1. ATMATM PETE 406 UBD ATMATM ATMATMATMATM PETE 406 - Underbalanced Drilling, UBD Lesson 8 Introduction Underbalanced Drilling Manual, UDM:Chapter 1

2. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Introduction What is UBD Why drill underbalanced Techniques and Limitations Historical perspectives

3. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Text “Underbalanced Drilling Manual”, Gas Research Institute, GRI, Chicago, 1997. –Can be purchased online from the SPE ($61.50 for members), IADC, and other Petroleum publishing companies –May be able to get it at the TAMU bookstore

4. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering 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

5. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering What is UBD Wellbore pressures “intentionally” maintained below formation pressure in the open hole section. Formation fluids flow into the well.

6. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions Flow (Live) operations; –wellbore pressures maintained below formation pressure and the well is intentionally allowed to flow during drilling or completion operations

7. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Gasified Fluid Operations (aerated fluid operated) –Operations intentionally undertaken with a two- phase drilling fluid containing some form of gas mixed with a liquid phase. –Gasified fluids normally do not contain a surfactant

8. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Foam Operations –Operations intentionally undertaken with a two- phase drilling fluid containing some form of gas mixed with a liquid phase and tied together with a surfactant –The liquid phase is continuous

9. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Mist Operations –Intentionally drilling with a two-phase fluid having a gas as the continuous phase –The liquid in this fluid system is suspended in the mixture as droplets

10. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Air Operations –Intentionally drilling using a pure gas as the drilling fluid. –The gas can be air, nitrogen, natural gas, or any combination of gases

11. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Mudcap Operations –Operations undertaken when the annular pressure during flow drilling exceeds the safe pressure limit of the rotating control element. –Mudcap operations are not underbalanced operation, but often are a result of drilling underbalanced and employ many of the same techniques and equipment

12. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Snubbing Operations –An intentional operation that employs either a snubbing unit or coiled-tubing unit in order to operate at surface pressures that exceed the limits of rotating control elements such as rotating heads or rotating blowout preventers

13. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Additional Definitions, con’t Coiled-tubing drilling –Use of a continuous-spool of pipe to drill with instead of the conventional jointed drillpipe. –CT units were originally designed to operate on live wells with surface pressure, without the requirement that the well be “killed” prior to entering the wellbore.

14. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives UBD operations are as old as the drilling industry –First wells were drilled with cable tool –Cable tool drilling was underbalanced

15. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives In 1866 a patent for air drilling was issued First recorded use of a gasified fluid was in West Texas in 1932

16. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives In 1938 mist was used by The Texas Company to drill in California. –Natural gas was continuous phase and oil was the liquid phase

17. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives Interest dropped off using gas as a drilling fluid until the 1950’s in: –Canada –West and Central Texas –Utah –San Juan Basin of New Mexico

18. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives Natural Gas drilling in West Texas

19. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives Early Air Compressors used in air drilling

20. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives In the 1960’s, the U.S. Atomic Energy Commission began to study the use of foams to clean wellbores as large as 60” in diameter

21. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives Until the mid 1980’s UBD was just a niche industry, and only utilized in certain areas around the world

22. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Historical perspectives Mid 1980’s Horizontal Drilling Became Fairly Common (Plot is for three companies)

23. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Growth in Horizontal Drilling spurred the resurgence in UBD (US operations)

24. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Rotating control Devices Until 1987 the maximum working pressure rating of rotating heads was was 150-300 psi. RBOP was developed with a working pressure of 1000 psi

25. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering More equipment development 1995 Varco-Shaffer introduced an RBOP with a rated to 3000 psi

26. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Closed loop system Allows re-use of the drilling fluids in foam systems environmentally friendly

27. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Nitrogen Generation System

28. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Electromagnetic MWD Tools

29. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Hollow Glass Spheres

30. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering Factors leading to increased UBD Horizontal drilling Closed systems High-pressure rotating control devices Electromagnetic MWD systems HP HV compressors Increased availability of Nitrogen Better reservoir and rock strength analysis Improved Hydraulics analysis Percussion tools Ability to re-circulate fluids

31. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering

32. ATMATM PETE 406 UBD ATMATM ATMATMATMATM Harold Vance Department of Petroleum Engineering