Enhancing Production Using Solid Expandable Tubulars in Workover Campaigns

Abstract

With drilling, completion and production costs rising as fast as commodity prices, some operators are looking to optimize existing production with workover projects that turn marginal wells into significant producers. Historically, workovers have been delegated to perfunctory status even though 70% of today's oil production comes from fields 30 years or older 1. Some operators relegate workover projects to strictly well repair, while others take the next step and focus on how to increase production rates. New technologies and processes have provided the impetus for these operations that are reaping compelling returns for projects that not only encompass well repair but production enhancement. In seven years, solid expandable tubulars have gone from an unconventional idea to a viable and recognized solution for wellbore construction and integrity. The appeal of these systems lies not just in the mechanism but the functionality including the ability to deepen the hole, shut off water zones and protect zones from stimulation pressures without sacrificing hole size. Maximizing inside diameter (ID) allows the operator to use the same completion previously used in the well. Operators that have planned and used expandable systems in preventive maintenance programs have realized more attractive economic and technical results than the usual one-off workover. This paper will explain how through a planned, multi-well workover campaign, solid expandable tubulars enhance production in an affordable manner. Case histories will be used to illustrate the planning, implementation and completion stage and the tangible results of the projects. In addition, this paper will explain how these systems provide solutions for challenging downhole conditions and situations. Introduction In today's energy industry, new drills are accounted for as a capital investment whereas workover projects are seen as an expense. This differentiation short changes the full potential of what a workover project could reap if enhancing technology was incorporated into the plan. Opportunity is missed when a workover project is relegated to a one-off re-entry job as opposed to a strategy. The effort needs to net maximum results with minimum cost. Preventative maintenance, applied at a field level, has proven to be an economically beneficial approach especially, in a market where consumption exceeds production. For example, in 2003, the United States produced ~10.5% of the world's oil but consumed ~25% of the resources. With that said, 59% of the world's producing wells are in the United States (Figure 1).2 If production from those wells can be maximized with a cohesive and aggressive workover campaign, production percentages would be more in line with demand. The Workover Campaign Reactive The conventional approach to workover operations identifies the well in need and adds it to a list. How and when the situation is addressed depends on the severity of the problem and the nature of the well. Traditionally, producing wells that require workover operations end up with a band aid fix rather than a long-term solution. The cement squeeze is a classic example of the staid, conventional workover approach that is often inefficient and lacks solution longevity. In addition, several squeezes may be needed during the production life of the well and the operator is limited in length. Another example of a fix rather than a solution is the casing patch. Patches are able to restore casing integrity but are only able to cover short lengths of perforations, have a limited pressure rating and lack the required longevity. The current oil and gas market demands a new approach that spends time and money efficiently. Rather than take the problems as they come, some operators are approaching the inevitable workover with an effective and cost-efficient strategy that incorporates the latest enabling technology and processes.

Comparison between fresh and exposed swelling elastomer

“…Apart from other important applications, one major task has been that of well completion. 1,2 More than 150 successful cases of SET-based drilling and recompletion works have already been reported. 3–5…”