KILLING FLUID SYSTEM OF HIGH DENSITY AND LOWDAMAGE

A well killing fluid of high density containing soluble bridging-plugging solids and of temporary plugging is used to prevent filtration or loss circulation of the work-over fluid into the formation during workover or perforating operations, so as to avoid the reservoir damages arising from water and solids blocking, water sensitivity and emulsion plugging, etc.It comprises XC polymer, YDC-LN additive and water soluble weighting agent.Formula selection and laboratory simulating tests show that this system has good stability, higher temperature tolerance over 105℃, lower filtration and stronger inhibition, and the core damaging ratio is below 20%.In addition, its density is easily adjustable and it can be easily displaced after servicing, and it has good compatibility with fresh water and the produced-water in the Oilfield.This sy stem is easy and convenient for field using.