摘要 |
The invention provides a method and fluid for drilling or servicing a well in a subterranean formation containing lost circulation zones or depleted, low pressure reservoirs. The fluid comprises an aqueous liquid having dispersed therein a polymer which increases the low shear rate viscosity of the fluid to the extent that the thixotropic index of the fluid is at least about 10 and a surfactant, and wherein the fluid contains less than about 15% by volume of aphrons preferably generated by the turbulence and pressure drop as the fluid exits the drill bit in the vicinity of the formation. The method of drilling a wellbore in a subterranean formation comprises continuously circulating, while drilling, such a drilling fluid.
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