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| | Use of low M.S. hydroxyethyl cellulose for fluid loss control in oil well applications - Patent 4629573 |
 | | Bridging particles comprised of solid carbonate powders which serve to "bridge" across or plug the pores of a permeable formation are disclosed in U.S. Pat. |
 | | As used throughout the specification and claims, the fluid loss of a drilling fluid is defined in terms of the API fluid loss test commonly used in the petroleum industry which is described in "Standard Procedure For Testing Drilling Fluids", Section 3, Filtration, American Petroleum Institute, API RP 13B, 7th Edition, April 1978, pages 8-9. |
 | | Accordingly, effective fluid loss control can be achieved with HEC in accordance with the invention in the absence of additional fluid loss additives or bridging particles in the drilling fluid, such as described in U.S. Pat. |
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