摘要 |
A water-based drilling mud additive comprising a pre-blended combination of about 2 parts of high softening point uintaite, about 1 part of a lower softening point uintaite, about 1 part of causticized lignite, and a strongly lipophilic, non-ionic surfactant is disclosed. This composition decreases shale sloughing and borehole instability during drilling of wells. |