Study On Hydraulic Fracturing Design Of Coalbed Methan

Coalbed Methan is autogenous and self-storage hydrocarbon gases in the coal which is composed of the matrix and the cleat system. Its main component is methane. Most of them are adsorbed on the particle surface of the coal matrix-based. And part of them are separated from the coal porosity or dissolved in the water of the coal seam. Coalbed Methan is a new, clean and efficient energy sources. Our country has rich coal and coalbed methane resources. Below the depth of2000metres the coal resources have five trillion and five hundred and seventy billion ton and coalbed methane resources are between thirty trillion and thirty five trillion cubic metres. And they mainly distribut in our country’s13basins. The exploitation of high-quality clean coalbed methane not only can solve the pollution problems caused by coal production and safety issues, but also can compensate for the shortage of conventional energy development and utilization. But due to the low-saturation, low-permeability and low-voltage characteristics, our country’s coalbed methane reservoir need to take certain measures to strengthen yield, in order to achieve the commercial development of coalbed methane. And the application of the most popular means of strengthening is the hydraulic fracturing technology. Because the low seam strength, natural fracture’s development, low rock Young’s modulus, high Poisson, low hardness and easily broken, hydraulic fracturing of coal seam is relatively easy. The purpose of CBM hydraulic fracturing wells are:Set up and connect borehole and remote high seepage paths-improve the seam water production-reduce the pore pressure of coal matrix-increase the amount of seam gas desorption-increase the single well coalbed methane production. And reasonable use of coalbed methane wells hydraulic fracturing technology can speed up the rate of coalbed methane desorption, proliferation and seepage to enhance coalbed methane recovery.Firstly, starting from the document of the research at home and abroad, I introduced the problems we faced of CBM development status, the hydraulic fracturing state of model development, the fracturing design, software development and coalbed methane development at home and abroad. Then I study the mechanism of coal and rock fracturing, And develp the purpose and principle of the hydraulic fracturing of coalbed methane wells, the difference between it and conventional oil and gas hydraulic fracturing and crack distribution law. The hydraulic fracturing technology is an important techtology means of CBM well stimulation at home and abroad. Choice of fracturing fluid is a key factor in determining its success or failure. And choice of proppant is the most important factor for the fracture conductivity. For fracturing fluid additives, we should add as little organic matter as possible into coal seams to reduce formation damage; For coalbed methane well injection technology, our main target is to build a long slit, to reduce formation damage, to improve the ability of fracturing and carrying capacity and to improve the fracture conductivity.The ultimate goal of the hydraulic fracturing of coalbed methane wells is to stimulate the production of coalbed methane. Whether fracturing process, construction parameters, the performance and compatibility of fracturing fluid, fracturing scale selection and optimization are reasonable will affect the final results of the hydraulic fracturing of coalbed methane wells. Therefore, before the hydraulic fracturing of coalbed methane wells, the collection of data, the necessary lab experiments, adequate domestic and international research and analyze and summarize the past fracturing coalbed methane well is very important for fracture design preparation work.In the process of fracturing design, the crack geometry and conductivity is the main focus. Fracture geometry and conductivity is determined by the factors of reservoir and the racturing construction and so on. In addition to obtain the geometry and conductivity, the fracturing design should ensure how to implement the engineering design of the cracks. The uncontrollable factors of design process involves the mechanical properties of coal, rock strata structure and stress field. There are many controllable factors. Such as the total fluid volume, the amount of sand, construction emissions, fracturing construction equipment, and formationthe compatibility of the fracturing fluid and the support agent. The optimization of fracturing design requires a variety of techniques to ensure the support crack geometry and the production after pressure, which includes two aspects of the optimization of support crack length and infusion procedures and construction parameters according to adjective crack length and support dose.Qinshui Basin, located in the southeast of Shanxi Province, is overall oval shape of long axis along the northeast extension and middle shrink. Qinshui Basin is the most important distribution area of northern China Carboniferous-Permian coal resources. Because its southeast has better coal structure, higher permeability and higher gas content, Qinshui Basin become coalbed methane development hotspots of our country.Shanxi CBM exploration and development branch of China Petroleum learns from success and failures and practical experience at home and abroad in the coalbed methane fracturing. And they carry on a large-scale fracturing developments of Fanzhuang block. To use active water fracturing fluid and clean fracturing fluid, this article use FracProPT2007fracturing design software to design and optimize Punan1-2 wells and select the appropriate parameters to make the design results more reasonable. And then choose active water fracturing fluid to optimize and design the well. On the basis of all relevant factors affecting coalbed methane fracturing effect and relevant information of the scene construction parameters and summary of the fracturing operation,I focus on Qinshui coalbed the effectiveness of measures of the gas field Fanzhuang one, three, four, six blocks of145fractured wells, fracturing operation parameters, the fracturing effect and fracturing size and gas production relationship regression statistical analysis, and further optimization of the coal seam gas well hydraulic fracturing process parameters.