scholarly journals Research and Application of Fuling Shale Gas Anti-Collapse and Anti-Leakage Drilling Fluid System

2021 ◽  
Vol 06 (02) ◽  
pp. 60-71
Author(s):  
Baijing Wang ◽  
Chunzhi Luo ◽  
Yidi Wang
Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pengcheng Wu ◽  
Chengxu Zhong ◽  
Zhengtao Li ◽  
Zhen Zhang ◽  
Zhiyuan Wang ◽  
...  

Finding out the reasons for wellbore instability in the Longmaxi Formation and Wufeng Formation and putting forward drilling fluid technical countermeasures to strengthen and stabilize the wellbore are very crucial to horizontal drilling. Based on X-ray diffraction, electron microscope scanning, linear swelling experiment, and hot-rolling dispersion experiment, the physicochemical mechanism of wellbore instability in complex strata was revealed, and thus, the coordinated wellbore stability method can be put forward, which is “strengthening plugging of micropores, inhibiting filtrate invasion, and retarding pressure transmission.” Using a sand bed filtration tester, high-temperature and high-pressure plugging simulation experimental device, and microporous membrane and other experimental devices, the oil-based drilling fluid treatment agent was researched and selected, and a set of an enhanced plugging drilling fluid system suitable for shale gas horizontal well was constructed. Its temperature resistance is 135°C and it has preferable contamination resistibility (10% NaCl, 1% CaCl2, and 8% poor clay). The bearing capacity of a 400 μm fracture is 5 MPa, and the filtration loss of 0.22 μm and 0.45 μm microporous membranes is zero. Compared with previous field drilling fluids, the constructed oil-based drilling fluid system has a greatly improved plugging ability and excellent performance in other aspects.


2015 ◽  
Vol 8 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Jun Gu ◽  
Ju Huang ◽  
Su Zhang ◽  
Xinzhong Hu ◽  
Hangxiang Gao ◽  
...  

The purpose of this study is to improve the cementing quality of shale gas well by mud cake solidification, as well as to provide the better annular isolation for its hydraulic fracturing development. Based on the self-established experimental method and API RP 10, the effects of mud cake solidifiers on the shear strength at cement-interlayer interface (SSCFI) were evaluated. After curing for 3, 7, 15 and 30 days, SSCFI was remarkably improved by 629.03%, 222.37%, 241.43% and 273.33%, respectively, compared with the original technology. Moreover, the compatibility among the mud cake solidifier, cement slurry, drilling fluid and prepad fluid meets the safety requirements for cementing operation. An application example in a shale gas well (Yuanye HF-1) was also presented. The high quality ratio of cementing quality is 93.49% of the whole well section, while the unqualified ratio of adjacent well (Yuanba 9) is 84.46%. Moreover, the cementing quality of six gas-bearing reservoirs is high. This paper also discussed the mechanism of mud cake solidification. The reactions among H3AlO42- and H3SiO4- from alkali-dissolved reaction, Na+ and H3SiO4- in the mud cake solidifiers, and Ca2+ and OH- from cement slurry form the natrolite and calcium silicate hydrate (C-S-H) with different silicate-calcium ratio. Based on these, SSCFI and cementing quality were improved.


2001 ◽  
Author(s):  
Xu Shaocheng ◽  
Xiaojian Jin ◽  
Li Zili ◽  
Xinjing Xiang
Keyword(s):  

2021 ◽  
Author(s):  
Zhao Xionghu ◽  
Saviour Bassey Egwu ◽  
Deng Jingen ◽  
Miao Liujie

Abstract The effect of corrosion inhibitor Benzotriazole on synthetic-based mud system was studied. Rheological performance of the benzotriazole enhanced synthetic-based fluid system was studied and compared against the base mud. To study its effect on dynamic wellbore conditions, different drilling fluid compositions were placed in a hot rolling oven for 16 hours at temperatures 150 °C and 170°C and the effect of temperature on mud properties were studied. Tests carried out include rheological test (before and after hot rolling), filtrate pH, lubricity test, and fluid loss test. The corrosion penetration rate was studied using the weight loss method. Based on experiment results, the synthetic-based mud system which comprised of benzotriazole displayed a reduction in coefficient of friction up to 95.93%. At ambient condition, optimal ratio of mineral oil:benzotriazole (M:B) which gives best lubricity performance on synthetic-based mud system is 80:20. This leads to improved corrosion inhibition and lubricity of the synthetic-based fluid by reducing the coefficient of friction up to 90.13%. Increased temperature led to further decrease in coefficient of friction with a % torque reduction of 95.93 displayed by the 80:20 ratio M:B mud composition at 170 °C. Significant alterations of the mud composition rheological and fluid loss parameters before and after exposure to high temperature in hot rolling oven were not observed. pH values were maintained ≥7 at the dynamic conditions highlighting solubility of the formulated fluid composition and absence of contaminants which can pose significant threats to the rates of corrosion in drill pipes. Increasing the concentration of Benzotriazole led to a reduction in corrosion rate. However, as the temperature effect increased, the corrosion rate elevated. Based on results from this investigation, it was concluded that Benzotriazole can be applied as a corrosion inhibitor in a synthetic-based drilling fluid system as an alternative corrosion inhibitor without significant alteration of the base mud properties. Benefits of this will be the optimization of extended reach well drilling operations due to excellent lubricity performance, corrosion rate reduction, compatibility with HPHT wellbore condition and fluid loss control.


1987 ◽  
Author(s):  
J.A. Wingrave ◽  
E. Kubena ◽  
C.F. Douty ◽  
D.L. Whitfill ◽  
D.P. Cords

2009 ◽  
Author(s):  
Yuxue Sun ◽  
Yanfen Zhang ◽  
Jingyuan Zhao

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