川东石炭系地层─构造复合圈闭气藏的预测、分类和评价

近年来川东石炭系天然气储产量急剧上升的主要原因,就是发现了一批高产地层─构造复合圈闭气藏,如五百梯、龙门场、门西等气藏,但其构式一般较复杂,不易识别和预测,特别是储层尖灭线很难确定.经对历年大量钻探资料的研究后,发现气藏主要分布在石炭系残厚>10m区.以石炭系残厚10m等厚线(据二叠系底界地震反射层的极性、振幅和时差等信息结合地面和井下资料确定)作为储层的尖灭边界,据其展布与石炭系构造和构造等高线相配置的关系,预测出川东石炭系地层-构造复合圈闭有8种类型48个圈闭,已探成功率达65%,还有多半圈闭未探,前景乐观.

FORECAST,CLASSIFICATION AND ASSESMENT FOR GAS RESERVOIRS OF CARBONIFEROUS STRATIGRAPHICSTRUCTURAL COMBINATION TRAPS IN EASTERN SICHUAN

The carboniferous gas reserves and production in Eastern Sichuan are abruptly increased in recent years.The important reason is a lot of highly productive gas reservoirs with strutigraphic-structural trap,such as Wubaiti,Longmenchang and Menxi reservoirs,were discovered.The structures of reservoirs are too complicated to be recognized and predicted especially for reservoir pinch-out line.According to the drilling data in past years,the gas reservoirs are mainly distributed in the areas where carboniferous residuum thickness is more than 10m.So the reservoir pinch-out boundary is fixed on the 10m isopach of carboniferous residuum thickness.(Based on drilling data and interpretation of polarity,amplitude and moveout of seismic reflector in Permian bottom.)On the basis of carboniferous structures and their structural contour lines,it is forecasted that there are 48 kinds of carboniferous stratigraphic-structural combination traps which is divided into 8 types in Eastern Sichuan.The success radio of drilling traps is up to 65%.Most traps are not drilled until now.So there is a bright prospect in Eastern Sichuan.