壤中游离气方法及其在油气化探中的应用

油气藏中的轻烃气体能够以微弱但可检出的量近似垂直地渗漏到地表土壤中,其中一部分烃类以游离态赋存在土壤或岩石颗粒空隙中。壤中游离气中的烃类能反映深部油气藏烃类的现代补偿性活跃微渗漏,被认为是油气地球化学勘探的最可靠方法之一。壤中游离气采集是获得第四系沉积层中微渗漏烃类地球化学异常的关键技术。自行研制了便携式游离气采集新装置,具有操作简便、携带方便、密封性好等特点。通过长期实践,总结了土壤游离气保真采集的方法。游离气方法在济阳坳陷惠民凹陷南坡临南—钱官屯地区、塔里木盆地阿克亚苏地区X井区的油气化探应用,获得的游离烃异常较好地反映了油气垂向微渗漏近地表信息,以及下伏油气的分布特征,油气微渗漏异常区与背景区分离明显,表明壤中游离气方法应用效果显著,在油气勘探中值得广泛推广。

The soil gas method and its application to geochemical prospecting for oil and gas

Light hydrocarbons in an underground hydrocarbon reservoir can reach the surface in a trace yet detectable amount through near-vertical microseepage,and some of them may occur in free form in the pores of soil or rock particles.Hydrocarbon in soil gas can indicate the current compensatory active microseepage of hydrocarbons in deep reservoirs;therefore,it is thought to be one of the most reliable methods in geochemical prospecting for oil and gas.The collection of free gas from soil is a key technique for obtaining the geochemical anomalies of microseepage hydrocarbons in Quaternary sediments.A new portable soil gas collection device was developed,which is easy to operate,easy to carry and has good air tightness.The ways of soil free gas fidelity collection are summarized through long-term practice.Soil gas method was applied to geochemical prospecting for oil and gas in Linan-Qianguantun area on the south slope of Huimin sag,Jiyang depression and X well block of Akyasu area,Tarim basin.The soil free hydrocarbon anomalies can well reflect the near surface information from vertical microseepage as well as the distribution characteristics of oil and gas accumulations underground.The surface geochemical anomaly of oil and gas accumulations is significantly different from that of the background area.The results show that the soil gas method is very effective and deserves wide application in oil and gas exploration.