From amplitude anomalies to physical properties: A quantitative approach

Journal Article · Mon Oct 24 04:00:00 EDT 1994 · Oil and Gas Journal; (United States)

OSTI ID:6851278

Murayama, Ryuhei ^[1]

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1. Japan National Oil Corp., Chiba (Japan)

Seismic amplitude anomalies are important exploration targets for oil and gas. Bright spots and amplitude vs. offset (AVO) anomalies are especially attractive because the change of acoustic impedance suggested by a bright spot and the change of Poisson's ratio suggested by an AVO anomaly often relate to the existence of hydrocarbon. On the other hand, there are bright spots and AVO anomalies that do not related to hydrocarbon. Acoustic impedance and Poisson's ratio are not direct indicators of hydrocarbon; they are indirect indicators. One of the problems in evaluating seismic amplitude anomalies is that the understanding of physical properties of reservoirs is qualitative. Table 1 shows that each physical property is affected by four kinds of lithologies, but it does not show the effect of each lithology quantitatively. This article quantitatively investigates basic behaviors of acoustic impedance and Poisson's ratio by model calculation using modified Gassmann's equation. The modification of Gassmann's equation and the subsequent derivation of simplified expressions of acoustic impedance and (Vp/Vs)[sup 2], which directly relates to Poisson's ratio, are shown in the accompanying article. The purpose of modification and simplification is to give explorationists a handy tool to evaluate reservoir physical properties quantitatively.

• OSTI ID: 6851278
• Journal Information: Oil and Gas Journal; (United States), Journal Name: Oil and Gas Journal; (United States) Vol. 92:43; ISSN OIGJAV; ISSN 0030-1388
• 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
CLAYS
DATA ANALYSIS
DENSITY
EQUATIONS
EXPLORATION
FLUIDS
GEOLOGIC DEPOSITS
GEOLOGY
GEOPHYSICAL SURVEYS
LITHOLOGY
MINERAL RESOURCES
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
PETROLOGY
PHYSICAL PROPERTIES
POROSITY
RESERVOIR FLUIDS
RESERVOIR ROCK
RESOURCES
SATURATION
SEISMIC SURVEYS
SURVEYS
WATER SATURATION