2014

Drilling Bit Selection

By

Karim Ahmed Shawky

Presented to :Dr: Taher El Faherny

A Dissertation Submitted to the Faculty of Engineering. The British University in Egypt.

In partial

Fulfillment of

The Requirements for the Bachelor Degree in petroleum engineering

June 2014

2014

Drilling Bit Selection

Dissertation Approved:

Dr. Taher El Faherny

Dissertation Adviser

Committee Member Name Here

Committee Member Name Here

Dean Faculty of Engineering

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Declaration of Originality

This is to certify that the work is completely my own and not of any other person,

unless explicitly acknowledged ( Including citation of published and unpublished

sources).

The work has not previously been submitted in any form to the British University

in Egypt or to any other institution for assessment for any purpose.

Signed: Karim Ahmed Shwaky

Date: 17 of June 2014

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Acknowledgements

I would like to express my sincere appreciation to my advisor, Dr.Taher El Fahareny, at the

Department of Petroleum Engineering at The British University in Egypt (BUE) for his

continuous technical and mental support as well as insights toward the completion of this work.

Undoubtedly, this work could not be possibly completed without such help.

I would especially like to thank Eng: Mohmoud Fathy for their generous support, coaching and

companionship during my Research Project shared their expertise with me very generously and I

have learned a lot from him. My thanks and appreciation also to (BUE) staff for willing to help

us, and above all to your good companionship.

My special thanks go to all my family members particularly, my parents for their unconditional

support, prayers, and love.

Karim Ahmed Shawky Mohmed , June 2014

Abstract

The drill bit represents the core of the drilling operation. The drill bit cut the rock by crushing

and gauging the cutting up to the annulus. The proper design for drill bit saves time and cost of

drilling the well. The drill bit may be rock bit or roller cone bit. Rock bit cut rock by shearing

action while the roller cone bit cut rock by gouging and scraping action. Selection of drill bit is

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affected by various criteria such as formation type, formation strength, cost per foot, and section

to be drilled (footage).

The design of drill bit includes:

- The design for the bit body

- The cutter structure and density

- The design of special feature such as back ream cutters in PDC bit

To have an effective rate of penetration using drill bit, bit hydraulics must be optimized for

effective rate of penetration using:

- Maximum hydraulic horse force

- Maximum impact force

Then the selection of proper nozzles sizes that achieve the hydraulic optimization is calculated

from the hydraulics.

Drill bit plays an important role in rate of penetration through two criteria; maximum hydraulic

horse power and maximum impact force. Optimization in these two criterions will give a

relationship between surface pressure Ps and Pbit that will enhance rate of penetration and hole

cleaning.

After drill bit has been used, bit dullness is performed to diagnose the condition of bit and

analyze the wear in the drill bit. Bit dullness is consisted of eight characters that represent the

overall condition of the bit.

Many factors in drilling operation will affect rate of penetration such as hole cleaning issues,

flow rate, hole deviation, drilling practices, drill bit type….etc.

Drill bit type, features will affect ROP as using the proper type of the bit and suitable features

that will increase bit life and bit efficiency. The drill is a bio-link in drilling cost estimation sheet

as the selection of the proper bit can save time and cost for the operator company.