深层砂岩次生孔隙的成因及其与异常超压泄漏的关系——以黄骅坳陷板桥凹陷板中地区滨油组为例

黄骅坳陷板桥凹陷老第三系埋藏深度超过 3 5 0 0 m的砂岩体普遍处于超压系统中 ,异常超压的形成与油气的初次运移直接相关 ,与断层相关的异常超压泄漏是形成次生孔隙的一个重要因素。次生孔隙是因颗粒或胶结物的溶解而形成的 ,异常超压并不是形成有效次生孔隙的直接原因 ;但由于超压在断层处的泄漏 ,导致砂岩体中的溶解物质得以搬运出储层 ,从而形成次生孔隙并伴随着孔隙度的净增加。板中地区深层异常超压的形成和泄漏是一个动态的平衡过程 ,次生孔隙形成后随着油气的介入而得以保存下来

SECONDARY POROSITY GENERATION AND THE RELATIONSHIP ASSOCIATED WITH OVERPRESSURE LEAKAGE

Sandstone bodies buried under 3500 m are in an overpressure system in Banqiao Basin. Generation of the overpressure is directly associated with the primary migration. The overpressure leakage associated with faults is the main factor of the secondary porosity generation. The generation of secondary porosity is because of dissolution or cement of grains in the sandstone. Overpressure is not the direct reason of secondary porosity generation, on the contrary, it is the overpressure leakage that makes the mineral dissolve and remove from the sandstone. This process results in a net gain in porosity. The generation and leakage of overpressure are amovable balance process in the Banzhong region. The secondary porosity is preserved by the intrusion of hydrocarbon.