TECHNICAL CHALLENGES IN THE DEVELOPMENT OF UNCONVENTIONAL GAS RESOURCES IN AUSTRALIA

Unconventional gas resources, defined as low- permeability sandstone, coal seam and naturally- fractured shale gas reservoirs, represent a huge potential resource for future natural gas supply in Australia and around the world. Because low individual well-production rates are often the norm, unconventional reservoir development may involve the drilling of hundreds of wells to make the economics attractive. Thus, careful planning, sound development strategies and cost control are critical for project success.Virtually all unconventional gas resources must be stimulated to be economic; stimulation costs are often the most significant amount of the total well expenditure. Thus, a cost-effective method for reservoir characterisation and fracture treatment optimisation is required. Because of marginal economics, techniques used to analyse the process and results are often oversimplified; this can lead to confusing or inadequate descriptions of the complex behavior of a hydraulically-fractured, low- permeability reservoir and in some cases bad development decisions. Detailed data collection programs and fracture treatment optimisation strategies are essential to adequately address the technical issues involved in unconventional reservoir development.Besides the technical challenges associated with unconventional gas development, good forethought is necessary as to the planning and execution of the overall project. The development scenarios for coal seam and low-permeability sandstone gas resources are highly statistical and succeed or fail based on the average performance of the group of wells within the project. Following proven guidelines and methods during development while integrating key technologies into the planning and optimisation process are essential for success in unconventional reservoir development.

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The Mechanism of Flue Gas Injection for Enhanced Light Oil Recovery

Journal of Energy Resources Technology ◽

10.1115/1.1725170 ◽

2004 ◽

Vol 126 (2) ◽

pp. 119-124 ◽

Cited By ~ 6

Author(s):

O. S. Shokoya ◽

S. A. (Raj) Mehta ◽

R. G. Moore ◽

B. B. Maini ◽

M. Pooladi-Darvish ◽

...

Keyword(s):

Oil Recovery ◽

Flue Gas ◽

Gas Injection ◽

Cost Effective ◽

Air Injection ◽

Oil Reservoirs ◽

Flue Gases ◽

Low Permeability ◽

Light Oil ◽

Light Oil Reservoirs

Flue gas injection into light oil reservoirs could be a cost-effective gas displacement method for enhanced oil recovery, especially in low porosity and low permeability reservoirs. The flue gas could be generated in situ as obtained from the spontaneous ignition of oil when air is injected into a high temperature reservoir, or injected directly into the reservoir from some surface source. When operating at high pressures commonly found in deep light oil reservoirs, the flue gas may become miscible or near–miscible with the reservoir oil, thereby displacing it more efficiently than an immiscible gas flood. Some successful high pressure air injection (HPAI) projects have been reported in low permeability and low porosity light oil reservoirs. Spontaneous oil ignition was reported in some of these projects, at least from laboratory experiments; however, the mechanism by which the generated flue gas displaces the oil has not been discussed in clear terms in the literature. An experimental investigation was carried out to study the mechanism by which flue gases displace light oil at a reservoir temperature of 116°C and typical reservoir pressures ranging from 27.63 MPa to 46.06 MPa. The results showed that the flue gases displaced the oil in a forward contacting process resembling a combined vaporizing and condensing multi-contact gas drive mechanism. The flue gases also became near-miscible with the oil at elevated pressures, an indication that high pressure flue gas (or air) injection is a cost-effective process for enhanced recovery of light oils, compared to rich gas or water injection, with the potential of sequestering carbon dioxide, a greenhouse gas.

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Advance Water-Flooding to Reduce the Stress Sensitivity Affect on Low Permeability Reservoir Development

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.361-363.520 ◽

2011 ◽

Vol 361-363 ◽

pp. 520-525

Author(s):

Jun Feng Yang ◽

Han Qiao Jiang ◽

Han Dong Rui ◽

Xiao Qing Xie

Keyword(s):

Physical Simulation ◽

Physical Property ◽

Stress Sensitivity ◽

Water Flooding ◽

Low Permeability ◽

Formation Pressure ◽

Exponential Relationship ◽

Low Permeability Reservoir ◽

Reservoir Development ◽

Water Cut

Physical simulation experiments were made to research on the stress sensitivity on physical property of low permeability reservoir rocks. The experimental results shown that effective pressure had good exponential relationship with reservoir permeability. Combining with materaial balance method, reservoir engineering and rational deducation was made to reserach on water-flooding timing of low permeability reservoir development. Several production targets were obtained by these method, such as formation pressure, water and oil production, water cut and so on. The results shown that advanced water-flooding was very important in low permeability reservoir development to reduce the bad impact of stress sensitivity on formation permeability and maintain formation pressure.

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Numerical Simulation of Low Permeability Unconventional Gas Reservoirs

10.2118/167711-ms ◽

2014 ◽

Cited By ~ 22

Author(s):

Yu Didier Ding ◽

Yu-Shu Wu ◽

Nicolas Farah ◽

Cong Wang ◽

Bernard Bourbiaux

Keyword(s):

Numerical Simulation ◽

Low Permeability ◽

Gas Reservoirs ◽

Unconventional Gas ◽

Unconventional Gas Reservoirs

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Mechanisms of Mass Exchange Between Light Oiland Petroleum Gas in Low-Permeability Reservoir Development Process

Chemistry and Technology of Fuels and Oils ◽

10.1007/s10553-018-0947-2 ◽

2018 ◽

Vol 54 (4) ◽

pp. 457-466

Author(s):

P. A. Gushchinu ◽

A. N. Cheremisin ◽

N. G. Glavnov ◽

P. M. Zobort ◽

N. A. Svarovskaya ◽

...

Keyword(s):

Mass Exchange ◽

Development Process ◽

Low Permeability ◽

Low Permeability Reservoir ◽

Reservoir Development

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Productivity evaluation of unconventional reservoir development with three-dimensional fracture networks

Fuel ◽

10.1016/j.fuel.2019.01.188 ◽

2019 ◽

Vol 244 ◽

pp. 304-313 ◽

Cited By ~ 9

Author(s):

Yun Chen ◽

Guowei Ma ◽

Yan Jin ◽

Huidong Wang ◽

Yang Wang

Keyword(s):

Three Dimensional ◽

Fracture Networks ◽

Unconventional Reservoir ◽

Reservoir Development

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Micropore Structure and Fractal Characteristics of Low-Permeability Coal Seams

Advances in Materials Science and Engineering ◽

10.1155/2018/4186280 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 2

Author(s):

Guang-zhe Deng ◽

Rui Zheng

Keyword(s):

Fractal Dimension ◽

Electron Microscope ◽

Scanning Electron Microscope ◽

Coal Seam ◽

Linear Relationship ◽

Surface Area ◽

Pore Volume ◽

Low Permeability ◽

Coal Seams ◽

Scanning Electron

With the raw coal from a typical low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang as the research object, this paper examined six kinds of coal samples with different permeabilities using a scanning electron microscope and a low-temperature nitrogen adsorption test that employed a JSM-6460LV high-resolution scanning electron microscope and an ASAP2020 automatic specific surface area micropore analyzer to measure all characteristic micropore structural parameters. According to fractal geometry theory, four fractal dimension calculation models of coal and rock were established, after which the pore structure characteristic parameters were used to calculate the fractal dimensions of the different coal seams. The results show that (1) the low-permeability coal seam in the coalfield of South Junger Basin in Xinjiang belongs to mesoporous medium, with a certain number of large pores and no micropores. The varying adsorption capacities of the different coal seams were positively correlated with pore volume, surface area, and the mesoporous surface area proportions, from which it was concluded that mesopores were the main contributors to pore adsorption in low-permeability coal seams. (2) The raw coal pore fractal dimension had a negative linear relationship to average pore size, a positive linear relationship with total pore volume, total surface area, and adsorption capacity, and a positive correlation with the mesoporous surface area proportion; that is, the higher the fractal dimension, the larger the pore volume and surface area of the raw coal. (3) The permeability of the low-permeability coal seam had a phase correlation with the micropore development degree; that is, the permeability had a phase negative correlation with the pore distribution fractal dimension, and there was a positive correlation between permeability and porosity. These results are of theoretical significance for the clean exploitation of low-permeability coal seam resources.

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