Evaluation Method For Fracability Of Shale Reservoirs Based On Analytic Hierarchy Process

Shale gas is organic matter of mud shale and the interlayer non-conventional natural gas. It is a kind of clean and high-efficient energy resources and industrial chemicals. Shale gas is abundant in C hina, 36 trillion cubic meters of recoverable resources is 1.6 times the amount of the conventional natural gas. More research was done on shale gas abundance condition, accumulation mechanism and rable area optimization of the innovation method of shale reservoirs by the majority of domestic scholars. To development of shale gas in China, the biggest problem is that neglecting on reservoir reconstruction is just constraint shale gas on development in C hina.Because shale gas reservoir belongs to low porosity that is called ultra low permeability reservoir. In order to realize the economic exploitation, it must to do fracturing operations. For achieving good economic results and avoiding the blindness fracturing of well selection, firstly the scientific evaluation of the compressibility of shale reservoir. Compressibility is Synthetic characteristics of the geological shale and reservoir under the hydraulic fracturing process. Compressibility shows that reservoir formed complex fracture networks and obtained large enough reservoir reconstruction volume and the capability of economic benefit under the same hydraulic fracturing technology. The key parameter of compressibility evaluation includes brittleness coefficient, mineral composition, diagenesis, natural fracture etc. According to various parameters on different influence of comperssibility, Analytical hierarchy process is applied to weighting the different parameters. After standardized value of various parameters, we can calculate comperssibility coefficient of the different shale reservoir through building evaluatio n model of comperssibility.By the detail learning of reservoir reconstruction from abroad, mainly researching on shale reservoir hydraulic fracturing technique. The familiar hydraulic fracturing technology of shale gas has multistage fracturing, hydraulic fracturing, hydrajet fracturing, refracturing and synchronous fracturing ect. According to different characteristics and applicability of shale reservoir, and the characteristics of domestic shale reservoir, it has provided the scheme of suitable for our country current shale reservoir reconstruction. The development of C hina shale gas at the present stage, it is suitable the use N itrogen foam fracturing or high energy gas fracture for the reservoir embedded depth 1500 meters above or exploration shallow well. It is suitable the use hydraulic fracturing for reservoir on embedded depth 1500~3000 meters. Mining large thickness of shale gas well, it can be combined with the characteristics of the reservoir and try to use hydraulic fracturing technology of hydraulic fracturing combined with multi-stage fracturing. It can stop to mine for reservoir on embedded depth 3000 meters below considering the the cost of extraction and the feasibility of the technology.