How Rig less intervention technology has extended the wire line applications bringing invaluable benefits to oil industry

In 1987, the first ideas for a conveyance device for horizontal well intervention were conceived. These ideas led to the foundation of Welltec® in 1994. Throughout March of 1996 the first Well Tractor® field trials were carried out successfully in Norway. From there on the Well Tractor® technology has changed the way Operators plan and drill their wells. This technology facilitates a step change in the technique of deploying tools into horizontal wells and highly deviated wells with out the use of drill pipe or coiled tubing.

The Well Tractor® technology has developed extensively over the last few years expanding the applications of the Well Tractor® to even more than just deploying tools down into horizontal wells; today this rig less intervention technology allows you to mill, clean, drill and manipulate different mechanical devices such as flapper valves, sliding sleeves, gas lift valves, etc down hole using nothing but conventional electric wire line.

Even though not all the operations can be performed with out a rig, the Well Tractor® technology still brings benefits to the operator and is also an alternative option to the conventional techniques; Well Tractor® technology performs well surgery by removing limited obstructions in a timely and safely manner eliminating the need for heavy lifts and reducing the head count directly involved in the operation by an average of 50%

Safety and Logistics

Drill pipe conveyance requires the rig to stay with its risks on location until the operation is finished. This kind of operation is considerably long and holds the rig back on location for extended periods of time. The next step to down size the operation is to convey tools with coiled tubing, but even when the rig is not held back on location the risk of lifting heavy equipment is considerably high and the overall operation foot print remains large requiring a greater number of people to successfully and safely run the operation.

After the rig has moved and a horizontal intervention is planned there, is no need to call out for an intervention rig; a small operation involving an electric wire line truck, a Well Tractor® and a mast truck is enough to convey tools and equipment down hole in a horizontal well. Usually only 3 men are required to run a wire line operation and 2 more are required to operate the Well Tractor®, a total of 5 men on location can deploy guns, logging equipment or mechanical services at the required depth and deviation. This minimizes the overall size and the risk involved in the operation.

Environment

When we talk about a Well Tractor® we are referring to an efficient operation that leads to the successful achievement of the objectives while minimizing the environmental impact on location. This impact minimization comes when the operation footprint has been down sized to require only the minimum equipment needed to run the horizontal well intervention, of course we are talking about 1 wire line truck, 1 mast and 1 Well Tractor®. With this combination of people and equipment the operation becomes environmentally friendly.

Budget

In addition to the safety and environmental impact gained in today’s modern oil field, the Well Tractor reduces the cost of the intervention by an average of 50% therefore decreasing the overall budgetary concerns. This results in a safe, cost efficient operation allowing the well operator to optimize their well intervention programs by performing smaller and simpler well operations.

Cases

1. In 2005 an Operator with assets in central Alberta, Canada had a field of low-pressure high-volume gas wells drilled at angles up to 72 degrees. These wells were logged through casing and gravity was able to convey the tools to the desired depth. However the guns were not able to reach the target depth, and after several wire line companies tried changing the gun size and length configuration with no success, the operator decided to use a Well Tractor®. All the operation was completed rig less allowing the land base service rig to be on different locations with in the area. The total operation consisted of conveying 23 guns ranging from 4 to 6 meters long and 2 bridge plugs in 3 different wells.
2. When drilling multilateral wells, a number of Operators employ a completion system that uses an LEM (lateral entry module) that can be left open, can have a diverter to access the lateral, or have can an isolation sleeve installed to block off the lateral and only allow flow from the main bore. These LEM’s were design for coil tubing interventions; however problems have developed and the wells can only be accessed with wire line operations. Welltec provided an answer in 2005 when proposed the use of 2 1/8” Tandem Well Tractors with a spacer between them that would allow the conveyance of the logging tools through the LEM’s providing the operators with valuable well data.
3. In October 2003 a Well Miller® and a Well Tractor® were deployed with conventional electric wire line for an Operator in the North Sea to mill a flapper valve at a depth of 2067 meters and 86 degrees of inclination. The milling operation itself took 7 minutes allowing the Operator to put the well back in production sooner and below budget.
4. In 2001 a North Sea Operator used the Well Stroker® in conjunction with the Well Tractor® to open a down hole completion valve. The whole operation was carried out from a fourth generation semi submersible located west of Shetlands in connection with the final part of the well tie back phase. The use of the Well Tractor® technology avoided an expensive work over the following year.
5. In February 2001 after running in the hole with a new BHA, the LWD drilling bit suddenly became stuck; the driller could not move the assembly in any direction and the circulation was eventually lost. After 100 jarring cycles were performed the Operator decided to run a 2 1/8” Well Tractor® to retrieve the radioactive source from the BHA due to the fact that the fishing tool could not be pumped down because of the lost circulation. The Well Tractor® technology was put to the test when it was required to retrieve a radioactive source and download logging data from the LWD assembly. The operation was successful and not only contributed to major cost savings for the operator but also complimented the protection of the environment by safely retrieving a radioactive source. Without this technology the Operator would have missed the first oil target.

The Well Tractor technology continues to develop on a daily basis to provide Operators with unique solutions to the challenges of today’s and tomorrow’s needs. Welltec is a solution driven company that continues to push the boundaries of conventional oil field technology to the limits to force the only constant parameter we know, which is change. It is only through constant change that we are capable of capturing the necessary improvements to assure a strong future for our industry, customers and employees.