THE WALLOON COAL MEASURES—THE NEXT COAL SEAM GASTARGET?

2000 ◽  
Vol 40 (1) ◽  
pp. 86
Author(s):  
S.G. Scott ◽  
P. Crosdale
Keyword(s):  
Coal Seam ◽  
Vitrinite Reflectance ◽  
Petroleum Exploration ◽  
Gas Content ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Permian Coal ◽  
Petroleum Wells ◽  
The Individual ◽  
Coal Measures

The Queensland coal seam gas industry has grown over the last 12 years. During this time the vast majority of exploration wells have targeted the Late Permian coal measures in the Bowen and Galilee Basins. These formations have been the major target because they contain coals with a vitrinite reflectance ranging above 0.7%. This range has always been seen as the main period for methane generation.As well as containing vast quantities of Permian coal, Queensland also has vast quantities of Middle Jurassic coals within its Mesozoic Basins. These coals have received little-to-no exploration for their coal seam gas potential as they have always been interpreted as being immature for gas generation.Over 550 petroleum exploration wells drilled in the Mesozoic Surat Basin of eastern Queensland were reviewed to determine the coal volume of the intersected Walloon Coal Measures. A significant number have intersected large volumes of sub-bituminous to high volatile bituminous coals, in seams ranging up to 11.7 m in thickness. While the individual seams are not laterally persistent, the coal packages can be traced over hundreds of kilometres of the eastern Surat Basin.While only one well has tested the gas content, gas quality and saturation of the Walloon Coal Measures, numerous water bores have reported gas flows from the zone, and petroleum wells intersecting the formation have recorded high mud gas readings during drilling.The relatively shallow depth of the unit over much of the basin, the thickness of the coal packages, the proximity to major gas trunk pipelines and markets make the Walloon Coal Measures an ideal target for the next generation of coal seam gas explorers.

The changing face of Queensland's petroleum industry

2011 ◽  
Vol 51 (1) ◽  
pp. 225 ◽  
Author(s):  
Alison Troup ◽  
Peter Green
Keyword(s):  
Coal Seam ◽  
Oil And Gas ◽  
Petroleum Industry ◽  
Petroleum Exploration ◽  
Success Rates ◽  
Coal Seam Gas ◽  
Petroleum Wells ◽  
Well Data ◽  
Coal Measures ◽  
Exploration Well

The cycles and related changes in exploration targets identified in this study show the evolution of the Queensland petroleum industry from conventional petroleum to coal seam gas dominance. Delineation of these cycles was undertaken using petroleum exploration well data, and production and reserves statistics. Although the cycles are defined on the basis of exploration activity, there is a very different history in the types of targets and commodities explored for in the Bowen-Surat and Cooper-Eromanga basins. Trends in exploration success have been influenced by technology improvements, better understanding of target reservoirs, proximity to infrastructure, government policy and world oil prices. Four distinct exploration cycles have been identified from the data. During the first cycle (1959–74) exploration focused predominantly on the shallower Jurassic-aged reservoirs in the Bowen-Surat basins resulting in the discovery of most of the major conventional oil and gas fields. The second cycle (1979–89) saw exploration begin in earnest in the Cooper-Eromanga basins and a switch to predominantly Triassic-aged reservoirs in the Bowen-Surat basins. The first coal seam gas exploration wells were drilled during this cycle. The third cycle (1990–99) shows a decrease in the number of conventional petroleum wells across both regions and the beginning of the switch to the present dominance of coal seam gas. The fourth cycle (2000–present) shows a significant decrease in the number of conventional exploration wells drilled across both regions, but an increase in the success rates. All conventional discoveries in the Bowen-Surat basins during cycle four have been in Permian-aged reservoirs, reflecting a change in the exploration focus to deeper parts of the Bowen Basin. Coal seam gas exploration has expanded significantly, with the Walloon Coal Measures being targeted, resulting in nearly four coal seam gas wells drilled for each conventional petroleum exploration well state-wide since 2000. Examination of coal seam gas exploration highlights the many false starts since the first well was drilled in 1980. Exploration has shifted from area to area as companies tested different exploration concepts and completion techniques. The most obvious shift has been from Permian-aged targets of the Bowen Basin into the Jurassic-aged Walloon Coal Measures in the Surat and Clarence-Moreton basins, as its prospectivity was realised.

Identification of Breakout Behind Casing: Methodology to Obtain Openhole-Equivalent Caliper Measurements Through Slotted Liner Using the Density Tool

2021 ◽  
Vol 62 (6) ◽  
pp. 651-669
Author(s):  
Laurent Mosse ◽  
◽  
Stephen Pell ◽  
Thomas J. Neville ◽  
◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Economic Implications ◽  
Gas Formation ◽  
Artificial Lift ◽  
Production Section ◽  
Permian Coal ◽  
Completion Fluids ◽  
Coal Measures

Growth in the coal seam gas industry in Queensland, Australia, has been rapid over the past 15 years, with greater than USD 70 billion invested in three liquified natural gas export projects supplied by produced coal seam gas. Annual production is of the order of 40 Bscm or 1,500 PJ, with approximately 80% of this coming from the Jurassic Walloon Coal Measures of the Surat Basin and 20% from the Permian Coal Measures of the Bowen Basin. The Walloon Coal Measures are characterized by multiple thin coal seams making up approximately 10% of the total thickness of the unit. A typical well intersects 10 to 20 m of net coal over a 200- to 300-m interval, interbedded with lithic-rich sandstones, siltstones, and carbonaceous mudstones. The presence of such a significant section of lithic interburden within the primary production section has led to a somewhat unusual completion strategy. To maximize connection to the gas-bearing coals, uncemented slotted liners are used; however, this leaves fluid-sensitive interburden exposed to drilling, completion, and produced formation fluids over the life of a well. External swellable packers and blank joints are therefore used to isolate larger intervals of interburden and hence minimize fines production. Despite these efforts, significant fines production still occurs, which leads to the failure of artificial lift systems and the need for expensive workovers or lost wells. Fines production has major economic implications, with anecdotal reports suggesting up to 40% of progressive cavity pump artificial lift systems in Walloon Coal Measures producers may be down at any one time. The first step in solving this problem is to identify the extent and distribution of fines production. The wellbore completion strategy above, however, precludes the use of mechanical calipers to identify fines-production-related wellbore enlargement. A new caliper-behind-liner technique has therefore been developed using a multiple-detector density tool. Data from the shorter-spacing detectors are used to characterize the properties of the liner as well as the density of the annular material. This is particularly important to evaluate as the annulus fill varies between gas, formation water, drilling and completion fluids, and accumulated fines. The longer-spacing detector measurements are then used in conjunction with pre-existing openhole formation density measurements to determine the thickness of the annulus, and hence hole size, compensating for liner and annulus properties.

IDENTIFICATION OF BREAKOUT BEHIND CASING: METHODOLOGY TO OBTAIN OPENHOLE EQUIVALENT CALIPER MEASUREMENTS THROUGH SLOTTED LINER USING THE DENSITY TOOL

2021 ◽  
Author(s):  
Laurent Mosse ◽  
◽  
Stephen Pell ◽  
Thomas Neville ◽  
◽  
...  
Keyword(s):  
Coal Seam ◽  
Density Measurement ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Economic Implications ◽  
Artificial Lift ◽  
Production Section ◽  
Open Hole ◽  
Permian Coal ◽  
Coal Measures

Growth in the coal seam gas industry in Queensland, Australia, has been rapid over the past fifteen years, with greater than USD 70 billion invested in three liquified natural gas export projects supplied by produced coal seam gas. Annual production is of the order of 40 Bscm or 1,500 PJ, with approximately 80% of this coming from the Jurassic Walloon Coal Measures of the Surat Basin and 20% from Permian coal measures of the Bowen Basin. The Walloon Coal Measures are characterized by multiple thin coal seams making up approximately 10% of the total thickness of the unit. A typical well intersects 10 to 20 m of net coal over a 200 to 300 m interval, interbedded with lithic-rich sandstones, siltstones, and carbonaceous mudstones. The presence of such a significant section of lithic interburden within the primary production section has led to a somewhat unusual completion strategy. To maximize connection to the gas-bearing coals, uncemented slotted liners are used; however, this leaves fluid-sensitive interburden exposed to drilling, completion, and produced formation fluids over the life of a well. External swellable packers and blank joints are therefore used to isolate larger intervals of interburden and hence minimize fines production. Despite these efforts, significant fines production still occurs, which leads to failure of artificial lift systems and the need for expensive workovers or lost wells. Fines production has major economic implications, with anecdotal reports suggesting up to 40% of progressive cavity pump artificial lift systems in Walloon Coal Measures producers may be down at any one time. The first step in solving this problem is to identify the extent and distribution of fines production. The wellbore completion strategy above, however, precludes use of mechanical calipers to identify fines production-related wellbore enlargement. A new caliper-behind-liner technique has therefore been developed using a multiple-detector density tool. Data from the shorter spacing detectors is used to characterize the properties of the liner as well as the density of the annular material. This is particularly important to evaluate as the annulus fill varies between gas, formation water, drilling and completion fluids, and accumulated fines. The longer spacing detector measurements are then used in conjunction with pre-existing open-hole formation density measurement to determine the thickness of the annulus, and hence hole size, compensating for liner and annulus properties. This methodology has been applied to several wells completed in the Walloon Coal Measures. Results have demonstrated the ability to identify zones of borehole enlargement behind slotted liner, as well as intervals of either gas or fines accumulation in the annulus. In addition, the technique has been successful in verifying the placement of swellable packers and their integrity. The application of this solution has been used to drive improvements in the design of in-wellbore completion programs and in the future will help drive recompletion decisions and trigger proactive workovers.

COAL SEAM GAS IN THE SOUTHERN SYDNEY BASIN, NEW SOUTH WALES

1997 ◽  
Vol 37 (1) ◽  
pp. 415 ◽  
Author(s):  
M.M. Faiz ◽  
A.C. Hutton
Keyword(s):  
Coal Seam ◽  
New South ◽  
Geological Structure ◽  
Gas Content ◽  
Gas Composition ◽  
Late Permian ◽  
Coal Seams ◽  
Coal Seam Gas ◽  
South Wales ◽  
Coal Measures

The coal seam gas content of the Late Permian Illawarra Coal Measures ranges from Methane that occurs within the basin was mainly derived as a by-product of coalification. Most of the CO2 was derived from intermittent magmatic activity between the Triassic and the Tertiary. This gas has subsequently migrated, mainly in solution, towards structural highs and accumulated in anticlines and near sealed faults.The total desorbable gas content of the coal seams is mainly related to depth, gas composition and geological structure. At depths

GEOLOGICAL CONTROLS ON EXPLOITABLE COAL SEAM GAS DISTRIBUTION IN QUEENSLAND

2006 ◽  
Vol 46 (1) ◽  
pp. 343 ◽  
Author(s):  
J. J. Draper ◽  
C.J. Boreham
Keyword(s):  
Coal Seam ◽  
Vitrinite Reflectance ◽  
Gas Production ◽  
Gas Content ◽  
Burial History ◽  
Coal Seam Gas ◽  
Gas Generation ◽  
Delta Plain ◽  
Wide Range ◽  
Gas Fields

Methane is present in all coals, but a number of geological factors influence the potential economic concentration of gas. The key factors are (1) depositional environment, (2) tectonic and structural setting, (3) rank and gas generation, (4) gas content, (5) permeability, and (6) hydrogeology. Commercial coal seam gas production in Queensland has been entirely from the Permian coals of the Bowen Basin, but the Jurassic coals of the Surat and Clarence-Moreton basins are poised to deliver commercial gas volumes.Depositional environments range from fluvial to delta plain to paralic and marginal marine—coals in the Bowen Basin are laterally more continuous than those in the Surat and Clarence-Moreton basins. The tectonic and structural settings are important as they control the coal characteristics both in terms of deposition and burial history. The important coal seam gas seams were deposited in a foreland setting in the Bowen Basin and an intracratonic setting in the Surat and Clarence-Moreton basins. Both of these settings resulted in widespread coal deposition. The complex burial history of the Bowen Basin has resulted in a wide range of coal ranks and properties. Rank in the Bowen Basin coal seam gas fields varies from vitrinite reflectance of 0.55% to >1.1% Rv and from Rv 0.35-0.6% in the Surat and Clarence-Moreton basins in Queensland. High vitrinite coals provide optimal gas generation and cleat formation. The commercial gas fields and the prospective ones contain coals with >60% vitrinite.Gas generation in the Queensland basins is complex with isotopic studies indicating that biogenic gas, thermogenic gas and mixed gases are present. Biogenic processes occur at depths of up to a kilometre. Gas content is important, but lower gas contents can be economic if deliverability is good. Free gas is also present. Drilling and production techniques play an important role in making lower gas content coals viable. Since the Bowen and Surat basins are in a compressive regime, permeability becomes a defining parameter. Areas where the compression is offset by tensional forces provide the best chances for commercial coal seam gas production. Tensional setting such as anticline or structural hinges are important plays. Hydrodynamics control the production rate though water quality varies between the fields.

Quantitative Evaluation of Coal Seam Gas Content Estimate Accuracy

1995 ◽  
Author(s):  
Matthew J. Mavor ◽  
Timothy J. Pratt ◽  
Charles R. Nelson
Keyword(s):  
Coal Seam ◽  
Quantitative Evaluation ◽  
Gas Content ◽  
Coal Seam Gas

Beneficial use of associated water in the Queensland coal seam gas industry

2010 ◽  
Vol 50 (2) ◽  
pp. 686
Author(s):  
Cristian Purtill
Keyword(s):  
Water Management ◽  
Coal Seam ◽  
Single Mode ◽  
Gas Production ◽  
Management Policy ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Beneficial Use ◽  
Challenges And Opportunities ◽  
Water Management Strategy

The Queensland Government has developed an associated water management policy that, among other things, strives to maximise the beneficial use of associated water derived from Queensland’s burgeoning coal seam gas industry. The Department of Infrastructure and Planning reports that domestic gas production alone (i.e. without an export LNG market) will produce on average 25 GL per annum in the next 25 years. Most of this water has sufficiently high total dissolved solids and other water quality issues to require some form of treatment prior to use. Clearly, the relatively large volumes of water present both challenges and opportunities to the communities in which the CSG industry is developing. In line with the philosophy of beneficial use of associated water, Santos has developed a portfolio of options within its associated water management strategy and plans for its Arcadia Valley, Fairview and Roma tenements. The strategy seeks to: provide enduring value for the community; maximise benefits while minimising the environmental footprint; provide a range of alternatives to avoid single-mode failure; use scalable options in response to uncertainty; deploy demonstrated technologies; and, meet and exceed all regulatory requirements. This paper will set some context around the broader CSG industry’s associated water challenges, and identify what parameters must be considered in arriving at beneficial uses for the water. The paper then explores some of Santos’ approaches to associated water management.

From wells to decisions—data management for coal seam gas operators in Australia as compared to conventional oil and gas operators

2011 ◽  
Vol 51 (2) ◽  
pp. 716
Author(s):  
Peter Smith ◽  
Iain Paton
Keyword(s):  
Coal Seam ◽  
Data Management ◽  
Case Studies ◽  
Oil And Gas ◽  
Data Access ◽  
Oil And Gas Industry ◽  
Coal Seam Gas ◽  
Gas Industry ◽  
Innovative Solutions ◽  
Conventional Oil

The large number of wells associated with typical coal seam gas (CSG) developments in Australia has changed the paradigm for field management and optimisation. Real time data access, automation and optimisation—which have been previously considered luxuries in conventional resources—are key to the development and operation of fields, which can easily reach more than 1,000 wells. The particular issue in Australia of the shortage of skilled labour and operators has increased pressure to automate field operations. This extended abstract outlines established best practices for gathering the numerous data types associated with wells and surface equipment, and converting that data into information that can inform the decision processes of engineers and managers alike. There will be analysis made of the existing standard, tools, software and data management systems from the conventional oil and gas industry, as well as how some of these can be ported to the CSG fields. The need to define industry standards that are similar to those developed over many years in the conventional oil and gas industry will be discussed. Case studies from Australia and wider international CSG operations will highlight the innovative solutions that can be realised through an integrated project from downhole to office, and how commercial off the shelf solutions have advantages over customised one-off systems. Furthermore, case studies will be presented from both CSG and conventional fields on how these enabling technologies translate into increased production, efficiencies and lift optimisation and move towards the goal of allowing engineers to make informed decisions as quickly as possible. Unique aspects of CSG operations, which require similarly unique and innovative solutions, will be highlighted in contrast to conventional oil and gas.

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.

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