Peer Reviewed Journal via three different mandatory reviewing processes, since 2006, and, from September 2020, a fourth mandatory peer-editing has been added.
The oil and gas industry routinely uses borehole tools for measuring
or logging rock and fluid properties of geologic formations to
locate hydrocarbons and maximize their production. Pore fluids
in formations of interest are usually hydrocarbons or water. Resistivity
logging is based on the fact that oil and gas have a substantially
higher resistivity than water. The first resistivity log
was acquired in 1927, and resistivity logging is still the foremost
measurement used for drilling and evaluation. However, the acquisition
and interpretation of resistivity logging data has grown
in complexity over the years.
Resistivity logging tools operate in a wide range of frequencies
(from DC to GHz) and encounter extremely high (several orders
of magnitude) conductivity contrast between the metal mandrel
of the tool and the geologic formation. Typical challenges
include arbitrary angles of tool inclination, full tensor electric
and magnetic field measurements, and interpretation of complicated
anisotropic formation properties. These challenges combine
to form some of the most intractable computational electromagnetic
problems in the world. Reliable, fast, and convenient
numerical modeling of logging tool responses is critical
for tool design, sensor optimization, virtual prototyping,
and log data inversion. This spectrum of applications necessitates
both depth and breadth of modeling software—from blazing
fast one-dimensional (1-D) modeling codes to advanced threedimensional
(3-D) modeling software, and from in-house developed
codes to commercial modeling packages.
In this paper, with the help of several examples, we demonstrate
our approach for using different modeling software to address
different drilling and evaluation applications. In one example,
fast 1-D modeling provides proactive geosteering information
from a deep-reading azimuthal propagation resistivity measurement.
In the second example, a 3-D model with multiple vertical
resistive fractures successfully explains the unusual curve separations
of an array laterolog tool in a shale-gas formation. The third
example uses two-dimensional (2-D) and 3-D modeling to prove
the efficacy of a new borehole technology for reservoir monitoring.
