石灰岩型礁滩储层特征及主控因素
——以四川盆地南部地区上二叠统长兴组为例

Characteristics and main controlling factors of limestone reef-shoal reservoir： a case study of Upper Permian Changxing Formation, southern Sichuan Basin

李明隆 谭秀成 李延钧 刘宇龙 江林 夏吉文

油气藏地质及开发工程国家重点实验室，四川 成都 610500 中国石油集团碳酸盐岩储层重点实验室西南石油大学分室，四川 成都 610500 成都创源油气技术开发有限公司，四川 成都 610500 西南石油大学地球科学与技术学院，四川 成都 610500 中国石油西南油气田分公司蜀南气矿，四川 泸州 646000

针对石灰岩型礁滩储层主控因素认识不清的问题，以四川盆地南部地区上二叠统长兴组为例，系统剖析石灰岩型台内礁滩储层的基本特征，讨论储层形成机制。通过分析测录井、取心及物性资料，发现研究区礁滩储集空间以粒内溶孔、铸模孔为主，粒间溶孔与溶洞次之；构造裂缝发育，喉道以缩颈型喉道为主；整体平均孔隙度2.82%，平均渗透率4.50×10^-3 um²。储层类型可分为裂缝-孔隙型与裂缝-孔洞型。储层的形成受礁滩体、岩溶作用与构造作用控制，其中：礁滩沉积为储层提供了物质基础，早成岩期岩溶作用是储层发育的根本原因，构造作用极大改善了储层的渗滤能力，并推动了储层最终成型。研究结果将为类似成因的碳酸盐岩储层勘探提供思路。

Aiming at the unclear main controlling factors of limestone reef-shoal reservoir, taking the Upper Permian Changxing Formation in southern Sichuan Basin as an example, the characteristics of limestone intra-platform reef-shoal reservoir was analyzed and the formation mechanism was discussed. Logging, coring and physical property data show that reef-shoal reservoir space is mainly composed of dissoved intragranular and moldic pores, followed by intergranular dissoved pores and vugs, and with lots of structural fractures. The reef-shoal reservoir is characterized by constricted throats, with mean porosity of 2.82%, and mean permeability of 4.50×10^-3 um². The reservoir is divided into two types: fracture-pore and fracture-vug. The formation of the reservoir was controlled by bioherm, karstification and tectonization. The reef-shoal deposition provided the material foundation for the reservoir, and eogenetic karstification was the primary cause of the reservoir development. The tectonization tremendously improved the filtration ability and promoted the formation of reservoirs. The results will provide guidance for the exploration of carbonate reservoirs with similar genesis.

10.6056/dkyqt202005008