Soltex® Additive Case Histories

Case History #1 - Soltex® Additive Shale Inhibitor Provides Operator Good Gauge Hole

One of the world’s largest oil companies made a very important discovery about Soltex® additive shale inhibitor. The discovery occurred during in-field drilling of four wells (#41, #43, #44 and #45) in south Montgomery County, Texas. These wells were less than one mile apart, all drilled to a TD of 13,000 ft through essentially the same formations.

Well #41 was drilled out from under surface with a 9 7/8 inch bit. Caliper logs showed the well experienced 5- to 13-inch hole washouts between 7,000 and 11,000 ft. A basic field mud was used in the well.

Well #43 was drilled out from under surface pipe with a 7 7/8 inch bit. At 8,000 ft, 3.0 lb/bbl blown asphalt was added to the mud with an asphalt emulsifier for activation. The asphalt concentration was increased to about 4.0 lb/bbl at 9,000 ft and then to 6.0 lb/bbl at 12,000 ft. The results were less than satisfactory, with hole washouts staying between 4 to 8 inches out of gauge throughout most of the wellbore.

Well #44 had 4.0 lb/bbl Soltex® additive added at 8,200 ft. This concentration was maintained until 11,000 ft. No additional additive was needed, and the concentration declined to about 1.0 lb/bbl by 13,000 ft. The caliper log on this well showed 2 inches or less hole erosion all the way to TD.

Well #45 had the hole fall in between 7,700 and 8,400 ft. At 8,400 ft, 4.0 lb/bbl Soltex® additive was added, and the product concentration reached 7.5 lb/bbl at 9,800 ft. The caliper log shows that Soltex® additive not only reclaimed the well, but actually reduced hole washout from 12 inches down to 2 inches over gauge in less than 200 ft.

Case History #2 - Liquid Soltex® Additive- Lubricity, Shale and HTHP Control

An independent oil and gas company operating in the Gulf of Mexico successfully used Liquid Soltex® additive for lubricity, shale and HTHP control. Two lb/bbl Liquid Soltex® additive were first added to the mud at 12,500 ft, and this concentration was maintained to TD at 14,830 ft.

By adding Liquid Soltex® additive to this section of the hole, the API filtrate dropped slightly from 3.4 mL to 2.8 mL and the 250°F HTHP dropped from 8.8 mL to 8.0 mL. This well was tripped four times between 12,500 and 14,830 ft, and each time no fill was found upon returning to bottom.

After logging, a core gun was differentially stuck at 13,444 ft, and 8 days were spent fishing, jarring and washing before the fish came free. The operator tripped in the hole with a hole opener and new BHA and then washed and reamed to bottom without encountering any bridges and very little fill on bottom. The operator stated that the Liquid Soltex® additive contributed to good borehole stability–even in the face of extensive fishing operations.

Another large independent Gulf Coast oil and gas company used Liquid Soltex® additive for lubricity, shale and HTHP control. Initially, Liquid Soltex® additive was added at 12,487 ft MD, then used all the way to TD at 15,169 ft MD (14,685 ft TVD). Initial treatment was about 1.0 lb/bbl, rising to 10.0 lb/bbl by TD. Although the well kicked and later on a packer separated upon retrieval, the mud stayed in great shape.

Cement contamination raised the API and HTHP filtrates to 3.4 and 18.8 mL respectively. Daily additions of Liquid Soltex® additive reduced the API filtrate to 1.6 mL and the HTHP to 7.4 mL at TD. Again, the operator was pleased with Liquid Soltex® additive and felt it contributed to a very successful mud job.

Case History #3 - Soltex® Additive Shale Inhibitor - A Tale of Offset Wells

In Dewitt County, Texas, two independent operators spudded wells within one mile of each other. The first well reached 9,964 ft and took a kick, which combined with lost circulation, was not totally corrected until six days later at 10,060 ft.

At that time, the well was logged with some difficulty. The rig reamed and washed seven days to return to bottom. The API fluid loss was lowered to 3.6 mL and the HTHP to 10 mL. Eventually, the problem was solved and intermediate pipe was run. The water-based mud was replaced with an oil-based system which was used until TD was reached at 13,445 ft. The well took 84 days to reach TD. On the first day of washing and reaming, the mud company suggested the use of Soltex® additive to solve the problem, but the suggestion was ignored. The second well was spudded 17 days after the first. This well reached 10,351 ft and was logged. On re-entering the hole, lost returns occurred at 7,680 ft and a 80 bbl pill of 35 lb/bbl LCM was spotted. Pipe became stuck shortly after 7,700 ft, was freed and pulled to 7,300 ft. The next 48 hours were spent washing and reaming.

On the advice of the service company, 160 sacks of Soltex® additive shale inhibitor were added to the system. The concentration of Soltex® additive was about 4.0 lb/bbl. After adding the product, the mud and shale problems cleared up and intermediate pipe was run. Rig time was reduced by four days in this hole section. The water-based mud system was then used all the way to TD. TD was at 15,000 ft and was completed in 85 days.

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