Research On Oil Displacement Spacers

Oil based drilling fluid has several properties just like high temperature resistance,good lubrication performance,good reservoir protection performance and high shale inhibition performance.Apply to the shale gas wells,ultra deep wells,high angle directional wells and complex strata with water sensitivity specially.Ordinary spacer fluid has been unable to play a very good displacement directed against the oil based drilling fluid.Therefore,we need to develop a kind of spacer fluid with more excellent performances.It should have good rheological compatibility with cement slurry,wide range of density,without corrosive effect on drivepipe,can reached to the disturbed flow condition under low up-hole velocity.It has very important significance to research and development such kind of spacer fluid.In this research,the flushing fluid is mixed with suspending agent and weighting agent in different proportion and different technological processes to get the spacer fluid which applied to displacement oil based drilling fluid.We need to determine the temperature resistance ability by static and dynamic temperature test,tested whether the settlement density difference is in a reasonable range by the means of stability of the suspension,get the data about cementing strength.Ensure the rheological compatibility by the anti-pollution thickening experiment,compressive strength test and the test of filtration ability.Make sure the spacer fluid can has good compatibility with drilling fluid and cement slurry,also will not make the cement slurry flocculation and early thickening.After the laboratory test,applied to the well cementing site,investigated its actual ability.The experiment results show that,the spacer fluid's maximum temperature ability is 160?,its density could adjustable from 1.0 to 2.20g/cm~3.It also has a good compatibility with cement slurry and drilling fluid.At last,the well cementing quality is good in the field experiment.