The mechanism of crust and its controlling on petroliferous property of sand lens

摘要

The formation of the sand lens crust at interface of mudstone/sandstone is co-action result of the mud (source rock), fluid (oil, gas and water) and sand rock (reservoir rock) in petroliferous basin (Zeng, 2003). The organic acid formed by mutual action of source rock and subsurface fluid will seriously effect on the mutual action. The formation of organic acid prompts the mineral solution in source rock, especially the carbonate mineral. The carbonate stability is friable, so its solution and deposition is frequent and complex. It is obvious that the organic acid affects on the carbonate mineral. The formation of acetic acid conduces to carbonate mineral solution. With increase of acetic acid content, the solution of carbonate is increasing, as well as the content of Ca and Sr.