Organized Petrophysical Field Study
William R. Berry
Throughout the oil and gas industry, increasing emphasis is being placed on
accurate reservoir
description through the medium of petrophysical field
studies. A petrophysical field study can be defined as "an assessment of the
lithologic, volumetric, and fluid properties of a
reservoir
." A petrophysical
field study integrates geological, engineering, and petrophysical data to obtain
a meaningful and accurate appraisal of
reservoir
properties. The increasing
availability of log and core data in existing or developing fields provides a
data base from which quantification of
reservoir
properties can be predicted.
These predictions are of value in the ongoing development of discovered fields,
the evaluation of enhanced oil recovery simulations, the development of
exploration s rategies, and other economically significant pursuits. The
accuracy of such studies can only be assured when adequate geologic input has
been provided. The petrophysical evaluation team must create mathematical models
in a computer environment that satisfactorily relate raw sensor measurements,
human observations, and laboratory measurements. The mathematical model must be
calibrated with geologic knowledge of the
reservoir
. Of primary concern to the
evaluation team are parameters influencing geologic phenomena. These include
grain size, pore geometry, clay type, cement in the matrix pore system, fracture
mechanisms
, cement in the fracture system, formation water condition, facies
types, facies changes, depositional environment, and zone correlations.
AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.