Lost circulation is a leading cause of downtime in drilling operations and is encountered in most drilling jobs. It can result in complete loss of the hole along with costly drilling equipment. To successfully prevent losses of drilling fluid, it is vital to rapidly prepare and place a lost circulation treatment into the loss zone when losses are encountered. A fibrous lost circulation pill has been developed to address common operational concerns that exist with current lost circulation materials and applications. This one-sack product does not require any activators, retarders, set time calculations, or temperature activation. It has been specifically designed for rapid mixing and pumping with minimal equipment.

Laboratory testing has demonstrated the ability of the fibrous pill slurries to rapidly dewater/de-oil and form a sealing plug on both ceramic filter discs and slotted metal discs. Testing also shows that the product forms a sealing plug in depleted sand formations. This pill can easily be weighted using barite to help control hydrostatic pressures. The fibrous product is suitable, and has been tested, with a wide range of fluids including freshwater, brines, and base oils. This product also meets strict environmental requirements for use in both the Gulf of Mexico and Norway. It can be rapidly mixed and pumped on location using standard rig equipment and only requires base fluid, barite and the product. The pill formulation is compatible with all mud systems and is easily removed using standard solids control equipment.

This new approach to control severe losses has been successfully applied in several field tests, which have reflected a variety of lost circulation conditions. A few of these field applications will be discussed in detail.

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