Improvements In Reservoir Fracture Network Characterization Using High Resolution Logging While Drilling Resistivity Images In Extended Reach Wells Under High Stick Slip Conditions
Middle East carbonates frequently are heterogeneous in nature,
encompassing variable pore types, strong diagenetic overprints, variable
wettability and fracture networks amongst other effects. Resistivity borehole
images have long been an integral constituent to understanding their complexity
and unlocking volumes. High resolution LWD resistivity images were first
introduced in the 1990's, however as downhole environments became progressively
more challenging, resistivity images suffered from the dynamic acquisition
environment resulting in severely degraded images.
The Al Shaheen field has been developed with Extended Reach Drilling
(ERD) wells, and wells of 30,000 feet are commonplace. Early LWD resistivity
image data suffered from excessive stick and slip, with approximately half of
the wellbore suffering from poor quality image data, degrading with depth. The
outer portion of the wellbore is prohibitive to impossible to access via
conventional drill pipe conveyed tools, resulting in an absolute requirement
for high quality LWD resistivity images.
The new methodology redefines the acquisition and processing
methodology, resulting in images unaffected by stick slip with a 100% success
rate in the most challenging of ERD environments.
This paper illustrates the improvements in logging while drilling images
(LWD) and subsequent fracture network characterization as a result of
implementing a new image acquisition strategy and processing algorithm. The
paper explores the close collaboration necessary to drive the innovation to
dramatically enhance existing technology, and demonstrates the results with
comparisons of the LWD images using the old and new methodologies.