Deep penetration well logging system and method using secondary electromagnetic fields

Patent · Tue Nov 11 04:00:00 EST 1986

OSTI ID:7077357

Cox, P T; Warren, W F; Johnson, Jr, D L

A well logging method is described for determining the dielectric constant and/or conductivity of earth formations, some of which has fluid invasion, in the vicinity of a well borehole comprising the steps of: transmitting electromagnetic energy into the earth formation from a first location in a borehole at a frequency within a frequency range of 10 MHz to 60 MHz, receiving transmitted electromagnetic energy at second, third and fourth locations in a borehole, where the second locations is a predetermined distance from the first location. The third location is at a greater predetermined distance from the first location than the second location and the fourth location is a greater predetermined distance from the first location than the third location, providing signals representative of total electromagnetic fields at the receiving locations in accordance with the received energy, deriving a secondary field ratio from portions of the signals representative of the secondary electromagnetic fields at the second and third locations, deriving a first phase difference between the signals representative of the total electromagnetic fields at the third and fourth locations, and deriving a second phase difference between the signals representative of the total electromagnetic fields at the second and third locations, and determining the dielectric constant and/or resistivity of the earth formations in accordance with the derived secondary field ratio and at least one of the derived phase differences.

• Assignee: Texaco, Inc., White Plains, NY
• Patent Number(s): US 4622518
• OSTI ID: 7077357
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
BOREHOLES
CAVITIES
DEPTH
DIELECTRIC PROPERTIES
DIMENSIONS
DISTANCE
ELECTRIC CONDUCTIVITY
ELECTRIC LOGGING
ELECTRICAL PROPERTIES
ELECTROMAGNETIC FIELDS
EQUIPMENT
FREQUENCY RANGE
GEOLOGIC DEPOSITS
INDUCTION LOGGING
MHZ RANGE
MHZ RANGE 01-100
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
PHYSICAL PROPERTIES
RESISTIVITY LOGGING
RESOURCES
SIGNALS
WELL LOGGING
WELL LOGGING EQUIPMENT