Numerical Simulation on Influence Parameters of Horizontal Well Hydraulic Fracturing
-
摘要: 水力压裂是低渗油气藏的主要开发手段,传统数值模型所得到的基质-裂缝窜流量以及断裂参数精度不足.为此以流固耦合理论与断裂力学相结合的压裂模型为基础,模拟了水力裂缝扩展过程.在模型中分别引入离散裂缝模型和广义J积分计算基质-裂缝流量交换和断裂参数,并采用动态网格技术对裂缝尖端进行局部加密,以提高模拟的效率和精度.模型计算结果显示,影响水力压裂过程的主要参数中:基质渗透率和压裂液粘度主要影响水力裂缝的最终形态;岩石弹性模量影响裂缝宽度.对压裂车而言,最高工作压力一般都能够满足压裂增产需求,其最大输出功率和最大输出流量是限制压裂能力的主要因素.Abstract: Hydraulic fracturing is the main development method of low permeability reservoir, so it is important to the engineering to address the issue. By combining the fluid-structure interaction theory with fracture mechanics, the propagation of hydraulic fracture is simulated in this paper. Discrete fracture model and generalized J integral are introduced in the proposed model to calculate the flux across the fracture-matrix interface and fracture parameters, respectively. To ensure high precision and efficient simulation, the adaptive mesh refinement technology is introduced in the grids near the crack tip. The results show that the matrix permeability and viscosity of fracturing fluid mainly influence the final shape of hydraulic fracture, while the elastic modulus of rock mainly influence the fracture width. For fracture trucks, the maximum working pressure can generally meet the demand for fracturing production, and the maximum output power and maximum output flow are the main factors limiting the fracturing capacity.
-
表 1 算例2.1参数取值
Table 1. Parameters of example 2.1
物性参数 取值 流体密度(kg/m3) 982.600 流体粘度(mPa·s) 0.456 井半径(m) 0.070 泊松比 0.220 断裂韧度(MPa·m1/2) 2.000 注入流量(m3/min) 0.500 弹性模量(GPa) 35.000 表 2 2.2节中算例参数取值
Table 2. Parameters in section 2.2
物性参数 取值 基质渗透率(mD) 2.000 流固耦合系数 0.890 流体粘度(mPa·s) 0.456 流体密度(kg/m3) 986.200 弹性模量(GPa) 35.000 泊松比 0.220 断裂韧度(MPa·m1/2) 2.000 表 3 在不同渗透率下压裂设备工作参数达到上限时的裂缝尺寸
Table 3. Sizes of fracture for different permeability under rated working conditions
渗透率
(mD)压力达到上限 流量达到上限 功率达到上限 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 1.5 - - - - - - 2.0 - - 91.783 0.222 3 77.851 0.183 3 2.5 95.318 0.233 9 71.749 0.169 0 60.878 0.142 7 3.0 77.450 0.185 9 59.063 0.140 4 49.833 0.121 3 注:表中“-”表示在本文计算的裂缝长度范围内,压力、流量或者功率未达到压裂设备参数的上限. 表 4 在不同弹性模量下压裂设备工作参数达到上限时的裂缝尺寸
Table 4. Sizes of fractures for different elasticity modulus under rated working conditions
弹性模量
(GPa)压力达到上限值 流量达到上限值 功率达到上限值 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 20 - - 92.776 0.383 1 78.161 0.310 8 25 - - 92.776 0.308 2 78.161 0.250 8 30 - - 92.776 0.258 8 78.161 0.221 6 35 - - 92.776 0.224 5 76.161 0.184 1 40 - - 92.776 0.199 8 78.161 0.164 2 注:表中“-”表示在本文计算的裂缝长度范围内,压力、流量或者功率未达到压裂设备参数的上限. 表 5 在不同粘度下压裂设备工作参数达到上限时的裂缝尺寸
Table 5. Sizes of fracture for different fracturing fluid viscosity under rated working conditions
压裂液粘度
(mPa·s)压力达到上限值 流量达到上限值 功率达到上限值 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 缝长(m) 最大缝宽(cm) 0.356 94.841 0.231 2 70.151 0.162 9 60.134 0.138 6 0.406 - - 81.564 0.193 5 68.963 0.159 9 0.456 - - 92.366 0.223 7 77.834 0.183 1 0.506 - - - - 87.258 0.209 3 0.556 - - - - 96.597 0.235 3 注:表中“-”表示在本文计算的裂缝长度范围内,压力、流量或者功率未达到压裂设备参数的上限. 表 6 压裂车主要参数
Table 6. Working parameters for fracturing equipment
产品型号 三一重工SYN5450TYL1860(Y) 杰瑞能源YLC140-1860 山东科瑞KTYL2500-105 设备编号 1 2 3 最大工作压力(MPa) 125 140 105 最大输出流量(m3/min) 1.90 2.17 2.46 最大输出功率(kW) 1 860 1 860 1 836 注:参数来源于三一重工、杰瑞能源和山东科瑞官网. -
[1] Adachi, J.I., Detournay, E., Peirce, A.P., 2010.Analysis of the Classical Pseudo-3D Model for Hydraulic Fracture with Equilibrium Height Growth across Stress Barriers.International Journal of Rock Mechanics and Mining Sciences, 47(4):625-639.doi: 10.1016/j.ijrmms.2010.03.008 [2] Biao, F.J., 2011.A Numerical Study on Horizontal Hydraulic Fracture Propagation (Dissertation).University of Science and Technology of China, Hefei (in Chinese with English abstract). [3] Biot, M.A., 1955.Theory of Elasticity and Consolidation for a Porous Anisotropic Solid.Journal of Applied Physics, 26(2):182-185.doi: 10.1063/1.1721956 [4] Dean, R.H., Schmidt, J.H., 2009.Hydraulic-Fracture Predictions with a Fully Coupled Geomechanical Reservoir Simulator.SPE Journal, 14(4):707-714.doi: 10.2118/116470-pa [5] Fan, T.Y., 2003.Fracture Theory Basis.Science Press, Beijing, 16-17 (in Chinese). [6] Geertsma, J., De Klerk, F., 1969.A Rapid Method of Predicting Width and Extent of Hydraulically Induced Fractures.Journal of Petroleum Technology, 21(12):1571-1581.doi: 10.2118/2458-pa [7] Karimi-Fard, M., Firoozabadi, A., 2003.Numerical Simulation of Water Injection in Fractured Media Using the Discrete-Fracture Model and the Galerkin Method.SPE Reservoir Evaluation & Engineering, 6(2):117-126.doi: 10.2118/83633-pa [8] Khristianovic, S., Zheltov, Y., 1955.Formation of Vertical Fractures by Means of Highly Viscous Fluids.Processing 4th World Petroleum Congress, Rome. [9] Kou, X.D., Zhou, W.Y., 2000.Using Element-Free Method to Trace Crack Propagation.Chinese Journal of Rock Mechanics and Engineering, 19(1):18-23 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSLX200001004.htm [10] Nordgren, R.P., 1972.Propagation of a Vertical Hydraulic Fracture.Society of Petroleum Engineers Journal, 12(4):306-314.doi: 10.2118/3009-pa [11] Perkins, T.K., Kern, L.R., 1961.Widths of Hydraulic Fractures.Journal of Petroleum Technology, 13(9):937-949.doi: 10.2118/89-pa [12] Rahman, M.M., Rahman, M.K., 2010.A Review of Hydraulic Fracture Models and Development of an Improved Pseudo-3D Model for Stimulating Tight Oil/Gas Sand.Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 32(15):1416-1436.doi: 10.1080/15567030903060523 [13] Rice, J.R., 1968.A Path Independent Integral and the Approximate Analysis of Strain Concentration by Notches and Cracks.Journal of Applied Mechanics, 35(2):379.doi: 10.1115/1.3601206 [14] Singh, K., Holditch, S.A., Ayers, W.B., 2008.Basin Analog Investigations Answer Characterization Challenges of Unconventional Gas Potential in Frontier Basins.Journal of Energy Resources Technology, 130(4):043202.doi: 10.1115/1.3000104 [15] Wang, H., 2013.A Numerical Study on Vertical Hydraulic Fracture Configuration and Fracture Height Control (Dissertation).University of Science and Technology of China, Hefei (in Chinese with English abstract). [16] Wu, C.G., 2008.Hydraulics: Part Ⅰ, 4th Edition.Higher Education Press, Beijing, 143-146 (in Chinese). [17] Zhang, B., Li, X., Wang, Y., et al., 2015.Current Status and Prospect of Computer Simulation Techniques of Hydraulic Fracturing in Oil and Gas Field.Journal of Engineering Geology, 23(2):301-310 (in Chinese with English abstract). http://www.gcdz.org/EN/abstract/abstract11683.shtml [18] Zhou, F.Q., Shi, A.F., Wang, X.H., 2014.An Efficient Finite Difference Model for Multiphase Flow in Fractured Reservoirs.Petroleum Exploration and Development, 41(2):262-266.doi: 10.1016/s1876-3804(14)60031-8 [19] 彪仿俊, 2011. 水力压裂水平裂缝扩展的数值模拟研究(博士学位论文). 合肥: 中国科学技术大学. http://cdmd.cnki.com.cn/Article/CDMD-10358-1011124961.htm [20] 范天佑, 2003.断裂理论基础.北京:科学出版社, 16-17. [21] 寇晓东, 周维垣, 2000.应用无单元法追踪裂纹扩展.岩石力学与工程学报, 19(1): 18-23. http://www.cnki.com.cn/Article/CJFDTOTAL-SLXB200601010.htm [22] 王瀚, 2013. 水力压裂垂直裂缝形态及缝高控制数值模拟研究(博士学位论文). 合肥: 中国科学技术大学. http://cdmd.cnki.com.cn/Article/CDMD-10358-1013244689.htm [23] 吴持恭, 2008.水力学:上册.北京:高等教育出版社, 143-146. [24] 张搏, 李晓, 王宇, 等, 2015.油气藏水力压裂计算模拟技术研究现状与展望.工程地质学报, 23(2): 301-310. http://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ201502017.htm