Epithermal neutron porosity measurement

Patent · Tue Jan 20 04:00:00 EST 1987

OSTI ID:6905250

Smith, H D; Verbout, J L

A method is described for determining the porosity of earth formations in the vicinity of a well borehole passing therethrough, comprising: (a) emitting, in a portion of the borehole substantially adjacent the formations of interest, repetitive relatively short duration with respect to a typical epithermal neutron decay time constant pulses of fast neutrons for moderation to epithermal energies by interaction with nuclei of materials in the borehole and surrounding earth formations. Repetitive bursts of populations of epithermal neutrons are hereby created in the borehole and surrounding earth formations, (b) detecting epithermal neutrons at a longitudinally spaced distance in the borehole during at least two non-overlapping predetermined time intervals, and (c) generating at least two count rate signals by generating, during at least two time intervals, corresponding count rate signals representative of the corresponding epithermal neutron populations.

• Assignee: Halliburton Co., Duncan, OK
• Patent Number(s): US 4638161
• OSTI ID: 6905250
• 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
BARYONS
BOREHOLES
CAVITIES
DECAY
DEPTH
DIMENSIONS
ELEMENTARY PARTICLES
EPITHERMAL NEUTRONS
FAST NEUTRONS
FERMIONS
GEOLOGIC DEPOSITS
HADRONS
MATHEMATICS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NEUTRON LOGGING
NEUTRONS
NUCLEI
NUCLEONS
PETROLEUM DEPOSITS
POROSITY
PULSES
RADIOACTIVITY LOGGING
RESOURCES
SIGNALS
SPACE DEPENDENCE
STATISTICS
TIME DEPENDENCE
WELL LOGGING