COAL SEAM GAS—PETROLEUM OR MINERAL

1997 ◽  
Vol 37 (1) ◽  
pp. 589
Author(s):  
D.J. Gately
Keyword(s):  
Private Sector ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Resource Development ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Commercial Use ◽  
Private Sector Investment ◽  
History Of ◽  
Policy Shift

1996 was a watershed year for gas exploration in Queensland: the increasing private sector investment in the search for and commercial use of methane gas from coal seams received legislative endorsement. Coal seam gas (CSG), also known as coalbed methane or CBM, was officially designated as petroleum, with exploration for and production of CSG to be administered under the Petroleum Act.The paper traces the history of exploration for CSG in Queensland since 1976, culminating in a policy shift in 1996. In Queensland there is now potential for overlapping titles and competitive resource development.

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.

scholarly journals The Role of Coal Mechanical Characteristics on Reservoir Permeability Evolution and Its Effects on CO2 Sequestration and Enhanced Coalbed Methane Recovery

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-28
Author(s):  
Hao Han ◽  
Shun Liang ◽  
Yaowu Liang ◽  
Xuehai Fu ◽  
Junqiang Kang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Coal Seam ◽  
Coalbed Methane ◽  
Co2 Sequestration ◽  
Mechanical Characteristics ◽  
Co2 Adsorption ◽  
Co2 Injection ◽  
Permeability Change ◽  
Coal Seams ◽  
Enhanced Coalbed Methane

Elastic modulus is an important parameter affecting the permeability change in the process of coalbed methane (CBM)/enhanced coalbed methane (ECBM) production, which will change with the variable gas content. Much research focuses on the constant value of elastic modulus; however, variable stiffness of coal during CO2 injection has been considered in this work. The coupled thermo-hydro-mechanical (THM) model is established and then validated by primary production data, as well as being applied in the prediction of CO2/N2-ECBM recovery. The results show that the harder coal seam is beneficial to primary production, while the softer coal seam results in greater CO2/N2-ECBM recovery and CO2 sequestration. N2 and CO2 mixture injection could be applied to balance early N2 breakthrough and pronounced matrix swelling induced by CO2 adsorption, and to prolong the process of effective CH4 recovery. Besides, reduction in stiffness of coal seam during CO2 injection would moderate the significant permeability loss induced by matrix swelling. With the increase of the weakening degree of coal seam stiffness, CO2 cumulative storage also shows an increasing trend. Neglecting the weakening effect of CO2 adsorption on coal seam stiffness could underestimate the injection capacity of CO2. Injection of hot CO2 could improve the permeability around injection well and then enhance CO2 cumulative storage and CBM recovery. Furthermore, compared with ECBM production, injection temperature is more favorable for CO2 storage, especially within hard coal seams. Care should be considered that significant permeability change is induced by mechanical characteristics alterations in deep burial coal seams in further study, especially for CO2-ECBM projects.

scholarly journals Nitrogen Injection To Flush Coal Seam Gas Out Of Coal: An Experimental Study

2015 ◽  
Vol 60 (4) ◽  
pp. 1013-1028 ◽  
Author(s):  
Lei Zhang ◽  
Naj Aziz ◽  
Ting Ren ◽  
Jan Nemcik ◽  
Shihao Tu
Keyword(s):  
Coal Seam ◽  
Clean Energy ◽  
Gas Content ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Recovery ◽  
Nitrogen Injection ◽  
Gas Desorption ◽  
Effective Role ◽  
Study Laboratory

Abstract Several mines operating in the Bulli seam of the Sydney Basin in NSW, Australia are experiencing difficulties in reducing gas content within the available drainage lead time in various sections of the coal deposit. Increased density of drainage boreholes has proven to be ineffective, particularly in sections of the coal seam rich in CO2. Plus with the increasing worldwide concern on green house gas reduction and clean energy utilisation, significant attention is paid to develop a more practical and economical method of enhancing the gas recovery from coal seams. A technology based on N2 injection was proposed to flush the Coal Seam Gas (CSG) out of coal and enhance the gas drainage process. In this study, laboratory tests on CO2 and CH4 gas recovery from coal by N2 injection are described and results show that N2 flushing has a significant impact on the CO2 and CH4 desorption and removal from coal. During the flushing stage, it was found that N2 flushing plays a more effective role in reducing adsorbed CH4 than CO2. Comparatively, during the desorption stage, the study shows gas desorption after N2 flushing plays a more effective role in reducing adsorbed CO2 than CH4.

WATER AND THE COAL SEAM GAS INDUSTRY

2007 ◽  
Vol 47 (1) ◽  
pp. 369
Author(s):  
G. Scott ◽  
C. Ammundsen
Keyword(s):  
Coal Seam ◽  
Environmental Protection Agency ◽  
Poor Quality ◽  
Gas Production ◽  
End User ◽  
Protection Agency ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Access To Water

Access to water is a significant issue in Queensland as much of the State continues to be affected by a prolonged drought. Coal seam gas production involves extracting water from coal seams to reduce the groundwater pressure that keeps the methane trapped in the coal. This process produces large volumes of water. Local councils, primary producers and industrial developers are potential end users of this water; however, if the water is of poor quality, it may be unsuitable for release in the environment and for other direct beneficial uses.This paper examines the complex legislative and regulatory hurdles that need to be overcome before any mutually beneficial agreement between the coal seam gas producer and end user may be completed. It also examines an operational policy recently released by the Queensland Environmental Protection Agency that proposes a framework for the regulation and management of water extracted from coal seams.

A review on transport of coal seam gas and its impact on coalbed methane recovery

2011 ◽  
Vol 5 (2) ◽  
pp. 139-161 ◽  
Author(s):  
Geoff G. X. Wang ◽  
Xiaodong Zhang ◽  
Xiaorong Wei ◽  
Xuehai Fu ◽  
Bo Jiang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Coal Seam Gas ◽  
Methane Recovery

Magnetotelluric monitoring of coal-seam gas and shale-gas resource development in Australia

2016 ◽  
Vol 35 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Nigel Rees ◽  
Simon Carter ◽  
Graham Heinson ◽  
Lars Krieger ◽  
Dennis Conway ◽  
...  
Keyword(s):  
Coal Seam ◽  
Shale Gas ◽  
Resource Development ◽  
Coal Seam Gas

scholarly journals Investigation on the CBM Extraction Techniques in the Broken-Soft and Low-Permeability Coal Seams in Zhaozhuang Coalmine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zhaoying Chen ◽  
Xuehai Fu ◽  
Guofu Li ◽  
Jian Shen ◽  
Qingling Tian ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Coalbed Methane ◽  
Research Result ◽  
Horizontal Stress ◽  
Gas Production ◽  
Vertical Stress ◽  
Low Permeability ◽  
Coal Seams

To enhance the coalbed methane (CBM) extraction in broken-soft coal seams, a method of drilling a horizontal well along the roof to hydraulically fracture the coal seam is studied (i.e., HWR-HFC method). We first tested the physical and mechanical properties of the broken-soft and low-permeability (BSLP) coal resourced from Zhaozhuang coalmine. Afterward, the in situ hydraulic fracturing test was conducted in the No. 3 coal seam of Zhaozhuang coalmine. The results show that (1) the top part of the coal seam is fractured coal, and the bottom is fragmented-mylonitic coal with a firmness coefficient value of less than 1.0. (2) In the hydraulic fracturing test of the layered rock-coal specimens in laboratory, the through-type vertical fractures are usually formed if the applied vertical stress is the maximum principal stress and is greater than 4 MPa compared with the maximum horizontal stress. However, horizontal fractures always developed when horizontal stress is the maximum or it is less than 4 MPa compared with vertical stress. (3) The in situ HWR-HFC hydraulic fracturing tests show that the detected maximum daily gas production is 11,000 m3, and the average gas production is about 7000 m3 per day. This implies that the CBM extraction using this method is increased by 50%~100% compared with traditional hydraulic fracturing in BSLP coal seams. The research result could give an indication of CBM developing in the broken-soft and low-permeability coal seams.

THE SIGNIFICANCE OF COAL SEAM GAS IN EASTERN QUEENSLAND

2006 ◽  
Vol 46 (1) ◽  
pp. 329 ◽  
Author(s):  
G.L. Baker ◽  
W.R. Skerman
Keyword(s):  
Natural Gas ◽  
Coal Seam ◽  
Commercial Production ◽  
Significant Part ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Company Limited ◽  
Reliable Source ◽  
Gas Supply

The commercial production of coal seam gas [CSG] in Australia is only a decade old. Over the last 10 years it has become a significant part of the Australian gas industry, particularly in Queensland where about 31 PJ or 30% of all natural gas used in the State was recovered from coal seams in eastern Queensland. In 2005 CSG was expected to have supplied 55 PJ or 44 % of the eastern Queensland gas demand. The mining, mineral processing and power generations in northwest Queensland, serviced by the Carpentaria Gas Pipeline, will continue to use gas from the Cooper-Eromanga Basin.The CSG industry is reaching a stage of maturity following the commissioning of a number of fields while some significant new projects are either in the commissioning phase or under development. By the end of 2008 CSG production in Queensland is expected to reach 150 PJ per year, the quantity needed to meet Gas Supply Agreements for CSG that are presently in place.Certified Proved and Probable (2P) gas reserves at 30 June 2005 in eastern Queensland were calculated to be 4,579 PJ, of which 4,283 PJ were CSG. Gas reserves (2P) for eastern Queensland a decade earlier were less than 100 PJ with those for CSG being less than 5 PJ.The coal seam gas industry in both the Bowen and Surat basins—which includes major gas producers such as Origin Energy Limited and Santos Limited along with smaller producers such as Arrow Energy NL, CH4 Gas Limited, Molopo Australia Limited and Queensland Gas Company Limited—is now accepted by major gas users as being suppliers of another reliable source of natural gas.

Impact of in-seam drilling performance on coal seam gas production and remaining gas distribution

2019 ◽  
Vol 59 (1) ◽  
pp. 328
Author(s):  
Fengde Zhou ◽  
Glen Fernandes ◽  
Joao Luft ◽  
Kai Ma ◽  
Mahmoud Oraby ◽  
...  
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Gas Content ◽  
Gas Distribution ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
Gas Saturation ◽  
Drilling Performance ◽  
Permeability Anisotropy ◽  
The Impact

Drilling horizontal wells in low permeability coal seams is a key technology to increase the drainage area of a well, and hence, decrease costs. It’s unavoidable that some parts of the horizontal section will be drilled outside the targeted coal seam due to unforeseen subsurface conditions, such as sub-seismic faulting, seam rolls, basic geosteering tools, drilling practices and limited experiences. Therefore, understanding the impact of horizontal in-seam drilling performance on coal seam gas (CSG) production and remaining gas distribution is an important consideration in drilling and field development plans. This study presents a new workflow to investigate the impact of horizontal in-seam performance on CSG production and gas distribution for coal seams with different porosity, permeability, permeability anisotropy, initial gas content (GC), initial gas saturation and the ratio of in-coal length to in-seam length (RIIL). First, a box model with an area of 2 km × 0.3 km × 6 m was used for conceptual simulations. Reduction indexes of the cumulative gas production at the end of 10 years of simulations were compared. Then, a current Chevron well consisting of a vertical well and two lateral wells, was selected as a case study in which the impact of outside coal drilling on history matching and remaining gas distribution were analysed. Results show that the RIIL plays an increasing role for cases with decreasing permeability or initial gas saturation, while it plays a very similar role for cases with varied porosity, permeability anisotropy and GC. The size and location of outside coal drilling will affect the CSG production and remaining gas distribution.

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