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
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.
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.