An Integrated Numerical Simulation Scheme to Predict Shale Gas Production of a Multi-Fractured Horizontal Well

2017 ◽  
Author(s):  
Jie Zhan ◽  
Jing Lu ◽  
Allan Fogwill ◽  
Ivan Ulovich ◽  
Jili Paul Cao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Horizontal Well ◽  
Gas Production ◽  
Fractured Horizontal Well ◽  
Simulation Scheme

Numerical Simulation for Shale Gas Flow in Complex Fracture System of Fractured Horizontal Well

2018 ◽  
Vol 19 (3-4) ◽  
pp. 367-377 ◽  
Author(s):  
Yingzhong Yuan ◽  
Wende Yan ◽  
Fengbo Chen ◽  
Jiqiang Li ◽  
Qianhua Xiao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shale Gas ◽  
Horizontal Well ◽  
Fracture Network ◽  
Gas Reservoir ◽  
Complex Fracture ◽  
Shale Gas Reservoir ◽  
Fracture Parameters ◽  
Fracture Systems ◽  
Fractured Horizontal Well

AbstractComplex fracture systems including natural fractures and hydraulic fractures exist in shale gas reservoir with fractured horizontal well development. The flow of shale gas is a multi-scale flow process from microscopic nanometer pores to macroscopic large fractures. Due to the complexity of seepage mechanism and fracture parameters, it is difficult to realize fine numerical simulation for fractured horizontal wells in shale gas reservoirs. Mechanisms of adsorption–desorption on the surface of shale pores, slippage and Knudsen diffusion in the nanometer pores, Darcy and non-Darcy seepage in the matrix block and fractures are considered comprehensively in this paper. Through fine description of the complex fracture systems after horizontal well fracturing in shale gas reservoir, the problems of conventional corner point grids which are inflexible, directional, difficult to geometrically discretize arbitrarily oriented fractures are overcome. Discrete fracture network model based on unstructured perpendicular bisection grids is built in the numerical simulation. The results indicate that the discrete fracture network model can accurately describe fracture parameters including length, azimuth and density, and that the influences of fracture parameters on development effect of fractured horizontal well can be finely simulated. Cumulative production rate of shale gas is positively related to fracture half-length, fracture segments and fracture conductivity. When total fracture length is constant, fracturing effect is better if single fracture half-length or penetration ratio is relatively large and fracturing segments are moderate. Research results provide theoretical support for optimal design of fractured horizontal well in shale gas reservoir.

scholarly journals Ensemble-based optimization of hydraulically fractured horizontal well placement in shale gas reservoir through Hough transform parameterization

2021 ◽  
Author(s):  
Liang Xue ◽  
Shao-Hua Gu ◽  
Xie-Er Jiang ◽  
Yue-Tian Liu ◽  
Chen Yang
Keyword(s):  
Simulation Model ◽  
Shale Gas ◽  
Horizontal Well ◽  
Gas Production ◽  
Design Parameters ◽  
Hydraulic Fractures ◽  
Gas Reservoir ◽  
Well Drilling ◽  
Shale Gas Reservoir ◽  
Fractured Horizontal Well

AbstractShale gas reservoirs have been successfully developed due to the advancement of the horizontal well drilling and multistage hydraulic fracturing techniques. However, the optimization design of the horizontal well drilling, hydraulic fracturing, and operational schedule is a challenging problem. An ensemble-based optimization method (EnOpt) is proposed here to optimize the design of the hydraulically fractured horizontal well in the shale gas reservoir. The objective is to maximize the net present value (NPV) which requires a simulation model to predict the cumulative shale gas production. To accurately describe the geometry of the hydraulic fractures, the embedded discrete fracture modeling method (EDFM) is used to construct the shale gas simulation model. The effects of gas absorption, Knudsen diffusion, natural and hydraulic fractures, and gas–water two phase flow are considered in the shale gas production system. To improve the parameter continuity and Gaussianity required by the EnOpt method, the Hough transformation parameterization is used to characterize the horizontal well. The results show that the proposed method can effectively optimize the design parameters of the hydraulically fractured horizontal well, and the NPV can be improved greatly after optimization so that the design parameters can approach to their optimal values.

IMPACTS OF ZONE FRACTAL PROPERTIES ON SHALE GAS PRODUCTIVITY OF A MULTIPLE FRACTURED HORIZONTAL WELL

Fractals ◽  
2019 ◽  
Vol 27 (02) ◽  
pp. 1950006 ◽  
Author(s):  
BOWEN HU ◽  
J. G. WANG ◽  
DI WU ◽  
HUIMIN WANG
Keyword(s):  
Fractal Dimension ◽  
Numerical Model ◽  
Shale Gas ◽  
Horizontal Well ◽  
Pore Diameter ◽  
Gas Production ◽  
Dual Porosity ◽  
Dimension Formula ◽  
Fractured Horizontal Well ◽  
Fractal Properties

A multiple fractured shale gas reservoir is divided into three zones, namely the single-porosity zone, the dual-porosity zone, and the hydraulic fracture zone. The distributions of pore size, fracture length, and fracture aperture vary in each zone and affect shale gas productivity. This paper developed a fractal numerical model to investigate the impacts of zone fractal properties on the shale gas productivity of a multiple fractured horizontal well. In this model, a fractal permeability model was developed, in which the diameter/aperture distribution of circular/slit pores and the length of fractures all follow fractal scaling law. This numerical model was solved by finite element method within the platform of COMSOL Multiphysics and verified through the history matching of production data from the Marcellus and Barnett shale reservoirs. Finally, the effects of the fractal dimension ([Formula: see text], [Formula: see text], [Formula: see text]) and the maximum diameter ([Formula: see text]) of the pores on gas productivity (measured by gas production rate and cumulative gas production) were investigated. Numerical results show that increasing the maximum pore diameter [Formula: see text] can enhance gas productivity, but increasing the pore diameter fractal dimension [Formula: see text] makes the gas productivity decrease and increasing tortuous fractal dimension [Formula: see text] decreases the gas productivity, too. The length fractal dimension [Formula: see text] of fractures is sensitive to the gas flow in the dual-porosity zone.

scholarly journals A Novel Shale Gas Production Prediction Model Based on Machine Learning and Its Application in Optimization of Multistage Fractured Horizontal Wells

2021 ◽  
Vol 9 ◽  
Author(s):  
Huijun Wang ◽  
Lu Qiao ◽  
Shuangfang Lu ◽  
Fangwen Chen ◽  
Zhixiong Fang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Shale Gas ◽  
Horizontal Well ◽  
Gas Production ◽  
Production Model ◽  
Support Vector ◽  
Gas Production Prediction ◽  
Half Length ◽  
Production Prediction

Shale gas production prediction and horizontal well parameter optimization are significant for shale gas development. However, conventional reservoir numerical simulation requires extensive resources in terms of labor, time, and computations, and so the optimization problem still remains a challenge. Therefore, we propose, for the first time, a new gas production prediction methodology based on Gaussian Process Regression (GPR) and Convolution Neural Network (CNN) to complement the numerical simulation model and achieve rapid optimization. Specifically, through sensitivity analysis, porosity, permeability, fracture half-length, and horizontal well length were selected as influencing factors. Second, the n-factorial experimental design was applied to design the initial experiment and the dataset was constructed by combining the simulation results with the case parameters. Subsequently, the gas production model was built by GPR, CNN, and SVM based on the dataset. Finally, the optimal model was combined with the optimization algorithm to maximize the Net Present Value (NPV) and obtain the optimal fracture half-length and horizontal well length. Experimental results demonstrated the GPR model had prominent modeling capabilities compared with CNN and Support Vector Machine (SVM) and achieved the satisfactory prediction performance. The fracture half-length and well length optimized by the GPR model and reservoir numerical simulation model converged to almost the same values. Compared with the field reference case, the optimized NPV increased by US$ 7.43 million. Additionally, the time required to optimize the GPR model was 1/720 of that of numerical simulation. This work enriches the knowledge of shale gas development technology and lays the foundation for realizing the scale-benefit development for shale gas, so as to realize the integration of geological engineering.

scholarly journals Production Rate Analysis of Fractured Horizontal Well considering Multitransport Mechanisms in Shale Gas Reservoir

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Qi-guo Liu ◽  
Wei-hong Wang ◽  
Hua Liu ◽  
Guangdong Zhang ◽  
Long-xin Li ◽  
...  
Keyword(s):  
Production Rate ◽  
Shale Gas ◽  
Horizontal Well ◽  
Production Performance ◽  
Natural Fractures ◽  
Gas Reservoir ◽  
Isothermal Adsorption ◽  
Well Production ◽  
Shale Gas Reservoir ◽  
Fractured Horizontal Well

Shale gas reservoir has been aggressively exploited around the world, which has complex pore structure with multiple transport mechanisms according to the reservoir characteristics. In this paper, a new comprehensive mathematical model is established to analyze the production performance of multiple fractured horizontal well (MFHW) in box-shaped shale gas reservoir considering multiscaled flow mechanisms (ad/desorption and Fick diffusion). In the model, the adsorbed gas is assumed not directly diffused into the natural macrofractures but into the macropores of matrix first and then flows into the natural fractures. The ad/desorption phenomenon of shale gas on the matrix particles is described by a combination of the Langmuir’s isothermal adsorption equation, continuity equation, gas state equation, and the motion equation in matrix system. On the basis of the Green’s function theory, the point source solution is derived under the assumption that gas flow from macropores into natural fractures follows transient interporosity and absorbed gas diffused into macropores from nanopores follows unsteady-state diffusion. The production rate expression of a MFHW producing at constant bottomhole pressure is obtained by using Duhamel’s principle. Moreover, the curves of well production rate and cumulative production vs. time are plotted by Stehfest numerical inversion algorithm and also the effects of influential factors on well production performance are analyzed. The results derived in this paper have significance to the guidance of shale gas reservoir development.

Analytical Solution for Shale Gas Productivity of a Multiple-Fractured Horizontal Well Based on a Diffusion Model

2017 ◽  
Vol 43 (5) ◽  
pp. 2563-2579 ◽  
Author(s):  
Jia Liu ◽  
J. G. Wang ◽  
Feng Gao ◽  
Yang Ju ◽  
Xiaolin Wang
Keyword(s):  
Analytical Solution ◽  
Diffusion Model ◽  
Shale Gas ◽  
Horizontal Well ◽  
Fractured Horizontal Well
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