Optimal Fracture Spacing And Stimulation Design For Horizontal Wells In Unconventional Gas Reservoirs

2011 ◽  
Author(s):  
Srimoyee Bhattacharya ◽  
Michael Nikolaou
Keyword(s):  
Horizontal Wells ◽  
Gas Reservoirs ◽  
Unconventional Gas ◽  
Fracture Spacing ◽  
Unconventional Gas Reservoirs

scholarly journals Development and Calibration of a Semianalytic Model for Shale Wells with Nonuniform Distribution of Induced Fractures Based on ES-MDA Method

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3718 ◽  
Author(s):  
Qi Zhang ◽  
Shu Jiang ◽  
Xinyue Wu ◽  
Yan Wang ◽  
Qingbang Meng
Keyword(s):  
Shale Gas ◽  
Fractal Dimensions ◽  
Nonuniform Distribution ◽  
Fracture System ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Fracture Spacing ◽  
Unconventional Gas Reservoirs ◽  
Induced Fractures

Given reliable parameters, a newly developed semianalytic model could offer an efficient option to predict the performance of the multi-fractured horizontal wells (MFHWs) in unconventional gas reservoirs. However, two major challenges come from the accurate description and significant parameters uncertainty of stimulated reservoir volume (SRV). The objective of this work is to develop and calibrate a semianalytic model using the ensemble smoother with multiple data assimilation (ES-MDA) method for the uncertainty reduction in the description and forecasting of MFHWs with nonuniform distribution of induced fractures. The fractal dimensions of induced-fracture spacing (dfs) and aperture (dfa) and tortuosity index of induced-fracture system (θ) are included based on fractal theory to describe the properties of SRV region. Additionally, for shale gas reservoirs, gas transport mechanisms, e.g., viscous flow with slippage, Knudsen diffusion, and surface diffusion, among multi-media including porous kerogen, inorganic matter, and fracture system are taken into account and the model is verified. Then, the effects of the fractal dimensions and tortuosity index of induced fractures on MFHWs performances are analyzed. What follows is employing the ES-MDA method with the presented model to reduce uncertainty in the forecasting of gas production rate for MFHWs in unconventional gas reservoirs using a synthetic case for the tight gas reservoir and a real field case for the shale gas reservoir. The results show that when the fractal dimensions of induced-fracture spacing and aperture is smaller than 2.0 or the tortuosity index of induced-fracture system is larger than 0, the permeability of induced-fracture system decreases with the increase of the distance from hydraulic fractures (HFs) in SRV region. The large dfs or small θ causes the small average permeability of the induced-fracture system, which results in large dimensionless pseudo-pressure and small dimensionless production rate. The matching results indicate that the proposed method could enrich the application of the semianalytic model in the practical field.

scholarly journals Optimization of Multiple Hydraulically Fractured Horizontal Wells in Unconventional Gas Reservoirs

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Wei Yu ◽  
Kamy Sepehrnoori
Keyword(s):  
Horizontal Wells ◽  
Barnett Shale ◽  
Hydraulic Fractures ◽  
Uncertain Parameters ◽  
Gas Reservoirs ◽  
Well Placement ◽  
Unconventional Gas ◽  
Fracture Conductivity ◽  
Gas Desorption ◽  
Unconventional Gas Reservoirs

Accurate placement of multiple horizontal wells drilled from the same well pad plays a critical role in the successful economical production from unconventional gas reservoirs. However, there are high cost and uncertainty due to many inestimable and uncertain parameters such as reservoir permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, gas desorption, and well spacing. In this paper, we employ response surface methodology to optimize multiple horizontal well placement to maximize Net Present Value (NPV) with numerically modeling multistage hydraulic fractures in combination with economic analysis. This paper demonstrates the accuracy of numerical modeling of multistage hydraulic fractures for actual Barnett Shale production data by considering the gas desorption effect. Six uncertain parameters, such as permeability, porosity, fracture spacing, fracture half-length, fracture conductivity, and distance between two neighboring wells with a reasonable range based on Barnett Shale information, are used to fit a response surface of NPV as the objective function and to finally identify the optimum design under conditions of different gas prices based on NPV maximization. This integrated approach can contribute to obtaining the optimal drainage area around the wells by optimizing well placement and hydraulic fracturing treatment design and provide insight into hydraulic fracture interference between single well and neighboring wells.

Simulated Annealing Algorithm-Based Inversion Model To Interpret Flow Rate Profiles and Fracture Parameters for Horizontal Wells in Unconventional Gas Reservoirs

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Hongwen Luo ◽  
Ying Li ◽  
Haitao Li ◽  
Xiaojiang Cui ◽  
Zhangxin Chen
Keyword(s):  
Simulated Annealing ◽  
Temperature Profile ◽  
Flow Rate ◽  
Horizontal Wells ◽  
Gas Reservoirs ◽  
Unconventional Gas ◽  
Inversion Model ◽  
Fracture Parameters ◽  
Unconventional Gas Reservoirs ◽  
Half Length

Summary With the increasing application of distributed temperature sensing (DTS) in downhole monitoring for multifractured horizontal wells (MFHWs), well performance interpretation by inversing DTS data has become a popular topic around the world. However, because of the lack of efficient inversion models, great challenges still exist in interpreting flow rate profiles and fracture parameters for MFHWs in unconventional gas reservoirs from DTS data. In this paper, a robust inversion system is developed to interpret flow rate profiles and fracture parameters for MFHWs in unconventional gas reservoirs by inversion of DTS data. A temperature prediction model serves as a forward model to simulate the temperature behaviors of MFHWs. A new inversion model based on a simulated annealing (SA) algorithm is proposed to find inversion solutions to flow rate profiles and fracture parameters. The simulated results of temperature behaviors indicate that the temperature profile of each MFHW is irregularly serrated, and the temperature drop in each serration is positively correlated with the inflow rate and fracture half-length. These results provide an excellent method to identify and locate effective hydraulic fractures for field MFHWs. Because of the far more significant influence of fracture half-length than conductivity on a temperature profile, fracture half-length was chosen as the inversion target parameter when performing the inversion of DTS data for MFHWs. Then a synthetic inversion task was accomplished using the SA algorithm-based inversion system, and it took only 110 iterations to reach the target inversion accuracy (10−6 level). Real-time inversion error distributions indicate that this novel inversion system shows great advantages in computational efficiency. Finally, a field application in a shale gas reservoir is presented to validate the reliability of the new inversion model. Based on accurate identification of effective fractures from DTS profiles, satisfactory inversion solutions (the maximum temperature deviation of less than 0.03 K) are obtained. The absolute error of the inversed gas production rate is less than 4 m3/d. The SA algorithm-based inversion system proves reliable to interpret flow rate profiles and fracture parameters, which is a great help to postfracturing evaluation and productivity improvement for MFHWs in unconventional gas reservoirs.

Investigating the pressure characteristics and production performance of liquid-loaded horizontal wells in unconventional gas reservoirs

2019 ◽  
Vol 176 ◽  
pp. 456-465 ◽  
Author(s):  
Hewei Tang ◽  
Zhuang Sun ◽  
Youwei He ◽  
Zhi Chai ◽  
A. Rashid Hasan ◽  
...  
Keyword(s):  
Horizontal Wells ◽  
Production Performance ◽  
Gas Reservoirs ◽  
Unconventional Gas ◽  
Unconventional Gas Reservoirs ◽  
Pressure Characteristics
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