First Sildril-K trial in Russia. Background. Region:Western Siberia, Russia Oil field:Samotlor Operator:TNK-Nizhnevartovsk Drilling contractor:NBN Drilling rig:BU-3000EUK (Russian) Solids control:2 linear shake shakers (Russian) mesh 1 mud cleaner (Russian) 1 centrifuge (Brandt) Well profile:Deviated, 16.5° max. Hole size:8.5” Interval:820 to 2694 m. TD (1874 m. to drill) Formation:Low permeable sandstone ( mD) 6.4 m. Formation pressure:Close to hydrostatic Problems:  Gumbo clays, sloughing shale, bit balling  High dilution, excessive mud build-up  Excessive mud weight  High LGS contamination, poor drill-in properties  Limited rig pit capacity  Environmental issues

First Sildril-K trial in Russia. Design criteria. The system must be recommended and used as a drill-in fluid High resistivity was required for open hole logging (above 1,0 Omxm) High level of inhibition was required to control gumbo clays High solids tolerance was required to compensate poor solids control Drilling fluid formulation must be simple to reduce mixing and maintenance cost Drilling fluid should offer low dilution ratio and hole washout to reduce WM cost Low fluid loss and good lubricity to minimize differential sticking The mud must be re-used on the next well Low toxicity is a plus Simplifies formulation No KCL/chlorides Best inhibition available Extreme LGS tolerance High filtrate resitivity Good ret.perm. results Twice as expensive vs sodium sil. Liquid product only High viscosity at low temperatures Why potassium silicate? +-

First Sildril-K trial in Russia. Properties and testing. PropertyLab initialLab heat agedField actual MW, SG PV, cps YP, lbs/100ft sec. gel, lbs/100ft min. gel, lbs/100ft RPM634-6 API F/L, cc/30min pH Resistivity, Ohm/m Mud properties Return permeability results Initial permeability4.7 mD Return permeability4.4 mD % return94% Pressure overbalance50 bar Temperature+90C Clean-up time2 hours

First Sildril-K trial in Russia. Formulation. 1.Crosfield K-78 liquid potassium silicate4% v/v active 2.Polypac ELV4.5-5 ppb. 3.Duovis ppb. 4.Calcium Carbonate20 ppb. 4 products ONLY! Formulation was tested on Stavanger prior to trial, including return permeability tests using actual cores from TNK.

First Sildril-K trial in Russia. Success. No formation damage. Instant clean-up. No drilling problems. Almost twice less mud volume was required (250 m 3 vs. ~400 m 3 ). Dilution ratio – 2.6 vs. ~5 on the offset wells. Saved 2 drilling days (+20% to ROP). Saved 2 bits / bit runs (+40% to bit life). Almost no washout. Excellent cement job. Excellent system stability and solids tolerance. Most of the mud was re-used on the next well. Initial production – 60 MT/day Skin-factor – -5

First Sildril-K trial in Russia. Futures. Still need to increase filtrate resistivity (above 0,5 Omxm at BH conditions) Powder form 5 wells (Na-Silicates) 1H, 2002 (contracts concluded) Spread the success over others Siberian operators. Required reservoir engineering involvement Potential “universal”* systems area market: wells/years * Glydrills, Ca base systems (Ultradrill), Modified silicates etc..