Accurate hydrocarbon estimates attained with radioactive isotope
To make accurate economic evaluations of new discoveries, an oil company needs to know how much gas and oil a reservoir contains. The porous rocks of these reservoirs are not completely filled with gas or oil, but contain a mixture of gas, oil and water. It is extremely important to know what volume percentage of this water--called connate water--is contained in the reservoir rock. The percentage of connate water can be calculated from electrical resistivity measurements made downhole. The accuracy of this method can be improved if a pure sample of connate water can be analyzed or if the chemistry of the water can be determined by conventional logging methods. Because of the similarity of the mud filtrate--the water in a water-based drilling fluid--and the connate water, this is not always possible. If the oil company cannot distinguish between connate water and mud filtrate, its oil-in-place calculations could be incorrect by ten percent or more. It is clear that unless an oil company can be sure that a sample of connate water is pure, or at the very least knows exactly how much mud filtrate it contains, its assessment of the reservoir's water content--and consequently its oil or gas content--will be distorted. The oil companies have opted for the Repeat Formation Tester (RFT) method. Label the drilling fluid with small doses of tritium--a radioactive isotope of hydrogen--and it will be easy to detect and quantify in the sample.
- Research Organization:
- The Oilman
- OSTI ID:
- 5632798
- Journal Information:
- Sea Technol.; (United States), Vol. 24:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
03 NATURAL GAS
54 ENVIRONMENTAL SCIENCES
CONNATE WATER
RADIOACTIVE TRACER LOGGING
NATURAL GAS
RESERVES
NATURAL GAS DEPOSITS
RESOURCE ASSESSMENT
PETROLEUM
PETROLEUM DEPOSITS
RESERVOIR ROCK
TRITIUM
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC DEPOSITS
GROUND WATER
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INTERSTITIAL WATER
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MINERAL RESOURCES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
RADIOACTIVITY LOGGING
RADIOISOTOPES
RESOURCES
TRACER TECHNIQUES
WATER
WELL LOGGING
YEARS LIVING RADIOISOTOPES
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration
520101 - Environment
Aquatic- Basic Studies- Radiometric Techniques- (-1989)