苏里格气田东区盒8段火山物质成岩作用特征

陈世悦 侯中帅 张顺

中国石油大学（华东）地球科学与技术学院，山东 青岛 266580

College of geosciences and technology, China University of Petroleum, Qingdao 266580, China

苏里格气田东区盒8段致密砂岩储层中广泛分布着火山物质。火山物质是石炭、二叠纪鄂尔多斯盆地周缘火山作用的产物被大气或流水携带沉积下来的。运用铸体薄片观察、扫描电镜、能谱分析等手段，对火山物质的成岩作用特征进行研究，认为其经历的主要成岩作用有水解作用、压实作用、脱水收缩、溶蚀作用、黏土化、碳酸盐交代作用、硅化作用，成岩作用受成岩阶段、储层沉积非均质性的控制。水解作用和脱水收缩可为后期酸性流体的进入提供通道；水解作用和溶蚀作用可抑制石英压溶作用和次生加大；溶蚀作用和高岭石化为储层增加了储集空间；硅化作用增强了储层的抗压实能力。水解作用降低了储层的抗压实能力；火山物质水解产物被压实变形，收缩缝闭合，降低了储层的孔隙度；火山灰黏土化形成的伊利石和绿泥石充填粒间，造成储层的致密化；碳酸盐交代火山物质的同时充填收缩缝和溶蚀孔隙；火山物质成岩作用的差异性增强了储层的非均质性。

Volcanic material is widely distributed in He 8 member, east block of Sulige Gas Field, which was the product of volcanic activities from the margin of the Ordos Basin in Carboniferous?鄄Permian and was carried by the atmosphere or water to the sedimentary area. Based on the thin?鄄section identification, SEM, EDS, the diagenesis characteristics of volcanic material is studied. The major diagenesises that the volcanic material has experienced are hydrolysis, compaction, syneresis, dissolution, clayization, being metasomatized by carbonate and silicification. The diagenesis of volcanic material is controlled by diagenetic stage and the sedimentary heterogeneity of reservoirs. Hydrolysis and syneresis can provide migration path for the acidic fluid; hydrolysis and dissolution can inhibit pressolution and overgrowth of quartz; dissolution and kaolinization can provide pore volume; silicification can enhance the compressive resistance of the reservoirs. Hydrolysis weakens the compressive resistance of the reservoirs; the porosity was reduced when volcanic material′s hydrolyzate was compacted to deform and the contraction joints were closed; the ash transformed illites or chlorites can make the reservoirs densified; carbonate metasomatized volcanic material fills the contraction joints and dissolution pores; the differences of volcanic material diagenesis enhance the heterogeneity of the reservoirs.

10.6056/dkyqt201502008