英西地区盐相关构造特征及其油气地质意义

Salt-related Structural Features and Their Oil and Gas Geological Significance in Yingxi Area,Qaidam Basin

英西地区深部碳酸盐岩地层油气勘探近年来取得突破。针对英西地区下干柴沟组上段膏盐岩-碳酸盐岩组合,以三维地震勘探为基础,运用盐构造理论,对其构造演化特征,及其在油气成藏中的作用进行分析。结果表明,挤压构造环境下,塑性膏盐岩发生流动、楔入作用,改变原始地层结构,并作为滑脱层促进推覆构造发育,最终形成研究区双层构造特征。挤压环境下盐构造运动,使下伏碳酸盐岩地层发育大量裂缝,改善了储层物性。建议膏盐-碳酸盐地层组合是该区深层油气未来勘探的重点。

The oil and gas exploration for deep part carbonate rocks in the Yingxi area,Qaidam Basin has made breakthroughs in recent years.In allusion to gypseous-salt and carbonate rock association in the Upper Member of the Xiaganchaigou Formation,on the basis of 3D seismic prospecting,using salt tectonic theory carried out analysis of tectonic evolution features and their functions in oil and gas reservoiring.The result has shown that under the compressional environment,plastic gypseous-salt rocks can present flowing and wedging actions,changed original strata configuration.As a decollement layer has promoted the development of nappe structures,finally formed double-layered structural features in the study area.The salt tectonic process under compressional environment can make underlying carbonate rock strata to develop a great deal of fissures,improve the reservoir physical properties.It is suggested that the gypseous-salt and carbonate rock association is the focus of oil and gas exploration for deep part of the area henceforth.