惠民凹陷下第三系砂岩经历了压实、胶结、溶蚀、交代和重结晶等多种成岩作用.其中压实、胶结和溶蚀作用对储层性质影响最大.压实作用的平均减孔率为0.78%/100m,中部和南部较高,北部较低.胶结作用对储层性质的影响表现在埋深大于1500m以后,其减孔率为8-20%.溶蚀作用主要出现在1400-2500m和2700-4000m两个深度段,以长石溶蚀为主,其次是碳酸盐胶结物的溶蚀作用,溶蚀作用新增的孔隙度大约为4-14%.砂岩经历了早成岩A、早成岩B和晚成岩A阶段,目前大多处于晚成岩A2期.砂岩储层孔隙可以分为原生孔隙和次生孔隙两大类.%The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes,such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three - compaction,cementation and dissolution - affect reservoir properties most intensively. An average porosity loss due to compaction is 0.78% per 100 meters, slightly higher in the central and southern parts and lower in the northern. Cementation has resulted in the porosity loss from 8% to 20% at a depth below 1,500 meters. Dissolution, which in most cases is the dissolution of feldspar and of carbonate cement, primarily occurs in two depth intervals, from 1,400 to 2,500 meters and 2,700 to 4,000 meters respectively. New porosity is created through dissolution from 4% to 14%. The sandstones experienced stage A and stage B of early diagenesis and stage A of late diagenesis. At present, most of them are experiencing Phase A2 of late diagenesis. The types of pores in the sand reservoir can be grouped into primary and secondary ones.
展开▼
