scholarly journals Wellbore Stability in Oil and Gas Drilling with Chemical-Mechanical Coupling

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chuanliang Yan ◽  
Jingen Deng ◽  
Baohua Yu
Keyword(s):  
Diffusion Coefficient ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Experimental Results ◽  
Mechanical Coupling ◽  
Gas Drilling ◽  
Study Results ◽  
Shale Formation ◽  
Oil And Gas Drilling

Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Hydration is produced in shale formation owing to the influence of the chemical property of drilling fluid. A new experimental method to measure diffusion coefficient of shale hydration is given, and the calculation method of experimental results is introduced. The diffusion coefficient of shale hydration is measured with the downhole temperature and pressure condition, then the penetration migrate law of drilling fluid filtrate around the wellbore is calculated. Furthermore, the changing rules of shale mechanical properties affected by hydration and water absorption are studied through experiments. The relationships between shale mechanical parameters and the water content are established. The wellbore stability model chemical-mechanical coupling is obtained based on the experimental results. Under the action of drilling fluid, hydration makes the shale formation softened and produced the swelling strain after drilling. This will lead to the collapse pressure increases after drilling. The study results provide a reference for studying hydration collapse period of shale.

scholarly journals Experimental Investigation of the Effects of Drilling Fluid Activity on the Hydration Behavior of Shale Reservoirs in Northwestern Hunan, China

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3151 ◽  
Author(s):  
Han Cao ◽  
Zheng Zhang ◽  
Ting Bao ◽  
Pinghe Sun ◽  
Tianyi Wang ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Drilling Fluid ◽  
Contact Angles ◽  
Wellbore Stability ◽  
Adsorption Rate ◽  
Drilling Fluids ◽  
Swelling Ratio ◽  
Gas Drilling ◽  
Surface Hydration ◽  
The Relationship

The interaction between drilling fluid and shale has a significant impact on wellbore stability during shale oil and gas drilling operations. This paper investigates the effects of the drilling fluid activity on the surface and osmotic hydration characteristics of shale. Experiments were conducted to measure the influence of drilling fluid activity on surface wettability by monitoring the evolution of fluid-shale contact angles. The relationship between drilling fluid activity and shale swelling ratio was determined to investigate the osmotic hydration behavior. The results indicate that, with increasing drilling fluid activity, the fluid–shale contact angles gradually increase—the higher the activity, the faster the adsorption rate; and the stronger the inhibition ability, the weaker the surface hydration action. The surface adsorption rate of the shale with a KCl drilling fluid was found to be the highest. Regarding the osmotic hydration action on the shale, the negative extreme swelling ratio (b) of the shale was found to be: bKCl < bCTAB < bSDBS. Moreover, based on the relationship between the shale swelling ratio and drilling fluid activity, shale hydration can be divided into complete dehydration, weak dehydration, surface hydration, and osmotic hydration, which contributes to the choice of drilling fluids to improve wellbore stability.

Finite Element Study of the Cutting Mechanics of the Three Dimensional Rock Turning Process

2015 ◽  
Author(s):  
Demeng Che ◽  
Jacob Smith ◽  
Kornel F. Ehmann
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Polycrystalline Diamond ◽  
Close Correlation ◽  
Experimental Results ◽  
Failure Behavior ◽  
Fe Model ◽  
Gas Drilling ◽  
Cutting Mechanics

The unceasing improvements of polycrystalline diamond compact (PDC) cutters have pushed the limits of tool life and cutting efficiency in the oil and gas drilling industry. However, the still limited understanding of the cutting mechanics involved in rock cutting/drilling processes leads to unsatisfactory performance in the drilling of hard/abrasive rock formations. The Finite Element Method (FEM) holds the promise to advance the in-depth understanding of the interactions between rock and cutters. This paper presents a finite element (FE) model of three-dimensional face turning of rock representing one of the most frequent testing methods in the PDC cutter industry. The pressure-dependent Drucker-Prager plastic model with a plastic damage law was utilized to describe the elastic-plastic failure behavior of rock. A newly developed face turning testbed was introduced and utilized to provide experimental results for the calibration and validation of the formulated FE model. Force responses were compared between simulations and experiments. The relationship between process parameters and force responses and the mechanics of the process were discussed and a close correlation between numerical and experimental results was shown.

Oil and Gas Drilling Optimization Technologies Applied Successfully to Unconventional Geothermal Well Drilling

2021 ◽  
Author(s):  
Junichi Sugiura ◽  
Ramon Lopez ◽  
Francisco Borjas ◽  
Steve Jones ◽  
John McLennan ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Oil And Gas ◽  
Optimization Techniques ◽  
Geothermal System ◽  
Well Drilling ◽  
Geothermal Well ◽  
Gas Drilling ◽  
Drilling Tools ◽  
Drilling Optimization ◽  
Oil And Gas Drilling

Abstract Geothermal energy is used in more than 20 countries worldwide and is a clean, reliable, and relatively available energy source. Nevertheless, to make geothermal energy available anywhere in the world, technical and economic challenges need to be addressed. Drilling especially is a technical challenge and comprises a significant part of the geothermal development cost. An enhanced geothermal system (EGS) is a commercially viable thermal reservoir where two wells are interconnected by some form of hydraulic stimulation. In a commercial setting, fluid is injected into this hot rock and passes between wells through a network of natural and induced fractures to transport heat to the surface system for electricity generation. To construct EGS wells, vertical and directional drilling is necessary with purpose-built drilling and steering equipment. This is an application where oil-and-gas drilling tools and techniques can be applied. A recent well, 16A(78)-32, drilled as part of the US Department of Energy's (DOE's) Utah Frontier Observatory for Research in Geothermal Energy (FORGE) program, highlights some of the technical challenges, which include drilling an accurate vertical section, a curve section, and a 5300-ft 65° tangent section in a hard granitic formation at temperatures up to 450°F (232°C). Extensive downhole temperature simulations were performed to select fit-for-purpose drilling equipment such as purely mechanical vertical drilling tools, instrumented steerable downhole motors, measurement-while-drilling (MWD) tools, and embedded high-frequency drilling dynamics recorders. Downhole and surface drilling dynamics data were used to fine- tune bit design and motor power section selection and continuously improve the durability of equipment, drilling efficiency, and footage drilled. Drilling optimization techniques used in oil and gas settings were successfully applied to this well, including analysis of data from drilling dynamics sensors embedded in the steerable motors and vertical drilling tools, surface surveillance of mechanical specific energy (MSE), and adopting a drilling parameter roadmap to improve drilling efficiency to minimize drilling dysfunctions and equipment damages. Through drilling optimization practices, the instrumented steerable motors with proper bit selections were able to drill more than 40 ft/hr on average, doubling the rate of penetration (ROP), footage, and run length experienced in previous granite wells. This paper presents a case study in which cutting-edge oil-and-gas drilling technologies were successfully applied to reduce the geothermal well drilling time by approximately half.

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