scholarly journals Formation mechanism of continuous gas leakage paths in cement sheath during hydraulic fracturing

2020 ◽  
Vol 8 (7) ◽  
pp. 2527-2547
Author(s):  
Wei Lian ◽  
Jun Li ◽  
Qian Tao ◽  
Jinlong Du ◽  
Lei Wang ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Formation Mechanism ◽  
Gas Leakage ◽  
Cement Sheath

A new numerical investigation of cement sheath integrity during multistage hydraulic fracturing shale gas wells

2018 ◽  
Vol 49 ◽  
pp. 331-341 ◽  
Author(s):  
Xi Yan ◽  
Li Jun ◽  
Liu Gonghui ◽  
Tao Qian ◽  
Lian Wei
Keyword(s):  
Hydraulic Fracturing ◽  
Numerical Investigation ◽  
Shale Gas ◽  
Gas Wells ◽  
Multistage Hydraulic Fracturing ◽  
Cement Sheath

Numerical Modelling of Radial Crack Propagation in Cement Sheath During Hydraulic Fracturing

2020 ◽  
Author(s):  
Yan Yan ◽  
Zhichuan Guan ◽  
Yuqiang Xu ◽  
Xuan Zhang ◽  
Weijun Yan
Keyword(s):  
Numerical Modelling ◽  
Hydraulic Fracturing ◽  
Crack Propagation ◽  
Radial Crack ◽  
Cement Sheath

Shakedown analysis on the integrity of cement sheath under deep and large-scale multi-section hydraulic fracturing

2022 ◽  
Vol 208 ◽  
pp. 109619
Author(s):  
Xiaoyu Zhang ◽  
Zhenhui Bi ◽  
Lei Wang ◽  
Yintong Guo ◽  
Chunhe Yang ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Large Scale ◽  
Shakedown Analysis ◽  
Cement Sheath

Impact of hydraulic fracturing on cement sheath integrity; A modelling approach

2017 ◽  
Vol 44 ◽  
pp. 265-277 ◽  
Author(s):  
W. Wang ◽  
A. Dahi Taleghani
Keyword(s):  
Hydraulic Fracturing ◽  
Cement Sheath ◽  
Modelling Approach

scholarly journals Numerical Simulation Study on Propagation of Initial Microcracks in Cement Sheath Body during Hydraulic Fracturing Process

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1260
Author(s):  
Yuqiang Xu ◽  
Yan Yan ◽  
Shenqi Xu ◽  
Zhichuan Guan
Keyword(s):  
Elastic Modulus ◽  
Hydraulic Fracturing ◽  
Internal Pressure ◽  
Element Model ◽  
Fluid Viscosity ◽  
Fracturing Fluid ◽  
Zone Method ◽  
Geological Conditions ◽  
Fracturing Process ◽  
Cement Sheath

Microcracks caused by perforating operations in a cement sheath body and interface have the potential to further expand or even cause crossflow during hydraulic fracturing. Currently, there are few quantitative studies on the propagation of initial cement-body microcracks. In this paper, a three-dimensional finite element model for the propagation of initial microcracks of the cement sheath body along the axial and circumferential directions during hydraulic fracturing was proposed based on the combination of coupling method of fluid–solid in porous media and the Cohesive Zone Method. The influence of reservoir geological conditions, the mechanical properties of a casing-cement sheath-formation system, and fracturing constructions in the propagation of initial axial microcracks of a cement sheath body was quantitatively analyzed. It can be concluded that the axial extension length of microcracks increased with the increase of elastic modulus of the cement sheath and formation, the flow rate of fracturing fluid, and casing internal pressure, and decreased with the increase of the cement sheath tensile strength and ground stress. The elastic modulus of the cement sheath had a greater influence on the expansion of axial cracks than the formation elastic modulus and casing internal pressure. The effect of fracturing fluid viscosity on the crack expansion was negligible. In order to effectively slow the expansion of the cement sheath body crack, the elastic modulus of the cement sheath can be appropriately reduced to enhance its toughness under the premise of ensuring sufficient strength of the cement sheath.

Study of the Heat Transfer in the Wellbore During Acid/Hydraulic Fracturing Using a Semianalytical Transient Model

SPE Journal ◽  
2019 ◽  
Vol 24 (02) ◽  
pp. 877-890 ◽  
Author(s):  
Yu Peng ◽  
Jinzhou Zhao ◽  
Kamy Sepehrnoori ◽  
Yibo Li ◽  
Wei Yu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Low Temperature ◽  
Laminar Flow ◽  
Hydraulic Fracturing ◽  
Forced Convection ◽  
Rock Type ◽  
Transient Heat Conduction ◽  
Fracturing Fluid ◽  
Cement Sheath

Summary Bottomhole-temperature variations have a significant influence on the rheological properties of fracturing fluid and the reaction rates of rock and acid in the operations of acid/hydraulic fracturing. In this work, a semianalytical model is developed for calculating the heat transfer in a wellbore under transient state. In the model, transient heat conduction in the cement sheath and forced convection in the tubing under different flow regimes are considered. Also in this model, calculation methods of heat-transfer coefficients of forced convection in the tubing and natural convection in the annulus are improved in relation to the existing methods. The semianalytical model is verified by monitoring the data of acid and hydraulic fracturing; it is accurate enough to estimate the physical properties of the fracturing fluid and perform simulations in the reservoirs. We studied transient heat conduction in a cement sheath, the influence of flow regimes on tubing, the variation of thermal properties in the wellbore, and the influence of vertical variations of rock type. Simulation results show that the influence of different heat-transfer states of the cement sheath on bottomhole temperature is much more significant under the injection rate of fracturing. Laminar flow is activated by extremely low injection velocity or low temperature in shallow layers. However, such low velocity can never be attained in the fracturing operation. Also, the high heat resistance caused by laminar flow in shallow layers cannot affect the bottomhole temperature significantly because of the low temperature difference between fracturing fluid and formation rock. We also found that the complex vertical variation of rock type and shale and sandstone interbedding could be approximated by the average temperature of simple models that are computationally faster and have an acceptable range of errors.

scholarly journals Full-Life-Cycle Analysis of Cement Sheath Integrity

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Jie Hu ◽  
Linlin Wang ◽  
Jili Feng ◽  
Jiyun Shen ◽  
Manchao He
Keyword(s):  
Life Cycle ◽  
Hydraulic Fracturing ◽  
Life Cycle Analysis ◽  
Hydraulic Pressure ◽  
Full Life Cycle ◽  
Wellbore Pressure ◽  
Sheath Formation ◽  
Cement Sheath ◽  
Full Life ◽  
Formation System

This paper addresses evaluating the evolution of stress inside the casing-cement sheath-formation system during the cement injection, setting, completion, and production stages of hydrocarbon recovery. This full-life-cycle analysis of cement sheath integrity gives rise to assessment of potential failure mode (i.e., tensile mode, shear mode, and microannulus) in different stages, and the prevention measures can be proposed accordingly. Considering the loading history, two regimes should be distinguished. Before the accomplishment of cementation, as the cement slurry can merely withstand its hydraulic pressure, the in situ stress and the wellbore pressure are withstood by the rock and the casing, respectively. Once the cementation process is completed, the stress increment (e.g., hydraulic fracturing pressure) is withstood by the casing-cement sheath-formation system. The autogenous shrinkage of cement adversely affects the resistance of the system to all types of failure, whereas a moderate swelling of cement is favorable to the cement sheath integrity. In addition, the cement sheath integrity is strongly influenced by the depth: the failure is encountered more easily at the shallow layer. Both the hydraulic fracturing pressure in the completion stage and the increase in casing temperature in the production stage may lead to tensile circumferential stress, and the hydraulic fracturing is the most critical stage for the integrity of cement sheath.

scholarly journals New Analytical Method to Evaluate Casing Integrity during Hydraulic Fracturing of Shale Gas Wells

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Jun Li ◽  
Xueli Guo ◽  
Gonghui Liu ◽  
Shuoqiong Liu ◽  
Yan Xi
Keyword(s):  
Stress Field ◽  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Poisson’S Ratio ◽  
New Method ◽  
Poisson's Ratio ◽  
Sensitivity Analyses ◽  
Fluid Temperature ◽  
Gas Wells ◽  
Cement Sheath

An accurate analysis of casing stress distribution and its variation regularities present several challenges during hydraulic fracturing of shale gas wells. In this paper, a new analytical mechanical-thermal coupling method was provided to evaluate casing stress. For this new method, the casing, cement sheath, and formation (CCF) system was divided into three parts such as initial stress field, wellbore disturbance field, and thermal stress field to simulate the processes of drilling, casing, cementing, and fracturing. The analytical results reached a good agreement with a numerical approach and were in-line with the actual boundary condition of shale gas wells. Based on this new model, the parametric sensitivity analyses of casing stress such as mechanical and geometry properties, operation parameters, and geostress were conducted during multifracturing. Conclusions were drawn from the comparison between new and existing models. The results indicated that the existing model underestimated casing stress under the conditions of the geostress heterogeneity index at the range of 0.5–2.25, the fracturing pressure larger than 25 MPa, and a formation with large elastic modulus or small Poisson’s ratio. The casing stress increased dramatically with the increase of in situ stress nonuniformity degree. The stress decreased first and then increased with the increase of fracturing pressure. Thicker casing, higher fluid temperature, and cement sheath with small modulus, large Poisson’s ratio, and thinner wall were effective to decrease the casing stress. This new method was able to accurately predict casing stress, which can become an alternative approach of casing integrity evaluation for shale gas wells.

Integrity Failure of Cement Sheath Owing to Hydraulic Fracturing and Casing Off-Center in Horizontal Shale Gas Wells

2018 ◽  
Author(s):  
Kui Liu ◽  
Deli Gao ◽  
Arash Dahi Taleghani
Keyword(s):  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Gas Wells ◽  
Cement Sheath
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