Snubbing
A Snubbing Unit is the most versatile, cost effective means available in the upstream oil and gas industry.
Snubbing Unit Services
The company offers snubbing services for the Asia Pacific region. In addition, we are able to service other global regions (European, African, Middle East & Americas) through our companies located in the United States of America, Netherlands, United Kingdom, Thailand and Malaysia.
We manage snubbing units in operations located offshore and onshore and the units are designed, operated and maintained to the highest industry standards.
Snubbing Unit Capability
- Velocity String Installation
- Live Well Completion Repair / Removal
- Through Tubing Fishing
- Tailpipe / Packer Installation Under Pressure
- Fishing Under Pressure
- Through Tubing Sand Clean Out
- Casing Leak Repair
- Straddle Pack Installation Under Pressure
- Liner Installation Under Pressure
- Underbalance Drilling / Well Deepening
- Packer / Plug Milling Under Pressure
- Re-abandonments / Shallow Plug Milling
- Drilling Rig Assist / Lost Circulation Control
What is Snubbing
Snubbing is a technique to install or remove tubular from a well, while the well remains pressurised (a live well). This technique is used when it is not possible or not desirable to kill a well (dead well). Killing a well means depressurising the well by pumping a heavy fluid or mud inside the well. The advantage of snubbing is that work can be performed without killing the well thus eliminating reservoir formation impairment or costly stimulation operations.
Before starting a snubbing operation, dedicated engineering is required; operational contingencies must be in place to ensure that operations on live wells can be performed safely.
The tubulars are pulled out of the well using hydraulic cylinders.
How Does it Work?
Snubbing operations require a Hydraulic Workover Unit (HWOU). The HWO/Snubbing unit is designed to deal with the technical challenges present during work on pressurised wells. Typical challenges are tubular buckling, push and pull forces and lubrication of tubular in and out of the pressurised well.
HWO/Snubbing units have a small footprint, are flexible and are easy to mobilise. These properties make these units very suitable to work offshore and onshore allowing tailored solutions for each well.
Snubbing has been developed as a technique to regain control over pressurised wells which were difficult to kill with conventional methods. Today, the advantages of Snubbing has made it a widely used well intervention technique which can be used for many applications, including:
- Underbalanced Sand Screen Deployment
- Underbalanced Packer Milling / Completions Removal
- Installation of Velocity Strings
- Underbalance Casing Drilling in Unstable Formations
- Installation and Removal of Tubular Out Of Gas Storage Caverns
- Installation of Kill Strings / Well Control
- Underbalance Well Cleaning / Deepening
- Setting of Bridge Plugs, Packers and Isolation Valves
- Underbalance Fishing
Snubbing Stages
There are 3 stages during Snubbing activities:
- Pipe Light
- Balance Point
- Pipe Heavy
Snubbing is the stage where the weight of the tubular is less then the upward acting forces caused by well pressure and buoyancy. This so called “pipe light” stage introduces a number technical challenges, such as tubular buckling and push forces instead of pull forces.
Once the weight of the tubular equals the upward acting force created by the well pressure and buoyancy, the balance point has been reached.
“Pipe heavy” refers to the stage where the weight of the tubular is larger then the upward acting forces.
During the entire Snubbing operation well pressure is controlled and sufficent barriers are in place to avoid uncontrolled pressure release.
