A composite lithology log while drilling

Conference · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6083279

Tannenbaum, E; Sutcliffe, B; Franks, A

A new method for producing a computerized composite lithology log (CLL) while drilling by integrating MWD (measurement while drilling) and surface data is described. At present, lithology logs are produced at the well site by mud loggers. They provide basic description and relative amounts of lithologies. Major difficulties are encountered in relating the cuttings to their original formations due to mixing in the drilling mud while transporting to the surface, sloughing shales, flawed sampling, etc. This results in a poor control on the stratigraphic sequence and on the depth of formation boundaries. A composite log can be produced after drilling this additional inputs such as wireline, petrography, and paleontology. This process is labor intensive and expensive. The CLL integrates three types of data (MWD mechanical, MWD geophysical, and surface cuttings) acquired during drilling, in three time stages: (1) Real Time. MWD drilling mechanical data including the rate of penetration and the downhole torque. This stage would provide bed boundaries and some inferred lithology. This would assist the driller with immediate drilling decisions and determine formation tops for coring, casing point, and correlation. (2) MWD Time. Recomputation of the above by adding MWD geophysical data (gamma-ray, resistivity, neutron-density). This stage would upgrade the lithology inference, and give higher resolution to bed boundaries, (3) Lag Time. Detailed analysis of surface cuttings to confirm the inferred lithologies. This last input results in a high-quality CLL with accurate lithologies and bed boundaries.

• OSTI ID: 6083279
• Report Number(s): CONF-880301-
• 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
99 GENERAL AND MISCELLANEOUS
990220 -- Computers
Computerized Models
& Computer Programs-- (1987-1989)
COMPUTERIZED SIMULATION
ELECTRIC LOGGING
EXPLORATION
EXPLORATORY WELLS
GAMMA LOGGING
GEOLOGIC DEPOSITS
GEOLOGIC MODELS
GEOPHYSICS
LITHOLOGY
MINERAL RESOURCES
MWD SYSTEMS
NATURAL GAS DEPOSITS
NEUTRON LOGGING
PETROLEUM DEPOSITS
RADIOACTIVITY LOGGING
RESERVOIR ROCK
RESISTIVITY LOGGING
RESOURCES
SIMULATION
WELL LOGGING
WELLS