Variable [Sigma]-matrix method to compensate for the influence of shaliness on pulsed-neutron-capture log response

Journal Article · Mon Feb 28 23:00:00 EST 1994 · SPE Formation Evaluation (Society of Petroleum Engineers); (United States)

DOI:https://doi.org/10.2118/24738-PA· OSTI ID:7115902

Neuman, C H ^[1]

---

1. Chevron U.S.A. Production Co., New Orleans, LA (United States)

An important limitation in applying pulsed-neutron-capture (PNC) logs to measure fluid saturation is the imperfect correction for the influence of rock-matrix shaliness. Most methods for calculating saturations when log data are influenced by shaliness use gamma ray response to divide the [Sigma] measured into clean sand and shale components. The nonlinear relation between wall volume and fractional gamma ray response commonly assumed results in significantly smaller correction for intermediate shaliness than would a linear relationship. This paper presents core data that support the idea that [Sigma][sub ma] varies almost linearly with gamma ray response. A simple method to compensate for shaliness is proposed that uses gamma ray response to predict composite [Sigma][sub ma] rather than dividing the rock matrix into sand and shale components.

• OSTI ID: 7115902
• Journal Information: SPE Formation Evaluation (Society of Petroleum Engineers); (United States), Journal Name: SPE Formation Evaluation (Society of Petroleum Engineers); (United States) Vol. 9:1; ISSN 0885-923X; ISSN SFEVEG
• 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
CALCULATION METHODS
DATA ANALYSIS
GAS SATURATION
GEOLOGIC DEPOSITS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NEUTRON LOGGING
OIL SATURATION
PETROLEUM DEPOSITS
RADIOACTIVITY LOGGING
RESOURCES
SATURATION
WELL LOGGING