Source Rock Analysis in Unconventional Tight Carbonate Reservoirs, Makhul Formation, Minagish Field

Abstract Kuwait Oil Company is investing in exploring unconventional hydrocarbon resources to boost production rates. Challenges like increased water production in fractured limestone formations impact oil productivity. Makhul reservoir, Minagish Field, focuses on the Lower Cretaceous Makhul Formation for improved reservoir development. The study aims to optimize production insights and ROI through advanced analysis techniques like pyrolysis and inorganic geochemistry data integration, offering cost-effective solutions for evaluating hydrocarbon content and maturity in refining production processes. To assess the source rock's potential as an unconventional reservoir, precise quantification of Total Organic Carbon (TOC) content is essential. The Makhul Formation's organic units were analyzed for TOC using various techniques like HAWK pyrolysis (organic) and advanced gas, XRF, and XRD geochemical analysis. A new Rock-Eval technology, the "Petroleum Assessment Method," was applied to cored well "A" to identify potential organic layers with extractable hydrocarbons. The study focused on source rock evaluation using HAWK and well log data, employing organic and inorganic geochemistry techniques. HAWK pyrolysis method provides detailed analysis, enabling better quantification of petroleum fractions and maturity assessment. The analysis and interpretation of the Makhul Formation through deviated wells, core acquisition, and production tests have provided a more detailed understanding, challenging the initial perception of the reservoir as too tight for exploration. This comprehensive study has accurately estimated the Total Organic Carbon (TOC) content in extractable hydrocarbon zones, shaping future development strategies for the Makhul Formation as an unconventional reservoir. The investigation focused on the interval from 11495 ft. to 12620 ft., revealing distinct sub-layers within the Makhul Formation based on inorganic geochemistry data (XRF & XRD) and organic geochemical analysis (Pyrolysis). The Upper Makhul layer comprises mainly calcite and clay, with decreasing Kerogen proxies downward. The Middle Makhul layer shows evolving dolomite and clay content, while the Lower Makhul layer exhibits increased dolomite and Paleredox proxies, indicating a different Kerogen presence. The HAWK PAM analysis of multiple intervals provides valuable insights into the organic composition and geological characteristics of the Makhul Formation. The study provides novel insights by integrating advanced techniques such as HAWK pyrolysis and XRF/XRD geochemical analysis to characterize the Makhul Formation. This approach reveals distinct sub-layers within the formation, shedding light on the organic and inorganic composition. The identification of extractable hydrocarbon zones and the detailed evaluation of Total Organic Carbon (TOC) content offer valuable information for future reservoir development strategies.