Innovative solution drills one of the longest slim sections (5,500 feet) on Norwegian Continental Shelf
CHALLENGE – In the previous operation of this ERD well, an expandable liner had been set to address formation instability. This expandable liner created a challenge, since the liner’s internal diameter was only 5.795 inches, which is extremely narrow. The wellbore’s narrow opening required a slim-version drill bit and the rotary steerable system (RSS) BHA also had to be engineered to successfully pass through this narrow opening in order to reach total depth (TD). An opening this narrow presented quite a challenge because the smallest wellbore size that Sperry Drilling had ever drilled with an RSS BHA was 57⁄8 inches in diameter. This would be the first time globally that Sperry Drilling had ever drilled with an RSS BHA in such a small 5¾-inch wellbore size. Another challenge for this operation included designing an RSS BHA with the right size of logging-while-drilling (LWD) stabilizers that would still be reliable and capable of logging the section. Additionally, the Sperry Drilling team had to mobilize with this newly engineered solution within a very short time frame. Not only did the operator needed to drill and log this small-hole section, but the operator also needed to run a 5-inch liner to complete the well.
SOLUTION – Sperry Drilling applied the strength of its worldwide network of products and expertise to provide a solution for this narrow opening. In only three days, the Sperry Drilling team designed and mobilized a drilling system, including a 5¾-inch Halliburton polycrystalline diamond compact (PDC) drill bit that was flown in from another location. The Geo-Pilot® RSS parts required specifically for the 5¾-inch hole size were brought in from the U.S., and LWD stabilizers were modified locally.
All products and services were hand-selected for their suitability for this specific application. With the Halliburton 5¾-inch drill bit, Sperry Drilling used a reamer to open the hole to a 6½-inch diameter.
In addition to the 5200 Geo-Pilot RSS, Sperry Drilling used quad-combo LWD tools to provide all the measurements needed while drilling – including azimuthal density, neutron porosity, gamma, azimuthal deep resistivity, pressure while drilling (PWD), downhole weight and torque on bit, and formation pressure points from ALD™, CTN™, DGR™, ADR™, PWD, DrillDOC®, and GeoTap® sensors respectively.
Sperry Drilling also included the Drilling Engineering Solutions (DES) with Applied Drilling Technology (ADT® service) specialists from an onshore operational center to monitor and advise on drilling operations and parameters in real time for improved drilling efficiency. The optimization team also used the StrataSteer® 3D geosteering service and MaxBHA™ software in order to model and advise on the stabilization of the 5-inch liner run to TD.
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