Silicate based muds: Chemical optimization based on field experience

Since the reintroduction of silicate fluids into the North Sea in 1994 over 45 hole sections have been drilled using these fluids. The performance of the fluid during the early field trials is discussed together with the comp ositional changes made as the envelope of performance was extended. The cur rent state of the art in sodium silicate and mixed silicate formulations is presented together with field data to illustrate drilling performance.