Below is the drilling fluid compounding slurry procedure recommended by USA M-I Swaco Company, for reference only.

Organic Bentonite formulated oil-based drilling fluids technology program

(1) Wash and prepare two clean mixing tanks

(2) Inject the base oil of slurry into the No. 1 tank by pump, add primary emulsifier, auxiliary emulsifier and wetting agentaccording to the precomputed volume,and then fully stir them until all the oil soluble constituents are dissolved. Under the ambient temperature condition, mix 31.8 m3 (200 BBL) takes about 2h or longer time, preheat the oil or violent mixing can short the dissolution time.

(3) Add the required water volume into tank No.2, and dissolve 70% of the required CaCl2 volume.

(4) Under the strong stirring ofdrilling fluid gun etc. equipment, addCaCl2 brine into oil tank slowly. It's preferable to use more than 3.45 MPa (500 psi) pump pressure through 1.27 cm (0.5 in) drilling fluid spray gun nozzle for drilling fluid mixing. If the pump pressure is less than 3.45 MPa, then you should choose a smaller nozzle, and slower the water adding speed.

(5) Add a certain amount of organic bentonite and lime under continuously stirring.After the emulsion is formed, you should measure its performancecomprehensively,such as rheological parameter, pH, demulsification voltage and HTHP filtration volume, etc.

(6) If the performance is in accordance with the requirements, barite can be added in order to achieve the required drilling fluid density.Barite adding speeds should be properly (it is advisable to add 200 ~ 200 bags per hour). Ifbarite got wet by water, granular solid may appear inthe drilling fluid.At this time, adding speed should be slowed down, andappropriate dosage of wetting agent should be increased.

(7) When the system reaches the required density, you can add the rest powdered CaCl2,and fully mixing it finally.

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