Coiled Tubing Operations at a Glance: What Do You Know About Coiled Tubing Operations!

Copyright © 2020 by Khosrow M. Hadipour. 802174

All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the copyright owner.

The views expressed in this work are solely those of the author and do not necessarily reflect the views of the publisher, and the publisher hereby disclaims any responsibility for them.

Xlibris

1-888-795-4274

www.Xlibris.com

ISBN:    Softcover           978-1-7960-7186-3

              Hardcover         978-1-7960-7187-0

              EBook                978-1-7960-7185-6

Library of Congress Control Number:      2019918683

Rev. date: 01/10/2020

Contents

Coiled Tubing Operation

Versus

Wireline and Conventional Workover Rigs

Operation: Coiled Tubing

What Do You Know about Well Pressure Control?

Water Disposal, Injection Wellbore, Low-

Pressure Gas Well Cleaning

Over-the-Land Operations

Disadvantages and Limitations of Coiled Tubing Applications

Professional Petroleum Engineer

The author’s presentation on the subject material is based on forty-two years of offshore and onshore downhole experience in drilling, completion, production, fracturing, downhole fishing, sidetrack drilling, remedial cementing, coiled tubing intervention operations, oil and gas remedial workover repairs, artificial fluid lift, gravel packing, plug and abandonment, and consulting experience while working for Gulf Oil company, Chevron USA, Pennzoil, Devon Energy, and AmeriCo Energy resources in Texas, Mississippi, Louisiana, New Mexico, the Gulf of Mexico, and Venezuela.

The written material is presented as basic information about coiled tubing only and is not intended to be a work procedure or a guideline for anyone to follow. We are not responsible for the information herein.

Application of Coiled Tubing in Oil and Gas Well Interventions

Coiled tubing is aggressive and fast growing in most wellbore intervention solutions. Maximizing well performance and oil and gas production are the coiled tubing achievements. Today’s advanced coiled tubing operation offers several unique, efficient, and cost-effective well intervention applications in oil and gas across the world.

Coiled tubing offers safety, well-controlled measures, and cost-saving alternatives in the oil and gas wellbore operations listed below:

• Oil and gas wellbore cleaning and pressure control techniques

• Snubbing and stripping operations (coiled tubing is the next best solution)

• Cost-effective in horizontal drilling

• Completion and through tubing gravel packing and fracturing

• Oil and gas stimulation and through tubing fracturing

• Fishing and remedial applications

• Cementing and borehole cleaning

• Zone isolation

• Hard-scale milling and junk snatcher techniques

You name it, coiled tubing can do it!

You will read about the advantages and limitations of coiled tubing applications as you go through this book. Oil and gas remedial interventions can be achieved using coiled tubing safely and cost-effectively without pulling the production equipment or killing a live well.

One of the major reasons for the development of coiled tubing is to prevent a time-consuming conventional workover rig from killing a well, releasing the mechanical isolation equipment, pulling the tubing string to conduct a minor remedial repair to a well, and placing the well back on production several days later.

Using standard offshore and/or onshore rigs often becomes expensive to work on a well. Some of the well interventions can be achieved in one day using coiled tubing without pulling production equipment and/or killing the well to save cost and production downtime (excellent invention and intervention).

Many challenging problems can develop in an oil and gas well as time passes. The reduction of oil and gas production because of sand and solids through perforations, saltwater disposal problems, casing problems, and through tubing gravel-packing operations are some of the few impressive intervention solutions offered by the coiled tubing industry worldwide.

What Is Coiled Tubing?

Coiled tubing is described as a long, continuous, flexible (enough) steel pipe that spools or is wound onto a large steel reel for transportation (deployed for well interventions).

The length of continuous coiled tubing spooled onto a steel reel depends on the well depth and the pipe’s outside diameter. In the old days, smaller-diameter coiled tubing strings of ¾″ and 1″ were spooled and applied in wellbore cleanup operations.

The improvement and rapid expansion of coiled tubing quality operations around the world enable the transporting of larger sizes of tubing strings for deeper and higher-pressure wellbores:

• 1″, 1 ¼″, 2, 2 ⅜″, 2 ⅞″, and even 3 ½″ pipe is used for offshore and onshore intervention operations (unbelievable!)

• Smaller coiled tubing strings generally are used in shallow well depths (3,000′ to 10,000′) in oil, gas, or saltwater disposable wells with low reservoir pressure safely

• Larger-diameter coiled tubing of 1 ½″, 2 ⅜″, 2 ⅞″, or 3 ½″ is normally spooled on huge steel reels for transportation, storage, or intervention operations in higher-pressure and deeper wells offshore or onshore (major projects with higher anticipated wellbore pressure)

The length of the continuous coiled tubing must meet or exceed the depth of a well before the equipment is transported to the well location (you do not want to be short of the pipe when reaching the target depth of 12,000′).

***

The basic invention of continuous flexible tubing started in 1944 by British engineers to supply and transport fuel across water channels to the Allied armies during the war. The project was called PLUTO (pipeline under the ocean). The coiled tubing was later improved in Canada and was called Flex-Tube.

In 1970, Brown Oil Tools, Otis Engineering, and Bowen Fishing started implementing the development of coiled tubing in oil and gas operations in Texas. In 1977, I used a coiled tubing unit from Otis Engineering in Bryan–College Station, Texas, for the first time, and I was anxious and wondered what coiled tubing could do at that time.

Since 1977, coiled tubing tools and equipment have significantly improved along with trained and knowledgeable operators of today. Many engineering thoughts and studies have been implemented in the improvement of coiled tubing tools and equipment of today (coiled tubing equipment may still need improvement!). I am impressed with coiled tubing’s cost-saving interventions in oil, gas, saltwater disposal, and other wellbore applications (I am still using coiled tubing today, in 2019).

Coiled tubing tools and equipment are designed to conduct specific challenging operations in oil and gas wells in safer, faster, and more cost-effective and efficient ways:

• Well control (keeping the well pressure under control while snubbing and stripping)

• Oil and gas well horizontal drilling

• Milling objects and continuously washing and circulating solids

• Washing the well and displacing liquid from wellbores (de-liquid gas wells)

• Cementing and spotting cement plugs

• Acid stimulation and reservoir fracturing

• Plugging wellbores

• Fishing and other well interventions

• Jetting and wellbore open-hole cleaning

What Is the Coiled Tubing Unit?

If you have not seen or worked on coiled tubing, you may run into or see units on the highway and/or at truck stops.