Abstract

For years the reduction of tubular internal diameter (ID) limited the exploration and production of oil and gas. Operators faced significant loss of ID in the course of the normal drilling process, during re-entry and deepening of existing wells, or when installing additional casing strings to remediate well problems. The industry confronted this dilemma with innovative problem solving that stretched the boundaries of physics in the guise of solid expandable tubular technology.

As this tubular system moved from its infancy and discovery phase into one of a more adolescent technology, successful applications proved its reliability in a variety conditions and environments. Solid expandable tubulars continue to build a legacy as a solution to problems involving gas shut off, subsidence repair, water shut off, lost circulation, and remediation of wells slated for abandonment

This paper will discuss solid expandable tubulars from theory to reality, following the technology from its inception through development to application. Case histories will be cited to illustrate how solid expandable tubular systems are applied in a myriad of drilling challenges The paper will also discuss how the technology continues to evolve, leading to the monodiameter well where casing diameter remains constant throughout the total length of the well.

Introduction

Since the first oil well was drilled, there has been one hard and fast rule of casing design: each string of pipe had to be able to pass through the previous string. Standard casing strings allow for annular room between casing strings. This rule has caused a number of problems throughout the history of the industry, ranging from simple inconvenience, to premature abandonment and loss of reserves, to the inability to complete an exploratory well, thus the loss of an expensive offshore lease.

All this has changed since the oil and gas industry has learned how to reliably and repeatedly pass smaller diameter API standard size and grade pipe, and expand it such that its outside diameter (OD) is nearly equal to the inside diameter (ID) of the previous casing string. With this development, solutions for many of the problems described above have been developed.

Since the Bronze Age man has had the ability to work or deform metal, and shape it into items he finds to be useful to control his environment. The production of normal oilfield pipe is a very distant offshoot of mans first efforts at metalworking. While the techniques employed to produce oilfield pipe have changed over the years, the fact remained that once the pipe left the mill, and certainly once it had cleared the rotary table, its size was fixed.

The oil and gas industry is a very competitive business, and the drive to reduce costs is a natural extension of this competition. Engineers designing wells are constantly striving to optimize bits, cement, mud, casing design, everything associated with the wells. It is quite natural that there is little contingency for problems built into drilling programs. Optimists fill the ranks of the companies in the oil and gas exploration industry.

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