluid substitution modeling for reservoir depiction of Jurassic Datta Formation in the Chanda oil field, Khyber Pakhtunkhwa, northwest Pakistan

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