Study On Fracturing Control Volume Of Shale Gas Reservoir

Learning from America’s shale gas successful exploitation, as the new unconventional resource, shale gas has been hot topics in our country natural gas development. Influenced by the ultra-low permeability in shale formation, shale gas reservoir always do not exist the natural productivity and must rely on some hydraulic stimulation treatments to achieve productivity, However, network fracturing technology.which’s attention is increase the stimulation reservoir volume, is the most prominent. Accurately predict the swept volume from network fracturing is the key link of hydraulic fracturing optimization design for shale gas, but at present, the mechanism of form network and the calculated model of swept volume are not perfect enough. This paper based on the related theory knowledge of fluid mechanics, elastic mechanics and seepage mechanics, considering hydraulic fracture and natural fracture interacted models and combining intersection criterion making a research and discuss deeply for the intersection mechanism of network fracturing for shale gas reservoir. In this paper, we set up the model of network fracturing and calculate the swept volume by numerical computation method, and make a detailed analysis that the related parameters" effect on swept area. The main content includes the following aspects:(1) Based on the theory of elastic mechanics and considered hydraulic fracture and natural fracture interaction, established the intersection criterion of different damage (shear, open and through) occurs in the intersection point, and made a full analysis and computation for the situation of possible occur.(2) and elastic mechanics, the inside natural fracture pressure and width distribution model of close and open of natural fracture, and made a numerical simulation analysis for the hydraulic fracture extend under the action of nature fracture.(3) Based on the theory of seepage mechanics and fluid mechanics, established the network fracturing models of shale gas reservoir, and combining the width equation of open natural fracture to calculate the swept volume of fracture network, and wrote the numerical program for simulating swept scope of shale gas reservoir by Visual Basic6.0software. At the same time, using the program to simulate the effect of injection fluid rate, injection fluid viscosity, natural fracture density, horizontal principal stress difference and elasticity modulus on stimulate reservoir volume.