The wellbore instability control mechanism of fuzzy ball drilling fluids for coal bed methane wells via bonding formation

Zheng, Lihui; Su, Guandong; Li, Zhonghui; Peng, Rui; Wang, Le; Wei, Panfeng; Han, Shu-xin

doi:10.1016/j.jngse.2018.05.008

Cited by 43 publications

(22 citation statements)

References 30 publications

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“…There are various theories on the fissures in coal origination, like tectonics, proceeding processes of drainage and of organic material shrinkage. Fissures and cracks in coal exist most often perpendicular to each other and perpendicular to the bedrock plane and may be 3-40 μm wide (Clarkson and Bustin, 2011;Baltoiu et al, 2016;Zhang et al, 2016;Li et al, 2017;Zheng et al, 2018). Stresses existing in such formations exceed the hard coal compression strength.…”

Section: Issues Occurring During Coal Deposits Developmentmentioning

confidence: 99%

Drilling muds for coal deposits

Błaż¹

2020

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The instability of coal beds, both in the overburden and in the production zone during drilling, in particular with directional borehole, is well known. One of the main coal attributes is presence of cracks and micro-fractures in it. This linked network of cracks is considered as the main source of many problems related to coal instability. Stresses occurring in such formations exceed the coal compressive strength. During drilling, coal becomes unstable, which can result in borehole wall collapsing, stuck pipe, or even complete loss of the borehole. Using improper drilling muds can cause additional problems. In coal, a poorly selected drilling mud can damage the natural permeability of the near-well zone. Drilling muds penetrating the pores and cracks in the coal can lead to permanent destruction of the near-well zone, partially or completely limiting the supply of methane to the borehole. Muds used for drilling in coal deposits should therefore both stabilize the borehole wall and affect minor damage to the drilled formation. The experience acquired while drilling low-permeability shale rocks generally does not correlate with the practices and guidelines used to drill holes in coal deposits due to the unique physical and mechanical characteristics of coal. One of the ways to improve the stability of coal deposits when using water-based drilling muds is to prevent the penetration of mud filtrate into the rock matrix, which can be achieved by chemical modification of the drilling mud composition or physical sealing of pores and fractures with special materials. The article presents research on the development of a new drilling mud system dedicated to coalbed methane (CBM) drilling.

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Section: Issues Occurring During Coal Deposits Developmentmentioning

confidence: 99%

Drilling muds for coal deposits

Błaż¹

2020

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“…Unconventional energy sources, such as coalbed methane (CBM), shale gas, and tight sandstone gas, have replaced some conventional energy sources (Akhtarmanesh et al., 2013; Lu et al., 2017; Shen et al., 2019; Wu et al., 2020; Zhong et al., 2011). In recent decades, CBM has become an important energy source worldwide (Cai et al., 2016; Chen et al., 2018; Law and Curtis, 2002; Zhang et al., 2020; Zheng et al., 2018). China has rich coalfield reservoirs containing large quantities of CBM.…”

Section: Introductionmentioning

confidence: 99%

“…Cai et al (2011) introduced an environmentally-friendly and bio-degradable drilling fluid for CBM; they tested it to evaluate the polymer type and concentration, as well as enzyme type and concentration on the viscosity and breaking behaviors of this drilling fluid. Zheng et al (2018) studied the fuzzy ball drilling fluid, which has now been successfully applied to approximately 1000 CBM wells to prevent collapse and block leakage in the Ordos stable block, and they discovered that the drilling fluid could significantly increase the wall thickness, thereby keeping the wall stable (Vryzas and Kelessidis, 2017). It is ideal to use low solid degradable drilling fluid systems in coal seams (Yang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid

Zhang

Lyu

et al. 2020

Energy Exploration & Exploitation

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Coal powders, as cuttings, invade the drilling fluid along a coal seam during coalbed methane development, thereby changing the properties of the drilling fluid. Therefore, this work aims to investigate the influence of coal powders on drilling fluid performance. The powders of lignite, anthracite, and contrasting shale were added to a water-based polymer drilling fluid. Then, the rheology, filtration, lubricity, and adhesiveness were measured, and the natural degradation, as well as the wettability were further evaluated. The results show that some parameters of the drilling fluid, including viscosity, lubrication coefficient, adhesion coefficient, contact angle, and surface tension, increase after adding coal powders, while other parameters, such as filtration loss and natural degradation, decrease. Compared with lignite and shale, anthracite powders, with the lowest mineral content, exhibit the smallest change in the rheological property, lubricity, adhesion, and natural degradation of the drilling fluid. Moreover, the content and size of the coal powders generally have opposing effects on the drilling fluid. When the coal powder content reaches 3 wt.%, the surface tension and contact angle of the drilling fluid show more evident changes than other parameters. Based on the analysis of the stress intensity factor, the drilling fluid with coal powders exceeding 100 mesh can reduce the capillary force in microfractures, and in combination with other factors (such as reduced filtration loss and sealing and supporting of the microfractures), improves wellbore stability. Therefore, coal powders with suitable particle sizes and concentration levels are expected to become a new drilling fluid material to protect coal field reservoirs.

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“…Coal bed methane (CBM) or coal mine methane (CMM) is a signi cant and unavoidable resource for natural gas exploration and production (Chen et al 2020;Karacan and Warwick 2019;Zheng et al 2018;Vedachalam et al 2015;Moore 2012). Speci cally, India has tremendous potential for the extraction of methane from coal beds (Rathi et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

Rajkumar

Antony

Mahalingam³

et al. 2020

Preprint

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A laboratory based investigation has been conducted on permeability damage and CO2 storage or retention in the lignite core during alternative injection of brine and supercritical carbon dioxide. Moreover, anthracite and bituminous coal beds were focused by the scientific community for effective production and reservoir formation damage study. But, now-a-days, lignite based coal bed methane reservoirs have attracted attention for productive exploitation and formation collapse investigation. Hence, for this purpose, a single component injection two phase (Brine + Supercritical CO2) coreflood test analysis under alternative injections were performed to investigate the occurrence of lignite structural collapse, permeability damage, injectivity decline and CO2 retention as well. The experimental study reveals that, due to gravity segregation there is a high rate of fluid saturation in lignite core and also, moderate level of heat transfer coefficient was also noted. Also, lignite core structural collapse under the brine and supercritical CO2 injection at different velocities resulted in huge volume of coal and kaolinite fines concentration. Kaolinite and coal fines migration resulted in pressure change and permeability decline in lignite core. The suspensions produced were passed to microstructural analysis and it revealed that kaolinite fine particle tends to possess a leaflet geometrical structure, which obstructed the cleats and restricted the fluid flow. Subsequently, hysteresis modelling (Pranesh 2018) was applied to this problem to quantify the amount of CO2 retention in lignite core. Additionally, statistical model, multiple linear regression was applied to this problem to validate the experimental model, which showed good agreement.

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The wellbore instability control mechanism of fuzzy ball drilling fluids for coal bed methane wells via bonding formation

Cited by 43 publications

References 30 publications

Drilling muds for coal deposits

Drilling muds for coal deposits

Experimental study on the influence of coal powders on the performance of water-based polymer drilling fluid

Permeability Damage and Supercritical Fluid Storage in the Cauvery Basin Neyveli Lignite Bed Containing Kaolinite Deposits during Alternative Injection of Brine and CO2

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