| 摘要 |
A non polluting additive or spotting fluid which releases and/or prevents differentially stuck drill strings and casings in the wellbore of a subterranean well is presented. This additive composition comprises an ester, preferably monohydric alcohol esters of fatty acids in combination with particulate asphalt. A preferred ester is 2-ethylhexanol ester of a tall oil fatty acid. A preferred asphalt is the asphalt described in Patent 5,120,708. Other preferred components in addition to the ester and asphalt include one or more suitable surfactants, suspension agents such as lime (Ca(OH)2), anticaking and grinding agent such as calcium silicate and antigellation agents such as sodium bicarbonate. The present invention enhances the lubricity of a drilling fluid to prevent drill string sticking and when utilized as a spotting agent reduces the time required to release a stuck pipe. By eliminating the need for oil-based components, the present invention is non-toxic to marine life, environmentally acceptable, easy to prepare, and capable of being disposed of at the drill site without costly disposal procedures. |
