川西气田深层须家河组致密砂岩气藏成藏地质条件和勘探开发核心技术

The Geologic Condition of Gas Accumulation and the Key Technology of Exploration and Exploitation of the Deep Tight Sand Gas Reservoir of Xujiahe Formation in the West of Sichuan Basin

川西气田须家河组具有资源丰富、储层厚大、保存条件良好、圈闭发育、成藏配套条件良好等天然气成藏地质条件。大型古隆起和斜坡区是天然气区域成矿带,继承性发育的古构造是天然气富集的有利地区,相对优质储层发育是天然气富集和稳产的基础,裂缝发育是高产的关键,相对优质储层叠加规模裂缝构成高产富集带。气藏具有埋藏深、高应力、高压、高温、致密、非均质等特征,高产富集带预测和规模建产难度大。针对高产富集带特点和气藏工程地质特征,初步形成了转换波三维三分量地震勘探和超高压大型水力压裂开发两大核心技术。勘探开发成效表明,基于转换波三维三分量地震资料的高产富集带预测技术,能较好地解决川西气田深层须家河组致密裂缝型气藏优质储层识别、裂缝检测及含气性预测等问题。基于提高深层高应力储层单井产量的超高压大型压裂技术,能较好地解决川西气田深层须家河组致密气藏规模建产的难题。

The gas fields in the west of Sichuan Basin in Xujiahe formation have lots of geologic conditions of gas accumulation such as rich resources,thick reservoirs,good conservation conditions,trap growth and good matching conditions.The large scale palaeohigh and slope areas are the mineralization belts of the natural gas.The inherited palaeostructures are the enriched areas of the natural gas.The good development of relative high-quality reservoirs is the base of the gas enrichment and the stable production and fractures are the key point of high productivity.The productive enriched zone is made up of relative good reservoirs with a lot of sized fractures.The gas reservoirs have many characters of deep burial depth,high stress,high pressure,high temperature,tight rocks and the heterogeneity.It is difficult to predict the highly productive and enriched zones and to make the sized production.According to the features of highly productive and enriched zones and the gas reservoir engineering geology,it initially forms two key technologies:triaxial and three-component converted wave technology of seismic data and large-scale hydrofracturing at ultrahigh pressure.The result of exploration and exploitation shows that the former can effectively resolve many problems such as good reservoirs'identification,fractures detection and the gas bearing probability forecast of the deep Xujiahe formation in the west of Sichuan Basin.The latter based on the single well production's promotion of deep reservoirs with high stress can effectively work out the question how to construct the deliverability of the deep tight sand gas reservoir of Xujiahe formation in the west of Sichuan Basin.