scholarly journals Analysis of borehole stability in gas drilling using a thermal elastoplastic coupling model

2021 ◽  
Author(s):  
Zhongxi Zhu ◽  
Chaofei Wang ◽  
Yuchen Ye ◽  
Wanneng Lei
Keyword(s):  
Coupling Model ◽  
Borehole Stability ◽  
Gas Drilling

Finite Element Simulation of Freezing Technology for Borehole Stability of Gas Drilling

2014 ◽  
Vol 962-965 ◽  
pp. 415-418
Author(s):  
Zong Gang Wang ◽  
Zhen Wei
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Freezing Point ◽  
Drill String ◽  
Frozen Soil ◽  
Conductive Heat ◽  
Formation Water ◽  
Borehole Stability ◽  
Finite Element Program ◽  
Gas Drilling

The gas drilling mainly relies on the high speed air flow to carry the cuttings. The formation water or oil mixed with the cuttings and then they stick together in clumps after the formation water or oil went into the hole annulus, the clumps stick on the drill string and the borehole. The clumps may block the hole annulus and cause the stick or bury the drill string and many other complex accident. It could stop the cuttings from sticking with the liquid through freezing the formation fluid with the liquid nitrogen. And the natural geotechnical becomes into the frozen soil, and forms the temporary solid which is intact, high strength and low-permeability. This paper utilize the ANSYS finite element program to simulate the 3D model of borehole and hole wall to calculate the freezing radius of the steady state, heat loss, temperature of the freezing point and the conductive heat time of the unsteady state. And this study has provided the basis of the freezing technology for borehole stability of gas drilling.

scholarly journals A chemo-mechanical coupling model of deviated borehole stability in hard brittle shale

2014 ◽  
Vol 41 (6) ◽  
pp. 817-823 ◽  
Author(s):  
Hang WEN ◽  
Mian CHEN ◽  
Yan JIN ◽  
Kai WANG ◽  
Yang XIA ◽  
...  
Keyword(s):  
Coupling Model ◽  
Borehole Stability ◽  
Mechanical Coupling

Borehole Stability Challenges In Gas Drilling: Case Studies In West Sichuan Basin

2010 ◽  
Author(s):  
Gao Li ◽  
Yingfeng Meng ◽  
Houbin Liu ◽  
Yuliang Zhou ◽  
Yixin Zhu
Keyword(s):  
Case Studies ◽  
Sichuan Basin ◽  
Borehole Stability ◽  
Gas Drilling

scholarly journals Study on the Mechanism of Ionic Stabilizers on Shale Gas Reservoir Mechanics in Northwestern Hunan

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2453 ◽  
Author(s):  
Pinghe Sun ◽  
Junyi Zhu ◽  
Binkui Zhao ◽  
Xinxin Zhang ◽  
Han Cao ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Clay Minerals ◽  
Shale Gas ◽  
Drilling Fluid ◽  
Pore Wall ◽  
Mechanical Tests ◽  
Borehole Stability ◽  
Gas Drilling ◽  
New Material ◽  
Niutitang Formation

The shale of the lower Cambrian Niutitang formation in northwestern Hunan is an ideal reservoir for shale gas. There is a close connection between borehole stability and drilling fluid in shale gas drilling. Ionic stabilizer is a new type of stratum consolidation agent that inhibits the hydration expansion of clay minerals and improves mechanical strength of the borehole. The traditional idea of pore wall protection is to use drilling fluid additives to prevent shale from interacting with water. However, ionic stabilizer can change the hydrophilic of clay minerals in shale, making the particles become hydrophobic and dense, therefore, the formation stability can be enhanced simultaneously. The material used in this paper is different from the normal ionic stabilizer, some chemical bonds that have been changed in the new material called enhanced normality ionic (ENI) stabilizer. This paper utilized the shale samples those obtained from Niutitang formation to study the connection between ENI and the mechanical properties of shale. Mechanical tests and microscopic pore tests were performed on different samples which were soaked in water and the ENI with different concentrations. It has been found through tests that ENI can inhibit the development of shale pores, and as the concentration increases, the inhibition increases. In addition, as the ENI concentration increases, the uniaxial compressive strength and Young’s modulus of the shale increase, and the ratio of stability coefficients decreases. It can be concluded that the ENI can improve the mechanical strength of carbon shale, and prevent the development of rock damage. Moreover, it can improve the ability of rock to resist damage, and enhance borehole stability initiatively.

Freezing Technology for Borehole Stability of Gas Drilling

2014 ◽  
Vol 962-965 ◽  
pp. 419-421
Author(s):  
Zong Gang Wang ◽  
Zhen Wei
Keyword(s):  
Fluid Flow ◽  
High Speed ◽  
High Strength ◽  
Drill String ◽  
Frozen Soil ◽  
Low Permeability ◽  
Formation Water ◽  
Borehole Stability ◽  
Gas Drilling ◽  
Scope Of Application

The gas drilling mainly relies on the high speed air flow to carry the cuttings. The formation water or oil mixed with the cuttings and then they stick together in clumps after the formation water or oil went into the hole annulus, the clumps stick on the drill string and the borehole. The clumps may block the hole annulus and cause the stick or bury the drill string and many other complex accident. It could stop the cuttings from sticking with the liquid through freezing the formation fluid with the liquid nitrogen. And the natural geotechnical becomes into the frozen soil, and forms the temporary solid which is intact, high strength and low-permeability. This technology could achieve the purpose of strengthening the formation and reducing the fluid flow of the formation, and it greatly broadens the scope of application of gas drilling.

Scheme Optimization of Freezing Technology for Borehole Stability of Gas Drilling

2014 ◽  
Vol 962-965 ◽  
pp. 465-468
Author(s):  
Zong Gang Wang ◽  
Zhen Wei
Keyword(s):  
High Speed ◽  
High Strength ◽  
Drill String ◽  
Frozen Soil ◽  
Low Permeability ◽  
Formation Water ◽  
Borehole Stability ◽  
Gas Drilling ◽  
Scheme Optimization ◽  
Drilling Technology

The gas drilling mainly relies on the high speed air flow to carry the cuttings. The formation water or oil mixed with the cuttings and then they stick together in clumps after the formation water or oil went into the hole annulus, the clumps stick on the drill string and the borehole. The clumps may block the hole annulus and cause the stick or bury the drill string and many other complex accident. It could stop the cuttings from sticking with the liquid through freezing the formation fluid with the liquid nitrogen. And the natural geotechnical becomes into the frozen soil, and forms the temporary solid which is intact, high strength and low-permeability. In this paper, according to the characteristic of the gas drilling technology, we optimized the scheme of freezing technology for borehole stability to give the theoretical basis of the industrial application.

Borehole Stability Logging Analysis in Zhenjing Oilfield, Ordos Basin, China

2013 ◽  
Vol 344 ◽  
pp. 8-14
Author(s):  
Li Min Ran ◽  
He Ping Pan ◽  
Gong Qiang Li ◽  
Yong Gang Zhao
Keyword(s):  
Oil And Gas ◽  
Ordos Basin ◽  
Maximum Tensile Stress ◽  
Practical Significance ◽  
Borehole Stability ◽  
Collapse Pressure ◽  
Stress Theory ◽  
Gas Drilling ◽  
Fracture Pressure ◽  
Column Pressure

There is very important practical significance for borehole stability to oil and gas drilling and production. When the mud density is too large (mud column pressure too high),the formation will be fractured. When the the mud density is too low (mud column pressure too low), the borehole wall will be collapsed, and hole will be enlarged. In this paper, the fracture pressures of the formations were determined by using the maximum tensile stress theory. The formation collapse pressures were determined by using the Coulomb - Moore intensity criteria. According to the fracture pressure and collapse pressure to evaluate the borehole stability. The two wells stability evaluation examples were given, and the borehole security mud window were calculated.

Freezing Technology for Borehole Stability of Gas Drilling

2013 ◽  
Vol 433-435 ◽  
pp. 1995-1998
Author(s):  
Zong Gang Wang ◽  
Zhen Wei
Keyword(s):  
Fluid Flow ◽  
High Speed ◽  
High Strength ◽  
Drill String ◽  
Frozen Soil ◽  
Low Permeability ◽  
Formation Water ◽  
Borehole Stability ◽  
Gas Drilling ◽  
Scope Of Application

The gas drilling mainly relies on the high speed air flow to carry the cuttings. The formation water or oil mixed with the cuttings and then stick together in clumps after the formation water or oil went into the hole annulus, the clumps stick on the drill string and the borehole. The clumps may block the hole annulus and cause the stick or bury the drill string and many other complex accident. It could stop the cuttings from sticking with the liquid through freezing the formation fluid with the liquid nitrogen. And the natural geotechnical becomes into the frozen soil, and forms the temporary solid which is intact, high strength and low-permeability. This technology could achieve the purpose of strengthening the formation and reducing the fluid flow of the formation, and it greatly broadens the scope of application of gas drilling.

scholarly journals Borehole enlargement rate as a measure of borehole instability in hydrate reservoir and its relationship with drilling mud density

2021 ◽  
Vol 11 (3) ◽  
pp. 1185-1198
Author(s):  
Qingchao Li ◽  
Lingling Liu ◽  
Baohai Yu ◽  
Linian Guo ◽  
Sheng Shi ◽  
...  
Keyword(s):  
Natural Gas ◽  
Drilling Fluid ◽  
Coupling Model ◽  
Fluid Density ◽  
Drilling Mud ◽  
Borehole Stability ◽  
Hydrate Dissociation ◽  
Hydrate Reservoir ◽  
Fluid Seepage ◽  
Model Fluid

AbstractBorehole collapse will pose a threat to the safety of equipment and personnel during drilling operation. In this paper, a finite element multi-field coupling model for investigating borehole collapse in hydrate reservoir was developed. In this model, fluid seepage, heat transfer, hydrate dissociation and borehole deformation are all considered. Based on which, effects of drilling fluid density on both of hydrate dissociation and borehole collapse are investigated. The investigation results show that disturbance of drilling fluid invasion to hydrate reservoir will lead to hydrate dissociation around wellbore, and dissociation range narrows obviously with the increase in drilling fluid density. When the relative fluid density is 0.98, natural gas hydrates in reservoir with a width of about 16.65 cm around wellbore dissociate completely. However, dissociation range of natural gas hydrate has decreased to 12.08 cm when the relative fluid density is 1.10. Moreover, hydrate dissociation around wellbore caused by drilling fluid invasion may lead to borehole collapse, and borehole collapse can be significantly restrained with the increase in relative fluid density. Borehole enlargement rate is 33.67% when the relative fluid density is 0.98, but nearly no collapse area displays around wellbore when the relative fluid density increases to 1.12. In addition, investigation herein can provide an idea for designing drilling fluid density in hydrate reservoir when different allowable borehole enlargement rate is considered. The minimum fluid density designed for avoiding disastrous borehole collapse increases nonlinearly when higher requirements for borehole stability are proposed.

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