石油实验地质2026，Vol.48Issue(4)：795-809,15.DOI:10.11781/sysydz2026040795
致密砂岩储层成岩相类型及其孔隙度演化定量分析
Diagenetic facies types and quantitative analysis of porosity evolution in tight sandstone reservoirs:a case study of the Chang 6 Member of the Triassic Yanchang Formation in the X255 area,Ordos Basin
摘要
Abstract
To clarify the differential evolution of porosity in tight sandstone reservoirs,the Chang 6 Member of the Triassic Yanchang Formation in the X255 area,Ordos Basin,was selected as a case study.Cast thin sections,scanning electron microscopy,X-ray diffraction(XRD)analysis of clay minerals,and cathodoluminescence data were integrated to classify the diagenetic facies of the tight sandstone reservoirs and establish the diagenetic evo-lution sequence of each facies.Burial and thermal histories were reconstructed,and the porosity of reservoirs with different diagenetic facies at key stages of geological history was quantitatively calculated to determine their differential evolution patterns.As indicated by the research results,four diagenetic facies are mainly developed in the Chang 6 member reservoirs in the study area:moderate-compaction feldspar-dissolution facies,moderate-compaction chlorite-cementation facies,strong-compaction tight facies,and moderate-compaction carbonate-cementation facies.Their porosity evolution processes differ markedly.In the moderate-compaction feldspar-dissolution facies,com-paction and cementation caused a combined porosity loss of 20.21％during early diagenetic stage A.Dissolution increased porosity by 6.06％during early diagenesis,whereas a further porosity loss of 11.38％occurred during early diagenetic stage B and the mesodiagenetic stage.The final porosity is 11.85％,making this a favorable dia-genetic facies.In the moderate-compaction chlorite-cementation facies,compaction and cementation caused porosity losses of 16.45％and 14.0％,respectively,whereas dissolution increased porosity by 3.15％.Chlorite coatings provided some protection for primary pores,making this the second most favorable diagenetic facies.In the strong-compaction tight facies,compaction and cementation caused porosity losses of 27.61％and 2.70％,respectively,making this an unfavorable diagenetic facies.In the moderate-compaction carbonate-cementation facies,dolomite precipitation occupied approximately 10.0％of the pore space.Subsequent compaction and calcite-dominated cementation rendered the reservoir tight during early diagenesis,making this the least favorable diagenetic facies.关键词
成岩相/孔隙演化/致密砂岩储层/延长组/鄂尔多斯盆地Key words
diagenetic facies/porosity evolution/tight sandstone reservoir/Yanchang Formation/Ordos Basin分类
能源科技引用本文复制引用
张文,张凤奇,李程善,胥中义,张栋梁,茹荣,郭圆圆..致密砂岩储层成岩相类型及其孔隙度演化定量分析[J].石油实验地质,2026,48(4):795-809,15.基金项目
陕西省自然科学基础研究计划项目(2017JM4004),陕西省教育厅重点实验室科研计划项目(17JS110)和中国石油长庆油田分公司科学研究与技术开发项目(2023DM1012)联合资助. （2017JM4004）
