加拿大天然气资源概况

CANADA’S ESTIMATED MARKETABLE GAS RESOURCES (TCF) Conventional (Remaining GIP) 357 Natural Gas from Coal/Coalbed 34 - 129 Methane Tight Gas 215 - 476 Shale Gas TOTAL 128-343 733 - 1304
variety of sources (governments, companies, consultants). They are subject to escalation, rounding, and generalization, often creating a bewildering maze of numbers of uncertain provenance. The purpose of this work is to establish a set of estimates where the gas in place number is well grounded, and assumptions leading marketable resource estimates acknowledge the emergent nature of unconventional resources. A few definitions are key to understanding the categories and constraints for these resource estimates. The following definitions from “Canada’s Conventional Natural Gas Resources” (NEB 2004) and “Saskatchewan’s Ultimate Potential for Conventional Natural Gas” (NEB 2008) serve the purpose, although authors of different documents may use variations on these definitions. Gas in Place (GIP) This is the total quantity of gas that is estimated to be contained in any given pool or reservoir and includes both the portion that can be recovered and the portion that will remain in the reservoir” after production operations are concluded. A distinction should be made between Original Gas in Place (OGIP) which is the amount of gas before accounting for cumulative production, and Remaining Gas in Place which is OGIP minus cumulative raw gas production. Given the magnitude of resource estimates for unconventional resources and the short production history, OGIP is often considered to be equivalent to Remaining GIP for those resources. The cumulative production from conventional reservoirs is material however, and the conventional potential is the Remaining GIP. Recovery Factor A factor applied to the gas in place (or oil in place) in a reservoir in order to obtain the volume of gas that can be physically recovered at the surface.” Recovery factors can be quite explicit in small well defined development areas, but at a regional level must necessarily be broader. Recovery factors can range from very low (some unconventional reservoirs) to very high (some conventional reservoirs), and reflect assumptions about the applicability of technology, as well as resource access considerations such as ecological or environmental constraints, stakeholder issues and considerations with respect to urbanization. Marketable Gas The volume of gas that can be sold to the market after allowing for removal of impurities and after accounting for any volumes used to fuel surface facilities.” Impurities include both non-hydrocarbon constituents and valuable liquid byproducts. Recoverable gas is simply “Gas in place” X “Recovery factor” Marketable gas is “Recoverable gas” X a “marketable factor” (or minus losses attributable to processing and fuel). Estimators can and do arrive at different conclusions about recoverable or marketable gas, even when using the same gas in place starting point, simply because they have made different assumptions about recovery factors and processing losses.
CANADA’S GAS IN PLACE RESOURCES (TCF) Conventional (Remaining GIP) Natural Gas from Coal/Coalbed Methane Tight Gas Shale Gas TOTAL 692 801 1311 1111 3915
AN OVERVIEW OF CANADA’S NATURAL GAS RESOURCES
Leabharlann Baidu
K. Heffernan and F.M. Dawson Canadian Society for Unconventional Gas May 2010
Executive Summary
Canada’s gas in place from both conventional and unconventional resources is estimated to be almost 4000 TCF (Petrel Robertson, 2010), a function of including the very large contribution unconventional resources make to the total resource estimate, dramatically changing the picture of Canada’s gas potential.
Introduction Although there is an abundance of natural gas resource information available for Canada, from a wide variety of sources, no one source provides a comprehensive assessment which reflects the tremendous advances in understanding unconventional gas resources in Canada. CSUG considered it important to look at the available information and the limitations of the various assessments in order to generate a comprehensive understanding of the resource that, as Canadians, we can all rely on. This report provides an assessment addressing both conventional and unconventional resources, and highlights our country’s strength in the resource. It confirms that we have access to a reliable source of clean energy to heat our homes and run our businesses. These data also provide businesses with assurances of a source of energy upon which they can base their long-term business decisions and provides government with good usable information to factor into decisions regarding Canada’s energy future. Natural gas is a strategic resource for the country. It’s abundant, safe, reliable, and affordable. It’s the lowest emitting hydrocarbon and an ideal energy partner for transportation and power generation. It has a key role to play in meeting Canada’s long term energy, environment and economy objectives. Background Petrel Robertson Consulting Ltd. (PRCL) prepared a report summarizing the range of assessments of Canada’s natural gas resource base (“Assessment of Canada’s Natural Gas Resource Base”, March 2010) for the Canadian Society for Unconventional Gas (CSUG). Using the PRCL report CSUG has estimated the total Canadian marketable gas resource to be 700 – 1300 TCF, a wide range, reflecting the emergent nature of many of Canada’s unconventional resources. Individual inputs to the resource estimate will change with time: some will go up, some will go down. As more information becomes available, particularly in emerging resource areas, adjustments in the estimates will be made dependent on the confidence level of the new additional data. It should be noted that at present, because the CSUG resource estimate has been developed at a broad, high level some of the assumptions made are also broad. Given the early development stage of many of the resource areas, coupled with geographic regions that are believed or even known to contain natural gas but for which no estimates are available, the estimates presented in this document represent the best current assessment of Canada’s aggregate natural gas resource potential. The foundation Gas in Place inputs for CSUG’s estimate of Canada’s recoverable marketable gas are public, transparent, and well grounded estimates of the gas in place resource for various reservoir types, regions or development opportunities. The media often reports resource estimates without specification of the nature of the estimate or the source of the information. Estimates of resources for individual plays or opportunities are often available from a wide
Canada’s marketable natural gas resource potential is estimated to be between 700 and 1300 TCF, after providing for considerations that constrain gas recovery and allowing for removal of impurities and fuel for surface facilities. This estimate is a significant increase from previous estimates which addressed conventional resources, while acknowledging that natural gas from unconventional sources could play a significant role in the future without quantifying the potential. This assessment includes both conventional and unconventional resources. During the past several years the development and widespread deployment of a variety of horizontal drilling and companion reservoir stimulation technologies has demonstrated that vast additional natural gas resources within coal seams, tight gas reservoirs and shales will play a major role in shaping Canada’s long term natural gas supply opportunity. The emerging nature of much of Canada’s unconventional gas resource is reflected in the broad range of potential marketable gas.