Experimental technologies of shale gas exploration and development:Research progress and development direction
The success of shale gas development is attributed to the establishment of brand-new geological theories and the advancement of engineering and technologies.The innovation of geological theories is inseparable from the breakthrough and development of experimental technologies.As the new stage of extensive development of shale gas is ushered,however,higher requirements and technological challenges are raised to experimental methods,basic theories and so on.In view of the key problems in shale gas exploration and development,this paper illustrates the progress and application cases of geological experimental technologies from the aspects of shale mineral composition,petrophysics,pore structure,gas content and fracability,analyzes the problems in and challenges to the experimental research of shale gas exploration and development,and predicts the future development directions and trends.The following results are obtained.First,for shale mineral analysis,thin section identification and X-ray diffraction are the most effective qualitative and quantitative methods,but the experimental study on mineral genesis is of more important guiding significance to reveal the shale reservoir-forming patterns and selecting the geology-engineering sweet spots.Second,for shale physical property testing,there are various methods and the standards are not unified,so it is necessary to select the suitable testing methods based on research objectives,and performing physical property testing under formation conditions is more beneficial for reserve estimation and development effect evaluation.Third,for shale pore structure characterization,a comprehensive evaluation method has been developed from macroscopic to microscopic,from qualitative to quantitative,and from two-dimensional to three-dimensional,which can guide the division of development layers and the selection of horizontal well target window.Fourth,for shale gas content evaluation,experimental methods such as field gas content test,isothermal adsorption and gas carbon isotope monitoring have been established,which reveal the occurrence states and desorption patterns of shale gas and can provide an effective guidance for the formulation of gas well production system and the enhancement of recovery efficiency.Fifth,for shale fracability evaluation,experimental methods such as X-ray diffraction,multi-scale fracture network depiction,triaxial mechanics,differential strain method,acoustic anisotropy method and acoustic emission method have been developed,which can guide the design of horizontal wells and the optimization of fracturing process.The future efforts are proposed to focus on establishing an experimental system integrating multi-scale methods,enhancing the evaluation of shale gas reservoirs under in-situ conditions,conducting dynamic evolution of key parameters,and implementing artificial intelligence experimental evaluation based on big data models.The continuous improvement of the experimental geological technology system for shale gas can provide a better theoretical foundation and technical support for the efficient exploration and development of shale gas.
万方数据
维普
