塔里木盆地火成岩对碳酸盐岩储层的改造作用

Alteration of the igneous rock on the carbonate reservoirs in Talimu Basin

塔里木盆地形成与演化过程中出现过多期的岩浆侵入与喷发活动,形成了多种类型的火成岩体.岩浆活动形成的火成岩带来了地壳深部的热液流体,其中富含二氧化碳、硫化氢、硫、及少量一氧化碳、氢、HCl、NH3、NH4Cl、HF等的酸性流体对上部碳酸盐岩储层产生了多种多样的改造作用,包括大理岩化作用、萤石化作用、热液白云岩化作用、热液溶蚀作用等.多种改造作用的结果,使得原本致密的碳酸盐岩储层,形成了大量各种类型的孔洞,孔隙度大大增加,储集性能得到改善.勘探过程中,火成岩的出现可以预示附近地区良好储层的发育,为勘探油气起到了示踪作用.

Multiple phases of the intrusion and eruption of magma took place during the genesis and evolution of Talimu Basin, which leads to the formation of numerous types of igneous rock bodies in the basin. The igneous rocks from magmatic activities brings hydrothermal fluids from the deep crust, which are rich in CO2, H2S, S and also contain a small quantity of CO, H2, HCl, NH3, NH4Cl and HF. The deep fluids are acidic and they alter the upper carbonate reservoirs through marblization, fluoritization, hydrothermal fluid dolomitization and hydrothermal fluid corrosion. As a result, various types of secondary pores and cavities are created in the once tight carbonate rocks. The porosity of the carbonate reservoirs is significantly increased and the petrophysi-cal property of them is improved. For the oil and gas exploration in this area, therefore, the presence of igneous rocks may indicate that good reservoirs develop in nearby areas, and it can guide the exploration in this area.