储层孔隙结构特征及其对开发的影响-以辽河盆地西部凹陷某试验区于楼油层为例

以辽河盆地西部凹陷某试验区为例,综合7口取心井岩心、镜下薄片、分析测试以及400口井测井精细解释储层物性等多种资料,从微观和宏观角度对稠油热采储层孔隙结构进行研究。研究区储层为高孔高渗,平均孔隙度31.25%,平均渗透率1 829.3 md。从微观成因角度,将研究区目的层孔隙结构划分为原生孔隙和次生孔隙等2大类,同时进一步细分为粒间孔隙、粒内孔隙、基质内微孔、解理缝、粒间溶孔、粒内溶孔、铸模孔、特大溶蚀粒间孔、构造缝和溶蚀缝等10种亚类,其中以粒间孔隙和粒间溶孔为主。宏观上,基于精细测井解释资料,绘制了不同单层孔隙结构分布特征图。高孔隙度的区域主要呈北西-南东向条带状分布与水下分流河道主流线部位,指示孔隙度主要受沉积微相控制。在蒸汽吞吐转蒸汽驱开发方式转换时,应该充分考虑储层孔隙度的影响作用,在保证注汽井和采油井位于孔隙度高值区与的同时,应该尽量使得同一井组位于高孔隙度连片区域,已取得最好的注采对应效果。同时应该适当控制注入压力,防止蒸汽沿着高孔隙度发育条带突进,从而降低波及体积和提高石油采收率。

Pore structure characteristics and its influence to reservoir development

Taking Yulou oil bearing sets in some experimental area in south end of westward slope of West depression in Liaohe Basin as an example, Pore structure characteristics of thermal recovery reservoir heavy oil is studied. In this process, seven wells data of cores and thin-sections and analysis and testing and four hundred data of fine interpretation logging are used. Reservoir in study area is high pores and permeability reservoir, and average porosity is 31.25% and average permeability is 1829.3md.Pore structure in study area are carved into two kind of primary pores and secondary pores from microscopic causes view. These two kind of pores could be carved into ten subclass of intergranular pores and intergranuler pores and microporous in matrix and cleavage crack and intergranular dissolved pores and intragranular dissolved pores and mould pores and supermajor intergranular dissolved pores and structural seam and dissolution fractures, and intergranular pores and intergranular dissolved pores take the leading roles. Area with high pores distributed from northwestward to east-south macroscopic angle, which is same as main streamline of underwater distributary channel. Pore structure characteristics mainly controlled by sedimentary facies. It should be fully considered that impacts of pore structure to development mode conversion from steam stimulation to steam flooding. One development well-group should lie in one area with high pores in order to reach the best effect of injection-production. Injection pressure should be controlled to prevent steam breakthrough from band with high pore structure and reduce swept volume and oil recovery.