Print this pageGeoscience Technology in the Planning, Drilling, and Post-Drilling Evaluation of Horizontal Wells
MATHISEN, MARK E.
Increasing horizontal well (HW) activity and continuing technical advances
are leading to improvements in HW geoscience technology which increase
hydrocarbon recovery and reduce costs. This paper provides a review of the
geoscience technology necessary for the successful planning, drilling and
post-drilling evaluation of horizontal wells. Since different types of
geoscience 
data
and interpretation may be required during the various phases of
a HW program, the review is divided into planning, drilling and post-drilling
reservoir evaluation sections. In the planning section, the geoscience
technology necessary to define well objectives, location, target zone(s) and
well path is reviewed. Examples of the geoscience input, or variables to be
evaluated by reservoir modeling and simulation are also discussed. Once the well
path is chosen, aspects of drilling methods/materials needed to reach the
target, the need for a pilot hole and coring are discussed, followed by a review
of logging program tools, methods and limitations. Drilling phase geoscience
data include MWD/LWD/geosteering and mud log data, as well as the optional
acquisition of borehole seismic data. Drilling phase data acquisition and
geoscience interpretation require input
from an interdisciplinary team to guide
the bit to, and through, the desired reservoir zone. Post-drilling HW reservoir
evaluation includes the interpretation of commonly available MWD/LWD logs, the
optional acquisition and interpretation of MAD wireline logs, horizontal core
description and analysis, core-log calibration, reservoir seismic
interpretation, and the development of an integrated geoscience reservoir model.
Ongoing and future developments in HW geoscience technology are also discussed.