基于井-震结合的水下分流河道砂岩储层展布分析与评价——以什邡气藏JP35砂组为例

为了评价川西什邡地区蓬莱镇组三段气藏的开发潜力，优选有利区，通过岩心→测井→地震标定，对该气藏及主要目的层的沉积相、储层特征和有利含气储层分布进行分析。结果表明：该气藏可进一步划分为5个砂组，各砂组厚度稳定，沉积时期构造稳定，地势平缓，沉积类型属于浅水湖盆河控三角洲前缘，水下分流河道是砂体发育的最有利沉积微相。目的层JP₃⁵砂组储集岩主要为中—低孔隙度特低渗透率溶孔细粒岩屑砂岩，渗流能力差，是影响储层评价的重要因素。井-震结合的储层展布与含气性综合分析结果显示，相对水下分流河道砂体分布，研究区优质含气储层范围局限，呈不连续条带状，其展布受到沉积微相、河道规模以及局部构造高部位的控制。该方法和研究结果可为研究区及类似地区沉积相分析和储层特征、展布与评价研究以及有利区带优选等提供参考。

Distribution and evaluation of underwater distributary channel sandstone reservoir based on well-seismic combination:a case study of JP35 sand group in Shifang gas reservoir

In order to evaluate the potential and optimize favorable zones of gas reservoir of the third member of Penglaizhen Formation in Shifang area,western Sichuan,joint calibration method of core data,log data and seismic data were used to analyze the sedimentary facies,reservoir characteristics and favorable gas-bearing reservoir distribution of the gas reservoir and JP35 sand group.The results show that the gas reservoir can be further divided into five sand groups,and the thickness of each sand group is stable.The tectonic setting was stable and the strata were gentle during the sedimentary period.The sediment belongs to shallow-water river-controlling delta front,and the underwater distributary channel is the most favorable sedimentary microfacies.The reservoir rock of JP35 sand group is dominated by of medium-low porosity and ultra-low permeability dissolved fine-grained lithic sandstone,with poor seepage capacity,which is an important factor affecting reservoir quality evaluation.The comprehensive analysis results of reservoir distribution and gas-bearing property based on well-seismic combination show that,compared with the distribution of underwater distributary channel sand bodies,the distribution range of high-quality effective gas-bearing reservoirs is relatively limited with the characteristics of discontinuous bands,and its distribution is controlled by sedimentary microfacies,distributary channel scale and local high part of the structure.This method and research results can provide reference for analyses of sedimentary facies,reservoir characteristics,distribution and evaluation of the study area and similar areas,as well as the optimization of favorable zones.