川东北开江—梁平海槽发育对T_1f 鲕粒岩分布的控制

CONTROL OF KAIJIANG-LIANGPING TROUGH GROWING ON T_1f OOLITE DISTR IBUTION IN NORTHEAST SICHUAN BASIN

四川盆地东北部地区飞仙关期可划分为海槽、陆棚、台地 3个基本的沉积相带。开江—梁平海槽的发育对鲕粒岩的分布有明显控制作用。随着台地的不断增生 ,海槽萎缩消亡 ,鲕粒岩分布在纵横向上呈有规律的变化。鲕粒岩分布区不断向海槽迁移 ,发育层位从台地向海槽亦逐渐抬升。研究表明 ,在开江—梁平海槽两侧分布有铁山—梁平、铁山坡—开县两个鲕粒岩发育厚区 ,鲕粒岩累计厚度大 ,横向分布较稳定 ,是寻找鲕滩气藏的有利地区 ,目前在铁山坡—开县地区已展示出飞仙关组鲕滩气藏勘探的大场面。海槽内部的宣汉、开江一带无鲕粒岩分布 。

Northeast Sichuan Basin might be divided in to three basic sedimentary fac ies zones,i.e.trough,continental shelf and tableland sedimentary facies zones,du ring Feixianguan Age,The growing of Kaijiang Liangping trough is of obvious con t rol on oolite distribution.Along with an unceasing accretion of the tableland,th e trough was shrunken and finally withered away,which makes the oolite distribut ion showing a regular change in vertical and lateral,the oolite distribution are a being uninterruptedly moved toward the trough and its growing horizon being gr adually freshened from the tableland to the trough.Through research it is indica ted that the Tieshan Liangping and Tieshanpo Kaixian oolite distribution regio ns being located at both sides of the kaijiang Liangping trough are the two benef i cial areas of prospecting for oolitic beach gas reservoirs,being of the properti es as the large accumulative thickness and stable lateral distribution of the oo lite,and a large scale exploration for the oolitic beach gas reservoirs in Fei xianguan Formation has been carried out in the Teishanpo Kaixian region at pres e nt;and there is no oolite distribution at Xuanhan Kaijiang region within the tr ough,where it is unfavourable to prospect for the oolitic beach gas reservoir.