川西北双鱼石地区下二叠统栖霞组气水分布特征及主控因素

川西北双鱼石地区下二叠统栖霞组是目前最有潜力的勘探领域之一,针对该地区栖霞组气藏气水分布特征和主控因素不清的问题,通过对实验测试、钻测井、地震解释、生产动态等资料综合分析,系统阐明了该区流体性质和气水分布特征,并进一步讨论了气水分布的主控因素。结果表明:双鱼石地区栖霞组天然气是典型的干气,产出液分为地层水、返排液、凝析水3种类型,地层水化学特征表明气藏保存条件较好;有地层水产出的井主要分布在构造低部位或紧邻构造低部位的断层附近,气藏具有构造高部位储层连片含气,构造低部位受断层封堵局部含水的特征,局部气水关系复杂;气水分布主控因素有构造位置和构造幅度、断层局部封堵性、烃源岩生烃强度、储层物性和非均质性以及古地貌特征等。该成果可为指导栖霞组有利勘探区带评价及寻求规模储量接替领域提供理论支撑。

Gas-water distribution characteristics and main controlling factors of Lower Permian Qixia Formation in Shuangyushi area,NW Sichuan Basin

The Lower Permian Qixia Formation in Shuangyushi area of northwestern Sichuan Basin is one of the most potential exploration fields at present. Aiming at the unclear gas water distribution characteristics and main controlling factors of gas reservoirs of Qixia Formation in this area,the fluid properties and gas water distribution characteristics in this area were systematically clarified through experimental test analysis,drilling and logging data analysis,seismic data interpretation and production dynamic data analysis,and the main controlling factors of gas-water distribution were further discussed. The results show that the natural gas of Qixia Formation in shuangyushi area is typical dry gas,and the produced fluid can be divided into three types:formation water,flow-back fluid and condensate water. The chemical characteristics of formation water show that the gas reservoir has good preservation conditions. The production wells are mainly distributed in the low part of the structure or near the fault close to the low part. The gas reservoir has the characteristics of continuous gas-bearing in the high part of the structure,local water-bearing in the low part of the structure blocked by the fault,and the local gas-water relationship is complex. The main controlling factors of gas-water distribution are structural location and amplitude,local sealing of faults,hydrocarbon generation intensity of source rocks,reservoir physical properties,heterogeneity and paleogeomorphology. The research results can provide theoretical support for guiding the evaluation of favorable exploration zones of Qixia Formation and seeking the replacement field of large-scale reserves.