Aanlysising The Gas Reservoir Forming Conditions And Forecasting For Favorable Areas Of Yingcheng Formation In Yingtai Fault Depression

Sience ls1well got gas in the volcanic rock of Yingcheng Formation in2007year, thereare31wells in the volcanic rock and volcanic clastic rocks of Yingcheng Formation in Yingtaifault depression, including21industrial gas flow wells and4failed wells, the natural gas expl-oration has achieved great success in this area. In order to clarify the accumulation mechanis-m of natural gases in Yingcheng Formation, some studies have ro be taken.Shahezi Formation and the second member of Yingcheng Formation are the source rocksin the Yingtai fault depression, most of the organic matter type of the source rocks are Ⅱ2andⅡ2~Ⅱ1, abundance of them are at the middle-goog level, they are all at high mature or overmature lever and have thick mudstone, the gas generating amount is42.7×1011m3and98.3×1011m3in Shahezi Formation and the second member of Yingchen Formation, the goodsource rocks provide sufficient gas to the gas reservoir of Yingcheng Formation. Acid volcanic rocks and explosive facies have goog physical property in the first member of YingchengFormation. The mainly pore type of the the first member of Yingcheng Formation is primarypore and the reserovir is thick in this member. Sedimentary tuff and shen tuff breccia are themainly rocks of effective reservoir, the pore type of the reservoir is mostly dissolution pore.The single reservoir thickness is thin, but they are stacking together in vertical.The second member of Yingcheng Formation and Denglouku Formation are two sets ofmudstone caprock to the first member of Yingcheng Formation, the sealing level are mainlybetter and medium.There are three types of gas reservoir in Yingchen Formation: lowergenerating upper reservoiring, side generating side reservoiring and self generating self reserv-oiring, fault and reservoir migration system are the mainly migration pathway to these gas re-servoir.The distribution of lower generating upper reservoiring gas reservoir is dominated by thesource, reservior and fault, the first member of Yingcheng Formation in ls1well will be thefavorable area. The side generating side reservoiring gas reservior is controlled by the dockin-g mode of source and reservior, the first member of Yingchen Formation in ls1and ls2wellwill be the favorable area. The self generation self reservoiring gas reservior is influenced bysource and reservoir, the second member of Yingchen Formation will be the favorable area.