东濮凹陷杜桥白地区深部储集层次生孔隙成因探讨

东濮凹陷杜桥白地区主要发育有 4个次生孔隙发育带 ,第一、第二、第三发育带主要是由干酪根脱羧及黏土矿物脱水产生的酸性水在压实流机制下溶解铝硅酸盐矿物 (如长石 )等形成的 ,在全区分布较广 ,具可比性。第四次生孔隙发育带分布范围局限 ,不具可比性 ,推测可能是浅层次生孔隙在异常高压条件下保存下来的剩余孔隙。同时 ,在 4 0 0 0m以下深层 ,有机酸脱羧形成CO2 进入孔隙水 ,使孔隙水仍保持酸性 ,在热循环对流机制下 ,砂体中的碳酸盐矿物进行再分配 ,从而对砂体的物性起了微调作用 ,此微调作用对深部天然气储集层横向物性的演变具重要影响。图 4参 7

An approach to the generating mechanism of secondary pores in Duqiaobai area of Dongpu depression.

There vertically exist four secondary pore zones in Duqiaobai area of Dongpu depression. The first, second and third zones are generated as a result of aluminosilicate dissolution caused by acid water from decarboxylation of kerogen and dehydration of clay minerals, so they are wide spread and can be forcasted to some degree. However, the generating mechanisms of the fourth zone, which is mainly under 4000m, are still under discussion at present. The author concludes that they are the remaining pores of those upper three ones preserved by abnormal high pressure. At the same time, convective flow of acid water from decarboxylation of organic acids redistributed the carbonate cements in sand body, which made important contributions to porosity distribution.