The invention relates to slurries of materials that fuse under pressure to act as lost circulation prevention materials, fluid loss agents, or cementacious materials in oil and gas wells. In particular, it relates to such slurries containing fibers and materials that fuse together under pressure.
In drilling and completion operations in the oilfield, fluids such as drilling muds are sometimes lost to the surrounding formation through natural fractures, cracks, fissures, or vugs, or through fractures and the like created during treatments or through fractures and the like created by prior treatments. Lost circulation is reduced, or total, loss of fluid flow up the annulus when fluid is pumped down through a drillstring. Substances called loss control agents or lost-circulation control agents are added to drilling fluids and the like when fluids are being lost to the formation downhole. Commonly used lost-circulation materials include fibrous (cedar bark, shredded cane stalks, mineral fiber and hair), flaky (mica flakes and pieces of plastic or cellophane sheeting) or granular (ground and sized limestone or marble, wood, nut hulls, FORMICA™, corncobs and cotton hulls).
Granules, fibers and flakes in loss control agents are known (see for example U.S. Patent Application No. 2005/0269080), including all three in one slurry; see for example U.S. Pat. No. 4,579,668. Gilsonite has been used in drilling muds as an extender and as a lost circulation material on a regular basis.