Dual excitation acoustic paramagnetic logging tool

Patent · Tue Feb 14 00:00:00 EST 1989

OSTI ID:7271362

Vail, III, W B

New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be performed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described. 6 figs.

• DOE Contract Number: FG06-84ER13294
• Assignee: ParaMagnetic Logging, Inc., Woodinville, WA (United States)
• Patent Number(s): US 4804918; A
• Application Number: PPN: US 7-153061
• OSTI ID: 7271362
• Resource Relation: Patent File Date: 8 Feb 1988
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
OIL WELLS
SONIC LOGGING
RESERVOIR ROCK
PARAMAGNETISM
WELL LOGGING EQUIPMENT
DESIGN
OPERATION
AQUIFERS
CONCENTRATION RATIO
RESERVOIR FLUIDS
VISCOSITY
EQUIPMENT
FLUIDS
MAGNETISM
WELL LOGGING
WELLS
020200* - Petroleum- Reserves
Geology
& Exploration
400400 - Electrochemistry