Water-base drilling fluid

During the period of 1920s~1960s, water-based drilling fluid was used. At that time, water-based drilling fluid was rather simple and the main type in this stage was dispersed water-based drilling fluid. (1) From 1921 to 1922, barite and iron oxide powder were used as weighting materials. (2) In 1926, bentonite was used as suspending agent. (3) In 1930, sodium tannate, the earliest mud treatment agent, was developed. (4) From 1931 to 1937, various mud measuring instruments were developed and the requirements on mud performance control were put forward. (5) From 1944 to 1945, Na-CMC (carboxymethyl cellulose) was applied as filtrate reducer in drilling fluid. (6) In 1955, FCLS (ferric chrome lignin sulfonate) was applied as thinner in drilling fluid. (7) Since the 1960s, a coarse dispersed w