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

Author(s):  
Gao Li ◽  
Yingfeng Meng ◽  
Houbin Liu ◽  
Yuliang Zhou ◽  
Yixin Zhu
2014 ◽  
Vol 962-965 ◽  
pp. 415-418
Author(s):  
Zong Gang Wang ◽  
Zhen Wei

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.


2012 ◽  
Author(s):  
Gao Li ◽  
Houbin Liu ◽  
Yingfeng Meng ◽  
Xueshuang Leng ◽  
Hongjun Jia ◽  
...  

2021 ◽  
Vol 861 (6) ◽  
pp. 062075
Author(s):  
Rong-Chao Cheng ◽  
Ming-Ming Chu ◽  
Jie Zhang ◽  
Hui-Jiun Hao ◽  
Hai Lin ◽  
...  

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2453 ◽  
Author(s):  
Pinghe Sun ◽  
Junyi Zhu ◽  
Binkui Zhao ◽  
Xinxin Zhang ◽  
Han Cao ◽  
...  

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.


2014 ◽  
Vol 962-965 ◽  
pp. 419-421
Author(s):  
Zong Gang Wang ◽  
Zhen Wei

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.


2014 ◽  
Author(s):  
Haifang Sun ◽  
Jing Bai ◽  
Bing Huang ◽  
Weiqing Chen ◽  
Yuandong Hong ◽  
...  

2014 ◽  
Vol 962-965 ◽  
pp. 465-468
Author(s):  
Zong Gang Wang ◽  
Zhen Wei

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.


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