川中龙女寺地区中二叠统茅口组储层特征及其主控因素

Characteristics and main controlling factors of reservoirs in the Middle Permian Maokou Formation， Longnvsi area， central Sichuan Basin

彭军 刘芳兰 张连进 郑斌嵩 唐松 李顺 梁新玉

Jun PENG Fanglan LIU Lianjin ZHANG Binsong ZHENG Song TANG Shun LI Xinyu LIANG

近年来，川中龙女寺地区JT1井和MX145井等多口钻井在中二叠统茅口组获得高产工业气流，展现出茅口组良好的勘探开发潜力，但由于储层特征及其发育主控因素不清楚，严重制约了龙女寺地区茅口组进一步的油气勘探。以川中龙女寺地区茅口组储层为对象，开展储层岩性、物性和孔喉结构等地质特征及地球化学特征研究，提出了川中龙女寺地区中二叠统茅口组优质储层主控因素。研究结果表明：①龙女寺地区茅口组储层岩性为白云岩及灰岩2类，晶粒白云岩、角砾白云岩和颗粒灰岩为主要储层岩石类型。白云岩储层可划分为3大类、6个亚类，灰岩储层可划分为4大类、5个亚类。②晶间孔、非选择性溶孔和溶洞为茅口组储层主要储集空间类型，裂缝-孔洞型储层的构造-溶蚀缝、洞体系储集空间大，分布广泛且连通性好，为有利储层。③茅口组储层具有“沉积作用-白云石化作用构建骨架，岩溶作用-构造作用叠加改造”的形成与发育模式。沉积作用、白云石化作用和构造作用是优质储层的主要控制因素，角砾白云岩为优质储集岩。

In recent years， high-yield industrial gas flow has been obtained from the Maokou Formation in multiple wells such as JT1 and MX145 in the central Sichuan Basin， indicating great potential for hydrocarbon exploration and exploitation of this formation. However， the characteristics of and main factors controlling the reservoirs therein remain unclear， severely restricting in-depth hydrocarbon exploration. Aiming to investigate reservoirs of the Maokou Formation in Longnvsi area， central Sichuan Basin， the study delves into the geological characteristics such as lithology， physical properties， and pore-throat structure， along with the local geochemical characteristics via rock and ore tests under the guidance of reservoir geology. Accordingly， the major factors governing the development of high-quality reservoirs within the formation are proposed. The results indicate that dolomite and limestone reservoirs occur in the Maokou Formation， with primary reservoir rocks of crystal dolomites， brecciated dolomites， and granular limestones. The dolomite reservoir rocks can be categorized into three types and six subtypes， while the limestone reservoir rocks can be divided into four types and five subtypes. Storage spaces in the reservoirs consist primarily of intercrystalline pores， nonselective dissolution pores， and karst caves. The structural-dissolution fractured-vuggy system formed by the matching of vugs and fractures， exhibits a large storage space， extensive distribution， and high connectivity， which establish this system as a favorable reservoir. Regarding the formation and evolutionary pattern of the reservoirs， the reservoir framework is caused by sedimentation and dolomitization， and reservoir modification can be attributed to superimposed karstification and tectonism. In all， the primary factors governing the development of high-quality reservoirs include sedimentation， diagenesis， and tectonism， and brecciated dolomites are identified as high-quality reservoir rocks.

10.11743/ogg20240510