彬长地区下古生界风化壳岩溶储层特征及分布

Characteristics and Distribution of Lower Paleozoic Weathering Crust Reservoir in Binchang Area

刘玲 冷佳宣 张军涛 杨飞 袁春燕

LIULing LENGJiaxuan ZHANGJuntao YANGFei YUANChunyan

中国石化石油勘探开发研究院, 北京 昌平 102206 中国石化华北油气分公司, 河南 郑州 450006

Petroleum Exploration and Production Research Institute, SINOPEC, Changping, Beijing 102206, China North China Oil and Gas Company, SINOPEC, Zhengzhou, Henan 450006, China

鄂尔多斯盆地彬长地区下古生界风化壳岩溶储层勘探前景良好，是实现油气突破和未来增储上产的重要阵地。但该区勘探程度低，风化壳岩溶储层尚未进行系统研究，储层发育特征及分布规律认识不清，严重制约了进一步勘探。为此，基于钻井及地震资料，剖析了研究区储层发育特征，明确了储层形成主控因素，建立了发育模式，并预测了其分布。结果表明，彬长地区下古生界风化壳岩溶储层岩性多样，主要为鲕粒云岩、鲕粒灰岩、粉—细晶白云岩等，储集空间以溶蚀孔洞、裂缝为主，可见晶间孔；古地貌及断裂是储层发育主控因素，岩溶储层主要发育于断裂发育的残丘地貌。综合考虑风化壳岩溶储层形成主控因素及平面分布，彬长地区风化壳岩溶可分为4类区：类型I为有利储层发育区，与加里东期断层及裂缝分布相关，聚集分布，规模大，断裂对岩溶影响较强，岩溶储层品质好；类型II为次有利储层发育区，分布于北西向小型走滑断裂附近，断裂对岩溶影响小，岩溶储层品质较好，分布有限；类型III为较有利储层发育区，与古生界裂缝有关，断裂不发育，对岩溶影响弱，风化壳岩溶储层零星分布；类型IV为不利储层区，与燕山—喜山期构造运动改造形成的线性大断层有关，分布规模大，但处于侵蚀高地，剥蚀作用强，储层品质差。

The Lower Paleozoic weathering crust karst reservoir in Binchang Area of southern Ordos Basin has good exploration prospect, which is an important area for achieving petroleum breakthrough and increasing reserves and production in the future. However, the exploration in the area is not adequate, the weathering crust karst reservoir not been systematically studied, and the development characteristics and distribution law of the reservoir unclear. This seriously restricts the further exploration. Based on drilling and seismic data, the development characteristics and the main controlling factors of the weathering crust karst reservoir had been analyzed. In addition, the reservoir development model had been established and its distribution law had been predicted. The research showed that reservoir lithology mainly includs oolitic dolomite, oolitic limestone, slit-fine-grained dolomite and argillaceous dolomite. The reservoir space was dominated by dissolution pores and fractures, and intercrystalline pores could be seen. Paleogeomorphology and faults were the main controlling factors of reservoir development. High-quality reservoirs mainly developed in the dissolved hills where faults developed. Considering the main controlling factors and plane distribution of weathering crust karst reservoir, Binchang area can be divided into four types of reservoir areas. Type I was the most favorable area for reservoir development, which related to Caledonian faults and has large distribution. The faults had strong influence on it. The reservoir quality was good. Type II was a first-level reservoir development area, which was distributed near the minor strike-slip fault in NW direction. The fracture had little influence on karst and the distribution of karst reservoirs was limited. Type III was a relatively developed reservoir area, which was related to Paleozoic fractures and had little influence on karst, and the weathered crust karst reservoirs were scattered. Type IV was a disadvantageous reservoir area, which was related to the large linear faults formed by the Yanshan-Himalayan tectonic movement. It had a large scale. Due to its location, there was serious denudation and the reservoir quality was poor.

10.11885/j.issn.1674-5086.2023.12.01.01