Well log evaluation of natural gas hydrates
Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.
- Research Organization:
- US Geological Survey, Denver, CO (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AI21-83MC20422
- OSTI ID:
- 6824342
- Report Number(s):
- DOE/MC/20422-3319; ON: DE93000255
- Country of Publication:
- United States
- Language:
- English
Similar Records
Natural gas hydrates on the North Slope of Alaska
METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST
Related Subjects
47 OTHER INSTRUMENTATION
NATURAL GAS HYDRATE DEPOSITS
WELL LOGGING
EVALUATION
GAS HYDRATES
METHANE
NUMERICAL DATA
POROSITY
RESOURCE ASSESSMENT
WATER SATURATION
ALKANES
DATA
GEOLOGIC DEPOSITS
HYDRATES
HYDROCARBONS
INFORMATION
ORGANIC COMPOUNDS
SATURATION
030200* - Natural Gas- Reserves
Geology
& Exploration
440400 - Well Logging Instrumentation