Investigation of the hydrocarbon generative potential of Eocene, Cretaceous, and Late Triassic age sequences in the Punjab Platform Basin, Pakistan, using geochemical and petrophysical techniques

• Main Author: Shah, Syed Bilawal Ali
• Format: Article
• Published: Springer 2023
• Subjects: GE Environmental Sciences
• Online Access: http://eprints.um.edu.my/38736/

An investigation of the hydrocarbon source and reservoir rock potential of Eocene, Cretaceous, and Late Triassic age sequences in the Punjab Platform Basin, Pakistan, was conducted using geochemical and petrophysical techniques. The petrophysical properties of reservoir rock in the Sakesar Formation were evaluated using a set of wireline logs and interpreted carefully to estimate water saturation, porosity, and hydrocarbon saturation. The source rock potential of two formations, the Lumshiwal (Cretaceous) and Kingriali (Late Triassic) formations, was evaluated using geochemical techniques on twenty nine 29 fresh well cutting samples. The Lumshiwal Formation samples showed poor to fair TOC contents, ranging from 0.28 to 1.6wt%; however, the Kingriali Formation had poor to good TOC contents ranging from 0.27 to 0.88wt%. The S2 values of both formations' samples, ranging from 0.01 to 1.63 mg HC/g rock, showed poor generative potential. Additionally, the HI values were generally low, ranging between 5 and 263 mg HC/g TOC, and the Tmax values ranged from 431 to 443 degrees C. Both formation samples lie in the immature to early maturity window zone, as indicated by both S2 vs TOC and HI vs Tmax plots. The samples have primarily Type III kerogen with poor generative potential, as indicated by the S2 vs TOC plot, HI vs Tmax plot, S1 vs TOC plot, and PI. The results show that some light gas may have been produced. Petrophysical analysis of the Sakesar Formation showed higher levels of porosity at depths between similar to 4163 and 4197ft; the lithology was identified as limestone, the average porosity was similar to 11.2%, the average water saturation was 32.58%, and average hydrocarbon saturation was 67.42%, thus indicating that the Sakesar Formation has average to good reservoir potential.