Mapping horizons and fracture patterns in coal measures using magnetics for coalbed methane exploration in Queensland

High resolution magnetic data has successfully been used to map the top and base of coal measures, related faults and fracture patterns across the Red Hill area in the northern Bowen Basin, eastern Australia. A horizon mapping technique, based on energy spectral analysis (ESA), was used to detect magnetic susceptibility contrasts that were laterally merged to form two magnetic interfaces, corresponding to the top of the Fair Hill Formation and base of the Goonyella Middle Seam in the Permian Moranbah coal measures. The depth estimates were made at stations on a regular mesh of 400 m x 400 m and at nine wells. The final detailed mapping of both horizons was constructed from spectral depth estimates on a regular mesh of 100 m x 100 m. Major faults, associated structures and fractures were mapped in 3D from the magnetic data by using automatic curve matching (ACM). This technique was applied to detect single magnetic anomalies produced by inter-sedimentary sources. These results were used to interpret magnetic lineaments in, above and below the coal measures to produce a rock fabric model. The results obtained from the interpretation of the magnetic data are consistent with structures mapped from existing seismic and well data. The mapped rock fabric was also confirmed by well results to be a fair representation of the open fracture set, which has an orientation that is consistent with the existing stress regime.

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COALBED METHANE RESOURCES IN THE PERMIAN OF EASTERN AUSTRALIA AND THEIR TECTONIC SETTING

The APPEA Journal ◽

10.1071/aj92013 ◽

1993 ◽

Vol 33 (1) ◽

pp. 161 ◽

Cited By ~ 2

Author(s):

S. Miyazaki ◽

R.J. Korsch

Keyword(s):

Coalbed Methane ◽

Tectonic Setting ◽

Temporal Distribution ◽

Low Permeability ◽

Burial History ◽

Coal Seams ◽

Methane Drainage ◽

Eastern Australia ◽

Permian Coal ◽

Coal Measures

The Bowen and Sydney Basins in eastern Australia contain vast coal resources which provide a source for coalbed methane. Through studies of the spatial and temporal distribution of the sedimentary packages, the structural geometry and tectonic setting of the sedimentary packages, and the maturation and burial history, the Australian Geological Survey Organisation (AGSO) is mapping the distribution and structural styles of the sources of methane, in particular, the Late Permian coal measures. AGSO's results from the Bowen Basin show at least two distinctly different structural styles of potential targets for coalbed methane drainage: on the Comet Ridge, the Permian coal measures are essentially subhorizontal and tectonically undisturbed, whereas in the western Taroom Trough, the coal measures are folded into a series of anticlines, each of which occurs above a thrust fault which in turn forms part of an imbricate thrust fan. Both of these styles occur at depths of less than 1000 m.Calculations by the Bureau of Resource Sciences (BRS) indicate that the inferred coalbed methane resources-in-place are 62 trillion cubic feet (1760 billion m3) for Australia, in which the Bowen and Sydney Basins are currently the only potential provinces of coalbed methane. The low permeability of the coal seams hinders attempts to utilise this vast amount of energy resources.Further exploration is necessary to delineate commercially feasible areas. This delineation is the only process that will be able to determine demonstrated coalbed methane resources.

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Application of high resolution airborne geophysics to epithermal gold exploration in Northeast Queensland and Coromandel, New Zealand

Exploration Geophysics ◽

10.1071/eg989099 ◽

1989 ◽

Vol 20 (2) ◽

pp. 99 ◽

Cited By ~ 1

Author(s):

S.S. Webster ◽

R.W. Henley

Keyword(s):

High Resolution ◽

Regional Scale ◽

Cost Effective ◽

Gold Deposits ◽

Ore Deposits ◽

Magnetic Data ◽

Mapping Technique ◽

Epithermal Gold ◽

Airborne Geophysics ◽

Airborne Geophysical Data

High resolution airborne geophysical data over broad areas have been found to optimize exploration for epithermal gold deposits in differing geological environments.Genetic exploration models may be tested in favourable sites by the recognition of geophysical signatures. These signatures reflect structural, lithological and alteration patterns arising from controls on ore deposits and can be applied at regional or detailed scales, using the same data set.At regional scale (e.g. 1:100,000) the magnetic data reflect the regional tectonics and divide the area into domains for the application of appropriate genetic models. At prospect scale (e.g. 1:25,000) the radiometric data allow the extrapolation of poorly outcropping geology to provide a cost-effective mapping technique. The magnetic data can be used to supplement this interpretation or can be used to target deeper sources for direct investigation by drilling.

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Geological Characteristics of Unconventional Gas in Coal Measure of Upper Paleozoic Coal Measures in Ordos Basin, China

Earth Sciences Research Journal ◽

10.15446/esrj.v20n1.54140 ◽

2016 ◽

Vol 20 (1) ◽

pp. 1-5 ◽

Cited By ~ 6

Author(s):

Jinxian He ◽

Xiaoli Zhang ◽

Li Ma ◽

Hongchen Wu ◽

Muhammad Ashraf

Keyword(s):

Shale Gas ◽

Coalbed Methane ◽

Oil And Gas ◽

Ordos Basin ◽

Tight Sandstone ◽

Gas Reservoir ◽

Unconventional Gas ◽

Geological Characteristics ◽

Upper Paleozoic ◽

Coal Measures

<p>There are enormous resources of unconventional gas in coal measures in Ordos Basin. In order to study the geological characteristics of unconventional gas in coal Measures in Ordos Basin, we analyzed and summarized the results of previous studies. Analysis results are found that, the unconventional gas in coal measures is mainly developed in Upper Paleozoic in Eastern Ordos Basin, which including coalbed methane, shale gas and tight sandstone gas. The oil and gas show active in coal, shale and tight sandstone of Upper Paleozoic in Ordos Basin. Coalbed methane reservoir and shale gas reservoir in coal measures belong to “self-generation and self- preservation”, whereas the coal measures tight sandstone gas reservoir belongs to “allogenic and self-preservation”. The forming factors of the three different kinds of gasses reservoir are closely related and uniform. We have the concluded that it will be more scientific and reasonable that the geological reservoir-forming processes of three different kinds of unconventional gas of coal measures are studied as a whole in Ordos Basin, and at a later stage, the research on joint exploration and co-mining for the three types of gasses ought to be carried out.</p>

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Optimization of Coal Seam Connectivity via Multi-Seam Pinpoint Fracturing Operations in the Walloons Coal Measures, Surat Basin

10.2118/204190-ms ◽

2021 ◽

Author(s):

Vibhas J. Pandey ◽

Sameer Ganpule ◽

Steven Dewar

Keyword(s):

Coal Seam ◽

History Matching ◽

Design Matrix ◽

Coal Seams ◽

Major Step ◽

Well Completion ◽

Eastern Australia ◽

Treatment Designs ◽

Coal Measures ◽

Gas Bearing

Abstract The Walloons coal measures located in Surat Basin (eastern Australia) is a well-known coal seam gas play that has been under production for several years. The well completion in this play is primarily driven by coal permeability which varies from 1 Darcy or more in regions with significant natural fractures to less than 1md in areas with underdeveloped cleat networks. For an economic development of the latter, fracturing treatment designs that effectively stimulate numerous and often thin coals seams, and enhance inter-seam connectivity, are a clear choice. Fracture stimulation of Surat basin coals however has its own challenges given their unique geologic and geomechanical features that include (a) low net to gross ratio of ~0.1 in nearly 300 m (984.3 ft) of gross interval, (b) on average 60 seams per well ranging from 0.4 m to 3 m in thickness, (c) non-gas bearing and reactive interburden, and (d) stress regimes that vary as a function of depth. To address these challenges, low rate, low viscosity, and high proppant concentration coiled tubing (CT) conveyed pinpoint stimulation methods were introduced basin-wide after successful technology pilots in 2015 (Pandey and Flottmann 2015). This novel stimulation technique led to noticeable improvements in the well performance, but also highlighted the areas that could be improved – especially stage spacing and standoff, perforation strategy, and number of stages, all aimed at maximizing coal coverage during well stimulation. This paper summarizes the findings from a 6-well multi-stage stimulation pilot aimed at studying fracture geometries to improve standoff efficiency and maximizing coal connectivity amongst various coal seams of Walloons coal package. In the design matrix that targeted shallow (300 to 600 m) gas-bearing coal seams, the stimulation treatments varied in volume, injection rate, proppant concentration, fluid type, perforation spacing, and standoff between adjacent stages. Treatment designs were simulated using a field-data calibrated, log-based stress model. After necessary adjustments in the field, the treatments were pumped down the CT at injection rates ranging from 12 to 16 bbl/min (0.032 to 0.042 m3/s). Post-stimulation modeling and history-matching using numerical simulators showed the dependence of fracture growth not only on pumping parameters, but also on depth. Shallower stages showed a strong propensity of limited growth which was corroborated by additional field measurements and previous work in the field (Kirk-Burnnand et al. 2015). These and other such observations led to revision of early guidelines on standoff and was considered a major step that now enabled a cost-effective inclusion of additional coal seams in the stimulation program. The learnings from the pilot study were implemented on development wells and can potentially also serve as a template for similar pinpoint completions worldwide.

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NEW IDEAS ON THE RIFTING HISTORY AND STRUCTURAL ARCHITECTURE OF THE WESTERN OTWAY BASIN: EVIDENCE FROM THE INTEGRATION OF AEROMAGNETIC, GRAVITY AND SEISMIC DATA

The APPEA Journal ◽

10.1071/aj93042 ◽

1994 ◽

Vol 34 (1) ◽

pp. 529 ◽

Cited By ~ 5

Author(s):

G.W. O'Brien ◽

C.V. Reeves ◽

P.R. Milligan ◽

M.P. Morse ◽

E.M. Alexander ◽

...

Keyword(s):

Seismic Data ◽

Normal Fault ◽

Magnetic Data ◽

Data Sets ◽

Stress Regime ◽

Petroleum Potential ◽

History Of ◽

New Ideas ◽

Structural Architecture ◽

Great Australian Bight

The integration of high resolution, image-processed aeromagnetic data with regional geological, magnetic, gravity and seismic data-sets has provided new insights into the structural architecture, rifting history, and petroleum potential of the western onshore and offshore Otway Basin, south-eastern Australia.Three principal structural directions are evident from the magnetic data: NS, NE-ENE and NW-WNW. The structural fabric and regional geological data suggest that the rifting history of the basin may have taken place in two distinct stages, rather than within a simple rift-to-drift framework. The initial stage, from 150 to ~120 Ma, took place within a stress regime dominated by NW-SE extensional transport, similar to that of the basins within the Great Australian Bight to the west. ENE-striking extensional rift segments, such as the Crayfish Platform-Robe Trough and the Torquay Sub-Basin, developed during this period, contemporaneous with the deposition of thick sediments of the Early Cretaceous (Tithonian-Hauterivian) Crayfish Subgroup. In other parts of the basin, NW-striking rift segments, such as the Penola, and perhaps Ardonachie, Troughs onshore, developed within a strongly trans-tensional (left-lateral strike-slip) environment. At ~120 Ma, the regional stress field changed, and the Crayfish Subgroup-aged rift segments were reactivated, with uplift and block faulting extending through to perhaps 117 Ma. Rifting then recommenced at about 117 Ma (contemporaneous with the deposition of the Barremian-Albian Eumeralla Formation), though the extensional transport direction was now oriented NNE-SSW, almost perpendicular to that of the earlier Crayfish Subgroup rift stage. This later rift episode ultimately led to continental breakup at ~96 Ma and produced the 'traditional' normal fault orientations (NW-SE to WNW-ESE) throughout the Otway Basin.

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The present-day stress regime of the southwestern part of the Aquitaine basin, France, as indicated by oil well data

Journal of Structural Geology ◽

10.1016/0191-8141(92)90033-s ◽

1992 ◽

Vol 14 (8-9) ◽

pp. 1019-1032 ◽

Cited By ~ 10

Author(s):

J.S Bell ◽

G Caillet ◽

A Le Marrec

Keyword(s):

Oil Well ◽

Southwestern Part ◽

Stress Regime ◽

Well Data ◽

Aquitaine Basin

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DISCOVERY AND DEVELOPMENT OF THE KOGAN NORTH AND TIPTON WEST COAL SEAM GAS (CSG) FIELDS, SURAT BASIN, SOUTHEAST QUEENSLAND

The APPEA Journal ◽

10.1071/aj05020 ◽

2006 ◽

Vol 46 (1) ◽

pp. 367 ◽

Cited By ~ 4

Author(s):

R.W. Day ◽

R.F. Prefontaine ◽

P.A.J. Bubendorfer ◽

M.H. Oberhardt ◽

B.J. Pinder ◽

...

Keyword(s):

Coal Seam ◽

Cultural Heritage ◽

Gas Flow ◽

Heritage Management ◽

Management Systems ◽

Coal Seam Gas ◽

Cultural Heritage Management ◽

Well Completion ◽

Eastern Australia ◽

Coal Measures

In 2001, Arrow Energy NL, a fledgling coal seam gas (CSG) explorer, drilled the first wells of a multi-well exploration program in two Authorities To Prospect (ATP) permits—ATPs 683P and 676P—that covered an area totalling 13,817 km2 of the Jurassic Walloon Coal Measures in the eastern Surat Basin. The objective was to discover significant CSG resources and, if successful, to commercialise to reserve status. Early exploration success in 2002 saw the discovery of the Kogan North and Tipton West CSG fields. This paper reviews the discovery and subsequent appraisal and development work that Arrow Energy has completed to establish production from these fields.By 2004, Arrow Energy had independently certified Probablereserves in the Kogan North field of 85 PJ, and Possible reserves of 157 PJ. Results from a five-well CSG pilot operation demonstrated the feasibility of commercial gas flow rates sufficiently to justify commercialising CSG from the Walloon Coal Measures in the Kogan North field. Under the terms of a staged development agreement, CS Energy Ltd—Queensland’s largest electricity generator—farmed into the Kogan North Project to earn a 50% interest in PL194 and an adjoining portion of ATP 676P by funding A$13.1 million of the project’s development and appraisalcosts. The funds provided by CS Energy covered the majority of the development costs required for Arrow’s Kogan North development project. The initial gas sales contract from Kogan North will supply sales gas of 4 PJ/a for 15 years to CS Energy from March 2006. Arrow Energy retains the remaining 50% interest and operates the project.With 25 PJ Probable, 90 PJ Probable and 1,980 PJ Possiblegas reserves certified independently, the Tipton West field could potentially be one of the largest onshore gas fields in eastern Australia. Final appraisal of the Tipton West field is currently underway with financial close on the development expected in late 2005. Beach Petroleum Ltd has entered into an agreement to fund the A$35 million required for upstream developmentto supply the initial 10 PJ/a sales gas from the field in 2007, in exchange for 40% interest in th Dalby block of ATP683P. Arrow Energy retains the remaining 60% interest and operates the project.Diligent environmental and land management systems are required with the development of any CSG field. For example, formation water produced from CSG activities needs to be managed effectively. To deal with this water Arrow Energy is developing and implementing several innovative strategies, including forced evaporation dams, water supply to local coal-washing plants and trialling desalination plants to provide drinking water for nearby towns, aquaculture and stock watering.Arrow Energy has also implemented a Cultural Heritage Management Plan within the development areas in cooperation with the local indigenous claimant groups, the Western Wakka Wakka and the Barunggam peoples. The plan was designed to minimise risk of any disturbance to indigenous artefacts and areas of significance during the exploration, construction and ongoing operations associated with the development of both gas fields.The discovery and future development of the Kogan North and Tipton West fields has been achieved by using an appropriate mix of geological evaluation, efficient drilling techniques, innovative well completion methods and successful marketing strategies, integrated with cooperative environmental and cultural heritage management systems.

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TECTONIC CONTROLS ON SEDIMENTATION AND MATURATION IN THE OFFSHORE NORTH PERTH BASIN

The APPEA Journal ◽

10.1071/aj88037 ◽

1989 ◽

Vol 29 (1) ◽

pp. 450 ◽

Cited By ~ 3

Author(s):

John F. Marshall ◽

Chao- Shing Lee ◽

Douglas C. Ramsay ◽

Aidan M.G. Moore

Keyword(s):

Seismic Reflection ◽

Source Rocks ◽

Hydrocarbon Generation ◽

Late Permian ◽

Early Permian ◽

The West ◽

Australian Continent ◽

Multichannel Seismic Reflection ◽

Well Data ◽

Coal Measures

The major tectonic and stratigraphic elements of the offshore North Perth Basin have been delineated from regional BMR multichannel seismic reflection lines, together with industry seismic and well data. This analysis reveals that three sub- basins, the Edel, Abrolhos and Houtman Sub- basins, have formed as a result of three distinct episodes of rifting within the offshore North Perth Basin during the Early Permian, Late Permian and Late Jurassic respectively. During this period, rifting has propagated from east to west, and has culminated in the separation of this part of the Australian continent from Greater India.The boundaries between the sub- basins and many structures within individual sub- basins are considered to have been produced by strike- slip or oblique- slip motion. The offshore North Perth Basin is believed to be a product of transtension, possibly since the earliest phase of rifting. This has culminated in separation and seafloor spreading by oblique extension along the Wallaby Fracture Zone to form a transform passive continental margin.This style of rifting and extension has produced relatively thin syn- rift sequences, some of which have been either partly or completely removed by erosion. While the source- rock potential of the syn- rift phase is limited, post- rift marine transgressional phases and coal measures do provide adequate and relatively widespread source rocks for hydrocarbon generation. Differences in the timing of rifting across the basin have resulted in a maturation pattern whereby mature sediments become younger to the west.

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