二连盆地乌兰花凹陷安山岩成藏主控因素分析

Analysis on Accumulation Controlling Factors of Andesite in Wulanhua Sag of Erlian Basin

近期,二连盆地乌兰花凹陷安山岩油藏勘探取得了重大突破,展现了该凹陷新领域良好的勘探前景,然而对安山岩油藏成藏模式及成藏主控因素的认识不清,制约着该区块油气勘探开发的正常进行,多数井存在失利。为进一步研究安山岩油藏成藏规律,从油源、储集条件、储盖组合以及安山岩油藏的成藏条件等方面进行系统分析,在此基础上构建了乌兰花凹陷安山岩油藏“源内-相控复合岩性油藏”成藏模式。结果表明:优质烃源岩的分布控制着火成岩成藏的物质基础,溢流相的展布控制着有效储层的发育程度,断层的发育程度控制着安山岩展布以及油气运移。该研究为安山岩油藏的成藏规律研究提供了新的思路和方法,对类似地区安山岩油藏的勘探开发具有借鉴意义。

Recently, great breakthroughs have been made in the exploration of andesite reservoirs in Wulanhua Depression, Erlian Basin, which shows good prospects for exploration in the new area of the depression. However, the unclear understanding of the reservoir-forming model and main controlling factors of andesite reservoirs restricts the normal exploration and development of oil and gas in this area, and most wells fail. In order to further study the reservoir-forming regularity of andesite reservoir, this paper systematically analyses the source, reservoir conditions, reservoir-cap assemblages and reservoir-forming conditions of andesite reservoir, and on this basis, builds the reservoir-forming model of“intra-source-facies controlled composite lithologic reservoir”of andesite reservoir in Wulanhua sag. The results show that the distribution of high quality source rocks controls the material basis of igneous reservoir formation, the distribution of overflow facies controls the development of effective reservoirs, and the development of faults controls the distribution of andesite and hydrocarbon migration. This study provides new ideas and methods for the study of reservoir-forming law of andesite reservoirs, clears up obstacles for later exploration and development deployment, and has certain reference significance for the exploration and development of andesite reservoirs in similar areas.