川西坳陷低阻致密砂岩储层测井评价方法  

WELL-LOGGING IDENTIFICATION OF LOW-RESISTIVITY TIGHT SANDSTONE RESERVOIRS, WESTERN SICHUAN DEPRESSION

作　　者：张世懋[1] 葛祥[1] 

机构地区：[1]中国石化西南石油工程有限公司测井分公司

出　　处：《天然气勘探与开发》2016年第3期25-29,4-5,共5页Natural Gas Exploration and Development

摘　　要：对四川盆地川西坳陷叠覆型致密砂岩气藏的勘探由正向构造转向负向构造中的有利圈闭,在低阻致密储层中也获得了较好的油气发现,但低阻致密砂岩储层难以利用沉积微相分析、井间类比分析等方法进行识别与有效评价。通过对低阻致密储层地质与测井特征进行分析,总结低阻致密储层与常规致密储层的特征差异,研究储层、地层水特征,结合其构造特征,认为在中—高地层水矿化度背景下,孔隙结构复杂、束缚水饱和度偏高是导致气层低阻的主要原因,其分布规律受构造因素控制。利用测井方法对低阻致密储层进行评价时,可先对储层的含气性进行判别,再通过可动水饱和度计算与侵入特征分析等多方法的结合,对地层水的可动性进行分析,并计算储层品质参数,对低阻致密储层进行综合评价。该方法较好地解决了川西坳陷低阻致密储层测井评价的难题,在天然气勘探开发中取得了良好的应用效果。An exploration of tight sandstone gas reserior in the Western Sichuan Depression had been started to devote to favorable traps in negative structures rather than positive ones. In particular, many better discoveries had been obtained from low-resistivity tight reservoirs. However, it is very hard to effectively identify and evaluate them by such methods as sedimentary microfacies analysis and wells analogy. In this study, we analyzed their geological and well-logging characteristic, summarized the differences between these reservoirs and conventional tight ones,and explored the reservoir and formation-water features. It's deemed that(1)both complex porous structure and high irreducible-water saturation are the main factors for low resistivity if formation water has middle to high salinity; and(2)the distribution of low resistivity is affected by structural factors. So, during a well-logging evaluation, the gas-bearing property should be identified at first;secondly the mobility of formation water should be analyzed by calculation of water-movable saturation and analysis of invasion features; thirdly some reservoir parameters are calculated; finally this low-resistivity tight reservoir is evaluated. Through these procedures, some difficulties in evaluating these low-resistivity tight sandstone reservoirs may be solved, and a better application effect may also gain.

关 键 词：四川盆地 川西坳陷 负向构造 致密砂岩 气藏 低阻储层 束缚水饱和度 测井评价 

分 类 号：P618.13[天文地球—矿床学] P631.81[天文地球—地质学]