盐类物质对泥质烃源岩生排烃过程的影响

The Effect of Salts on Hydrocarbon Generation and Expulsion of Argillaceous Source Rock

根据中国东部下第三系盐湖相沉积存在的地质实际,利用地层孔隙热压生排烃模拟仪开展了仿真地层条件下的含盐和不含盐泥质烃源岩的生排烃模拟实验,通过对烃类产物的分析探讨了盐类物质参与烃源岩生排烃的过程。研究表明:(1)盐类的存在加速了成烃演化,促进了石油和天然气的生成;(2)盐类的存在降低了对有机质的吸附能力,加速了粘土转化和脱水过程,且盐层易解理,使烃源岩中微孔隙及孔缝发育,促进了油气的初次运移;(3)无盐泥质源岩发育区虽然滞留大量的石油资源,但由于其岩石本身难压裂,对于商业化开采页岩油并无太大意义,到达过成熟阶段后,可能是页岩气开采的有利区带。盐岩发育区虽然其整体演化过程中生成的油气易于排出,但在Ro=1.28%时仍然滞留着20%的石油资源,富含大量的盐类脆性矿物而低含粘土矿物,有利于产生裂缝,易于压裂,是页岩油藏勘探的有利区带。

According to the presence of aalt lake sediments of the Tertiary in the east of China, we make use of hydrocarbon generation and expulsion of pore hot simulation instrument to carry out the simulation under the conditions of formation of salt and no salt argillaceous source rock hydrocarbon generation and expulsion simulation experiments, through the analysis of hydrocarbon products of the salts in hydrocarbon source rocks in the process of hydrocarbon generation and expulsion. The results have shown that： （1） the presence of salts accelerated the evolution of hydrocarbon generation, and promoted oil and gas generation. （2） the presence of salt reduces the adsorption capacity of organic matter, accelerated the process of transformation and dehydration of clay, and promoted the initial operation of oil and gas shift easy cleavage and other reasons, the source rocks in the development of micro-pores and apertures in source rocks. （3） Although there exist a large number of stranded oil resources, salt-free zones in shale source rocks has little value of commercial exploitation because of the difficulties in fracturing. But they may be favorable of shale rock gas exploitation when reaching maturing. Although it is easy to discharge oil and gas generated in the process of evolution of salt rocks, 20% of oil resources were still stuck, when R0=1.28%a large number of salts rich in minerals and low brittleness with clay minerals, are conducive to creating cracks, and are easy for fracturing, which makes salt rock areas favorable shale zones for reservoir exploration.