准噶尔盆地腹部侏罗系油气成藏主控因素定量分析及有利区预测

摘要

侏罗系是准噶尔盆地的主力油气层，资源潜力巨大；但其探明程度却很低，石油探明程度为17．5％，天然气探明程度仅为3％，油气聚集规律十分复杂。为此，本文应用要素匹配成藏模式（T CDMS）预测了准噶尔盆地侏罗系的有利成藏领域。通过对准噶尔盆地腹部侏罗系四大主控因素（区域盖层（C）、优质沉积相（D）、古隆起（M）和烃源岩（S））的控藏地质特征研究，建立了各个主控因素的控藏定量数学模型。将单因素控藏概率加权平均得到功能要素综合控藏概率指数，依据该指数预测了准噶尔盆地侏罗系目的层在两个不同成藏期的有利成藏区域。结果表明：侏罗系最有利的成藏区域为陆梁隆起地区、车莫古隆起地区和沙北断阶带地区。经验证已发现的油气藏落入预测区带的概率达90％以上。%Jurassic System is the main oil and gas bearing stratum in Junggar basin,which contains enormous potential resources.However,the exploration degree of Jurassic System is very low.Only 17.5% of oil and 3% of natural gas are found.The pattern of oil and gas accumulation is very complicated.By applying the multi-factor recombination model,we predicted the favorable reservoir areas of Jurassic System in Junggar basin.Based on this model,the authors studied the geological characteristics of the four controlling factors (cap cover,sedimentary facies,paleo uplift,and source rocks)of Jurassic reservoirs in Junggar basin,established the quantitative mathematical model of the four controlling factors,and obtained the comprehensive index on the weighted average probability of single controlling factor.According to this index,we predicted the favorable accumulation areas of Jurassic System in Junggar basin.The results show that the most favorable areas of Jurassic System are Luliang uplift, Chepaizi-Mosuowan paleo-uplift, and Shabei fault zone. The probability to find a reservoir is more than 90% in the favorable areas predicted by the model.It proves the validity and feasibility of this model.