The Guide to Oilwell Fishing Operations

Tools, Techniques, and Rules of Thumb

Joe P. DeGeare, David Haughton, Mark McGurk

• Publisher: Gulf Professional Publishing
• Year: 2003
• eBook ISBN:
  9780080542492
• Topic: Technologie et ingénierie
• Subtopic: Géologie et sciences de la Terre

No fishing job is a welcome operation, but this new edition of a classic reference helps you do the job efficiently and economically. This practical guide is packed with illustrations and descriptions of fishing equipment and tools to help you solve just about any fishing problem. Foremen, engineers, and superintendents who write procedures, make drilling decisions, and supervise operations will find this handy book invaluable, and trainees will find it an excellent learning manual. Oilwell Fishing Operations tells how to free stuck pipe, part the pipe string, and repair casing. It describes the various types of catching tools, jars, mills, junk, baskets, and hydrostatic and rotating bailers, along with washover operations, wireline fishing, fishing in cavities, and fishing in high angle deviated and horizontal wells. The author's tips and warnings are sure to save you time and money in avoided misruns, downtime, and lost equipment.* Currently, there is no other book on the market focused only on oilwell fishing operations.* Covers all of the best practices for oilwell fishing operations and all of the latest equipment.* The first book in the "Gulf Drilling Guides" series, the first, last, and only stop for the drilling engineer with a problem to solve.

1

Conventional Fishing

In oilfield operations, fishing is the technique of removing lost or stuck objects from the wellbore. Fishing jobs fall into three classifications: open hole, when there is no casing in the area of the fish; cased hole, when the fish is inside casing; or thru-tubing, when it is necessary to fish through the restriction of a smaller pipe size (tubing).

The term fishing is taken from the early days of cable-tool drilling. At that time, when a wireline would break, a crew member simply put a hook on a line and attempted to catch the wireline to retrieve the tool or “fish.” Necessity and ingenuity led these oilfield fishermen to develop new “baits.” The trial-and-error methods of industry’s early days built the foundation for many of the catch tools in use today.

Fishing-tool companies have kept pace with the oil industry’s rapid development and the deployment of new technology. Today many are capable of fishing successfully in well depths exceeding 20,000 ft., in high-angle and horizontal wellbores, and in deep water.

A fish can be any number of things, including stuck pipe, broken pipe, drill collars, bits, bit cones, dropped hand tools, sanded-up or mud-stuck pipe, stuck packers, or other junk in the hole. Washovers, overshot runs, spear runs, wireline fishing, stripping jobs, and jar runs are among the many fishing techniques developed to deal with the different varieties of fish.

Because there are so many different kinds of fish and fishing jobs, many different tools and methods can be applied. Some of them can be very simple; others are extremely complex. No two fishing jobs are alike, yet many are similar. An experienced fishing-tool supervisor will draw from the experience gained from many jobs.

Fishing jobs are very much a part of the planning process in drilling and workover operations. With the increasing cost of rig time and deeper, more complicated wells, operators will often budget for fishing operations. When a fishing operation is a planned procedure for a workover, the operator will work closely with a fishing-tool company to design a procedure and develop a cost estimate. Taking into account the probability of success for a fishing job, the cost of the fishing job has to be less than the cost of re-drilling or sidetracking the well for it to make economic sense.

Fishing can be thought of as a “risk management” tool. When used successfully, it can save a well. Because fishing is more of an art than an exact science, there can be more than one approach to a problem. Fishing-tool company personnel have valuable experience gained from performing many fishing jobs under a variety of circumstances. This experience usually points to a specific approach when all factors are considered. Although no fishing job can be guaranteed to succeed, the combination of experienced personnel and continuing advances in fishing-tool technology usually offers an option with a good probability of success.

To maximize this probability, properly planning a fishing job is most important. Pre-planning meetings should be held and should include everyone involved in the job, such as fishing-tool operators or supervisors, mud-company personnel, rig personnel, electric-wireline company representatives (where applicable), and any others who might become involved. It is much cheaper to determine that a certain procedure will not work before doing it.

THRU-TUBING FISHING

The increased use of coiled tubing in the last 20 years has led to many technological advancements in thru-tubing workover applications. These include cleanouts, acid stimulations, milling, underreaming, cutting, and coiled-tubing conveyed thru-tubing fishing systems. The ability to perform these operations without having to pull the production string has provided the operator with a cost-effective alternative to conventional rig workovers. Coiled tubing conveyance also allows remedial operations to be completed without having to kill the well. This eliminates possible formation damage from heavyweight kill fluids in the well. Operations using coiled tubing are usually completed in a much shorter time frame than conventional rig workovers, which means the shut-in time of the well is reduced during the operation, resulting in less loss of production.

Early thru-tubing fishing systems were simply composed of tools designed for wireline conveyance and did not take advantage of the attributes of the coiled tubing. These tools did not allow circulation through the tool, and early tools modified to allow circulation had restricted flow paths. Also, these tools did not have the tensile strength required to handle the impact loads of the jarring systems being developed for coiled tubing use. In addition, some tools developed for other coiled tubing services, such as inflatable-packer operations, proved inadequate for fishing applications. Some tools had to be designed specifically for thru-tubing fishing operations. A dramatic evolution in thru-tubing fishing-tool technology and design has occurred in the last decade, and individual tool components can now be assembled to meet much more demanding and varied applications.

Thru-tubing fishing systems that run on coiled tubing are used to retrieve many different types of fish. These include coiled tubing conveyed bottom-hole assemblies (BHAs) that have been disconnected, stuck flow-control devices in landing nipples that cannot be retrieved with wireline, inflatable bridge plugs, wireline lost in the hole, and coiled tubing itself. Coiled tubing conveyed fishing gives the operator another alternative, if wireline fishing is unsuccessful, before a conventional rig workover is required.

Chapters 22 to 30 will outline the specific tools and techniques used in coiled-tubing conveyed thru-tubing fishing applications and services. Tool-string hookup design will also be discussed for common thru-tubing fishing applications being carried out today.

This book will not make you a fishing expert, but it will give you a basic understanding of fishing, fishing tools, and fishing problems you may encounter. With this knowledge, you should be better prepared to make logical decisions when fishing becomes necessary.

2

Communication and Avoiding Hazards

Like many other oilfield operations, fishing jobs bring together rig, operating-company and service-company personnel who may not work closely together every day. When such a group is formed to solve the complex problems fishing jobs can present, the importance of clear and precise communication cannot be over-emphasized. Never assume people understand the explanation or description of the problem. Because fishing jobs are potentially hazardous, it is critical to make sure all descriptions of the problem and plans for its solution are thoroughly understood by all the parties involved.

To avoid hazards, the following steps should be followed prior to and during a fishing job. Remember, these steps can only be taken successfully by employing clear and accurate communication among all parties.

Collect complete and accurate information.

Notify all parties involved, such as the fishing-tool company, mud company, wireline company, etc. It is imperative that all parties cooperate and communicate at all times. This is the largest factor in a successful fishing operation, and it is only through effective communication that the individuals involved will be able to select the proper tools and plan the proper methods to do the job in the safest, most cost-effective manner.

Every effort should be made to recover something or to improve the situation on each trip into the hole. Mis-runs waste money, and on every additional trip into the hole, additional mishaps are possible.

Drawings noting dimensions should always be made of everything run in the wellbore. This responsibility should not be left to service-company personnel alone. Operating-company personnel should also make independent measurements and sketches. Keeping track of accurate dimensions of all equipment is critical for economical fishing.

If a large or unusual tool or downhole assembly is being run, a contingency plan should be created to fish it. Always ask these questions: Can this be fished? Can it be washed over? Do I have the tools available to fish it? What is the risk of the fishing tools becoming stuck or lost based on my hole conditions?

Confirm that all tools will work properly downhole prior to running them, either by surface testing or by having the service company supply copies of test and inspection reports.

When running any fishing tool in a well, use a moderate speed. Most fishing tools are designed to go over and around the fish. For a tool to do this, it has to be larger than the fish diameter. In most cases this makes the tool close to the hole’s size. If the tool is run at a fast speed while going into the hole, it will act as a piston and cause excess pressure below it. This can cause lost circulation. If a tight place in the well is hit, the tool might wedge so tightly that it cannot be pulled out.

Caution should be taken when pulling fishing equipment ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Preface
• Acknowledgments
• Chapter 1: Conventional Fishing
• Chapter 2: Communication and Avoiding Hazards
• Chapter 3: Economics of Fishing
• Chapter 4: Cardinal Rules in Fishing
• Chapter 5: Pipe Sticking
• Chapter 6: Determining Stuck Point
• Chapter 7: Parting the Pipe String
• Chapter 8: Catch Tools
• Chapter 9: Jarring Stuck Pipe or Tools
• Chapter 10: Washover Operations
• Chapter 11: Loose-Junk Fishing
• Chapter 12: Mills and Rotary Shoes
• Chapter 13: Wireline Fishing
• Chapter 14: Retrieving Stuck Packers
• Chapter 15: Fishing in Cavities
• Chapter 16: Sidetracking Methods
• Chapter 17: Section and Pilot Milling
• Chapter 18: Repair of Casing Failures and Leaks
• Chapter 19: Fishing in High-Angle Deviated and Horizontal Wells
• Chapter 20: Plug-and-Abandon Operations
• Chapter 21: Miscellaneous Tools
• Chapter 22: Thru-Tubing Standard Tools
• Chapter 23: Thru-Tubing Fishing
• Chapter 24: Thru-Tubing Fishing Jars and Accelerators
• Chapter 25: Thru-Tubing Debris Catchers
• Chapter 26: Thru-Tubing Workover Motors
• Chapter 27: Thru-Tubing Milling
• Chapter 28: Thru-Tubing Underreaming
• Chapter 29: Coiled-Tubing-Conveyed Tubing and Drill-Pipe Cutting
• Chapter 30: Thru-Tubing Impact Drilling
• Glossary
• Bibliography
• Index