A simple and practical method for estimating undiscovered hydrocarbons for a specified timeframe

2015 ◽  
Vol 55 (2) ◽  
pp. 449 ◽  
Author(s):  
Nick Eustance ◽  
Steve Newman

A simple approach has been developed to predict yet-to-find (YTF) hydrocarbons to be discovered in a basin within a specified timeframe. The methodology uses basic exploration and resource data to address the requirement of oil companies, governments, utilities and financial institutions so that these understand the resources available for future markets within a defined timeframe (e.g, in the next 15 years). In contrast, conventional approaches to estimate the YTF in a moderately mature basin tend to predict the ultimate resource of a basin, unqualified by time. Such techniques reply on data-intensive geological assessments or use the parabolic form of a log-log plot of cumulative hydrocarbon resource against field rank, coupled with an extrapolation of a cumulative resource against field rank (the creaming curve) to an asymptote. The approach uses annual exploration data, dry hole and discoveries, and the discovery size. Three parameters are defined for the forecast period: the average number of wells per year, the average chance of a discovery, and its average size. Low, mid and high case values of each parameter are estimated, and these are combined probabilistically to produce P90, P50, P10 YTF volumes. These become end points for the forecast period, that are used to extrapolate the creaming curve. Iterating with the input parameters optimises forecasts with respect to the historical dataset. The approach can be extended to predict future field size distributions. Forecasts are made for the Bonaparte, Browse, Carnarvon and Perth Basins. The total P50 undiscovered gas resource for these basins for the next 15 years is estimated at 25.1 Tcf.


2011 ◽  
Vol 57 (206) ◽  
pp. 1017-1026 ◽  
Author(s):  
Tsutomu Uchida ◽  
Atsushi Miyamoto ◽  
Atsushi Shin’yama ◽  
Takeo Hondoh

AbstractAir-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.



1990 ◽  
Vol 8 (3) ◽  
pp. 245-257
Author(s):  
Emil D. Attanasi ◽  
Lawrence J. Drew


1995 ◽  
Vol 399 ◽  
Author(s):  
P. E. Quesenberry ◽  
P. N. First

ABSTRACTIsland size distributions have been derived from scanning tunneling microscope (STM) images of Ni deposited on cleaved GaAs(110) at room temperature and above. For submonolayer coverages, this system forms 3-dimensional (3-D) reacted islands with the degree of reaction dependent upon the growth temperature. As has been found for other systems, the average island size (sαυ) increases with temperature. The high temperature data (∼ 150° C) shows two distinct island types, each with substantially different average size. The island size distributions have maxima at the smallest island sizes. For different coverages, plots of the area-normalized island size distributions versus the scaled variable s/sαυ show significant differences. However, above a cutoff value for s/sαυ the distributions can be renormalized to fall on a common curve. These characteristics and direct atomic-scale evidence are consistent with nucleation of islands via adatom-substrate exchange, but the temperature dependence of the total island density appears to be inconsistent with this being the only first-order rate process taking place.



2002 ◽  
Vol 5 (02) ◽  
pp. 146-153 ◽  
Author(s):  
R.M. Jonkman ◽  
C.F.M. Bos ◽  
J.N. Breunese ◽  
D.T.K. Morgan ◽  
J.A. Spencer ◽  
...  

Summary On behalf of a group of sponsors consisting of the Norwegian Petroleum Directorate (NPD) and most E&P companies active in Norway, a work group was established to author a report on the best practices and methods in hydrocarbon resource estimation, production and emissions forecasting, uncertainty evaluation, and decision making. The work group is part of Norway's forum for Forecasting and Uncertainty evaluatioN (FUN). Following a detailed data acquisition and interviewing phase used to establish an inventory of the current practice of all sponsors involved, the work group postulated a relationship between a company's practices and its economic performance. A key distinguishing factor between companies is the degree to which probabilistic methods are adopted in integrated multidisciplinary processes aimed at supporting the decision-making process throughout the asset life cycle and portfolio of assets. Companies have been ranked in terms of this degree of integration, and best practices are recommended. In many companies, a gap seems to exist between available and applied technology. Data and (aggregated) information exchange between governments and companies is also discussed. A best practice based on their respective decision-making processes is recommended. Introduction FUN1 was established in 1997 and has 18 member companies, in addition to NPD. The forum is a Norwegian Continental Shelf (NCS) arena used to determine best practices and methods for hydrocarbon resource and emissions estimation, forecasting uncertainty evaluation, and decision making. It focuses on matters related to forecasting and uncertainty evaluation of future oil and gas production. Its main purpose is to optimize the interplay between the private industry and the national authorities wishing to regulate their national assets. The basic question that began the FUN Best Practices project was whether the accuracy of Norway's historical production forecasts has been disappointing because of erroneous contributions from the companies or because of wrong aggregation by NPD. Which best practices could improve this situation? Whereas reserves form the basis for production, capital expenditures, operating expenditures, and emissions forecasting, the decision-making process in the various companies and national authorities links the various components together. Using the latest guidelines created by SPE, the World Petroleum Congresses (WPC), and the American Assn. Of Petroleum Geologists (AAPG)2 for reserves reporting (allowing the use of probabilistic methods), the project concentrated on assessing the potential advantages of probabilistic techniques when used in combination with fully integrated asset management workflow processes. After a discussion of the current practices of the various companies and authorities visited, best practices are formulated in the fields of estimating reserves, production, costs and emissions forecasting, decision making, planning, and communications. The paper concludes with recommendations on how to move from the current practices to the desired best practices. Methodology of the Study The methodology used by the FUN Best Practices Team involved a series of interviews with:The Norwegian Operating Units of the oil companies sponsoring the project to obtain their views on the current practices.The Norwegian authorities.The headquarters of several major oil companies to obtain their views on best practices in production and emissions forecasting and decision making.Government officials in other major oil- or gas-producing countries to learn from their experiences. The interview comments were analyzed, and a set of best practices was formulated. A project currently in progress concentrates on disseminating the best practices through workshops and elearning combined with classical training courses. Current Practices Reserves Estimation. All companies trading on the New York Stock Exchange (NYSE) use the U.S. Securities and Exchange Commission (SEC) reporting standards, which are encumbered with anomalies as to changes in (end-year) oil prices, novel contracts (production sharing), and a modification for North Sea fields (by exception). They are difficult to change because such changes would have consequences for financial reporting by means of the (unit of production) depreciation of capital assets by the oil companies. Most companies adhere to the SEC rules for reporting proved reserves as a single, deterministic number. Commonly, however, probabilistic methods are used internally; only recently did a few governments start to ask for probabilistic reserves reporting from the companies. In response, SPE, WPC, and AAPG have formulated guidelines that include the option for probabilistic reserves reporting. The standard adopted by NPD3 relates reserves to their maturity and is, with a few minor modifications, eminently suitable to be linked with business processes, as is done internally by several oil companies. It appears that, for a number of companies, the NPD classification is not too different from the systems used internally, which are indeed linked, in some cases, to a business process. For some companies with simpler classifications, additional work will be required to comply with the NPD standards. In Table 1, the various standard classifications and those used by the companies are compared.





1980 ◽  
Vol 1 ◽  
pp. 103-112 ◽  
Author(s):  
W. F. Budd ◽  
T. H. Jacka ◽  
V. I. Morgan

The melt rates of Antarctic icebergs derived by Morgan and Budd (1978) were based primarily on the distribution of iceberg concentrations, data on iceberg size distribution being limited. Recently, more detailed data have been obtained, especially north of lat. 60°S which allow more precise calculations of the changes in size during drifting. On Australian National Antarctic Research Expedition (ANARE) voyages each summer since 1977, observations of icebergs have included photographs, number per unit area from ship’s radar, widths, heights, and shapes. These data have allowed separate calculations to be made for tabular icebergs which give a clearer indication of the contribution to average size changes of melting, breakage, and rollover. New data from satellite transponders placed on icebergs have provided more definite estimates of the average northward and then eastward drift rates of icebergs near 90°E. Combined with the new data on size more accurate melt rates have been derived. Detailed measurements with expendable bathy-thermographs (XBT) along the shipping routes have provided more definite data on water temperature which allow the melt rates to be studied as a function of temperature. Historical data on iceberg locations have been used to estimate the melt and decay rates of the icebergs at higher temperatures.



Author(s):  
Emre Tatli ◽  
Nigel N. Clark ◽  
Richard J. Atkinson ◽  
Gregory J. Thompson

Researchers concerned both with diesel exhaust health effects and with mechanisms of particulate matter (PM) formation have an interest in gaining understanding of PM size distributions from heavy-duty on-road diesel engines. Prior research has been done on particulate size measurement but the results fall short in understanding PM size distributions because of the response time or size range of the instruments used. This study reports the transient size distributions of PM from a 1992 Detroit Diesel Series 60 on an engine dynamometer from a full flow dilution tunnel for a FTP Transient Cycle using a Cambustion ® Differential Mobility spectrometer (DMS 500). The size bins selected for this study for the nucleation and accumulation modes were 20nm and 60nm bins, respectively. The accumulation mode during the accelerations and the nucleation mode during the decelerations were clearly observed from the distributions with respect to time. Distributions were also observed during the test cycle showing the transition between the two modes. From the results obtained from the analysis, no strong correlation between the 60nm particles and engine speed was observed even though higher counts of accumulation particles were observed at the same time that the vehicle activity occurred. Similarly, there was no correlation between the accumulation mode particles and power. When the distributions of nucleation and accumulation mode particles were plotted against each other, there was no correlation or anti-correlation. The average size distributions were also analyzed during the four periods of the FTP Transient cycle and the highest counts were observed during the Los Angeles Freeway (LAF) period. Also, higher counts at the second New York Non Freeway (NYNF) were observed during the cycle.



Sign in / Sign up

Export Citation Format

Share Document