鄂尔多斯盆地胡尖山地区长61致密砂岩储层成岩特征与孔隙度定量恢复

在对大量岩心和薄片分析的基础上，运用扫描电镜、阴极发光、高压压汞等实验手段，系统分析了鄂尔多斯盆地胡尖山地区长6₁储层的成岩作用特征及其对储层物性的影响，并进一步对孔隙演化进行了定量恢复。结果表明：胡尖山地区长6₁储层整体处于中成岩阶段A期，主要经历了压实—压溶、胶结、溶蚀等成岩作用，且不同成岩作用对储层的孔隙发育造成了不同程度的影响。压实作用破坏了大量原生粒间孔，是导致研究区储层致密最主要的因素，孔隙度平均减少了18.41%，孔隙空间损失率达56.62%；胶结作用次之，在堵塞了孔隙空间的同时也一定程度地增强了颗粒的抗压实强度，孔隙度平均降低了10.38%，孔隙空间损失率达19.78%；溶蚀作用使碎屑颗粒及填隙物等不稳定组分溶解而产生大量的次生孔隙，从而改善了储层物性，增加的孔隙度平均为2.26%。根据成岩作用对物性的影响，结合测井响应特征，将该区长6₁致密砂岩储层划分出绿泥石膜剩余粒间孔相、剩余粒间孔相、长石溶蚀相、黏土矿物胶结相、碳酸盐胶结相及压实相等6种成岩相带，绿泥石膜剩余粒间孔相是研究区最有利的油气储集相带，剩余粒间孔相次之。

Diagenetic characteristics and quantitative porosity restoration of Chang 61 tight sandstone reservoir in Hujianshan area,Ordos Basin

Based on the analysis of a large number of cores and casting thin slice,the diagenetic characteristics of Chang 61 reservoir in Hujianshan area of Ordos Basin and its influence on reservoir physical properties were systematically analyzed by means of SEM,cathodoluminescence and high-pressure mercury injection,and the pore evolution was quantitatively restored.The results show that the Chang 61 reservoir in Hujianshan area was in the middle diagenetic phase A,mainly underwent compaction-pressure dissolution,cementation and dissolution,resulting different influences on the pore development of the reservoir.The compaction destroyed a large number of primary intergranular pores,which was the most important factor for reservoir compaction in the study area.The average porosity decreased by 18.41%,and the loss rate of pore space reached 56.62%.The cementation not only blocked the pore space,but also enhanced the anti-compaction strength of particles to a certain extent.The porosity decreased by 10.38%on average,and the loss rate of pore space reached 19.78%.The dissolution dissolved unstable components such as clastic particles and interstitial materials,resulting in a large number of secondary pores,thereby improving the physical properties of the reservoir,and the increased porosity was 2.26%on average.According to the impact of the diagenesis on reservoir properties and logging response characteristics,six types of diagenetic facies were identified,namely chlorite film phase-residual intergranular pore facies,residual intergranular pore facies,feldspar dissolution facies,clay mineral cementation facies,carbonate cementation facies and compaction facies.Chlorite film phase-residual intergranular pore facies is the most favorable diagenetic facies for oil enrichment,followed by residual intergranular pore facies.