Production performance of horizontal wells with dendritic-like hydraulic fractures in tight gas reservoirs

Abstract Nowadays horizontal wells, combined with hydraulic fracturing technology, have been widely used to produce tight gas at an economic rate. The production performance of the horizontal well can be predicted by analytical or numerical models. In most models, the horizontal wells are assumed to be fractured by bi-wing fractures. However, recent micro-seismic measurements depict a dendritic-like morphology of hydraulic fractures in tight gas reservoirs. This indicates the conventional fracture models are sometimes inapplicable for tight gas simulation. In this paper, a modified off-center well model was coupled in the discrete fracture model (DFM) to predict the production performance of dendritic-like stimulated horizontal wells. Finite volume method was used to discretize the partial differential equations, and the linearized equation system was solved iteratively in a fully implicit scheme. The off-center well model was verified against ECLIPSE. A field case of multi-stage fractured horizontal well from a shale gas reservoir was studied. In addition, the effects of some fracture geometric parameters (e.g., fracture angle, fracture asymmetry and fracture branch number) on well production were investigated in detail. Results show that fracture angle has high relevance to the production performance in that cumulative production tends to be higher with more evenly distributed angles. Fracture asymmetry seems to have little influence upon the production. Fracture branch number has a strong influence on enhancing gas production, but the influence becomes weaker with increasing branch number. This paper provides us a better understanding of dendritic-like fractured gas reservoirs.

[1]  Thomas Alwin Blasingame,et al.  Constant-Rate Drawdown Solutions Derived for Multiple Arbitrarily-Oriented Uniform-Flux, Infinite-Conductivity, or Finite-Conductivity Fractures in an Infinite-Slab Reservoir , 2006 .

[2]  D. W. Peaceman.  Interpretation of well-block pressures in numerical reservoir simulation with nonsquare grid blocks and anisotropic permeability , 1983 .

[3]  Leonid N. Germanovich,et al.  Hydraulic fracture with multiple segments I. Observations and model formulation , 1997 .

[4]  Michael J. Mayerhofer,et al.  Stimulating Unconventional Reservoirs: Maximizing Network Growth While Optimizing Fracture Conductivity , 2009 .

[5]  Morphology and Growth of Fractures in Unconventional Reservoirs , 2011 .

[6]  Wanjing Luo,et al.  Pressure-Transient Analysis of Multiwing Fractures Connected to a Vertical Wellbore , 2015 .

[7]  Hanqiao Jiang,et al.  The investigation of fracture aperture effect on shale gas transport using discrete fracture model , 2014 .

[8]  A. Firoozabadi,et al.  Control‐volume method for numerical simulation of two‐phase immiscible flow in two‐ and three‐dimensional discrete‐fractured media , 2004 .

[9]  Jan M. Nordbotten,et al.  An efficient multi-point flux approximation method for Discrete Fracture-Matrix simulations , 2012, J. Comput. Phys..

[10]  Y. Saad,et al.  GMRES: a generalized minimal residual algorithm for solving nonsymmetric linear systems , 1986 .

[11]  Christopher R. Clarkson,et al.  Integration of microseismic and other post-fracture surveillance with production analysis: A tight gas study , 2011 .

[12]  F. Javadpour.  Nanopores and Apparent Permeability of Gas Flow in Mudrocks (Shales and Siltstone) , 2009 .

[13]  Louis J. Durlofsky,et al.  An Efficient Discrete Fracture Model Applicable for General Purpose Reservoir Simulators , 2003 .

[14]  K. Sepehrnoori,et al.  Sensitivity analysis of hydraulic fracture geometry in shale gas reservoirs , 2014 .

[15]  Lucas W. Bazan,et al.  Optimization of Multiple Transverse Hydraulic Fractures in Horizontal Wellbores , 2010 .

[16]  T. Blasingame,et al.  Improved Permeability Prediction Relations for Low Permeability Sands , 2007 .

[17]  Yu Ding,et al.  A New Representation of Wells in Numerical Reservoir Simulation , 1994 .

[18]  Ho-Jeen Su.  Modeling of Off-Center Wells in Reservoir Simulation , 1995 .

[19]  Li Li,et al.  Development of a new compositional model with multi-component sorption isotherm and slip flow in tight gas reservoirs , 2014 .

[20]  John E. Chappelear,et al.  Representing Wells in Numerical Reservoir Simulation: Part 1 - Theory , 1981 .

[21]  Mario H. Gonzalez,et al.  The Viscosity of Natural Gases , 1966 .

[22]  Hanqiao Jiang,et al.  The impact of diffusion type on multiscale discrete fracture model numerical simulation for shale gas , 2014 .

[23]  L. Klinkenberg.  The Permeability Of Porous Media To Liquids And Gases , 2012 .

[24]  Christine Ehlig-Economides,et al.  Rate-Normalized Pressure Analysis for Determination of Shale Gas Well Performance , 2011 .

[25]  Hussein Hoteit,et al.  An efficient numerical model for incompressible two-phase flow in fractured media , 2008 .

[26]  Kamy Sepehrnoori,et al.  Development of a Coupled Dual Continuum and Discrete Fracture Model for the Simulation of Unconventional Reservoirs , 2013, ANSS 2013.

[27]  A. Firoozabadi,et al.  An efficient numerical model for multicomponent compressible flow in fractured porous media , 2014 .

[28]  Jiamin Jiang,et al.  Numerical study of complex fracture geometries for unconventional gas reservoirs using a discrete fracture-matrix model , 2015 .

[29]  Patrick Jenny,et al.  A hierarchical fracture model for the iterative multiscale finite volume method , 2011, J. Comput. Phys..

[30]  Chen Yizhou,et al.  Productivity estimations for vertically fractured wells with asymmetrical multiple fractures , 2014 .

[31]  Todd Arbogast,et al.  Derivation of the double porosity model of single phase flow via homogenization theory , 1990 .

[32]  Sebastian Geiger,et al.  A Novel Multi-Rate Dual-Porosity Model for Improved Simulation of Fractured and Multiporosity Reservoirs , 2013 .