SOURCE ROCK EVALUATION OF SEMBAR FORMATION, MIDDLE INDUS BASIN, PAKISTAN

Abstract

Sembar Formation’s shale samples were collected from the single well located in Eastern Sulaiman Fold Belt, Middle Indus Basin, Pakistan. This study utilized geochemical techniques such as a TOC and Rock-Eval VI instruments. The purpose of this study was to determine the quantity, quality, and maturity of organic matter in the Sembar Formation, as well as its potential for petroleum generation. According to organic matter quantity studies, the Sembar Formation has good source rock potential, as indicated by TOC values ranging from 1.01 to 1.91 wt.%. The presence of kerogen type-IV was indicated by modified van Krevelen diagrams and very low HI values (4- 5 mg/g) in organic matter quality studies. Organic matter maturity studies suggested that the source rock was thermally mature, with Tmax values ranging from 449 to 455oC, indicating peak to late maturity stage. Additionally, HI vs. TOC and S2/S3 vs. TOC plots indicated no petroleum-generation potential at the depths studied. The occurrence of kerogen type-IV (inert) may be due to the high maturity of organic matter, which results in a decrease in HI values, indicating that these samples might have generated hydrocarbons in the past but lack them at the current stage.