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One role of the petrophysicist is to characterize the fluids encountered in the reservoir. Detection of a change in fluid type in the rocks while drilling is usually straightforward with the use of gas and chromatographic measurements. Gas shows and oil shows while drilling are time-honored indicators of zones that need further investigation through logs, testers, and cores. In the rare case of gas-bearing, high-permeability rock drilled with high overbalance, gas will be flushed from the rock ahead of the bit, will not be circulated to the surface in the mud, and will not produce a gas show. Because hydrocarbons are not always part of a water-based-mud formulation, sophisticated analytical chemical techniques can be used on the oil and gas samples circulated to the surface and captured to determine the properties of hydrocarbons in a given zone penetrated by the drill bit.
Moridis, G.J.. J. (Lawrence Berkeley National Laboratory) | Collett, T.S.. S. (US Geological Survey) | Pooladi-Darvish, M.. (Fekete Associates and University of Calgary) | Hancock, S.. (RPS Group) | Santamarina, C.. (Georgia Institute of Technology) | Boswell, R.. (US Department of Energy) | Kneafsey, T.. (Lawrence Berkeley National Laboratory) | Rutqvist, J.. (Lawrence Berkeley National Laboratory) | Kowalsky, M.B.. B. (Lawrence Berkeley National Laboratory) | Reagan, M.T.. T. (Lawrence Berkeley National Laboratory) | Sloan, E.D.. D. (Colorado School of Mines) | Sum, A.K.. K. (Colorado School of Mines) | Koh, C.A.. A. (Colorado School of Mines)
Given the sheer magnitude of the resource, ever-increasing global energy demand, and the finite volume of conventional fossil-fuel The current paper complements the Moridis et al. (2009) review resources, GHs are emerging as a potential energy source of the status of the effort toward commercial gas production for a growing number of nations. The attractiveness of GH is from hydrates. We aim to describe the concept of the gas-hydrate further enhanced by the environmental desirability of natural gas, (GH) petroleum system; to discuss advances, requirements, and as it has the lowest carbon intensity of all fossil fuels. Thus, the suggested practices in GH prospecting and GH deposit characterization; appeal of GH accumulations as future hydrocarbon-gas sources is and to review the associated technical, economic, rapidly increasing and their production potential clearly demands and environmental challenges and uncertainties, which include technical and economic evaluation. The past decade has seen a the following: accurate assessment of producible fractions of the marked acceleration in GH research and development (R&D), GH resource; development of methods for identifying suitable including both a proliferation of basic scientific endeavors and the production targets; sampling of hydrate-bearing sediments (HBS) strong emergence of focused field studies of GH occurrence and and sample analysis; analysis and interpretation of geophysical resource potential, primarily within national GH programs (Committee surveys of GH reservoirs; well-testing methods; interpretation of on Assessment 2010). Together, these efforts have helped well-testing results; geomechanical and reservoir/well stability to clarify the dominant issues and challenges facing the extraction concerns; well design, operation, and installation; field operations of methane from GHs. and extending production beyond sand-dominated GH reservoirs; A review paper by Moridis et al. (2009) summarized the status monitoring production and geomechanical stability; laboratory of the effort for production from GHs. The authors discussed the investigations; fundamental knowledge of hydrate behavior; the distribution of natural GH accumulations, the status of the primary economics of commercial gas production from hydrates; and international R&D programs (including current policies, focus, associated environmental concerns.
Moridis, G. J. (Lawrence Berkeley National Laboratory) | Collett, T. S. (US Geological Survey) | Pooladi-Darvish, M.. (University of Calgary and Fekete) | Hancock, S.. (RPS Group) | Santamarina, C.. (Georgia Institute of Technology) | Boswell, R.. (US Department of Energy) | Kneafsey, T.. (Lawrence Berkeley National Laboratory) | Rutqvist, J.. (Lawrence Berkeley National Laboratory) | Kowalsky, M.. (Lawrence Berkeley National Laboratory) | Reagan, M. T. (Lawrence Berkeley National Laboratory) | Sloan, E. D. (Colorado School of Mines) | Sum, A. K. (Colorado School of Mines) | Koh, C.. (Colorado School of Mines)
Abstract The current paper complements the Moridis et al. (2009a) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas hydrate petroleum system, to discuss advances, requirement and suggested practices in gas hydrate prospecting and GH deposit characterization, and to review the associated technical, economic and environmental challenges and uncertainties, including: the accurate assessment of producible fractions of the GH resource, the development of methodologies for identifying suitable production targets, the sampling of hydrate-bearing sediments and sample analysis, the analysis and interpretation of geophysical surveys of GH reservoirs, well testing methods and interpretation of the results, geomechanical and reservoir/well stability concerns, well design, operation and installation, field operations and extending production beyond sand-dominated GH reservoirs, monitoring production and geomechanical stability, laboratory investigations, fundamental knowledge of hydrate behavior, the economics of commercial gas production from hydrates, and the associated environmental concerns.
Parameters in Archie''s equation are usually determined in labs through experiments on the electric properties of rocks. We discuss a new method using saturation analysis data to determine the parameters. Correlations among saturation, resistivity, and porosity derived from the two Archie equations convert calculation for values of electric parameters to a problem of calculation for the coefficients of an equation with several unknowns. Based on calculation and study on actual saturation analysis data in several oilfields in the Junggar basin, the calculated parameters are all within the theoretical range. which can be used to obtain a water saturation value using logging data. We discuss the factors that influence Archie''s parameters, especially the influence of petrophysical properties and wettability. This can be proved using saturation analysis data for a wide range of Archie''s parameters. Archie''s parameters determined through electric property experiments can''t prove this. More importantly, to determine Archie''s parameters using saturation analysis data makes it unnecessary to calculate the resistivity of the formation water, Saturation should be measured in well preserved core since large errors can exist between the measured values and the original values due to degasification and volatilization. This will influence the effectiveness of the saturation data. Therefore, the key to the problem is to correct the measured saturation values.
This paper describes a well-based analysis program, written in the C programming language, called "Quantitative Petrophysical and Seismic Evaluation Technique'''' (QPSET). The program is designed to accomplish the evaluation of reservoir parameters in shaly-sand sedimentary sections in marginal hydrocarbon zones. The program flow is designed to complete an analysis in a single pass and uses two modified approaches for the evaluation of water saturation and acoustic impedance. Output values are stored in ASCII format and are therefore available for plotting in any graphic software package. Either the user selects the precise analysis algorithms employed, or they may be restricted by the data available. This paper reports results obtained using the program on data from seven wells located in the northern portion of the Gulf of Suez Rift Basin, spanning the Lower Middle Miocene Rudeis sedimentary section. (Rudeis thickness ranges from 500 ft. to 5000 ft. within the basin.) The program has successfully characterized the essential features of the Rudeis and permits some speculation as to the depositional environment for the sediments and the tectonic setting of the basin at the present day. In this latter regard, it is stressed that other information is required before adequate interpretations can be established.