Pushing the Boundaries with Oilfield Tractors

As extended reach drilling (ERD) sets new records with improved equipment and science, so is the technology surrounding the intervention side of the business evolving. For example, Schlumberger is breaking new grounds with wireline tractors and mechanical services. Schlumberger TuffTRAC* casedhole- services tractor enabled a Canadian major E&P operator to accomplish all intervention objectives, and in the process achieved an 85,987 meters tractorconveyance world record; thereby, redefining the acceptable limits in well construction and the necessary supporting intervention services.

The Technology

The Schlumberger TuffTRAC cased-hole-services tractor is a 3 1/8-in. diameter tool, which runs on a multi-conductor wireline cable and has a pushing capacity of 300-lb per drive section. A maximum string of six drive sections can be deployed in tandem for a heavy-duty 1,800-lb of pushing power. Active traction control provides the ability to monitor and change the pressure on each drive wheel to optimize traction in either direction (i.e., full reverse capability).

Capable of operation to 350 degF (177 degC) and 20,000 psi (1,361 Bar), the system’s robust power pack can operate without requiring cool-down periods. The tractor includes a built-in head-tension measurement, electrical release capability, casing collar locator (CCL), Addressable Tractor Protection Switch (ATPS*) for perforating safety, and shock absorber in a compact robust design, that minimizes tool length to provide the shortest tractor in the market.

This technology is capable of conveying a large line of intervention services, including perforating operations, plug setting, production logging, Analysis Behind Casing (ABC*), cement and corrosion evaluation and mechanical intervention services. In addition to wireline logging and perforating services conveyance, the TuffTRAC tractor can convey the mechanical intervention platform. This new wireline mechanical intervention suite of services performs a variety of operations in producer and injector wells, including plug setting, anchoring and linear actuation. Pushing the Boundaries with Oilfield Tractors Only the simple, robust TuffTRAC cased hole services tractor continuously applies active traction control to the radial force applied by the tractor arms.

Multiple wireline operations in a complicated well

The aforementioned operator had multiple operations to conduct in the well: log for well integrity, perforate, and release and pull a plug. In addition to the well’s challenging geometry, the well completions included Gas Lift Mandrels (GLM), which would have to be navigated by the downhole wireline equipment and tractor.

TuffTRAC with the mechanical intervention platform

Utilizing the tractor technology in this operation, the operator was able to accomplish all the objectives. An 85,987 meter world record conveyance was achieved, comprising 19 descents in the well over 38 days. Wireline acoustic and cement evaluation services, perforating gun runs using the CIRP* completion insertion and retrieval under pressure gun deployment system, and mechanical intervention services for release and pulling of a bridge plug were efficiently and safely executed. Use of the TuffTRAC tandem sub enabled the tractor to successfully navigate the GLMs in the completion.

This operation is a trendsetter for future key ERD projects in Canada as well as worldwide.

Though this is just one example of how the oilfield services technology is advancing hand in hand with the drilling side, it shows how tools and services help operators push the limits every day in delivering record setting and cost effective wells.