scholarly journals Mechanism of shear failure near fracture face during drainage process of CBM well

2018 ◽  
Vol 10 (8) ◽  
pp. 3309-3317
Author(s):  
Ping Xiong ◽  
Wang-shui Hu ◽  
Hai-xia Hu ◽  
Hailong Liu
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracture ◽  
Shear Failure ◽  
Failure Envelope ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Induced Stress ◽  
In Situ Stresses ◽  
Bottom Hole

Abstract In this paper, whether the coal fines can be induced by shear failure during drainage process has been discussed in detail. By coupling with the percolation theory, the elasticity mechanics were used to construe the extra stresses in the formation surrounding with the hydraulic fracture. The safe window of the bottom hole pressure was also calculated from the failure envelope. The research shows that the formation pressure on the fracture surface of the coal seam is negatively related with the bottom hole pressure, and the induced stress is positively related with the bottom hole pressure during the drainage process of fractured CBM wells. The pore pressure around the fracture changed due to pore-elastic effects, which also caused a significant change of the in situ stresses. In order to avoid the breakout of the coal seam around hydraulic fracture during drainage process, the model of the reasonable bottom hole pressure is also built.

Self-similar solution analysis of hydraulic fracture growth with bottom hole pressure restriction

2020 ◽  
Author(s):  
Grigory Paderin
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Environmental Science ◽  
Height Growth ◽  
Similar Solution ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole ◽  
Self Similar Solution ◽  
Self Similar

<p>Nowadays hydraulic fracturing is an essential part of the development of low-permeability oil and gas fields. Moreover, the well productivity dynamics is radically depends on the effectiveness of fracturing treatment. One of the main hydraulic fracturing design problem is create a long fracture without crack height growth into the intervals saturated with non-target fluid (e.g. water). The obtaining self-similar solution to this problem in the framework of the Pserudo3D [1-3] model is considered in the presented study.</p><p>The presented crack propagation analysis shows that in the case of constant bottom hole pressure the automodel solution of one variable could be derived. A study on the dependence of the solution on pressure, time, hydraulic fluid properties and leak off is also conducted.</p><p>REFERENCES<br>[1] J.I. Adachi, E. Detournay, and A. P. Peirce // 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. 2010. 47 (4): 625–639. <br>[2] X. Weng, O. Kresse, C. Cohen, R. Wu, and H. Gu // Modeling of hydraulic-fracture-network propagation in a naturally fractured formation. SPE Production & Operations  2011. 26 (4): 368–380. doi:10.2118/140253-PA.<br>[3] G.V. Paderin // Proxy Pseudo3D model: the optimum of speed and accuracy in hydraulic fracturing simulation. IOP Conference Series: Earth and Environmental Science. 2018.</p>

scholarly journals Production behavior evaluation on multilayer commingled stress-sensitive carbonate gas reservoir

2020 ◽  
pp. 014459872096415
Author(s):  
Jianlin Guo ◽  
Fankun Meng ◽  
Ailin Jia ◽  
Shuo Dong ◽  
Haijun Yan ◽  
...  
Keyword(s):  
Early Stage ◽  
Sedimentary Environment ◽  
Production Performance ◽  
Total Production ◽  
Inversion Algorithm ◽  
Gas Reservoir ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole ◽  
Production Behavior

Influenced by the complex sedimentary environment, a well always penetrates multiple layers with different properties, which leads to the difficulty of analyzing the production behavior for each layer. Therefore, in this paper, a semi-analytical model to evaluate the production performance of each layer in a stress-sensitive multilayer carbonated gas reservoir is proposed. The flow of fluids in layers composed of matrix, fractures, and vugs can be described by triple-porosity/single permeability model, and the other layers could be characterized by single porosity media. The stress-sensitive exponents for different layers are determined by laboratory experiments and curve fitting, which are considered in pseudo-pressure and pseudo-time factor. Laplace transformation, Duhamel convolution, Stehfest inversion algorithm are used to solve the proposed model. Through the comparison with the classical solution, and the matching with real bottom-hole pressure data, the accuracy of the presented model is verified. A synthetic case which has two layers, where the first one is tight and the second one is full of fractures and vugs, is utilized to study the effects of stress-sensitive exponents, skin factors, formation radius and permeability for these two layers on production performance. The results demonstrate that the initial well production is mainly derived from high permeable layer, which causes that with the rise of formation permeability and radius, and the decrease of stress-sensitive exponents and skin factors, in the early stage, the bottom-hole pressure and the second layer production rate will increase. While the first layer contributes a lot to the total production in the later period, the well bottom-hole pressure is more influenced by the variation of formation and well condition parameters at the later stage. Compared with the second layer, the scales of formation permeability and skin factor for first layer have significant impacts on production behaviors.

Study of the process of changing of the bottom hole pressure in time under the conditions of gaslift flowing

2020 ◽  
Author(s):  
M. Mokliak ◽  
B. Mishchuk ◽  
A. Hrytsanchuk ◽  
M. Schepanskyi
Keyword(s):  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole

scholarly journals A Unified Formula for Determination of Wellhead Pressure and Bottom-hole Pressure

2013 ◽  
Vol 37 ◽  
pp. 3291-3298 ◽  
Author(s):  
Mingze Liu ◽  
Bing Bai ◽  
Xiaochun Li
Keyword(s):  
Wellhead Pressure ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole
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