利用岩石物理相流动单元“甜点”筛选致密储层含气有利区——以苏里格气田东区为例

Identification of tight gas play fairways according to flow unit sweet spots of petrophysical facies:A case study from the eastern Sulige Gas Field

针对苏里格气田东区致密储层受多期不同类型沉积、成岩作用及构造因素影响,储层孔隙空间细小、孔隙类型结构和测井响应复杂等问题,分析致密储层岩石物理相分类评价,提出利用岩石物理相流动单元"甜点"来筛选致密储层含气有利区。选用反映致密储层特征的流动层带指标、储能参数、单渗砂层能量厚度、气层有效厚度、含气层厚度、渗透率、孔隙度、含气饱和度等多种参数,利用灰色理论从不同角度对储层渗流、储集及含气特征进行全面分析,筛选出一、二类岩石物理相流动单元"甜点",并圈定近期可开发或评价后可开发的多期叠置的一系列含气有利区97个,其中下二叠统山西组山2段筛选圈定26个、山1段圈定27个、中二叠统下石盒子组盒8下亚段圈定30个、盒8上亚段圈定14个。该研究成果反映出鄂尔多斯盆地广覆式生气和满盆子储气特色,为气田增储上产提供了更多的有利勘探目标。

Influenced by multiple stage deposition and diagenesis of various types, the tight reservoirs in the eastern Sulige Gas Field are featured by tiny pore space, complex pore structure and logging response. In view of this, this paper classified petrophysical facies of tight reservoirs and identified tight gas play fairways according to flow unit sweet point of petrophysical facies. Various parameters reflecting the tight reservoir features were first selected, including flow zone index, reservoir capacity, single sand layer thickness, net gas pay, gross thickness, permeability, porosity and gas saturation, and then the grey theory was applied to analyze seep- age flow, poroperm and gas bearing characteristics of the reservoirs. Type I and II sweet spots of petrophysical facies were selected and used to identify 97 play fairways, among which 26 were identified in the 2nd member of the Shanxi Fro, 27 in the 1st member of the Middle Permian Shanxi Fm, 30 in the lower 8th member of the Shihezi Fm and 14 in the upper 8th member of the Middle Permian Shihezi Fm. The results reveal the pervasiveness of gas generation and the adequateness of gas preservation in the Ordos Basin.