| 摘要 |
<p>A water-based drilling fluid (WBM) comprises as additive one or more alcohol ethoxylates in which the alcohol chain has at least 5 carbon atoms. The number of carbon atoms in the alcohol is preferably in the range 5 to 14, more preferably 6 to 10, and the alcohol is preferably straight chain. The number of ethylene oxide units is preferably in the range 5 to 20, more preferably 6 to 12. Two typical additive molecules suitable for use in the drilling fluid of the invention are: C6H13O(C2H5O)7H and C8H17O(C2H5O)7H. Drilling fluids in accordance with the invention have been found in laboratory tests to exhibit improved shale inhibition properties as compared with known polyol containing WBM, particularly in the absence of added potassium ions. This is environmentally advantageous.</p> |
