摘要
渝东地区位于四川盆地川东高陡构造带的东缘 ,钻探程度较低 ,属于勘探新区。近些年来 ,经勘探证实 ,区内石炭系成藏条件与勘探程度较高的川东地区相似 ,但是 ,石炭系气藏的充满度普遍较低。以川东地区石炭系的勘探经验和研究成果为指导 ,通过开展渝东地区石炭系成藏条件综合研究工作 ,发现影响石炭系气藏充满度的因素较多 ,主要表现在以下几个方面 :区内构造变形强烈导致局部构造破碎、区域盖层厚度减薄导致封盖能力较差、石炭系上覆地层多为常压导致上覆地层压力封堵作用消失及区内普遍存在的区域拉张泄压现象 ;此外 ,与川东地区相比 ,区内尚存在下石炭统河洲组 ,其致密的岩性可能对志留系烃类向上运移起一定的阻隔作用。总体上看 ,区内方斗山以西地区受上述影响相对最小 ,气藏充满度相对最高 ,应是今后勘探的重点地区。
East Chongqing belongs to a new exploration reg ion with a few exploration wells drilled,being located at the east edge of East Sichuan high angle structu r al belt in Sichuan Basin.Through drilling in recent years,it is proved that the Carbo niferous gas formation conditions in this region are similar to those in East Si chuan with higher exploration degree,the full up coefficients,however,of the Ca r boniferous gas reservoirs in this region are relatively low in general.By means of synthetically studying the Carboniferous gas reservoir formation conditions i n East Chongqing on the basis of the exploration experiences and research achiev ements of Carboniferous in East Sichuan,it is found that the factors influencing the full up coefficients of Carboniferous gas reservoirs are mainly as follows : strong regional structural deformation causing local structures to be broken,reg ional caprock thickness thinning making seal capacity be reduced,pressure seal f unction losing of overlying formations because most of them are of normal pressu res,and commonly existing extensional pressure release phenomena in this region; and in comparison with the East Sichuan region,there is Hezhou Formation of Low er Carboniferous in this region,which tight lithology might prevent the hydrocar bons originated in Silurian from migrating upwards to a certain extent.In genera l,this area on the west of Fangdoushan structure should be the key exploration region in the future because the full up coefficients of Carboniferous gas rese rvoirs are relatively large owing to a little influence by the above mentioned f actors
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2002年第z1期20-22,共3页
Natural Gas Industry
基金
中国石油西南油气田分公司科研项目<四川盆地渝鄂边区石炭系成藏条件评价及勘探目标研究>的部分成果 项目编号 :2 0 0 0 0 30 2- 0 4
关键词
四川盆地
东
石炭纪
气藏
充满度
Sichuan Basin,East,Carboniferous period,Ga s reservoir,Full up coefficient
