贵州煤层气储层特征及勘探开发技术对策——以比德—三塘盆地为例

Characteristics and technical measures of exploration and development of coalbed methane reservoir in Guizhou Province:A case of Bide-Santang area

合理的储层改造和排采工艺技术是煤层气勘探开发的关键环节。在剖析比德—三塘地区煤层气地质与储层特征基础上,总结贵州省煤层气地质特征为:煤层多、累计厚度大(20 m以上)、含气量高(一般大于15 m^3/t)、资源丰度高(一般大于2亿m^3/km^2)、临储比高(一般0.8以上);但断层多、煤层跨度大(300 m左右)、地应力高、渗透性低、含水性差。提出可捞式桥塞分段压裂、连续油管水力喷射射孔分段压裂、电缆射孔桥塞联作分段压裂、复配低伤害压裂液等工艺技术。采用递进排采技术,优化管柱结构,实施动态分析的精细化排采。

The rational transformation of reservoir and reasonable drainage technology are the key links for CBMexploration and development.On the analysis of CBM geological and reservoir characteristics in Bide-Santang area,the CBM geological characteristics are summarized as multiple seams,big cumulative coal thickness(more than20m),and high gas content(more than15m3/t),high resource abundance(more than2×108m3/km2),high ratio ofcritical desorption pressure and reservoir pressure(more than0.8).But there exist many faults,big distance amongcoalseams(about300m),high ground stress,low permeability,poorly water-bearing.The technologies were proposedsuch as sataged fracturing by fishable bridge plug,staged fracturing by hydraulic jet with coiled tubing,staged fracturing by combined operation of cable perforation and bridge plug,fracturing fluid compound of littledamage.Progressive drainage technology was adopted.Pipe string was optimized.Refined drainge with dynamicanalysis was carried out.