An Integrated Team Approach to Underbalanced Drilling
Authors: Lunan B. , Curtis F. 
Published: March 2010

Abstract
As underbalanced drilling becomes a mature technology in the Western Canadian Basin, with more underbalanced horizontal and vertical wells being drilled in pressure depleted reservoirs, it is worthwhile to investigate how this technology can be applied in overseas markets. Many operators understand the concept of underbalanced drilling but do not understand the "process" of gaining the knowledge, equipment and personnel to drill particular reservoirs underbalanced. This paper sets out to look at the process of putting an integrated team together and the steps required to take any reservoir from its present status to an improved condition by building the cross functional units with capability of applying the technology correctly. Included in the paper are updated procedures for handling underbalanced drilling occurrences using the engineering processes developed by the cross-functional team for both onshore and offshore underbalanced drilling operative.

Introduction
At the time of writing there have been more than 800 wells drilled underbalanced in the Western Canadian Basin, with the prospect of passing the 1,000 mark over the winter drilling season. Most of these wells have been drilled with jointed pipe though there has been a significant emergence of coil tubing drilling technologies as an alternative approach to conventional underbalanced drillpipe techniques. The unique position that underbalanced drilling finds itself in Canada is due to the fact that the technology has been applied in many different types of reservoirs making the Western Canadian Basin a real life laboratory(1–4). Visitors can come to Western Canada to investigate first hand how, why, when, and where this technology is being applied and participate in a field trip to an actual operation. This is a direct result of the various Canadian operators and service companies willingness to share ideas, methods, technology and results with the rest of the world. As a reservoir driven technology, attempts are made to recover more hydrocarbons by correctly applying modern drilling techniques. In this regard, underbalanced drilling has moved into phase two of the evolution process where instrumentation and control both downhole and at surface have become major tools for the successful implementation of this state of the art drilling process. From these control processes, the data acquired during drilling and the post drilling analysis, a substantial knowledge base has been developed which has greatly assisted both the operators and the service companies to further improve on the underbalanced drilling results. The question which now arises is that having applied the technology correctly in Canada what are the upside benefits to applying this technology on a worldwide basis. Success results from a learning process which involves the building of the correct cross-functional teams with highly motivated personnel who focus on particular reservoirs and develop a system that will allow drilling and reservoir optimization to proceed in a timely and cost effective manner.

The Original Concept
Most oil and gas technologies progress from an embryonic stage to full maturity because there is a real need to increase recovery of hydrocarbons from the ground.