特低渗透储集层成岩作用及孔隙演化定量表征——以鄂尔多斯盆地姬塬地区为例

采用薄片镜下观察、储集层物性分析相结合的方法,开展了成岩作用和成岩过程中孔隙演化的定量分析。研究表明,姬塬地区延长组长4+5、长6 储集层以相对致密、低渗储集层为主,长石含量高、埋藏深度大及孔隙结构复杂等是储集层物性变差的重要因素;延长组长4+5、长6 储集层经过了压实、胶结、溶蚀及交代等成岩作用改造,目前已处于中成岩阶段A 期的晚期到B 期的早期,压实作用造成孔隙度大量丧失,是储集层物性变差的最主要原因。

Quantitative Characterization of Diagenesis and Pore Evolution of Super-Low Permeability Reservoirs—An example from Jiyuan area in Ordos basin

This quantitative study is conducted by means of cast thin-section observation and petrophysical property analysis of the reservoir. It is shown that the Chang 4+5 and Chang 6 of Yanchang formation in Jiyuan area is dominated by relatively tense and low permeable reservoirs with high feldspar, deep buried and complicated pore structure, which are important factors causing the reservoir quality to become poor. By reformations of compaction, cementation, dissolution and metasomatism, these reservoirs are now in diagenesis periods of late A and early B, of which the compaction could be result in overwhelming loss of reservoir porosity as the most important reason of the reservoirs becoming poor.