Economical Multilateral Well Technology For Canadian Heavy Oil
Authors: Fipke S. 
Published: March 2010

In the last several years there has been a dramatic increase in the pace of the evolution of multilateral systems. Many systems with new features and improved functionality have been introduced that have enhanced the application of multilateral technology. Few of these systems, however, have been designed with the needs of the Canadian heavy oil producer in mind.

Canadian energy producers face a different set of economical variables than do internationally based companies. As a result, very few of the multilateral systems that are presently commercially available can add value to a heavy oil development project. Very often the extra capital cost, the lengthy installation process, or the perceived operational risk will defeat a multilateral well proposal based on a NPV comparison with the obvious alternative: drilling two wells to capture the same reserves.

With the Canadian operator's economical and functional parameters in mind, a system was developed as a practical solution Alberta's multilateral equation. The multilateral system was developed in response to need for:A junction that does not require cementing of the lateral LinerA lateral liner that is mechanically tied-back to the main casing StringMinimal casing restrictions for re-entry access of the lateral and mainboreA reduced number of operational steps to complete the JunctionA lower up-front capital cost of a multilateral installation.Optional sand-control for the lateral wellbore near the junction.

This solution lends itself to a TAML level 3 junction for a variety of practical reasons. This system can be installed faster and more economically than a level 4 system, while lending more structural strength to the junction than a level 2. A level 3 system is particularly applicable to heavy oil reservoirs where the wells are drilled horizontally through the reservoir because it provides mechanical integrity to the junction without requiring cementing of the lateral liners.

Most importantly, the system must be designed to minimize the additional capital cost of constructing a multilateral junction. The cost of drilling a shallow heavy oil well in Alberta is relatively low compared to many other places in the world. Rig costs are lower and drilling operations are extremely efficient. Therefore operators require an affordable junction construction system that can be installed with minimal additional rig time.

It was with these challenges in mind that Halliburton/Sperry- Sun went towards designing the MACH-3 ™ system. It is an innovative, hybrid system capitalizing on the proven commercial success of the RMLS ™ (Retrievable Multi-Lateral System) which is responsible for over 217 junctions globally.

MACH-3 Sequence of Operations

Step 1–9 (available in full paper)

As can be seen from the preceding operations sequence, the system can be used to create a complete level 3 junction with only three additional rig trips and minimal operational steps. Installation could be further simplified by eliminating the lateral ACP, which is an optional feature included to prevent the flow of formation solids through the casing-wellbore annulus and then into the junction itself.