A Case Study of Improved Well Construction Operations Employed by Asia Pacific Operator Where Cutting Edge Technology Resulted in Measurable Cost Savings: Phase Two Results Evaluated
Authors: Rogers Henry Eugene , Cornwall Mark , Lazaroo Peter 
Published: December 2009

Abstract
With the ever-increasing demand for oil and gas, operators around the world have increased their drilling budgets in an effort to meet forecasted demand. However, the increased budgets are often eroded or offset by increasing drilling costs. Therefore, operators are continually looking to new technology, processes, or procedures to improve drilling operations and maximize drilling speed.
One Asia Pacific operator identified a common redrill operation as a possible area where cost could be easily reduced. Specifically, improvements in procedures and equipment used during shoe-track drilling operations resulted in time savings. This paper expands on previous work (Rogers et al. 2009) and documents the successful introduction of wholly-composite, subsea-release cementing plugs and their subsequent drillout offshore Western Australia in the Indian Ocean. Historical data is compared to results achieved that validated the anticipated results. The lessons learned and a decision-tree matrix is presented to enable other operators globally to apply similar cost-saving measures to land, offshore, and deep-water operations.

Introduction
Global drilling operations cover a wide range of environments in search of recoverable reserves that can be produced economically. From shallow drilling operations in the central United States to the jungles of Columbia or drillships operating in the open expanse of the largest oceans, the industry continually strives to operate effectively, efficiently, and safely by fine-tuning processes or workflows that are used to implement conventional technology. However, in some cases, operators challenge service companies to provide new technologies that provide more than incremental improvements in effectiveness and efficiencies. Rather, operators demand game-changing technologies to be developed and deployed. Examples of game-changing technologies developed for well-construction operations throughout the past few decades are rotary steerable systems (RSS), casing while drilling (CWD), and expandable tubulars. Each of these technologies were developed and deployed successfully throughout the past couple of decades. On a smaller scale, operators continually push service companies to develop new technologies and equipment for primary cementing operations.
In the case of cementing casing equipment and cementing plugs, improved drillability is one area that is constantly challenged because of the high spread costs of today's drilling platforms. With spread costs for mobile offshore drilling units (MODU) in the range of ﹩400,000 to ﹩1,000,000 USD per day (4.63 to 11.57 USD per second or 278 to 694 USD per minute), the savings gained by the operator for improving shoe track drillout times by 30 minutes or more justifies the cost of new technology. The development of composite resin materials as a replacement of cast-and-wrought aluminum components has enabled equipment suppliers to design, test, and deploy equipment that performs effectively during cementing operations while also allowing shorter drillout times (Rogers et al. 2006). In some cases, several hours can be saved in the drillout of the shoe track alone. This paper details the development, testing, and deployment of composite subsea-release plug assemblies and the value realized by several operators operating off the west coast of Africa and in the Indian Ocean off the western coast of Australia.