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Well: 2/7A-22
Operator: Phillips Petroleum Co.
Date: 10/11/2000
Location: North Sea - Eldfisk Alpha
Subject: Thuslick™ Test
Phillips Petroleum Company Norway
From: Arvid Mosnes, Senior Drilling Supervisor

Test of Thuslick™ Friction Reducer

       When drilling 8.5" section on Eldfisk Alpha well no. A-22 excessive drag and torque were experienced. This caused severe directional problems as steering and sliding became more and more difficult. Thuslick™ was added twice in 50 bbl pills with 4 PPB concentration, but with little or no improvement in sliding. When pills returned to surface we found that Thuslick™ plugged the screens. On the VSM 300 shakers we were running 240 as bottom screens to take out the majority of drilled chalk form the mud to keep mud weight as low as possible. As the pill of Thuslick™ returned screens were plugged and we had to change to 120 mesh screens to avoid losses. As a total of 400 lbs Thuslick™ was added to a circulation system of 1000 bbl it was not really expected to see any positive effect from these two Thuslick™ pills. A couple of days later severe losses were encountered and we could not keep up with mixing mud. As reservoir pressure is extremely low form depletion, an inexpensive mud of drill water with polymer normally used. Due to severe mud losses, we now changed to seawater only, without any additives. Losses leveled off at 200bbl/hr. while circulation at a rate of 800 bbl/hr. Now high and erratic torque was experienced, and Thuslick was added to the seawater.

Conclusions drawn from using Thuslick™ when drilling 8.5" chalk reservoir section was very positive and contributed greatly in completing the section as planned.

Thuslick™ plugged the shaker screens finer than 240 mesh. However, solids control equipment varies from rig to rig, and in many set-ups this is not representing any problem at all.

Positive findings:
Adding Thuslick™ had an immediate effect on drilling parameters. Torque was significantly reduced an made it possible to continue drilling to target. The reduced torque also resulted in increased ROP (Rate of Penetration), with less WOB (Weight on Bit). Even when we stopped adding Thuslick™ for some time, the torque remained low, indicating that Thuslick™ had successfully added a lasting coating in the well bore and casing.

It is beyond any doubt, that Thuslick™ was
extremely efficient in this application,
and it may well have been one of the
main contributors in TDing the well as per plan.

       To fully find out about Thuslicks™ qualities, more test will have to be carried out with different mud systems and in other hole sections.

Yours truly,
Phillips Petroleum Company Norway
Arvid Mosnes
Senior Drilling Supervisor

       The problem associated with shaker screens plugging was extensively examined and found not to be related to Thuslick™. Thuslick™ has a particle size distribution below 70 microns and will not plug shaker screens.