Geo-Constrained
Real Time Model Update (RTMU) While Drilling of the 3D Structural Framework
Model
Jones, Serena1, Simon Stewart2,
Stuart Bland3, Norman Armstrong1, Robert Humphreys4,
Michael Doe5 (1) Midland Valley, Glasgow, United Kingdom (2) BP
Azerbaijan, Sunbury on Thames, United Kingdom (3) Statoil ASA, 9481 Harstad,
Norway (4) BP Exploration, United Kingdom (5) Midland Valley Exploration,
Golden
Geological models often contain
uncertainties. During drilling, anticipated stratigraphic tops are often located
higher or lower and with different orientations than the current model. These
geometric modifications to the model mean that the drilling targets are likely
to change in morphology and position. The integration of dynamic structural
modelling tools and LWD data enables RTMU of the 3D structural framework model
while drilling enhancing the well placement and steering workflow. The
modelling workflow is as follows:
1) Acquisition of tops and orientation
data from LWD. 2) Reshaping of the 3Dmodel, including drilling targets to honor
new data. 3) Interrogation of the new model geometry providing well-steering
feedback.
Structural geometric algorithms at the
core of the model-reshaping tool make it possible for the 3D model to be
intrinsically ‘linked' to the reshaping of a horizon. Horizons and faults
carried during reshaping will retain the structural integrity and stratigraphic
coherency of the model. The technique supports minor and major changes to the
model geometry while the data can be as little as a single well top or a
modified section line.
A case study from a compressional
prospect is presented. The seismic image is obscured and unclear due to various
reasons including steep dips, the structural detail of the target is therefore
uncertain. Use of this workflow added significant value to the drilling
program.
Geo-constrained RTMU while drilling is
widely applicable. Minor and major changes to the 3D model require precise
interrogation of the new target positioning and geometry for geo-steering
feedback.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California