【摘要】 对川西南部地区侏罗系砂泥岩剖面“泥包砂”气藏,储层的“裂缝性”和含气砂体的“隐蔽性”是制约气藏勘探的两大难点,开辟了从声波测井资料探讨有利储层分布的新思路。认为,地层的声波平均速度差异反映了两种地质现象:一是砂/泥比的变化;二是岩石疏松程度的变化,即孔隙度和裂缝的变化。当砂/泥比为固定值时,声波测井速度的变化实际上反映了孔隙度和裂缝的变化,即储层物性的好坏。通过对白马庙气田沙溪庙组产气井的验证,符合率达75%~100%。该方法能够回避以往只针对某一单砂层的地震储层预测技术,使声波平均速度探讨有利储层的分布更具宏观性、合理性,为地震储层预测砂泥岩剖面的有利目标提供了新思路。更多还原

【Abstract】 For the ‘sand in shale’gas reservoirs of Jurassic sand and shale rocks in the southwest Sichuan area, the ‘fractured property’of reservoirs and the‘hidden property’of gas-bearing sand bodies are the 2 problems to curb the exploration of gas reservoirs. The article opens a new idea to find the distribution of the favorable prospects by sonic logging data. It is thought the difference of the sonic average velocities of the formation reflects the following 2 geological phenomena: one is the variation of sand/shale ratio, the other is the variation of rock looseness (i.e. the variation of porosity and fractures). When the sand/shale ratio is constant, the variation of sonic logging velocity actually reflects the variation of porosity and fractures,i.e.,how the physical property of the reservoir is. With the gas wells of Shaximiao Group of Baimamiao Gas Field to verify the conclusion, the fitting rate reaches 75%~100%. The method can be used besides the seismic reservoir prediction technology that only aims to a single sand formation in the past. It is more macro and logical to study the distribution of favorable prospects by sonic average velocity, which provides a new idea for favorable targets finding on the sand/shale sections with seismic reservoir prediction.更多还原