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Description:
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The supply and demand situation is crucial for the oil and gas industry during the first half of the 21st century . For the future , we will see two trends going in opposite directions : a decline in discoveries of conventional oil and gas reservoirs and an increase in world energy demand . Therefore , the need to develop and produce unconventional oil and gas resources , which encompass coal -bed methane , gas -shale , tight sands and heavy oil , will be of utmost importance in the coming decades . In the past , large -scale production from tight gas reservoirs occurred only in the U .S . and was boosted by both price incentives and well stimulation technology . A conservative study from Rogner (1997 ) has shown that tight gas sandstone reservoirs would represent at least over 7 ,000 trillion cubic feet (Tcf ) of natural gas in place worldwide . However , most of the studies such as the ones by the U .S . Geological Survey (U .S .G .S . ) and Kuuskraa have focused on assessing the technically recoverable gas resources in the U .S . with numbers ranging between 177 Tcf and 379 Tcf .
During the past few decades , gas production from tight sands field developments have taken place all around the world from South America (Argentina ) , Australia , Asia (China , Indonesia ) , the Russian Federation , Northern Europe (Germany , Norway ) and the Middle East (Oman ) . However , the U .S . remains the region where the most extensive exploration and production for unconventional gas resources occur . In fact , unconventional gas formations accounted for 43 % of natural gas production and tight gas sandstones represented 66 % of the total of unconventional resources produced in the U .S . in 2006 . As compared to a conventional gas well , a tight gas well will have a very low productivity index and a small drainage area . Therefore , to extract the same amount of natural gas out of the reservoir , many more wells will have to be drilled and stimulated to efficiently develop and produce these reservoirs . Thus , the risk involved is much higher than the development of conventional gas resources and the economics of developing most tight gas reservoirs borders on the margin of profitability . To develop tight gas reservoirs , engineers face complex problems because there is no typical tight gas field . In reality , a wide range of geological and reservoir differences exist for these formations . For instance , a tight gas sandstone reservoir can be shallow or deep , low or high pressure , low or high temperature , bearing continuous (blanket ) or lenticular shaped bodies , being naturally fractured , single or multi -layered , and holding contaminants such as CO2 and H2S which all combined increase considerably the complexity of how to drill a well .
Since the first tight gas wells were drilled in the 1940's in the U .S . , a considerable amount of information has been collected and documented within the industry literature . The main objective of this research project is to develop a computer program dedicated to applying the drilling technologies and methods selection for drilling tight gas sandstone formations that have been documented as best practices in the petroleum literature . |