Rock mechanics characteristic of complex formation and faster drilling techniques in Western South China Sea oilfields

Zhu, Hehua; Deng, Jingen; Xie, Yuyuan; Huang, Kangyou; Jinghui, Zhao; Yu, Bo

doi:10.1016/j.oceaneng.2012.01.031

Cited by 25 publications

(9 citation statements)

References 32 publications

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“…There is no isotropic homogeneous formation in nature (Graziani et al 2012). There are two or more different formations in the direction of the contact surface of the PDC bit broken rock and drilling extension, and the geotechnical mechanics, engineering geology and hydrogeology of these formations are quite different (Zhu et al 2012). The combined formations are defined as complex strata.…”

Section: Specific Energy Prediction Of Complex Stratamentioning

confidence: 99%

Abrasiveness evaluation of complex strata based on PDC special energy consumption

Zhang¹,

Wang

Liu³

et al. 2021

J Petrol Explor Prod Technol

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The rock abrasiveness is determined with various methods, which results in no uniform standard formed. In order to predict the PDC bit wear and the abrasiveness of complex strata, the force analysis of the PDC broken rock was carried out, and the bit axial load and torque were obtained, respectively. Then, the calculation model of PDC special energy consumption is deduced. Combining the typical distribution patterns of different strata, the specific energy prediction model of complex strata is established. The wear coefficient of PDC is obtained by the relationship between the triaxial compressive strength of rock and the specific energy of rock breaking, and the grading coefficient and grading standard of abrasiveness of the composite formation are derived, which led to the grading coefficient and grading standard of complex strata abrasiveness. The field test of a well in the north of Songliao Basin verified the rationality and effectiveness of the abrasiveness grading standards and provided the basis for the selection and design of the bit.

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Section: Specific Energy Prediction Of Complex Stratamentioning

confidence: 99%

Abrasiveness evaluation of complex strata based on PDC special energy consumption

Zhang¹,

Wang

Liu³

et al. 2021

J Petrol Explor Prod Technol

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show abstract

“…From experiments, the prediction models of rock mechanics parameters were established to increase the rate of penetration and to reduce cost, and the rock-breaking mechanism of complex formation of cone and PDC bit was studied [18]. In addition, according to the properties of the rock mechanics and the bit applications of adjacent wells, structures, such as tooth type, crown prole, tooth assembly parameters, and the hydraulic structure of selected bits, were optimized [19].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Rock‐Fracturing Mechanism by Using Splitter under Hole Assistance

Liu

Guo

2019

Shock and Vibration

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In this work, a numerical model of rock breaking under hole assistance was established based on the finite element method (FEM) coupling with smoothed particle hydrodynamics (SPH) to reveal rock-breaking mechanisms and analyze the reasons for crack formation and propagation under hole assistance. In addition, the numerical model was verified by experiment with and without a hole, and the simulation results are basically consistent with the experimental results in rock breaking. During the process of rock fracturing, the hydraulic splitter was first inserted into the predrilling hole, and then the wedges were pushed into the rock under the action of the hydraulic pressure. In this process, the splitter wedge was separated from the two sides, and the transverse bursting force was transmitted to the rock. Finally, the main fracture formed and the rock mass broke due to the bursting force. The results show that the cracks propagate along the approximately straight lines OO1 (the distance between the auxiliary holes and the left predrilled fracturing hole) and OO2 (the distance between the auxiliary holes and the right predrilled fracturing hole) before extending to the auxiliary hole which is unlike the crack propagation in rock without auxiliary holes, and the crack propagating direction gradually approaches horizontally and is vertical to the side after passing through the auxiliary holes. Moreover, when the auxiliary holes are located at the prefabricated angles α = 40° and 45°, the crack propagation can be well induced and the cracks pass through the auxiliary holes. However, at α = 50°, the auxiliary holes can no longer well induce the crack propagation in the process of rock breaking; however, the fracturing pressure is still less than that with no auxiliary holes, indicating that the auxiliary holes play a positive role in guiding rock breaking.

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“…Consequently, the cutting efficiency of cement sheaths and rocks is extremely low and it often costs several taper mills for window sidetracking operation on high-strength thick-walled casing, 4 thus resulting in long operation time, low window sidetracking efficiency, and even window sidetracking failures due to broken taper mill. [5][6][7] It is thus clear that existing taper mills can no longer meet the window sidetracking requirements of casing in deep/ultra-deep well sections with hard formation.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, current taper mill structure should meet cutting requirements of not only casing but also cement sheaths and stratum rocks and in effect the taper mill also needs to be equipped with a whipstock, which often causes the cemented carbide particles of the taper mill to be severely worn when cutting metal. Consequently, the cutting efficiency of cement sheaths and rocks is extremely low and it often costs several taper mills for window sidetracking operation on high-strength thick-walled casing, 4 thus resulting in long operation time, low window sidetracking efficiency, and even window sidetracking failures due to broken taper mill. [5][6][7] It is thus clear that existing taper mills can no longer meet the window sidetracking requirements of casing in deep/ultra-deep well sections with hard formation.…”

Section: Introductionmentioning

confidence: 99%

Research on cutting mechanics of window bit cutting teeth

Kong

Zheng

Zhang

et al. 2016

Advances in Mechanical Engineering

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According to structural characteristics of dual-effect strong side-cut window bit (hereinafter referred to as window bit) and the theory of metal cutting and the rule of teeth arrangement of window bit, a cutting mechanical model of window bit cutting teeth is established, window bit geometric equations deduced and the solution of the cutter cutting mechanical model completed; finally, the casing window experiment is conducted with the dual-effect strong side-cut window bit developed to verify the accuracy of the cutting mechanical calculation model and the simulation results. The results show that the variation tendency of the main cutting force of the bit and the experimental data are similar in the windowing process, the simulation results can accurately reflect the change rule of the main cutting force and the requirements of engineering applications are basically met. The research results of this article provide theoretical basis for the analysis and calculation of the cutting force of the window bit and can serve as a reference for the design of deep/ultra-deep well casing window bits and cutting mechanics research.

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Rock mechanics characteristic of complex formation and faster drilling techniques in Western South China Sea oilfields

Cited by 25 publications

References 32 publications

Abrasiveness evaluation of complex strata based on PDC special energy consumption

Abrasiveness evaluation of complex strata based on PDC special energy consumption

Numerical Investigation on Rock‐Fracturing Mechanism by Using Splitter under Hole Assistance

Research on cutting mechanics of window bit cutting teeth

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