Differential Sticking Tester

MUD TESTING EQUIPMENT

For years, Inmotion Energy has supplied
precision instruments and drilling tools for
testing drilling fluids, well cements, and
completion fluids.

From our Bangalore facility, we provide
customers across India and the Middle East
with quality products and exceptional
service.

As an independent manufacturer, we have one priority: our customers.

INDUSTRIES WE SERVE

— Onshore & offshore drilling contractors
— National & independent oil companies
— Mud engineering & testing laboratories
— Well completion & workover operations

WHY CHOOSE US

— Rigorous quality control on every unit
— Fast turnaround on spares &
replacements
— Field-tested designs, built for uptime

INMOTION ENERGY (OPC) PRIVATE LIMITED

PRODUCT SPECIFICATION — Differential Sticking Tester

Model: IM-DST-NF2 Compliance / target standard: Wellbore Adhesion Analysis

The differential sticking tester assesses the tendency of a drilling fluid to cause differential pipe sticking. A stainless steel cell is filled with mud and pressurised so that a filter cake builds on a filter medium; a torque plate is then pressed into the cake under differential pressure and the torque needed to turn it is measured. The result, the stuck-tendency coefficient, reflects both the stickiness and the cake-building ability of the fluid.

Figure 13. Reference photograph of the Differential Sticking Tester, with the pressure cell mounted for mud-cake formation. Components are listed on page 2.

Intended applications

• Comparing the sticking tendency of different mud formulations.
• Evaluating lubricants, filtration-control agents and weighting materials.
• Testing the effectiveness of spotting fluids (pipe release agents).
• Well planning for depleted or high-overbalance intervals.

FEATURES

• Pressure cell of about 200 mL capacity with N2 supply and gauge.
• Flat torque plate and a spherical-radius plate representing pipe or collar contact.
• Torque handle and shaft for timed sticking measurements.
• Bottom drain valve for filtrate collection.
• Stainless steel construction.

TECHNICAL SPECIFICATIONS

Standard test pressure	About 477.5 psi (3,292 kPa) differential
Cell capacity	About 200 mL, stainless steel
Torque plates	Flat-faced plate; spherical plate (12.5 in radius)
Pressure source	Nitrogen
Measurement	Torque required to turn the plate after a timed stick period
Result	Stuck-tendency coefficient
Related equation	Sticking force = differential pressure × contact area × friction coefficient

Values are typical for this equipment class based on API/ASTM practice and manufacturer literature (OFITE, Fann, Chandler); confirm against the Inmotion datasheet before use in a certificate or specification.

Main components (see Figure 1)

No.	Component
1	Torque handle
2	Pressure gauge
3	Shaft
4	Pressure cell
5	Torque plate and filter medium
6	Base and drain valve

Principle of operation

Differential sticking occurs when pipe lies in filter cake against a permeable zone and the mud pressure exceeds pore pressure. The pressure pushes the pipe into the cake, increasing contact area and friction. The tester reproduces this: mud filters through the medium and builds a cake, the torque plate is pressed into the cake by pressure, and after a chosen time the torque needed to break it free is measured. A high torque indicates a high tendency to stick.

Basic operating procedure

1. Place the filter medium in the cell, fill with mud and fit the lid.
2. Apply the test pressure (about 477.5 psi) and allow a filter cake to form for the specified time.
3. Position the torque plate against the cake so that it is embedded under differential pressure.
4. Wait for the specified stick time, then turn the handle with a torque wrench and record the peak torque.
5. Vent pressure, drain the cell and remove the plate and cake.
6. Calculate and report the stuck-tendency coefficient; clean the cell thoroughly

Calibration and maintenance

• Inspect O-rings, plates and the filter support for wear.
• Calibrate the torque wrench and pressure gauge annually.
• Clean the cell and plate immediately after use; avoid scratching surfaces.
• Lubricate threads and check the drain valve.

Safety precautions

• The cell is pressurised: vent fully before opening.
• Wear eye protection and gloves.
• Use nitrogen only and secure the cylinder.

Reference sources