Production Performance Analysis for Multi-Branched Horizontal Wells in Composite Coal Bed Methane Reservoir Considering Stress Sensitivity

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Ruizhong Jiang ◽  
Xiuwei Liu ◽  
Yongzheng Cui ◽  
Xing Wang ◽  
Yue Gao ◽  
...  
Keyword(s):  
Superposition Principle ◽  
Horizontal Wells ◽  
Stress Sensitivity ◽  
Field Application ◽  
Model Verification ◽  
Production Performance ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Element Discretization ◽  
Type Curves

Abstract Coal bed methane (CBM) significantly contributes to unconventional energy resources. With the development of the drilling technology, multi-branched horizontal wells (MBHWs) have been put into the exploitation of CBM. In this paper, a semi-analytical mathematical model is introduced to study the production characteristics of MBHWs in the composite CBM reservoir. Stress sensitivity, composite reservoir, and complex seepage mechanisms (desorption, diffusion, and Darcy flow) are taken into consideration. Through Pedrosa transformation, Perturbation transformation, Laplace transformation, Finite cosine transformation, element discretization, superposition principle, and Stehfest numerical inversion, pseudo-pressure dynamic curves and production decline curves are plotted and 13 flow regimes are divided. Then, the sensitivity analysis of related parameters is conducted to study the influences of these parameters based on these two type curves. Model verification and field application are introduced which shows that the model is reliable. The model proposed in this paper and relevant results analysis can provide some significant guidance for a better understanding of the production behavior of MBHWs in the composite CBM reservoir.

scholarly journals Pressure Transient Analysis for Horizontal Wells in Coal Bed Methane Reservoirs with Pressure-Sensitive Permeabilities

2021 ◽  
Author(s):  
Juan Camilo Sepúlveda ◽  
Sebastián Díaz ◽  
Edwin Alexander López
Keyword(s):  
Flow Behavior ◽  
Horizontal Wells ◽  
Transient Behavior ◽  
Production Performance ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Coal Seams ◽  
Pressure Transient ◽  
Type Curves ◽  
Flow Mechanisms

Abstract: Coal bed methane (CBM) reservoirs are complex systems whose properties differ from those of conventional reservoirs. Coal seams are dual-porosity systems that comprise the porosities of the matrix and cleat system. Gas in the coal seams can be stored as free gas in the cleat system and as adsorbed gas in the porous medium. The flow mechanisms of the natural gas through the formation include desorption, diffusion, and Darcy’s flow regimes. The permeability of CBM reservoirs is more sensitive to pressure variations than conventional gas reservoirs. To study the flow behavior of CBM reservoirs it is mandatory to use a model that considers their unique characteristics. The objective of this study was to propose a physical and mathematical model of production performance for horizontal wells in CBM reservoirs whose permeability is dependent on pressure. A solution for the model was obtained by applying Pedrosa´s transformation, perturbation theory, Laplace transformation, the point source method, and Sthefest´s algorithm. The solution to this problem was validated with previous work thoroughly. The type curves of the model were built and the pressure transient behavior of the model was analyzed and discussed. The effects of several parameters on pressure behavior were also discussed.

A Semi-Analytical Fractal-Fractional Mathematical Model for Multi-Fractured Horizontal Wells in Coalbed Methane Reservoirs

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Ruizhong Jiang ◽  
Xiuwei Liu ◽  
Xing Wang ◽  
Qiong Wang ◽  
Yongzheng Cui ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Coalbed Methane ◽  
Fractal Theory ◽  
Superposition Principle ◽  
Horizontal Wells ◽  
Clean Energy ◽  
Stress Sensitivity ◽  
Element Discretization ◽  
Proposed Model ◽  
Fractured Horizontal Wells

Abstract Coalbed methane (CBM) which is clean energy has received great emphasis recently, and the multi-fracturing technology is widely applied in the exploitation of CBM. Due to the complexity, the randomness, and the anisotropism of the porous medium and the anomalous diffusion process, the fractal theory and fractional calculus are utilized to establish a semi-analytical fractal-fractional mathematical model considering the stress sensitivity of the cleat system for multi-fractured horizontal wells in CBM reservoirs. Through line-sink theory, Pedrosa transformation, perturbation theory, Laplace transformation, element discretization, superposition principle, and Stehfest numerical inversion, the pressure-transient analysis curves are plotted in the double logarithmic coordinates. By comparing with the existing model, the validation of the proposed model is illustrated. Also, nine flowing stages are identified according to different characteristics. Then, sensitivity analysis is conducted and influence laws are summarized. At last, a field application is introduced to furtherly verify the reliability of the proposed model. The relevant results analysis can provide some new significant guidance for interpreting the field data more precisely.

scholarly journals Production performance analysis for horizontal wells in composite coal bed methane reservoir

2017 ◽  
Vol 35 (2) ◽  
pp. 194-217 ◽  
Author(s):  
Zhang Wei ◽  
Jiang Ruizhong ◽  
Xu Jianchun ◽  
Gao Yihua ◽  
Yang Yibo
Keyword(s):  
Performance Analysis ◽  
Flow Regime ◽  
Transient Analysis ◽  
Horizontal Well ◽  
Radial Flow ◽  
Production Performance ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Pressure Transient Analysis ◽  
Pressure Transient

In this paper, the mathematical model of production performance analysis for horizontal wells in composite coal bed methane reservoir is introduced. In this model, two regions with different formation parameters are distinguished, and multiple mechanisms are considered including desorption, diffusion, and viscous flow. Then the solution of horizontal well performance analysis model is obtained by using point source function method, Laplace transform, and Stehfest algorithm comprehensively. The solution of the proposed model is verified with previous work thoroughly. The pressure transient analysis for horizontal well when producing at a constant rate is obtained and discussed. At last, different flow regimes are divided based on pressure transient analysis curves. They are early wellbore storage period, skin factor period, first radial flow regime, transition regime, second radial flow regime, transfer regime, and late pseudo-radial flow regime. The effects of related parameters such as storativity ratio, transfer coefficient, adsorption coefficient, ratio of vertical permeability to horizontal permeability, skin factor, horizontal well position in vertical direction, and inner region radius are analyzed as well according to pressure transient analysis and rate transient analysis curves. The presented work in this paper can give a better understanding of coal bed methane production performance in composite reservoir.

Pressure-Transient Behavior of Multisegment Horizontal Wells With Nonuniform Production: Theory and Case Study

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Youwei He ◽  
Shiqing Cheng ◽  
Jiazheng Qin ◽  
Yang Wang ◽  
Zhiming Chen ◽  
...  
Keyword(s):  
Horizontal Wells ◽  
Transient Behavior ◽  
Field Application ◽  
Pressure Derivative ◽  
Pressure Transient ◽  
Type Curves ◽  
Horizontal Wellbore ◽  
Estimate Rate ◽  
Calculated Average

Field data indicate production profile along horizontal wells is nonuniform. This paper develops an analytical model of multisegment horizontal wells (MSHWs) to estimate rate distribution along horizontal wellbore, interpret the effective producing length (EPL), and identify underperforming horizontal sections using bottom-hole pressure (BHP) data. Pressure solutions enable to model an MSHW with nonuniform distribution of length, spacing, rate, and skin factor. The solution is verified with the analytical solution in commercial software. Type curves are generated to analyze the pressure-transient behavior. The second radial-flow (SRF) occurs for the MSHWs, and the duration of SRF depends on interference between segments. The pressure-derivative curve during SRF equals to 0.5/Np (Np denotes the number of mainly producing segments (PS)) under weak interference between segments. The calculated average permeability may be Np times lower than accurate value when the SRF is misinterpreted as pseudoradial-flow regime. The point (0, 0, h/2) are selected as the reference point, and symmetrical cases will generate different results, enabling us to distinguish them. Finally, field application indicates the potential practical application to identify the underperforming horizontal segments.

scholarly journals Transient-Flow Modeling of Vertical Fractured Wells with Multiple Hydraulic Fractures in Stress-Sensitive Gas Reservoirs

2019 ◽  
Vol 9 (7) ◽  
pp. 1359 ◽  
Author(s):  
Ping Guo ◽  
Zhen Sun ◽  
Chao Peng ◽  
Hongfei Chen ◽  
Junjie Ren
Keyword(s):  
Hydraulic Fracture ◽  
Transient Flow ◽  
Superposition Principle ◽  
Pressure Profile ◽  
Stress Sensitivity ◽  
Hydraulic Fractures ◽  
Transient Pressure ◽  
Gas Reservoirs ◽  
Type Curves ◽  
Vertical Well

Massive hydraulic fracturing of vertical wells has been extensively employed in the development of low-permeability gas reservoirs. The existence of multiple hydraulic fractures along a vertical well makes the pressure profile around the vertical well complex. This paper studies the pressure dependence of permeability to develop a seepage model of vertical fractured wells with multiple hydraulic fractures. Both transformed pseudo-pressure and perturbation techniques have been employed to linearize the proposed model. The superposition principle and a hybrid analytical-numerical method were used to obtain the bottom-hole pseudo-pressure solution. Type curves for pseudo-pressure are presented and identified. The effects of the relevant parameters (such as dimensionless permeability modulus, fracture conductivity coefficient, hydraulic-fracture length, angle between the two adjacent hydraulic fractures, the difference of the hydraulic-fracture lengths, and hydraulic-fracture number) on the type curve and the error caused by neglecting the stress sensitivity are discussed in detail. The proposed work can enrich the understanding of the influence of the stress sensitivity on the performance of a vertical fractured well with multiple hydraulic fractures and can be used to more accurately interpret and forecast the transient pressure.

scholarly journals The Stress Sensitivity of Coal Bed Methane Wells and Impact on Production

2012 ◽  
Vol 31 ◽  
pp. 571-579 ◽  
Author(s):  
Yu Yang ◽  
Xiaodong Peng ◽  
Xin Liu
Keyword(s):  
Stress Sensitivity ◽  
Coal Bed ◽  
Coal Bed Methane

scholarly journals Novel method for optimizing the dewatering rate of a coal-bed methane well

2020 ◽  
Vol 38 (4) ◽  
pp. 1099-1117
Author(s):  
Xiuqin Lu ◽  
Zhiqi Wu ◽  
Xuefei Li ◽  
Chen Zhang ◽  
Ning Wang ◽  
...  
Keyword(s):  
Methane Production ◽  
Single Phase ◽  
Fluid Velocity ◽  
Stress Sensitivity ◽  
Initial Permeability ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Bottom Hole ◽  
Phase Water ◽  
Pressure Propagation

The reasonable dewatering rate in the single-phase water flow plays an essential role in pressure propagation and coal-bed methane production. However, current fluid velocity sensitivity experiments cannot provide an optimum dewatering rate for field coal-bed methane production. This study proposes a new method to optimize the dewatering rate for coal-bed methane wells by assuming the investigation distance reaches the well boundary when the bottom hole pressure declines to the critical desorption pressure. The effect of the stress sensitivity and fluid velocity sensitivity on pressure propagation was first simulated with COMSOL Multiphysics software. The results showed that the expansion area considering the stress sensitivity is shorter than that neglecting the stress sensitivity when the bottom hole pressure reached to the critical desorption pressure at 200 days. The expansion area with high dewatering rate will be shorter about 35 m than that with low dewatering rate at 200 days. The relationship between the maximum investigation distance and required time was established to optimize the dewatering rate by combining the pressure profile considering the influence of stress sensitivity with material balance equation. The new model indicates that the initial permeability, porosity, and cleat compressibility have an important effect on investigation distance. The simulation of these parameters’ sensitivity suggests that the bigger the ratio of initial permeability and porosity, the longer the investigation distance is, and the smaller the cleat compressibility is, the longer the expansion area is. According to this model, we need to take more than 600 days at 0.58 m/d constant dewatering rate to reach the maximum investigation distance of 0.67 mD initial permeability. This work can be conducive to choose reasonable dewatering rate in single-phase water flow for coal-bed methane well production.

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