大巴山南缘中岗岭—黑楼门剪切断裂带识别及其勘探实践中的意义

IDENTIFICATION OF ZHONGGANGLING-HEI-LOUMEN SHEAR FAULT ZONE ALONG THE SOUTHERN MARGIN OF DABA MOUNTAINS AND ITS SIGNIFICANCE IN EXPLORATION PRACTICE

重磁力异常揭示沿中岗岭—黑楼门存在分隔四川盆地地块和大巴山地块的基底断裂 (中岗岭—黑楼门剪切断裂带 ) ;地质体分析 ,由北往南 ,再造南秦岭地区、大巴山地块、中岗岭—黑楼门剪切断裂带、四川盆地地块 ,孤峰期和长兴晚期—大隆期沉积建造 ,表明中岗岭—黑楼门剪切断裂带是古生代业已存在的隐伏断裂带 ;通过构造区带划分 ,使勘探热点大巴山地块、黑楼门构造带、铁山坡构造—五宝场构造归属不同大地构造单元。进而初步建立“稳定地台、台缘隆起地块与油气成藏模式” ;获得稳定地台边缘有利于形成大型复合性圈闭油气藏 ,推覆体滑脱层之下台缘隆起地块的大型断褶构造是潜在勘探目标。用此模式预测五宝场北斜坡存在白马庙—尖山峰—青龙飞仙关组鲕粒滩勘探有利区带 ,提出了地震重点勘探建议、预测铁山坡构造存在飞仙关组 1～ 3段鲕粒 (粒屑 ) (云化 )灰岩储层 ,提出了坡 1井钻探建议、钻前预报了黑楼门 1井风险等勘探建议 ,均为勘探实践验证。

Through gravitational and magnetic exploration,i t is revealed that there is a basement fault along Zhonggangling Heiloumen (i.e .Zhonggangling Heiloumen shear fault zone)separating Sichuan Basin land block f rom Daba Mountain massif.Geological body analysis through reconstructing the sedime ntary formation,formed during Gu feng Age and late Changxing Age Dalong Age,of t he South Qinling region,Daba Mountains massif,Zhonggangling Heiloumen shear fau l t zone and Sichuan Basin land block from north to south inidicates that the Zhon ggangling Heiloumen shear fault zone has been a buried fault zone since Paleozo i c.According to tectonic division,the current key exploration areas,as Daba Mount ain massif,Heiloumen structural belt and Tieshanpo structure Wubaochang structu r e,belong to different geotectonic units,thus preliminarily setting up 'a reserv oir formation model of stable platform and platform edge uplift land block' .The stable platform edge being beneficial to forming large sized oil and gas r e servoir with combination trap and the large sized fault fold structure of the pl atform edge uplift land block under nappe detachment horizon are the potential e xploration targets.By use of such a model,the beneficial exploration area of ool itic beach in Feixianguan at Baimamiao Jianshanfeng Qinglong region being loca te d in the North Wubaochang slope is predicted;a suggestion on seismic key explora tion area is proposed;it is predicted that there is T 1 f 1～3 oolitic (grainy,dolomitized) limestone reservoir in Teishanpo structure;and the suggestions on drilling well P o 1 and predicting the risk of the well Heiloumen 1 before drilling are pu t forward in the paper.All of these were examined by exploration practice.