苏里格SW区块高含水致密砂岩气藏优势储层主控因素分析

Analysis of main controlling factors of favorable reservoirs in tight gas sands with high water saturation in SW block,Sulige Gas Field

针对苏里格SW区块储层物性差、含水饱和度高、投产井出水严重、优势储层分布规律认识不清的问题,通过综合分析岩心、测井、地震、生产动态等资料,讨论了影响区块优势储层分布的主要因素。研究表明:SW区块气、水分异差,优势储层需同时考虑含气性和含水性,主要受沉积微相、构造活动及砂泥配置关系等因素控制;优势储层岩性以石英砂岩为主,粒度以中-粗粒为主,孔隙度、渗透率相对较高,含水饱和度相对较低;有利沉积微相是高产井储层发育的基础,同时影响储层的岩石学特征和物性特征,边滩、心滩微相控制优势储层展布;局部构造高部位、逆断层上盘控制局部甜点储层发育,构造高部位有利于天然气富集以及气、水分异;砂泥配置关系对油气运移及封存、储层物性有较大影响,研究区纯砂岩上下发育泥岩的“薄砂厚泥”“砂泥等厚”以及“厚砂薄泥”模式利于优质储层发育。基于以上分析,优选心滩、边滩沉积微相相带,构造高部位且砂泥匹配良好区域为优势储层分布区,为苏里格气田产能建设提供指导。

For the problems of poor physical properties,high water saturation,serious water breakthrough in brought in wells,and unclear understanding of the distribution law of favorable reservoirs in SW block,Sulige Gas Field,this paper discusses the main factors affecting the distribution of favorable reservoirs in the block through comprehensive analysis of core,well logging,seismic,production performance and other data.In SW block,the gas and water are incompletely separated,and gas⁃bearing property and aquosity should be considered in the favorable reservoirs,which are mainly controlled by sedimentary microfacies,tectonic activity and sandstone and mudstone configuration.The lithology of favorable reservoirs is mainly quartzose sandstone,the grain size is mainly medium⁃coarse,the porosity and permeability are relatively high,and the water saturation is relatively low.Favorable sedimentary microfacies are the basis for the reservoir development of high⁃yielding wells,and also affect the reservoir characteristics of petrology and physical property.The point bar and channel bar microfacies control the distribution of favorable reservoirs.Local structural highs and the hanging wall of reverse faults control the development of local sweet⁃spot reservoirs.The high position of structure is conducive to the enrichment of natural gas and the differentiation of gas and water.The configuration of sandstone and mudstone has a great impact on oil⁃gas migration and sealing,and reservoir physical properties.The"thin sand layer with thick mud layer","uniform thickness of sand and mud layers"and"thick sand layer with thin mud layer"models of mudstone developed above and below the clean sandstone in the study area are favorable to develop high⁃quality reservoirs.Based on the above analyses,the channel bar and point bar sedimentary microfacies belts,and the regions in the high position of the structure with well⁃matched sandstone and mudstone are the favorable reservoir distribution areas,providing guidance for the productivity construction of Sulige Gas Field.