Technical Capabilities In Offshore Completion And Workover Operations to Maximize Safety
Authors: Silcox William H. 
Published: October 2008

During completion and workover operations on oil and gas wells, producing zones are exposed in the well bore, consequently the presence of oil and gas under pressure in the well is always a real possibility. The oil industry, operators, contractors and suppliers, have long recognized the sensitive nature of offshore completion and workover operations and through the years have worked continuously to improve the procedures and equipment necessary to insure proper well control.

Well completion and workover operations will be reviewed along with the respective procedures and equipment utilized to maximize safety. Consideration will be given to the oil industry's ability to comply with the offshore rules and regulations promulgated by governmental agencies.

The author concludes that the oil industry has the capability, equipment and experience required to insure safe, clean offshore completion and workover operations.

INTRODUCTION

There are many ways to complete oil and gas wells. The completion method will vary with the gravity of the oil, the amount of gas, the type of formation, the presence of water, formation porosity, type of reservoir drive, the need for sand control, whether or not the well will flow, artificial lift requirements, the number of producing zones, stimulation needs, etc., etc.

Similarly, workovers will vary through a wide range of operations tailored to the specific problems of any given well. Because of this, rather than attempting to generalize, specific completion and workover operations will be discussed.

Before starting a detailed discussion on offshore well completion and workover operations, definition of what these operations consist of is necessary. In reviewing literature on these subjects, it appears that each author has his own ideas on what the definitions should be. For this paper they will be defined as follows:

Well Completion Operations:

All operations performed within the well bore and on the wellhead from the time the producing horizon is penetrated until the well is placed on production.

Well Workover Operations:

One or more of a variety of remedial operations on a producing well with the hope of restoring or increasing production. Examples of workover operations are deepening, plugging back, pulling or resetting the liners, squeeze cementing, fracturing, shooting, sidetracking and other operations which would change the mechanical condition of a well.

The question then arises, what is the difference between a workover and well servicing? For the purposes of this paper, well servicing will be defined as follows:

Well Servicing Operations:

Any operation on a well which does not change its mechanical condition. For example, bailing sand, acidizing, replacing failed tubing, changing pumps or gas lift valves, etc., are considered well servicing operations.

Since the title of the session at which this paper will be presented is "Safety in Offshore Resource Development on the Outer Continental Shelf," the rules and regulations which will be discussed are those prepared by the United States Geological Survey for the Outer Continental Shelf. Local and State regulations will not be considered.