Prediction and management of solids production in typical Surat Basin coal seam gas reservoirs, eastern Australia

2015 ◽  
Vol 55 (2) ◽  
pp. 444
Author(s):  
Abbas Khaksar ◽  
Morteza Jami ◽  
Ahmadreza Younessi
Keyword(s):  
Coal Seam ◽  
Water Saturation ◽  
Gas Production ◽  
Control Measures ◽  
Coal Seam Gas ◽  
Gas Reservoirs ◽  
Short Life Span ◽  
Sand Control ◽  
Eastern Australia ◽  
Different Characteristics

The exploiting of coal seam gas (CSG) reservoirs worldwide has developed rapidly. These reservoirs are located in different geological settings and have different characteristics. In eastern Australia for instance, Surat Basin CSG reservoirs are typically thin and interbedded with thick layers of sandstone, siltstones and shales, and occur at shallow depths, adjacent to fresh-water aquifers. For commercial gas production from wet- and low- permeability thin CSG reservoirs, both the hydrostatic pressure and the water saturation have to be reduced through a de-watering and pressure depletion process. These mechanisms increase the risk of rock failure and solids production before or from the onset of gas production in many CSG wells. In thinly bedded CSG reservoirs, solids production from coals may not be a concern, but sanding from interbed rocks—some with abundant water sensitive clay minerals—may be a significant source of solids production. Given the relatively low drilling and completion costs and short life span of the CSG wells, many of the conventional sand control measures such as screens or gravel packs may be of limited use or not applicable. In this extended abstract, examples of solids production issues and the potential sources of solids in typical Surat Basin CSG wells are shown, and options for solids control are discussed.

Vertical gas migration associated with coal seam gas production

2016 ◽  
Vol 56 (2) ◽  
pp. 602
Author(s):  
Ludovic Ricard ◽  
Julian Strand
Keyword(s):  
Coal Seam ◽  
Risk Evaluation ◽  
Critical Role ◽  
Gas Production ◽  
Mitigation Strategies ◽  
Gas Migration ◽  
Coal Seam Gas ◽  
Gas Reservoirs ◽  
Gas Leakage ◽  
Migration Pathways

Gas migration outside coal seam gas reservoirs has been identified as a risk associated with CSG production. While such an event has not been reported or scientifically associated with CSG production, understanding the physical mechanism of the vertical migration in the overburden involved should gas leakage occur would improve mitigation strategies and risk evaluation. In this extended abstract, a series of key modelling scenarios of gas migration above the reservoir are developed. Interpretation of the scenarios highlights that: the seal/leakage nature of the overburden strongly impacts gas migration and volume of gas leaked; when leakage does occur, the leaked volume represents a very small portion of the original gas in place and volume of gas produced; the connectivity of the overburden plays a critical role on the gas migration pathways and volume of gas leaked; and, residual gas saturation, and relative permeability hysteresis provide means to trap the mobile gas, significantly reducing the volume of gas leaked reaching shallower formations.

Implications of LNG exposure on the competitiveness of Australia

2016 ◽  
Vol 56 (2) ◽  
pp. 589
Author(s):  
Ross Lambie ◽  
Nicole Thomas ◽  
David Whitelaw
Keyword(s):  
Coal Seam ◽  
Gas Production ◽  
Fundamental Importance ◽  
Gas Flows ◽  
Coal Seam Gas ◽  
Market Outcomes ◽  
Spot Prices ◽  
Eastern Australia ◽  
Gas Market

Australia’s eastern gas market has historically been one of low prices and stable, long-term contracts. The development of coal seam gas (CSG) and the construction of Queensland’s three CSG to LNG projects is driving a tripling of gas production in eastern Australia and changes to historical patterns and directions of gas flows throughout the market. This transition from an isolated market to one linked to international LNG markets, coinciding with the unwinding of many legacy contracts, is leading to unprecedented change and will have profound effects on all participants. This extended abstract considers the implications of LNG exposure on the competitiveness of Australia’s eastern gas market. It will draw on the expertise of the gas market specialists in the Office of the Chief Economist, and the oligopolistic model of the market, to consider impacts on supply, demand, price, and the level of competition in various sectors of the market. One of the initial findings is that the volatility of global LNG spot prices is likely to have a significant impact on both gas production and demand in east Australia, given the scale of LNG exports relative to the eastern market. The extended abstract explores a range of LNG demand scenarios for the eastern gas market. It will emphasise the fundamental importance of expanded gas production on market outcomes, and the need for ongoing gas exploration and development to support the market through the transition.

Formation Damage Issues Impacting the Productivity of Low Permeability, Low Initial Water Saturation Gas Producing Formations

2005 ◽  
Vol 127 (3) ◽  
pp. 240-247 ◽  
Author(s):  
D. Brant Bennion ◽  
F. Brent Thomas
Keyword(s):  
Capillary Pressure ◽  
Water Saturation ◽  
The United States ◽  
Gas Production ◽  
Pressure Effects ◽  
Formation Damage ◽  
Low Permeability ◽  
Gas Reservoirs ◽  
Initial Water ◽  
The Impact

Very low in situ permeability gas reservoirs (Kgas<0.1mD) are very common and represent a major portion of the current exploitation market for unconventional gas production. Many of these reservoirs exist regionally in Canada and the United States and also on a worldwide basis. A considerable fraction of these formations appear to exist in a state of noncapillary equilibrium (abnormally low initial water saturation given the pore geometry and capillary pressure characteristics of the rock). These reservoirs have many unique challenges associated with the drilling and completion practices required in order to obtain economic production rates. Formation damage mechanisms affecting these very low permeability gas reservoirs, with a particular emphasis on relative permeability and capillary pressure effects (phase trapping) will be discussed in this article. Examples of reservoirs prone to these types of problems will be reviewed, and techniques which can be used to minimize the impact of formation damage on the productivity of tight gas reservoirs of this type will be presented.

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.

Determining the impacts of coal seam gas extraction on water-dependent assets

2016 ◽  
Vol 56 (2) ◽  
pp. 545
Author(s):  
David Post ◽  
Peter Baker ◽  
Damian Barrett
Keyword(s):  
Coal Seam ◽  
Indigenous Peoples ◽  
Rural Areas ◽  
Scientific Information ◽  
Gas Production ◽  
Specific Reference ◽  
Catchment Management ◽  
State Governments ◽  
Coal Seam Gas ◽  
Coal Resource

Many Australians, particularly in rural areas, are seeking clear scientific information about the potential impacts of coal seam gas production on groundwater and surface water across the country. In response to the resultant community concern, the Australian Government commissioned an ambitious multi-disciplinary program of bioregional assessments to improve understanding of the potential impacts of coal seam gas (and large coal mining) activities on water-dependent assets across six bioregions in eastern and central Australia. Delivered through a collaboration between the Department of the Environment, the Bureau of Meteorology, CSIRO, and Geoscience Australia—and including close engagement with natural resource management and catchment management organisations, coal resource companies, Indigenous peoples and state governments—the results will allow coal resource companies, governments, and the community to focus on the areas where impacts may occur so that these can be minimised. Key findings of the program will be presented with specific reference to the potential impacts on water-dependent assets due to CSG development by Metgasco and AGL in the Clarence-Moreton and Gloucester regions, respectively.

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