Potential For Future Production Research Articles

Fahud Field Review: A Switch From Water to Gas Injection

Summary The water injection schemes implemented in the Fahud field during the early 1970's led to poor recoveries because the reservoirs were both fractured and oil-wet. On the basis of the results of a thorough performance review, it was decided in 1983 to promote gas/oil gravity performance review, it was decided in 1983 to promote gas/oil gravity drainage fully by drilling rows of downdip producers and switching completely from water to gas injection. This paper investigates the reasons behind each stage of development and reviews recent efforts to evaluate the future production potential through the use of dual-porosity simulators. Introduction The Fahud field (Fig. 1), which has a stock-tank oil initially in place (STOIIP) of 1000 × 10(6) stock-tank m3 [6,300 × 10(6) STB], is an elongated monocline with an eroded fault escarpment. The field is divided by a permeability barrier into two accumulations, Fahud North-West (NW) and South-East (SE), each of which contains three fractured Natih limestone reservoirs. The three Fahud NW reservoirs (NW-A, NW-C/D, and NW-E/F/G) are separated by continuous shales but are in communication with each other across the eroded fault escarpment (Figs. 2 and 3). The same applies to the three Fahud SE reservoirs (SE-A, SE-C/D, and SE-E). The oil has a density of 870 kg/m3 [31 deg.API] with initial reservoir fluid properties as presented in Table 1. The field was discovered in 196 properties as presented in Table 1. The field was discovered in 196 and started production in 1967. To date, 12 % of the field's STOIIP has been produced. This paper reviews the field's performance during four distinct phases of development: initial, waterflood, reassessment, and present development. Initial Development 1967–71. The field was initially produced under natural depletion supplemented in 1968 by gas injection. The high offtake rates led to a rapid displacement of the gas/oil contact (GOC), which resulted in the early gassing out of a number of relatively downdip completions. Simulation studies and field trials were conducted, which concluded that better recoveries would be obtained through waterflooding. Waterflood Period-1972–80. Following the recommendations, water injection schemes were implemented in four of the six Fahud reservoirs. However, they failed to arrest either the pressure or oil production decline. Reassessment Period-1981–83. The poor performance of the waterflood led to a thorough review during which a number of thermal decay time (TDT) logs and tracer tests were conducted. It was concluded that because the reservoir rock was both fractured and oil-wet, recovery factors from waterflooding were low and could be substantially improved by reverting to full-scale gas/oil gravity drainage. Present Development-From 1984. The present policy is to promote gas/oil gravity drainage fully. This ongoing development promote gas/oil gravity drainage fully. This ongoing development requires the phasing out of water injection, the completion of downdip grids of producers, and the full replacement of voidage by gas injection. Dual-porosity simulation studies are currently being conducted to optimize the remaining development and to predict the future field performance.

China's energy resources: Potential supply, problems, and implications

If the People's Republic of China is to achieve its current modernization and economic objectives, primary energy production in the nation must increase significantly by the year 2000. To support and sustain this projected rapid economic growth, indigenous supplies of primary energy resources will have to be developed at rates greater than those of today. This paper presents a preliminary systematic resource assessment of China's primary energy resources by province. Petroleum, natural gas, coal and uranium are assessed and examined in terms of availability and future production potential. China's policies for long-term development of these energy resources are also analysed, with particular emphasis on the scope of problems that may be encountered during future development.

Planting and Removal Relationships for Perennial Crops: An Application to Cling Peaches

AbstractSupply response for a perennial crop is influenced by the age composition of existing plant stocks which, in turn, is determined by historical patterns of plantings and removals. This paper develops estimates of functions that relate the planting and removal of cling peach trees to measures of past profitability, potential future production from existing acreage, and structural changes associated with market intervention programs. The analysis also provides indications of useful forms for these functions, patterns of yield variation by age of tree, and the nonlinear relation of removal response to age of tree.

Uncertain Future of Natural Gas Production in U.S. Lower 48 States: ABSTRACT

The Office of Technology Assessment (OTA), an analytic support agency of the United States Congress, has examined the process of forecasting future supplies of conventional, domestically produced natural gas in the U.S. lower 48 states to the year 2000. Its investigation focused particularly on the technical sources of uncertainty, including the incomplete geologic understanding of the remaining resources and the difficulties involved in properly interpreting and extrapolating past trends in natural gas discovery. The OTA examined the arguments developed by supply optimists and pessimists regarding both the size of the recoverable resource base and the speed with which new resources can be discovered and produced. As part of the investigation, resource-base estimates, ranging from those of H. King Hubbert and Richard Nehring to those of the U.S. Geological Survey and the Potential Gas Committee, were reviewed and compared. The OTA concluded that the credible ranges of estimates for lower-48 resources and future production potential are very wide--400 to 900 tcf for the remaining recoverable resources of conventional gas at near-current prices and technology, and 9-19 tcf/yr for the year 2000 production under the same price and technology conditions. End_of_Article - Last_Page 517------------

Health Effects of Energy-Generating Sources

To the Editor.— The American Medical Association Council on Scientific Affairs does not appear to have performed its evaluation of the health effects of energy-generating sources with a view toward the ultimate purpose of its analysis (240:2193, 1978). The document is of interest as a summary of the occupational health risks associated with nuclear and fossil-fuel power production in the recent past, but it is not adequate to serve as a guide to future policy for the following reasons: The risks attributed to coal mining reflect hazards associated with underground mining. 1,2 The expansion of coal mining under the National Energy Plan, especially in the western states where the potential for future production is greatest, will be preponderantly surface mining. 3,4 The AMA council report bases its evaluation on extrapolation from the most hazardous coal extraction technology rather than the technology that will in fact be employed. Surface mining

Teapot Dome--Past, Present, and Future

The Teapot Dome field is the 99th largest oil field in the United States with a proved reserve of 42,515,000 bbl, yet the field is sparsely drilled and underdeveloped. The writer credits Naval Petroleum Reserve No. 3 with 38 million bbl of future reserves. The long history of Teapot Dome since the early 1900s, sometimes turbulent, sometimes dormant, was marred by government scandal, akin to Watergate in notoriety, in the 1920s. Harry F. Sinclair's Mammoth Oil Company obtained leases from the Department of the Interior in a fraudulent manner which led to prison sentences for some of the principals. Oil production in the Teapot Dome field is from three formations--the shallow Shannon at depths of 400 to 1,000 ft (122 to 305 m); the Second Wall Creek member of the Frontier Formation at 2,500 to 3,000 ft (362 to 914 m); and the Tensleep Sandstone at 5,500 ft (1,676 m). The Second Wall Creek is the principal producing sandstone and has the greatest future production potential. Current production is small. As of December 1973, each of the 42 Navy wells averaged 4.4 b/d from the Shannon Sandstone, and 49 offset wells averaged 2.2 b/d each. In the Second Wall Creek, each of the 23 Navy wells averaged 10 b/d and 8 offset wells averaged 14.9 b/d each. Total daily production was 416 bbl and grand total for Teapot Dome through December 1975 was 7,762,709 bbl.