Performance Report: BLACK FURY Additive Puts the Brakes on Severe Sloughing Shales

Zapata County, South Texas

Challenge: While drilling the 6 ¾-in. interval of a sidetrack, with about 100 ft (30 m) of the original wellbore exposed below the 7 ⅝-in. casing, the operator encountered considerable amounts of shale at the shaker, making it difficult to return to bottom. The BHA became stuck after an unsuccessful attempt to wash and ream to bottom. Once the BHA was jarred free, the operator was unable to reach bottom successfully, thus preventing the hole from being logged and casing run. At that point, the hole was unloading shale at an estimated rate of 6 bbl/hr and could not be stopped using sulfonated asphalt.

Solution: To stop the sloughing shale, Alpine Specialty Chemicals recommended the operator add 2% by volume of BLACK FURY additive to the active mud system. The BLACK FURY liquid Gilsonite suspension is formulated specifically to stabilize water-sensitive and micro-fractured shales when drilling with water-base drilling fluids. BLACK FURY additive seals micro-fractures, thereby reducing dynamic fluid loss and remediating and minimizing the potential for differential sticking.

Result: Once the programmed volume was circulated effectively in the mud system, the hole became slick and the sloughing ceased completely. The amount of shale generated was reduced to less than one-half barrel per hour, none of which was observed as splintery or swollen. As a result, the hole was logged successfully and casing run to bottom trouble free.

The Details

After pulling out of the hole (POOH) and laying down one stabilizer, the operator raised the yield point of the active mud system before adding 2% by volume of BLACK FURY product. The well was circulated at the casing shoe until the full volume of BLACK FURY product was in the system.

Download: BLACK FURY Additive Puts the Brakes on Severe Sloughing Shales (0.58 MB PDF)

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