Differential Sticking Tester / Mud Sticking Tester

Differential Sticking Tester / Mud Sticking Testers

Differential sticking may be identified by the following characteristics:

1. Pipe sticks after remaining motionless for a period of time

2. Pipe cannot be rotated or moved when ciSXulation is maintained

Most incidences of stuck pipe are caused by differential-pressure effects. Excessive differential pressures across lower-pressure permeable zones can cause the drillstring to push into the wellbore wall where it becomes stuck. When differential sticking occurs, spotting fluid can sometimes free the drillpipe.

The Differential Sticking Tester was designed to determine how likely a given drilling fluid will be to produce a stuck pipe situation and how effective a given drilling fluid treatment or application of spotting fluid in any given drilling fluid would be in reducing this tendency. This measurement is called the Stuck Tendency Coefficient. It takes into account both the stickiness and the cake building capability of the drilling fluid. The Stuck Tendency Coefficient is determined by the Timed Filtrate Test.

The use of the optional yoke attachment along with the radius’d torque plate allows a measurement called Bulk Sticking Coefficient to be obtained. By measuring the area of caking using a controlled cake thickness during the test, the Bulk Sticking Coefficient is obtained. The Bulk Sticking Coefficient is determined by the Fixed Cake Thickness Test.

The unit can be pressurized by the CO² regulator assembly or from any nitrogen source. If Nitrogen is to be used, the Differential Sticking Tester must be fitted with a suitable Nitrogen regulator, gauges, relief valve, hose and fittings.