摘要 |
An additive that increases the density of fluids containing a sized barite weighting agent. The wellbore fluid has rheological properties comparable to a conventional wellbore fluids but does not exhibit problems with sag and resulting variations in density. An illustrative embodiment is directed to a method for making the sized barite weighting agent and a method for using such sized barite weighting agent in a wellbore fluid. In one preferred embodiment the sized barite weighting agent has a particle diameter between 4 mum to 15 mum In another preferred embodiment, the additive has a D<SUB>50 </SUB>(by weight) of approximately 1 mum to 6 mum. In another preferred embodiment the additive has a D<SUB>90 </SUB>(by weight) of approximately 4 mum to 8 mum. The additive may be used in any wellbore fluid such as drilling, cementing, completion, packing, work-over (repairing), stimulation, well killing, and spacer fluid.
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