V/sub p//V/sub s/: a potential hydrocarbon indicator. [Incorporation of P wave data to detect zones of gas saturation]

Conference · Fri Oct 01 04:00:00 EDT 1976 · Geophysics; (United States)

OSTI ID:7247333

Tatham, R H; Stoffa, P L

Theoretically and experimentally, the shear-wave velocity of a porous rock has been shown to be less sensitive to fluid saturants than the compressional wave velocity. Thus, observation of the ratio of the seismic velocities for waves which traverse a changing or laterally varying zone of undersaturation or gas saturation could produce an observable anomaly which is independent of the regional variation in compressional wave velocity. One source of shear-wave data in reflection seismic prospecting is mode conversion of P waves to shear waves in marine areas of high water bottom P-wave velocity. A relatively simple interpretative technique, based on amplitude variation as a function of the angle of incidence, is a possible discriminant between shear and multiple compressional arrivals, and data for a real case are shown. A normal moveout velocity analysis carefully coupled with this offset discriminant leads to the construction of a shear-wave reflection section which can then be correlated with the usual compressional wave section. Once such a section has been constructed, the variation in the ratio of the seismic velocities can be mapped, and potentially anomalous subsurface regions observed.

• Research Organization: Texaco Inc., Bellaire, TX
• OSTI ID: 7247333
• Conference Information: Journal Name: Geophysics; (United States) Journal Volume: 41:5
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580203 -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
DATA ANALYSIS
EXPLORATION
GEOLOGIC DEPOSITS
GEOPHYSICAL SURVEYS
NATURAL GAS DEPOSITS
OFFSHORE OPERATIONS
RESOURCES
SEISMIC P WAVES
SEISMIC S WAVES
SEISMIC SURVEYS
SEISMIC WAVES
VELOCITY
WAVE PROPAGATION