lesson 1 bajo balance

8/3/2019 Lesson 1 Bajo Balance

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PETE 689Underbalanced Drilling(UBD)

Lesson 1

IntroductionRead: Underbalanced Drilling Manual

Chapter 1

Harold Vance Department of Petroleum Engineering


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Introduction

Course Syllabus Texts

Grading



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Introduction


What is UBD Why Drill Underbalanced

Techniques and Limitations

Historical Perspectives


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Course Syllabus


PETE 689:

Special Topics in Underbalanced Drilling

Prerequisites: Graduate Classification

Credit: 3 hours


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Course Description


This course provides an introduction andapplication of techniques that can beutilized in underbalanced drilling. It willcover topics such as BOP equipment, the

types of drilling fluids used (air, mistfoam, etc.), flow drilling, and mud capdrilling.


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Text


Underbalanced Drilling Manual

Gas Research Institute, GRI,Chicago, 1997.May be able to get it at the TAMU

Bookstore.

Can be purchased online from the SPE,IADC, and other Petroleum PublishingCompanies.


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References


A project Management Approach To

Underbalanced Operations.Signa Engineering Corp., Houston, 1998.

Mudlite Air/Mist/Foam Hydraulics

Model.Maurer Engineering Inc., Houston, 1988

Selected papers and texts.


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Grading

Exam A 10/15/2003 25%

Exam B 12/04/2003 25% Class Project (presentations) 25%

Homework 25%

Dates are subject to change depending on the studentand Instructor schedules. Please check your schedulesthis week and we will discuss the actual dates onThursday.



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Instructor

Dr. Jerome J. Schubert, PE, CPA

Phone: 979/862-1195 Office: Richardson Rm 501K

e-mail: [email protected]

Lecture Location:http://pumpjack.tamu.edu/~schubert

click on PETE 689_UBD



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Office Hours

Tuesday & Thursday.

10:00 - 11:30 a.m.

Or whenever I am in my office.



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What is UBD

Wellbore pressures intentionallymaintained below formation pressurein the open hole section.

Formation fluids flow into the well.



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Additional Definitions

Flow (Live) operations.

Operations intentionally undertakenwith a liquid drilling fluid systemwhere the hydrostatic pressure

exerted by the liquid column is belowformation pore pressure such that theformation fluid is allowed to flow tothe surface during the operations.



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Additional Definitions, cont Gasified Fluid Operations.

(Aerated Fluid Operated).

Operations intentionallyundertaken with a two-phasedrilling fluid containing some

form of gas mixed with a liquidphase.

Gasified fluids normally do notcontain a surfactant.



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Additional Definitions, cont

Foam Operations:

Operations intentionallyundertaken with a two-phasedrilling fluid containing someform of gas mixed with a

liquid phase and tied togetherwith a surfactant.

The liquid is the continuousphase.



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Mist Operations:

Intentionally drilling with atwo-phase fluid having a gasas the continuous phase.

The liquid in this fluidsystem is suspended in themixture as droplets.


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Air Operations:

Intentionally drilling using apure gas as the drilling fluid.

The gas can be air, nitrogen,natural gas, or any

combination of gases.



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Mudcap Operations:

Operations undertaken when the annularpressure during flow drilling exceeds thesafe pressure limit of the rotating controlelement.

Mudcap operations are not UB operation,but often are a result of drillingunderbalanced and employ many of thesame techniques and equipment.



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Snubbing Operations:

An intentional operation thatemploys either a snubbing unit orcoiled-tubing unit in order tooperate at surface pressures that

exceed the limits of rotatingcontrol elements such as rotatingheads or rotating blowoutpreventers.



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Coiled-tubing drilling:

Use of a continuous-spool of pipe todrill with instead of the conventional

jointed drillpipe.

CT units were originally designed to

operate on live wells with surfacepressure, without the requirementthat the well be killed prior toentering the wellbore.



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Why drill underbalanced?

Increased Penetration Rate.

Increased Bit Life.

Minimized Lost Circulation.

Minimize Differential Sticking.



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Why drill underbalanced?

Reduced Formation Damage.

Earlier Production.

Reduced Stimulation Requirements.

Improved Formation Evaluation.

Environmental Benefits.



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Historical perspectives

UBD operations are as old as thedrilling industry:

First wells were drilled with cabletool.

Cable tool drilling wasunderbalanced.



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In 1866 a patent for air drillingwas issued.

First recorded use of a gasifiedfluid was in West Texas in 1932.



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In 1938 mist was used by

The Texas Company to drill inCalifornia.

Natural gas was continuous

phase and oil was the liquidphase.



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Interest dropped off using gas asa drilling fluid until the 1950swere it showed a resurgence in:

Canada.

West and Central Texas.

Utah.

San Juan Basin of New Mexico.



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Typical of Nat Gas operations in New Mexico


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Early Air Compressors used in air drilling


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HistoricalPerspectives


Natural Gasdrilling in

West Texas.


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In the 1960s, the

U.S. AtomicEnergy

Commission

began to study the

use of foams toclean wellbores as

large as 60 in

diameter from 45

feet as 2000 feet.


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Until the mid 1980s UBD was

just a niche industry, and onlyutilized in certain areasaround the world.



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Mid 1980s Horizontal DrillingBecame Fairly Common (Plot

is for three companies)

Year

No.ofW

ells


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Mid 1980s Horizontal Drilling

Became Fairly Common (Plot is

for three companies)

Year

Total

LightweightFluidWells Growth in Horizontal Drilling

Spurred the Resurgence in UBD(US operations)


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Until 1987 the maximumworking pressure rating of

rotating heads was 150-300psi.

RBOP was developed with aworking pressure of 1000 psi.



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Rotating Control DevicesRBOP-1000 psi (1987) PCWD-3000 psi (1995) RCH-2500 psi (1995)


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Closed Loop System Allows re-use of the drilling fluids in foam

systems environmentally friendly.



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Nitrogen

Generation System



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Electromagnetic

MWD Tools



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Hollow Glass Spheres



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Factors Leading

to Increased UBD

Horizontal Drilling.

Closed Systems. High-Pressure Rotating Control

Devices.

Electromagnetic MWD Systems.

HP HV Compressors.



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Factors Leading

to Increased UBD


Increased Availability of Nitrogen.

Better Reservoir and Rock Strength

Analysis.

Improved Hydraulics Analysis.

Percussion Tools.

Ability to Re-Circulate Fluids.


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PETE 689Underbalanced Drilling(UBD)


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