scholarly journals Decreasing Coalbed Methane Formation Damage Using Microfoamed Drilling Fluid Stabilized by Silica Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jihua Cai ◽  
Sui Gu ◽  
Fawen Wang ◽  
Xianyu Yang ◽  
Ye Yue ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Performance Appraisal ◽  
Coalbed Methane ◽  
Gas Permeability ◽  
Foam Stability ◽  
Drilling Fluid ◽  
Formation Damage ◽  
Methane Formation ◽  
Coal Seams ◽  
20 Nm

Coalbed methane (CBM) reservoirs in China are featured in remarkable nanosized pores below 200 nm, acknowledged natural cleats, and tectonic fractures. This paper discussed the possibility that a clay free microfoamed drilling fluid could be stabilized by silica nanoparticles (CFMDF-NP) so as to avoid formation damage of CBM drilling. In accordance with the experimental results of foaming capacity and foam stability test, basic drilling fluid performance appraisal, micromorphology observation, swelling test, and gas permeability test, the mechanism of the CFMDF-NP was discussed in this paper. The results indicated that, with 10–20 nm nano-SiO2, the foaming volume of traditional foamed drilling fluid could be improved by up to 50% and an increased half-life period by up to 200%. Chemically treated nano-SiO2dispersions functioned as a foam stabilizer and a foaming agent as well. The CFMDF-NP had controllable density (0.7~1 g/cm3) and excellent rheological and sealing properties, which could satisfy the drilling requirements of the low pressure coal seams. With 5–8 mm slicing on the contaminated side of coal cores, the contaminated zone could be removed and the recovery rate of gas permeability could reach up to 70%. The CFMDF-NP laid good technical foundation to decrease formation damage of CBM reservoir.

scholarly journals Study on geological controls and enrichment models of coalbed methane in the Wuwei Basin in eastern North Qilian, northwestern China

2018 ◽  
Vol 37 (1) ◽  
pp. 429-452
Author(s):  
Wenchao Shen ◽  
Longyi Shao ◽  
Wenguang Tian ◽  
Gang Chen ◽  
Fei Chen ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Sedimentary Environment ◽  
Controlling Factors ◽  
Gas Content ◽  
Methane Formation ◽  
Coal Seams ◽  
Mineral Contents ◽  
The North ◽  
Taiyuan Formation ◽  
Lagoon Environment

The Wuwei Basin is located in the Gansu Corridor, which has abundant coalbed methane resources of 2.75 × 1011 m3. However, a low degree of coalbed methane exploration exists, and only a few wells have been drilled in local regions due to insufficient understanding of coalbed methane enrichment and its main controlling factors. This study analyzed the controlling factors of coalbed methane enrichment, including coal reservoir characteristics, hydrogeological conditions, and the original sedimentary environment of the coal-bearing strata. The results showed that the main coal seams were developed in the Taiyuan Formation, and were mostly concentrated in the Yingpan Sag in the south and the Ermahu Sag in the north of the study area. The macrolithotype of the coals in this basin was mainly semi-bright coal with a medium to high rank. Coal macerals were mainly vitrinite, ranging between 65.1% and 91.6% (averaged 81.70%), followed by liptinite, ranging between 1.9% and 29.5% (averaged 8.82%), and inertinite, ranging between 0.2% and 16.5% (averaged 3.66%). Mineral contents varied from 2.5% to 15.1% (averaged 6.16%). The macrolithotype and microlithotype of the Taiyuan Formation coals were favorable for coalbed methane formation. Through comparative analysis of moisture content, ash yield, gas content, and coal-forming sedimentary environments, it was found that the coal formed in the lagoon environment had a higher gas content and lower ash yield than that of the coal formed in the tidal flat environment. The high contents of total dissolved solids in aquifers around coal seams (1.75–16.70 g/L) reflected the closed hydrodynamic environment and were favorable for the preservation of coalbed methane in the Yingpan Sag. Considering various controlling factors (i.e., structure, sedimentation and hydrogeology), three coalbed methane enrichment models were proposed. The model of coalbed methane enrichment in the synclinorium was the most favorable for the enrichment of coalbed methane in the Yingpan Sag.

scholarly journals Experimental Research on Permeability of Coal and Rock Mass considering Postpeak Failure

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhiguo Cao ◽  
Hualei Zhang ◽  
Jiadi Yin ◽  
Baojie Fu
Keyword(s):  
Rock Mass ◽  
Coalbed Methane ◽  
Gas Permeability ◽  
Stable State ◽  
Confining Pressure ◽  
Effective Control ◽  
Coal Seams ◽  
Step Size ◽  
Fractured Coal ◽  
Seam Mining

In most mining areas of China, coal seams are characterized by low gas pressure, poor permeability, and high gas adsorption capacity, all of which have brought considerable difficulties to coal seam mining and coalbed methane (CBM) extraction. According to the multiyear scientific research and production practice of China, gas is migrated in quantity only after the coal body is directly mined, and the surrounding rocks deform and fracture under the mining influence. Thus, the key to effective control of gas migration and the coal and CBM comining technology lies in investigating the gas resolution, permeation, migration, and accumulation laws in the coal seams under the unloading confining pressure during mining. The MTS815.02 rock mechanics testing system and its supporting equipment are combined to test the permeability characteristics of coal and rock mass (postpeak fractured coal and sandstone specimens) under the loading and unloading of confining pressure using the steady method, and then, the permeation laws of the fractured coal and rock mass are obtained. Results show that after the postpeak rock crack propagation reaches a stable state, the confining pressure gradually increases, and the gas permeability presents an approximately linear reduction; in the postpeak unloading phase, the opening and coalescence degree of rock cracks gradually increase as the deformation extends. Thus, permeability reaches a peak value. The strain softening phase follows, where the cracks are closed and permeability declines to a certain extent. Moreover, the unloading step size of confining pressure has bearing on gas permeability. Specifically, as the unloading step size of confining pressure decreases, the change of gas permeability increases in stability.

scholarly journals Coupled Effects of Stress, Moisture Content and Gas Pressure on the Permeability Evolution of Coal Samples: A Case Study of the Coking Coal Resourced from Tunlan Coalmine

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1653
Author(s):  
Guofu Li ◽  
Yi Wang ◽  
Junhui Wang ◽  
Hongwei Zhang ◽  
Wenbin Shen ◽  
...  
Keyword(s):  
Moisture Content ◽  
Coalbed Methane ◽  
Gas Permeability ◽  
Axial Stress ◽  
Gas Pressure ◽  
Pressure Curve ◽  
Permeability Evolution ◽  
Confining Stress ◽  
Qinshui Basin ◽  
Gas Seepage

Deep coalbed methane (CBM) is widely distributed in China and is mainly commercially exploited in the Qinshui basin. The in situ stress and moisture content are key factors affecting the permeability of CH4-containing coal samples. Therefore, considering the coupled effects of compressing and infiltrating on the gas permeability of coal could be more accurate to reveal the CH4 gas seepage characteristics in CBM reservoirs. In this study, coal samples sourced from Tunlan coalmine were employed to conduct the triaxial loading and gas seepage tests. Several findings were concluded: (1) In this triaxial test, the effect of confining stress on the permeability of gas-containing coal samples is greater than that of axial stress. (2) The permeability versus gas pressure curve of coal presents a ‘V’ shape evolution trend, in which the minimum gas permeability was obtained at a gas pressure of 1.1MPa. (3) The gas permeability of coal samples decreased exponentially with increasing moisture content. Specifically, as the moisture content increasing from 0.18% to 3.15%, the gas permeability decreased by about 70%. These results are expected to provide a foundation for the efficient exploitation of CBM in Qinshui basin.

scholarly journals Environmental Risk Related to the Exploration and Exploitation of Coalbed Methane

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6537
Author(s):  
Barbara Uliasz-Misiak ◽  
Jacek Misiak ◽  
Joanna Lewandowska-Śmierzchalska ◽  
Rafał Matuła
Keyword(s):  
Coalbed Methane ◽  
Environmental Risks ◽  
Risk Category ◽  
Burial History ◽  
Exploration And Exploitation ◽  
Coal Seams ◽  
Mining Operations ◽  
Environmental Threats ◽  
And Migration ◽  
Coal Macerals

In coal seams, depending on the composition of coal macerals, rank of coal, burial history, and migration of thermogenic and/or biogenic gas. In one ton of coal 1 to 25 m3 of methane can be accumulated. Accumulation of this gas is included in unconventional deposits. Exploitation of methane from coal seams is carried out with wells from mining excavations (during mining operations), wells drilled to abandoned coal mines, and wells from the surface to unexploited coal seams. Due to the low permeability of the coal matrix, hydraulic fracturing is also commonly used. Operations related to exploration (drilling works) and exploitation of methane from coal seams were analyzed. The preliminary analysis of the environmental threats associated with the exploration and exploitation of coalbed methane has made it possible to identify types of risks that affect the environment in various ways. The environmental risks were estimated as the product of the probability weightings of adverse events occurring and weightings of consequences. Drilling operations and coalbed methane (CBM) exploitation leads to environmental risks, for which the risk category falls within the controlled and accepted range.

Natural Rubber Reinforced with Silica Nanoparticles Extracted from Jasmine and Riceberry Rice Husk Ashes

2018 ◽  
Vol 936 ◽  
pp. 31-36 ◽  
Author(s):  
Wichudaporn Seangyen ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
Peerapan Dittanet
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Silica Nanoparticles ◽  
Rice Husk ◽  
Sol Gel ◽  
Rubber Matrix ◽  
Reinforcing Fillers ◽  
Rubber Nanocomposites ◽  
Jasmine Rice ◽  
20 Nm

Silica nanoparticles were synthesized by rice husk ash (RHA) produced from jasmine rice husk and riceberry rice husk via sol-gel method for the use as reinforcing fillers in natural rubber (NR). The obtained silica nanoparticles are spherical in shape and the particle sizes were observed to be in the 10-20 nm range with uniformly size distribution. The surface of silica nanoparticles was treated with a silane coupling agent confirmed by FTIR. The treated silica nanoparticles were then incorporated into NR and vulcanized with electron beam irradiation. The rubber nanocomposites with silica nanoparticles, produced from jasmine rice husk and riceberry rice husk, resulted in higher mechanical properties (tensile strength and modulus) than neat rubber vulcanizate. The modified rubber vulcanizates revealed rougher surface with tear lines as compared to the neat rubber vulcanizates, indicating the improved strength. Interestingly, the rubber nanocomposites with silica nanoparticles from jasmine rice husk showed higher tensile strength and modulus than silica nanoparticles produced from riceberry rice husk. The micrographs indicated better dispersion of NR composites with jasmine rice husk which leads to a strong interaction between silica nanoparticles and rubber matrix, thereby improving the strength.

scholarly journals The prediction of structural fractures in coal seams of the Kuba coalfield, China: an application for coalbed methane (CBM) recovery development

2019 ◽  
Vol 72 (Special issue) ◽  
pp. 57-69
Author(s):  
Zhou Zhang ◽  
Min Zhoua ◽  
Yun-Xing Cao ◽  
Bao-An Xian ◽  
Di Gao
Keyword(s):  
Coalbed Methane ◽  
Coal Seams

scholarly journals Silica-Supported Co3O4 Nanoparticles as a Recyclable Catalyst for Rapid Degradation of Azodye

2016 ◽  
Vol 11 (3) ◽  
pp. 284 ◽  
Author(s):  
Ali Baghban ◽  
Esmail Doustkhah ◽  
Sadegh Rostamnia ◽  
Khadijeh Ojaghi Aghbash
Keyword(s):  
Silica Nanoparticles ◽  
Aqueous Media ◽  
Oxidative Degradation ◽  
Ammonium Persulfate ◽  
Recyclable Catalyst ◽  
Co3o4 Nanoparticles ◽  
Media Effect ◽  
Rapid Degradation ◽  
Ft Ir ◽  
20 Nm

<p>In this paper, silica nanoparticles with particle size of ~ 10-20 nm were selected as a support for the synthesis of Co<sub>3</sub>O<sub>4</sub> nanoparticles by impregnation of silica nanoparticles in solution of Co(II) in a specific concentrations and then calcination to 800 <sup>o</sup>C. This nanocomposite was then, used as a catalyst for oxidative degradation of methyl orange (MO) with ammonium persulfate in aqueous media. Effect of pH, temperature, contact time, amount of oxidant and catalyst were studied in the presence of manuscript. Scanning electron microscope (SEM), electron dispersive spectroscopy (EDS), FT-IR, and ICP-AES analyses were used for analysis of silica-supported Co<sub>3</sub>O<sub>4</sub> (Co<sub>3</sub>O<sub>4</sub>/SiO<sub>2</sub>). Treating MO with ammonium persulfate in the presence of Co<sub>3</sub>O<sub>4</sub>/SiO<sub>2 </sub>led to complete degradation of MO under the optimized conditions. Also, the catalyst exhibited recyclability at least over 10 consecutive runs. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 12<sup>nd</sup> December 2015; Revised: 27<sup>th</sup> January 2016; Accepted: 27<sup>th</sup> January 2016</em></p><p><strong>How to Cite</strong>: Baghban, A., Doustkhah, E., Rostamnia, S., Aghbash, K.O. (2016). Silica-Supported Co<sub>3</sub>O<sub>4</sub> Nanoparticles as a Recyclable Catalyst for Rapid Degradation of Azodye. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (3): 284-291 (doi:10.9767/bcrec.11.3.568.284-291)</p><p><strong>Permalink/DOI</strong>: <a href="http://doi.org/10.9767/bcrec.11.3.568.284-291">http://doi.org/10.9767/bcrec.11.3.568.284-291</a></p>

Research on Nano-Emulsion Relieving Coal Seam Water Block Damage

2021 ◽  
Author(s):  
Wei Sun ◽  
LongHao Zhao ◽  
Qian Wang ◽  
Yanchi Liu ◽  
Weiping Zhu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Mixed Micelles ◽  
Polymer Adsorption ◽  
Coal Seams ◽  
Fracturing Fluid ◽  
Flow Experiment ◽  
Nano Emulsion ◽  
Water Block ◽  
Lock In

Abstract Hydraulic fracturing is the most effective reservoirstimulation techniques in the coalbed methane. However, the polymer in the fracturing fluid has a strong effect on the surface of the coal, causing the water lock damage as high as 70% to 90%. It is important to develop an efficient method for releasing coal seam water lock. In this paper, adsorption experiment, SEM, particle size experiment, core flow experiment, wettability and surface tension experiment are used to study the cause of coal seam water lock damage during fracturing and the effect of nano-emulsion on releasing water lock damage in coal seams. Experimental results show that after coal fracturing, the adsorption amount of polymer on the surface of coal is 14.81 mg/g. The large amount of hydrophilic polymer adsorption causes the pore radius of the coal to narrow. And the surface wettability changes from weak hydrophilic to strong hydrophilic, which increase the water lock damage. Compared with conventional slick water, fracturing fluid, the composite of nano-emulsion and fracturing fluid forms mixed micelles, which reduces the polymer adsorption capacity from 14.81 mg/g to 7.42 mg/g. After scanning by electron microscope, it is observed that the surface roughness of the rock sample is restored; The size of the nano-emulsion is about 10nm, and the very small volume can act deep in the pores of the coal seam; After using nano-emulsion, the gas/water interfacial tension is reduced by 45.1mN/m, and the wettability of coal is improved from hydrophilic to neutral, which reduces the capillary pressure in the pores of the coal and reduces the breakthrough pressure of coalbed methane by 11.1KPa; The water lock release rate is as high as 53.09%. The Nano-emulsion is an ideal choice to remove water lock damage.

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