Utilising current technologies to understand permeability, stress azimuths and magnitudes and their impact on hydraulic fracturing success

2010 ◽  
Vol 50 (2) ◽  
pp. 736 ◽  
Author(s):  
Raymond Johnson ◽  
Brent Glassborow ◽  
Jeremy Meyer ◽  
Michael Scott ◽  
Ashish Datey ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Limited Area ◽  
Supporting Evidence ◽  
Coal Seam Gas ◽  
Structural Setting ◽  
Data Process ◽  
Petroleum Wells ◽  
Well Data ◽  
Sonic Logging

In coal seam gas exploration and appraisal, stress and permeability are often inter-related and play a large role in deliverability, particularly affecting hydraulic fracturing effectiveness. Generally, the structural setting for a coal seam gas (CSG) play can be defined by indirect data such as petroleum wells, core wells, or seismic data; however, the viability of a structure to be highly conducive to CSG development also requires direct measurements to fully define the effects associated with this interdependency of stress and permeability. Unfortunately, this interdependency may not be as apparent during the exploration phase as within the planning, execution and evaluation of a hydraulic fracturing program. We will present data from a limited area of the Surat Basin, in the Walloon coal measures, where initial regional and well data were available to allow drilling to evaluate a small, localised, structural setting for CSG development. While some permeability data were encouraging in the initial program, subsequent drilling indicated that permeability might become variable across this structure. Thus, further investigations were made and included novel, cross-dipole sonic logging in combination with acoustic and more advanced resistivity imaging logs. These data indicated that the stress and permeability azimuths may be aligned to take advantage of hydraulic fracturing. Thus, a hydraulic fracturing program was initiated in this area incorporating diagnostics to understand the potential benefit of this technology. The results of this program, while localised, do indicate that a potential pitfall can exist in some environments where the stress magnitudes along with stress and dominant permeability axes are not ideally positioned to take advantage of hydraulic fracturing. We will show how the data in this case were acquired, evaluated and integrated to support the overall understanding and interpretation of the results. Due to space constraints, this paper focusses primarily on the overall data process and is unable to elaborate fully on all diagnostics used and the fullness of their determinations; however, adequate supporting evidence is supplied in order to illustrate the problems in executing and achieving effective stimulation in similar structural settings.

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.

scholarly journals A Generic Method for Predicting Environmental Concentrations of Hydraulic Fracturing Chemicals in Soil and Shallow Groundwater

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 941 ◽  
Author(s):  
Dirk Mallants ◽  
Elise Bekele ◽  
Wolfgang Schmid ◽  
Konrad Miotlinski ◽  
Andrew Taylor ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Shallow Groundwater ◽  
Solute Concentration ◽  
Coal Seam Gas ◽  
Transport Modelling ◽  
Environmental Concentrations ◽  
Modelling Framework ◽  
Recharge Rates ◽  
Migration Pathways

Source-pathway-receptor analyses involving solute migration pathways through soil and shallow groundwater are typically undertaken to assess how people and the environment could come into contact with chemicals associated with coal seam gas operations. For the potential short-term and long-term release of coal seam gas fluids from storage ponds, solute concentration and dilution factors have been calculated using a water flow and solute transport modelling framework for an unsaturated zone-shallow groundwater system. Uncertainty about dilution factors was quantified for a range of system parameters: (i) leakage rates from storage ponds combined with recharge rates, (ii) a broad combination of soil and groundwater properties, and (iii) a series of increasing travel distances through soil and groundwater. Calculated dilution factors in the soil increased from sand to loam soil and increased with an increasing recharge rate, while dilution decreased for a decreasing leak rate and leak duration. In groundwater, dilution factors increase with increasing aquifer hydraulic conductivity and riverbed conductance. For a hypothetical leak duration of three years, the combined soil and groundwater dilution factors are larger than 6980 for more than 99.97% of bores that are likely to be farther than 100 m from the source. Dilution factors were more sensitive to uncertainty in leak rates than recharge rates. Based on this dilution factor, a comparison of groundwater predicted environmental concentrations and predicted no-effect concentrations for a subset of hydraulic fracturing chemicals used in Australia revealed that for all but two of the evaluated chemicals the estimated groundwater concentration (for a hypothetical water bore at 100 m from the solute source) is smaller than the no-effect concentration for the protection of aquatic ecosystems.

2011 PESA industry review: exploration

2012 ◽  
Vol 52 (1) ◽  
pp. 67
Author(s):  
Phillip Cooney
Keyword(s):  
Coal Seam ◽  
Regional Differences ◽  
High Rate ◽  
Coal Seam Gas ◽  
Geothermal Resources ◽  
Petroleum Wells ◽  
Liquid Natural Gas ◽  
Rate Of Success ◽  
Exploration Activity ◽  
Cooper Basin

A continuing high and stable oil price through the latter part of 2011, oscillating around US$120 in the case of Tapis Crude, underpinned a small increase in exploration in 2011 in Australia compared with 2010, although there were marked regional differences between the northwest and southeast parts of the country. Exploration continued to be focused on the northwest offshore seeking incremental reserve additions of conventional gas to support planned and proposed liquid natural gas (LNG) projects and although information is hard to confirm, in general this program appears to have been successful with a number of relatively smaller discoveries and at least one major find, Zola–1. In the Cooper Basin exploration activity resumed after almost being shut down by floods in 2010, although flooding continued to be a problem in 2011. In the South Australian part, 27 new field wildcat (NFW) wells were drilled in 2011 compared with 8 in 2010. The program was also marked by a high rate of success. The other current major area of activity, the Queensland coal seam gas (CSG) program was also affected by flooding early in 2011 with 524 coal seam gas (CSG) wells drilled this year, compared with 648 in 2010 and more than 900 in 2009. In many jurisdictions shale gas or shale oil wells are not reported separately and are included in conventional petroleum wells in this report. Exploration for geothermal resources continued at a relatively low level with only 10 wells drilled in Australia in 2011, the most active state was Victoria with five wells. Despite the increase in activity, preliminary indications are that total exploration expenditure in 2011 will be less than in 2010. It is interesting to note that while the exploration effort in terms of wells and seismic has not changed much in the last few years the total expenditure has steadily increased in part reflecting the movement into deeper water drilling.

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.

In vitro cytotoxicity assessment of a hydraulic fracturing fluid

2015 ◽  
Vol 12 (3) ◽  
pp. 286 ◽  
Author(s):  
Madeleine E. Payne ◽  
Heather F. Chapman ◽  
Janet Cumming ◽  
Frederic D. L. Leusch
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Human Health ◽  
Produced Water ◽  
Coal Seam Gas ◽  
Fracturing Fluid ◽  
Human Health Risks ◽  
Fracturing Fluids ◽  
Hydraulic Fracturing Fluid

Environmental context Hydraulic fracturing fluids, used in large volumes by the coal seam gas mining industry, are potentially present in the environment either in underground formations or in mine wastewater (produced water). Previous studies of the human health and environmental effects of this practice have been limited because they use only desktop methods and have not considered combined mixture toxicity. We use a novel in vitro method for toxicity assessment, and describe the toxicity of a hydraulic fracturing fluid on a human gastrointestinal cell line. Abstract Hydraulic fracturing fluids are chemical mixtures used to enhance oil and gas extraction. There are concerns that fracturing fluids are hazardous and that their release into the environment – by direct injection to coal and shale formations or as residue in produced water – may have effects on ecosystems, water quality and public health. This study aimed to characterise the acute cytotoxicity of a hydraulic fracturing fluid using a human gastrointestinal cell line and, using this data, contribute to the understanding of potential human health risks posed by coal seam gas (CSG) extraction in Queensland, Australia. Previous published research on the health effects of hydraulic fracturing fluids has been limited to desktop studies of individual chemicals. As such, this study is one of the first attempts to characterise the toxicity of a hydraulic fracturing mixture using laboratory methods. The fracturing fluid was determined to be cytotoxic, with half maximal inhibitory concentrations (IC50) values across mixture variations ranging between 25 and 51mM. When used by industry, these fracturing fluids would be at concentrations of over 200mM before injection into the coal seam. A 5-fold dilution would be sufficient to reduce the toxicity of the fluids to below the detection limit of the assay. It is unlikely that human exposure would occur at these high (‘before use’) concentrations and likely that the fluids would be diluted during use. Thus, it can be inferred that the level of acute risk to human health associated with the use of these fracturing fluids is low. However, a thorough exposure assessment and additional chronic and targeted toxicity assessments are required to conclusively determine human health risks.

Induced stress evolution of hydraulic fracturing in an inclined soft coal seam gas reservoir near a fault

2021 ◽  
Vol 88 ◽  
pp. 103794
Author(s):  
Qianting Hu ◽  
Zhizhong Jiang ◽  
Quangui Li ◽  
Wenbin Wu ◽  
Qingguo Wang ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Stress Evolution ◽  
Coal Seam Gas ◽  
Gas Reservoir ◽  
Soft Coal ◽  
Induced Stress ◽  
Soft Coal Seam

Applications of Indirect Hydraulic Fracturing to Improve Coal Seam Gas Drainage for the Surat and Bowen Basins, Australia

2021 ◽  
Author(s):  
Raymond Leslie Johnson ◽  
Honja Miharisoa Ramanandraibe ◽  
Ayrton Ribeiro ◽  
Matthew Ramsay ◽  
Kaa Tipene ◽  
...  
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Coal Seam Gas ◽  
Gas Drainage

scholarly journals Environmental issues associated with coal seam gas recovery: managing the fracking boom

2012 ◽  
Vol 9 (5) ◽  
pp. 425 ◽  
Author(s):  
Graeme E. Batley ◽  
Rai S. Kookana
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
New Technology ◽  
Surface Water Quality ◽  
Environmental Issues ◽  
Ecological Risks ◽  
Coal Seam Gas ◽  
Gas Recovery ◽  
Lack Of Information ◽  
Energy Needs

Environmental context Coal seam gas reserves are likely to make a major contribution to future energy needs. However, the new technology for exploiting these reserves, termed hydraulic fracturing, raises several environmental issues. We discuss the research required to assess the ecological risks from gas recovery. Abstract Coal seam gas reserves represent a major contribution to energy needs, however, gas recovery by hydraulic fracturing (fracking or fraccing), requires management to minimise any environmental effects. Although the industry is adapting where possible to more benign fracking chemicals, there is still a lack of information on exposure to natural and added chemicals, and their fate and ecotoxicity in both the discharged produced and flow-back waters. Geogenic contaminants mobilised from the coal seams during fracking may add to the mixture of chemicals with the potential to affect both ground and surface water quality. The research needs to better assess the ecological risks from gas recovery are discussed.

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