含浊沸石砂岩储层孔隙演化特征及其对储层质量的影响——以鄂尔多斯盆地东南部延长组长101储层为例

鄂尔多斯盆地延长组储层中具有分布极不规律、成因复杂的浊沸石胶结物，其成岩演化特征对储层孔隙的演化有一定影响。为了解盆地含浊沸石砂岩储层的孔隙演化特征，以鄂尔多斯盆地东南部长10₁储层为研究对象，运用铸体薄片、图像粒度分析、扫描电镜手段、X-衍射、包裹体测温等手段，分析了研究区长10₁储层的岩石矿物特征、成岩作用类型，结合埋藏史、热史、生烃史，明确了各成岩事件的形成序列，定性描述、定量分析了各成岩作用下孔隙度的演化模式，并重点刻画了浊沸石在该储层成岩演化中的角色及作用。研究表明：研究区长10₁储层以长石砂岩和岩屑长石砂岩为主，属于典型的低孔低渗储层，储集空间以粒间孔和长石溶孔、浊沸石溶孔等次生溶蚀孔为主。成岩作用类型主要包括压实作用、胶结作用和溶蚀作用，综合判断储层处于中成岩A期。经孔隙定量演化的计算，长10₁储层压实作用、胶结作用是储层致密化的原因，溶蚀作用可有效改善储层物性。储层中浊沸石的差异性成岩演化对储层物性产生了不同影响：早成岩B期呈嵌晶状充填于粒间孔中的浊沸石降低孔隙度的贡献率达27.1%，中成岩A期后随着大量生烃，浊沸石产生的次生孔隙对于孔隙度的增加贡献率为44.1%，总体看浊沸石对长10₁储层起到了改善储层储集性能作用。

Pore evolution characteristic of sandstone reservoir with laumontite cement and its influence on reservoirproperties: Chang101 reservoir of Yanchang Formation in Southeast of Ordos Basin

Laumonite is an important cement in Yanchang Formation of ordos basin with irregular distribution and complex genesis. Thediageneticevolutioncharacteristics of laumonite have a certain influence on the evolution of reservoir pores. In order to understand the pore evolution characteristics of sandstone reservoir with laumonite cement, the petrologic and diagenesis of Chang10₁ in southeastarea ofOrdosBasin are studied on the basis of the section examination, scanning electron microscopy, image granularity analysis, X-ray diffraction, fluid inclusions and other analytical methods. Combining with the burial history, thermal history and hydrocarbon generation history, the formation sequence of diagenetic event is defined, and the evolution mode of porosity diagenesis is qualitatively described and quantitatively analyzed. The role and function of laumonite in diagenetic evolution of this reservoir are mainly described. The research indicates that types of reservoir snadstone are arkose and lithic arkose. It is a typical low porosity and low permeability reservoir. The types of pores are inter-partical and dissolution pore of feldspar and laumonite. The diagenesis types include compaction, cementation and dissolution, and the comprehensive judgment shows that the reservoir is in the middle diagenetic stage A. The calculation of quantitative evolution of porosity shows that the compaction and cementation of Chang10₁ reservoir are the causes of reservoir densification and dissolution can effectively improve reservoir physical properties. The differential diagenetic evolution of laumonite in the reservoir has different effects on the reservoir physical properties：The contribution rate of laumonite filling in intergranular pores to porosity reduction is 27.1% in the early diagenetic stage B. After the middle diagenetic stage A, with A large amount of hydrocarbon generation, the contribution rate of secondary pores generated by laumonite to the increase of porosity is 44.1%. In general, laumonite plays an important role in improving the reservoir quality of Chang10₁ reservoir.