巴楚地区与塔中地区东河塘组储层储集性能差异分析

Reservoir property differences of Donghetang Formation in Bachu and Tazhong area

利用岩石薄片、阴极发光及物性等资料对塔里木盆地东河塘组储层特征进行了研究,并分析了巴楚地区与塔中地区储集性能差异的控制因素。塔中地区储集性能好于巴楚地区,发育中孔、中渗储层,而巴楚地区储层较致密。造成该差异性的原因主要是受到了沉积作用和成岩作用的共同影响。巴楚地区发育水动力较弱、泥质含量较高的临滨亚相,而塔中地区发育水动力较强、泥质含量较低的前滨亚相;与塔中地区相比,巴楚地区石英含量较低,岩屑含量较高,储层物性较差;巴楚地区的碳酸盐胶结作用强于塔中地区,且溶蚀作用较弱,储层孔隙度和渗透率均较低,而塔中地区早期的碳酸盐胶结物被大量溶蚀并形成了粒间溶孔,且构造活动强烈,裂缝发育,储层孔隙度和渗透率均较高,物性较好。

On the basis of rock thin section, cathodoluminescence and physical properties, the reservoir characteristics of Donghetang Formation in Tarim Basin were studied, and the reservoir property differences in Bachu and Tazhong area were analyzed. The reservoir properties in Tazhong area are better than that in Bachu area, and the reservoir is characterized by medium porosity and medium permeability, however the reservoir in Bachu area is tight. The differences are caused by sedimentation and diagenesis. The sedimentary facies in Bachu area is shoreface subfacies with weak hydrodynamic conditions and high content of clay. The Tazhong area developed foreshore subfacies which has strong hydrodynamic conditions and low content of clay. The content of quartz in Bachu area is less than that in Tazhong area, but the debris content is higher, so the reservoir properties are poor. Carbonate cementation in Bachu area is stronger than that in Tazhong area, but dissolution is weaker, and porosity and permeability is low. In Tazhong area, a lot of the early dissolution of carbonate cement formed intergranular dissolved pores, and fractures developed,which results in high porosity and good physical properties.