The Middle Jurassic carbonate succession (Samana Suk Formation) in Kala Chitta Range, North Pakistan was studied in detail to investigate the impact of diagenesis on reservoir potential of the rock unit. The current study integrates detailed geological field, petrographic, scanning electron microscopic, and advance geochemical studies to reconstruct the diagenetic history of Jurassic carbonates and to evaluate its role in re‐shaping the reservoir potential. Based on field observations, five lithological units along with diagenetic features are recorded. Furthermore, various microfacies are defined within each lithological unit. Based on petrographic studies, it is observed that various diagenetic features including micritization, neomorphism, dissolution, compaction (mechanical and chemical), dolomitization, and cementation have played a crucial role in the porosity modification of various lithological units. The paragenetic sequence established in this study reveals modification of the carbonates in various diagenetic phases, for example, marine, meteoric, and burial (shallow and deep) diagenesis, followed by a phase of uplifting. Based on different types of microscopic porosities generated during various diagenetic phases, mudstone to wackestone carries good reservoir potential while the grainstone has moderate to poor potential. The plug porosity and permeability data further corroborate these findings. At outcrop, various large‐scale dissolution activities and dense network of inter‐connected fractures in all lithological units may have further enhanced the reservoir potential of the studied strata.

中文翻译：

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研究成岩作用对侏罗系浅层碳酸盐岩储层质量的影响：巴基斯坦北部卡拉奇塔山脉

对巴基斯坦北部卡拉奇塔山脉中侏罗统碳酸盐岩演替（Samana Suk组）进行了详细研究，以研究成岩作用对岩石单元储层潜力的影响。目前的研究整合了详细的地质领域，岩石学，扫描电子显微镜以及先进的地球化学研究，以重建侏罗纪碳酸盐岩的成岩史，并评估其在重塑储层潜力中的作用。根据现场观察，记录了五个岩性单元以及成岩特征。此外，在每个岩性单元内定义了各种微相。根据岩相学研究，可以观察到各种成岩特征，包括微晶化，新形态，溶解，压实（机械和化学），白云石化，胶结作用和胶结作用在各种岩性单元的孔隙度改造中起着至关重要的作用。在这项研究中建立的共生序列揭示了碳酸盐在各种成岩作用阶段的修饰，例如海洋，陨石和埋藏（浅和深）成岩作用，随后是隆升阶段。根据在不同成岩作用阶段产生的不同类型的微观孔隙，从泥岩到瓦克石具有良好的储层潜力，而粒岩则具有中等至差的潜力。塞孔隙率和渗透率数据进一步证实了这些发现。在露头处，所有岩性单元中各种大规模的溶蚀活动和相互连接的裂缝的致密网络可能进一步增强了所研究地层的储层潜力。