| abstract |
The invention describes the use of water-insoluble esters with flash points above 80 DEG C., from monohydric alcohols of natural and/or synthetic origin with at least 4 carbon atoms, preferably at least 6 carbon atoms in the alcohol radicals, as the oil phase, or a constituent of the oil phase of invert drilling fluids which exist as W/O-emulsions, have a dispersed aqueous phase and ideally also have further usual additives in the continuous oil phase, which is fluid and pumpable in the temperature range of 0 DEG to 5 DEG C., and which are suitable for the environment-friendly development of, e.g., petroleum and natural gas deposits. Drilling fluids of the above type are also described which are characterized in that they contain as the continuous oil phase, or dissolved in ecologically-acceptable water-insoluble oils, an additive of at least largely water-insoluble ethers from monohydric alcohols, the oil phase in each case being fluid and pumpable in the temperature range of 0 DEG to 5 DEG C. and having flash points above 80 DEG C. |