Pakistan Journal of Hydrocarbon Research

Quantitative assessment of the petroleum generation potential of early Cretaceous source rock in the northern part of Mari-Kandhkot High, north Sindh and southern Punjab, Pakistan

2024-04-15T14:48:51+05:00

ABSTRACT

A source rock study and thorough petroleum system modelling have been performed as part of an exploration evaluation programme in one of the blocks in the northern part of the Mari-Kandhkot High (northern Sindh and southern Punjab) to determine the potential of Early Cretaceous sources and evaluate petroleum generated volumes in cubic feet gas per sq. km. The primary source rock in this region are the shales of the Early Cretaceous Sembar Formation (BerriasianValanginian, 145-132 Ma), while the Lower Goru Formation (Albian-Aptian, 125-113 Ma) shales can be considered the second most efficient source due to their high organic content.

Our study database involved 10 wells in the study area, where detailed source rock analyses were carried out on 106 samples in the Maluk -1, POGC Sabzal X-1, and Sara -1 wells, and the Total Organic Carbon (TOC) on seven additional wells was calculated through the Δlog R method. Study has determined, the mixed Type-II and Type-III kerogen, the TOC in the Sembar Formation ranges from 0.06% to 2.15%, with an average of 1.0%, and vitrinite reflectance (Ro) ranges from 0.7% to 1.95%. As a secondary source rock in the region, the Lower Goru Formation primarily contains Type-III organic matter, with TOC averaging 0.9% and Ro ranging from 0.80% to 1.45%. Depending on the quantity and quality of organic matter, oil generation depth ranges from 2200 to 2700 metres at temperatures between 100⁰ and 125⁰ C, whereas the minimum depth at which gas generation begins is 3000 metres at a temperature of approximately 125⁰C.

According to the results of the petroleum system modelling, the first hydrocarbon generation reached maturity at 53 Ma and peaked at 25 Ma, with a potential to generate 60–80 bcf/sq km of gas.

In our paper, we discussed the results of the organic geochemical analysis of the Lower Goru and Sembar formations from the Early Cretaceous, and we presented maps of the thickness of the organically rich layers, the distribution of thermally mature areas, and the intensity of hydrocarbon expulsion. These maps may offer future operators interested in exploring the area substantial data by supporting them understand the geological history of a source rock.

The Sedimentological and provenance analysis of the Cambrian succession in the Saiduwali Section, Trans Indus ranges, Pakistan

2024-04-15T14:49:55+05:00

The Cambrian Khewra, Kussak and Jutana Formation from the Saiduwali section, Chashma, Dera Ismael Khan has been studied in detail in order to investigate the sedimentology and provenance. This paper describes the litho-facies changes, depositional environment, and provenance analysis of the Cambrian Khewra, Kussak and Jutana Formation, Saiduwali section, Trans Indus Ranges, Pakistan. The sedimentological investigation shows that the depositional environment for the Khewra sandstone was Marginal Marine, for the Kussak Formation restricted marine, and for the Jutana formation supratidal to the intertidal depositional environment are suggested. The model classification of the Khewra Sandstone shows that, the Quartz percentage ranges from 85 to 93%, Feldspar 1 to 5%, and the percentage of lithic ranges from 0.5 to 3%. Based on these classifications the Khewra Sandstone falls in the Quartz Arenite Category. The model classification of the Kussak Formation shows that, the Quartz percentage ranges from 80 to 90%, Feldspar 2 to 5%, and the percentage of lithic ranges from 0.5 to 5%. Which shows that the Kussak Formation fall in the Quartz Arenite Category. The source area for Khewra Sandstone, and Kussak Formation was cratonic interior. And the source area for the sandstone of the Khewra and Kussak Formation is from cratonic interior of Indian shield. In the Jutana Formation, the clastic sedimentation has come from the foreign basin (mostly igneous, and sedimentary rocks). These sediments may be derived from the Cambrian Sea, which was near to the source.

An Appraisal of Microfacies and Depositional Environment of the Early Eocene Habib Rahi Limestone, Sulaiman Range, Pakistan

2024-04-15T14:51:20+05:00

Early to middle Eocene Habib Rahi Limestone was investigated in Sulaiman Range at four outcrops in Afiband and Mughal kot areas, where its measured thickness range from 25 to 40 m. The formation comprehensively studied based on sedimentological parameters that lead to its paleoenvironment. According to field observations, the lower part of the formation mainly comprises fossiliferous limestone, the middle part with platy limestone bedded with chert, and upper part associated with marl and shale. Moreover, formation makes conformable lower and upper contacts with Baska Shale and Domanda Shale, respectively. Under a microscope, five microfacies of the Habib Rahi Limestone were examined, which are abundantly associated with larger benthic foraminifera of Assilina spinosa, Assilina subspinosa, Nummulites mammillatus, and Nummulites atacicus. Therefore, litho- as well as microfacies of the Habib Rahi Limestone depicts the shallow shelf marine depositional environment of the formation.

Sedimentology and Reservoir characterization of Pirkoh Formation in well-1 Guddu E.L Sindh, Pakistan

2024-04-15T14:54:30+05:00

Sedimentology and reservoir characteristics of Pirkoh Formation of Middle Eocene have been carried out in well -1 of Guddu E.L. by studying the two cores and well cuttings samples. Pirkoh Formation was the primary objective reservoir in this well. It consist of entirely limestone penetrated in well with thickness of 102m. Two cores were cut from this formation (590-599m, 625-634m) and also incorporated in this study. The sedimentological investigation of cores and well cuttings of Pirkoh Formation revealed that it is mainly Wackestone-Packstone facie with larger benthics Forams (LBF) assemblages, consist of Discocyclina and Nummulite sp. in abundance. The Discocyclinoids Wackestone-Packestone facie along with micrite groundmass suggests that it was deposited over middle ramp settings. The presence of Discocyclina and Nummulites along with bioclasts of same microfossil suggests deposition under relatively high energy conditions over the ramp. The paleoecological attributes of Discocyclina and Nummulites also confer same environments. Micrite is the major ground mass matrix in the petrographic analysis which suggests relatively deep environment for its deposition most probably in Middle ramp settings.

Application of Remote Sensing for Geological Mapping Using Landsat etm+ Satellite image For Part of Western Hazara Ranges Across Siran River, North Pakistan

2024-04-15T15:04:49+05:00

The Aluli area, Western Hazara Ranges, comprises of Precambrian Tanawal Formation, Early Cambrian Abbottabad Formation and Recent alluvium. These formations consist of variety of lithological units including phyllite, quartzites, quartz mica schist, sandstones, siltstones, conglomerates, dolomites, limestones and alluvium. The geological mapping of these constituent lithologies is carried out using Landsat Enhanced Thematic Mapper Plus (ETM+) image enhancement techniques, which include band composition and band rationing. The False Color Composite (FCC) 5-3-1 is found significant to recognize the folds and faults on LandsatETM+ satellite image. The FCCs 7-5-4, 4-5-7 and 3/1-5/7-5/4 are best in differentiating the geological units. The field mapping along selected traverses gave a better control to identify the specific lithological units on the FCC images. This exercise gives a better geological control to extend the geological units to nearby areas. This study provides a simple supplementary and effective application of Landsat ETM+ satellite image to be used in the future as an aid to geological mapping.