School of Energy,China University of Geosciences ( Beiing) Bejing Key Lab of Unconventional Natural Gas Geology
Evaluation and Development Engineering Huabei Oilfield Branch,China National Petroleum Corporation Coalbed
Methane Pilot Test Base,China National Petroleum Corporation

为提高煤层气井的压裂效率,通过利用ANSYS有限元软件,模拟了煤层气井压裂过程中的降低煤层破裂压力的各种途径和方法,研究建立了套管射孔完井的应力计算模型,并计算了模拟煤岩破裂压力,分析了射孔长度、孔径、煤岩的泊松比与杨氏模量、地层深度等对煤岩破裂压力的影响。模拟结果表明,当射孔长度和射孔孔径分别控制在1 m左右和15 mm左右的情况下,有利于降低煤岩的破裂压力;较低的煤岩泊松比在一定程度上有利于减小破裂压力;煤岩杨氏模量对破裂压力的影响不大;而煤层的深度越大,其破裂压力受水平主应力差的影响越小。

In order to improve the fracturing efficiency of the coalbed methane well,an ANSYS finite element software was applied to simulate the different path and m ethod to reduce the seam fracturing pressure during the coalbed methane well fracturing process. A stress calculation model of the perforation completion was researched and established. Thus a simulated coal 1 rock fracturing pressure was calculated and the perforation borehole length, diameter,coal 1 rock Poisson's Ratio and Young's Mod ulus,strata depth and others affected to the coal 1 rock fracturing pressure were analyzed. The simulation results showed that when the perforation borehole length and dia meter were individually controlled about 1 m and 15 mm,the coal 1 rock fracturing pressure would be favorably reduced. A low coal 1 rock Poisson's ratio would be favorable to reduce the fracturing pressure in a certain degree. The coal 1 rock Young's Modulus would not have high influence to fracturing pressure. While more deep depth of sea m,the fracturing pressure would have a less influence by horizontal main stress difference.

国家科技重大专项资助项目(2011ZX05061,2011ZX05034-001)；国家自然科学基金青年基金资助项目(41102099)；