准南前陆盆地油气成藏条件及有利勘探区

OIL AND GAS RESERVOIR FORMATION CONDITIONS AND BENEFICIAL EXPLORATION A REAS IN SOUTH ZHUNGE'ER FORELAND BASIN

准南前陆盆地沉积厚度大 ,圈闭多 ,油气资源十分丰富 ,但目前发现的资源仅占预测资源量的 6 %左右 ,油气勘探潜力还很大。同时准南又是一个油气地质条件非常复杂、勘探风险较大的地区。针对准南油气勘探的难点和中心问题 ,从含油气系统、油气成藏机制、资源潜力和有利区带 4个方面 ,对准南油气成藏条件及勘探前景进行了较系统的研究 ,认为准南具备形成大中型气田的地质条件。油气富集规律为 :①含油气系统控制了油气区域分布 ;②各期生烃凹陷周围的圈闭是油气聚集的主要场所 ;③断层控制了次生油气藏的发育 ;④山前断褶带是油气的主要聚集带。含油气有利区带为四带一凹陷 ,即一、二、三排背斜带、隐伏背斜带和四棵树凹陷 ,在含油气有利区带和圈闭评价的基础上 ,优选出红石沟、昌吉、东湾和吐谷鲁背斜 4个有利的勘探目标。

South Zhunge'er Foreland Basin is very rich in o il & gas resources,being of a large sedimentary thickness and a great number of traps,the resource extent found at present,however,only accounts for about 6 per cent of the one predicted,therefore the potential of prospecting for oil and gas is still vast.Meanwhile it is also a region with complicated petroleum geologic al conditions and larger exploration risk.In light of the difficulties and key p roble ms with oil and gas exploration in the basin,a systematic research on the reserv oir formation conditions and exploration prospects was carried out from four asp ects as petroleum system,reservoir formation mechanism,resources and beneficial area,which indicates that the South Zhunge'er Foreland Basin possesses the condi tions of forming large and medium sized gas fields.In the basin,the oil a nd gas accumulation rules are:①regional oil and gas distribution is controlled by petroleum system;②the traps around the hydrocarbon generating segs formed i n different stages are the major places of oil and gas accumulation;③ the growin g of secondary reservoirs controlled by the faults;and ④ mountain front fault f old belt is the main oil and gas accumulation area.Four belts and a seg,i.e.the first,the second and the third rows of anticlinal belts and concealed anticlina l belts as well as Sikeshu seg,are the favourable oil and gas bearing areas.A nd four advantageous exploration targets as Hongshigou,Changji,Dongwan and Tugulu anticlines were optimized up on the basis of the favourable area and trap evaluation.