composite-bridge-plug

Be used for provisional plugging in oil and gas well，and fracturing construction。

Structure and Operational principle

Structure: It is mainly composed of soluble ball, mandrel, rubber cylinders, compound slips, cones, protection bowls, release / start pins, lower joint and so on.

Operational principle: The opposite power produced by setting tool（wireline or transmitting hydraulic pressure in oil tube）acts on the lower joint, shears the starting dowels, and exerts compressive force on rubber cylinder through cone. Inside the tension range, compound slips dehisce and inlay the inwall of the casing, rubber cylinders expand to the inwall of the casing and seal up it, finish setting. When the tension rise to the shear rating, the starting dowels be sheared, and the setting tool separates from the bridge plug, filish releasing. After taking out the setting tool, the soluble ball that be put into the well will work hermetically with the head face of the mandrel. After fracturing, the soluble ball will dissolve gradually by means of electrochemical reaction with fracturing fluid or formation water. The solubility and solution time of the ball  refer to the soluble ball direction for use. Large ID fracturing compound Bridge plug can be quickly drilled out under the necessity of the after steps.

Drilling out

Recommend the use of special milling tools. Recommend rotation rate: 60～150rpm, bit weight: 5～15kN, viscosity of drilling plug fluid: 15～30mPa·s and minimum cyclic velosity: 36.6m/min, to make sure the debris circulates out.

After the preparation is done, start the screw drill and drill slowly into the bridge plug. Ensure continuous drilling speed by applying drilling pressure. The torque added to the drilling tool should not be greater than the recommended value. Excessive drilling pressure increases the friction resistance of the pipe string and results in large pieces of debris which must be salvaged separately.