scholarly journals Mechanism of wellbore instability in continental shale gas horizontal sections and its water-based drilling fluid countermeasures

2020 ◽  
Vol 7 (6) ◽  
pp. 680-688
Author(s):  
Bo Wang ◽  
Jinsheng Sun ◽  
Feng Shen ◽  
Wei Li ◽  
Wenzhe Zhang
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Wellbore Instability ◽  
Water Based

Interdisciplinary Approach for Wellbore Stability During Slimhole Drilling at Volga-Urals Basin Oilfield

2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Sergey Mihailovich Karpukhin ◽  
Konstantin Urjevich Ruban ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev
Keyword(s):  
Drilling Fluid ◽  
Interdisciplinary Approach ◽  
Wellbore Stability ◽  
Vertical Wells ◽  
Wellbore Instability ◽  
Water Based ◽  
Chemical Studies ◽  
Fluid Rheology ◽  
Selection Of

Abstract The design features and the need to use a water-based solution make the task of ensuring trouble-free drilling of vertical wells non-trivial. This work is an example of an interdisciplinary approach to the analysis of the mechanisms of instability of the wellbore. Instability can be caused by a complex of reasons, in this case, standard geomechanical calculations are not enough to solve the problem. Engineering calculations and laboratory chemical studies are integrated into the process of geomechanical modeling. The recommendations developed in all three areas are interdependent and inseparable from each other. To achieve good results, it is necessary to comply with a set of measures at the same time. The key tasks of the project were: determination of drilling density, tripping the pipe conditions, parameters of the drilling fluid rheology, selection of a system for the best inhibition of clay swelling.

scholarly journals Oil-Based Drilling Fluid Plugging Method for Strengthening Wellbore Stability of Shale Gas

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pengcheng Wu ◽  
Chengxu Zhong ◽  
Zhengtao Li ◽  
Zhen Zhang ◽  
Zhiyuan Wang ◽  
...  
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Drilling Fluids ◽  
Fluid System ◽  
Horizontal Drilling ◽  
Wellbore Instability ◽  
Filtration Loss ◽  
Treatment Agent ◽  
Stability Method

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.

Successful Application of Unique High-Density Water-Based Drilling Fluid Used in Zhaotong Shale Gas Horizontal Wells

2015 ◽  
Author(s):  
Lili Yan ◽  
Congjun Li ◽  
Zhilei Zhang ◽  
Jianhua Wang ◽  
Xianguang Xu ◽  
...  
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Horizontal Wells ◽  
High Density ◽  
Water Based

Study on Shale Gas Drilling Fluids Technology

2013 ◽  
Vol 868 ◽  
pp. 651-656
Author(s):  
Gang Xie ◽  
Ming Yi Deng ◽  
Jun Lin Su ◽  
Liang Chun Pu
Keyword(s):  
Shale Gas ◽  
Drilling Fluid ◽  
Blocking Agent ◽  
Drilling Fluids ◽  
Collapse Pressure ◽  
Gas Drilling ◽  
Advantages And Disadvantages ◽  
Water Based ◽  
Column Pressure ◽  
Shale Gas Drilling

Via discussing the advantages and disadvantages of different types of oil-based drilling fluids, the main reason why oil-based drilling fluids are less used in our country is obtained that dont form a complete series of matching technology. The essence of wellbore instability caused by using water-based drilling fluids to drill shale is analyzed that the formation collapse pressure is greater than drilling fluids column pressure. The fundamental way of controlling borehole wall stability that use water-based drilling fluids to drill shale horizontal well was proposed that deeply researched the shale hydration mechanism, developed efficient blocking agent and inhibitors and established shale gas drilling fluid suppression system, which made water-based drilling fluids have excellent performance.

Drilling Fluid Design for Shale Gas Drilling

2015 ◽  
Vol 1113 ◽  
pp. 617-624 ◽  
Author(s):  
Mohamad Safwan Zazarli Shah ◽  
Arina Sauki ◽  
Wan Zairani Wan Bakar ◽  
Nurul Aimi Ghazali ◽  
Azlinda Azizi
Keyword(s):  
Shale Gas ◽  
Negative Impact ◽  
Drilling Fluid ◽  
Past Research ◽  
Gas Drilling ◽  
Water Based ◽  
Oil Water ◽  
The Impact ◽  
Rheological Performance ◽  
Shale Gas Drilling

Shale gas nowadays is an important source of unconventional gas. The limited conventional gas supply makes the unconventional sources as a new source of gas. In this research, the aim is to design a mud formulation that can carry out essential functions of mud for shale gas drilling. Commonly for shale gas drilling, water based mud is used. However, water based mud is ineffective when dealing with water-sensitive shale. The alternative way to deal with this type of shale is using synthetic-based mud (SBM) or oil-based mud (OBM). OBM is an effective mud while drilling well. However, it is toxic and gives negative impact to environment. SBM somehow is more environmental friendly compared to oil based and ester is one of the synthetic based fluids. In order to prove this statement, a toxicity test was carried out to investigate the impact of ester based mud on selected marine life. The results of the test were compared with past research results. The ester use in this research is methyl-ester C12-C14 derived from palm oil and the mud was formulated at different oil-water ratios which are 70/30, 80/20 and 90/10, respectively and the best rheological performance can be seen at 80/20 oil-water ratio. Then, the performance of this mud had been compared to other types of mud which are sarapar-based and WBM. The findings revealed that the rheological performance of ester based mud is comparable with common based mud used for shale gas drilling. Apart from that, it is less toxic than other based mud which can maintain 60% prawn’s survival even after 96 hours exposure in 100,000 ppm of mud concentration in artificial seawater.

Analysis of the Formation Mechanism of Crack Network in Shale by CT

2014 ◽  
Vol 568-570 ◽  
pp. 12-18
Author(s):  
Qing Hua Sun ◽  
Jin Gen Deng ◽  
Zhuo Chen ◽  
Yong Meng Xu ◽  
Heng Lin Yang ◽  
...  
Keyword(s):  
Shale Gas ◽  
Horizontal Well ◽  
Maximum Stress ◽  
Drilling Fluid ◽  
Fracture Plane ◽  
Chromatographic Technique ◽  
Drilling Process ◽  
Crack Network ◽  
Wellbore Instability ◽  
Shale Formation

During the drilling process of shale gas horizontal well, wellbore instability problem happens frequently. Especially in the horizontal interval, shale which has high levels of gamma is more likely to collapse which lead to delays, and exist certainly collapse period. The development of shale gas is restricted seriously. Research on the formation process of cracks network around the wellbore by CT chromatographic technique. The result reveals that under the condition of uniaxial compression, the cracks initiated inside the shale formation around the wellbore, with the propagation of cracks, between the orientation of cracks and the maximum stress direction will emerge a certain deviated angle. The drilling fluid filtrates into the formation and reduce the strength of rock which will prompt crack propagation and form crack network. Finally the wellbore will collapse with drilling fluid continuous invasion, because the invasion have altered the stress intensity factor at fracture tip, and changed the propagating direction of crack and the friction coefficient of fracture plane, which will reduce the strength of rock and the effective stress of the rock around the wellbore. Crack network dominates the mechanism of instability; mud weight increases do not necessarily lead to a more stable borehole and can further destabilize the wellbore.

The Influence of SiO2 and TiO2 Nanoparticles on the Properties of Water-Based Mud

2017 ◽  
Author(s):  
Petar Mijić ◽  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić
Keyword(s):  
Filter Cake ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Drilling Fluids ◽  
Drilling Mud ◽  
Shale Formations ◽  
Wellbore Instability ◽  
Water Based ◽  
Fluid Properties

About 75% of all formations drilled worldwide are shale formations and 90% of all wellbore instability problems occur in shale formations. This increases the overall cost of drilling. Therefore, drilling through shale formations, which have nanosized pores with nanodarcy permeability still need better solutions since the additives used in the conventional drilling fluids are too large to plug them. One of the solutions to drilling problems can be adjusting drilling fluid properties by adding nanoparticles. Drilling mud with nanoparticles can physically plug nanosized pores in shale formations and thus reduce the shale permeability, which results in reducing the pressure transmission and improving wellbore stability. Furthermore, the drilling fluid with nanoparticles, creates a very thin, low permeability filter cake resulting in the reduction of the filtrate penetration into the shale. This thin filter cake implies high potential for reducing the differential pressure sticking. In addition, borehole problems such as too high drag and torque can be reduced by adding nanoparticles to drilling fluids. This paper presents the results of laboratory examination of the influence of commercially available nanoparticles of SiO2 (dry SiO2 and water-based dispersion of 30 wt% of silica), and TiO2 (water-based dispersion of 40 wt% of titania) in concentrations of 0.5 wt% and 1 wt% on the properties of water-based fluids. Special emphasis is put on the determination of lubricating properties of the water-based drilling fluids. Nanoparticles added to the base mud without any lubricant do not improve its lubricity performance, regardless of their concentrations and type. However, by adding 0.5 wt% SiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 4.6%, and by adding 1 wt% TiO2-disp to the base mud with lubricant, its lubricity coefficient is reduced by 14.3%.

An High-Performance Water-Based Drilling Fluid and its Application

2012 ◽  
Vol 476-478 ◽  
pp. 2304-2310
Author(s):  
Kai He Lv ◽  
Xue Dong Wu ◽  
Tao Shi ◽  
Kuan Long Ren ◽  
Yu Xia Liu
Keyword(s):  
High Performance ◽  
Filtration Rate ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Field Application ◽  
Wellbore Instability ◽  
Water Based ◽  
Fluid Properties ◽  
Overall Performance ◽  
Inhibition Property

An high-performance water-based drilling fluid is a hot subject of research both at home and abroad in recent years. In this paper, the inhibition property and the influence of amino polyols AP-1 and aluminum polymer DLP-1 on drilling fluid properties were evaluated, on this basis, through the formula optimization, the high-performance water based drilling fluid was developed and and field applied. Both laboratory study and field application showed that aluminum polymer can reduce viscosity and filtration rate, and can effectively inhibit the hydration expansion of clay. Amino polyols had a little effect on the viscosity, gel strength and filtration of drilling fluid, but it had a good shale inhibition. This drilling fluid has good properties in rheology, filtration, inhibition and anti-contamination, with a satisfactory overall performance, which is helpful in solving wellbore instability that are due to unenven hydration or well developed micro fractures.

Solidifying Mud Cake to Improve Cementing Quality of Shale Gas Well: A Case Study

2015 ◽  
Vol 8 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Jun Gu ◽  
Ju Huang ◽  
Su Zhang ◽  
Xinzhong Hu ◽  
Hangxiang Gao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Calcium Silicate Hydrate ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Gas Well ◽  
Safety Requirements ◽  
Mud Cake ◽  
Gas Bearing

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.

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