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PETE 406 - Underbalanced Drilling, UBD. Lesson 8 Introduction Underbalanced Drilling Manual, UDM: Chapter 1. Introduction. What is UBD Why drill underbalanced Techniques and Limitations Historical perspectives. Text.
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PETE 406 - Underbalanced Drilling, UBD Lesson 8 Introduction Underbalanced Drilling Manual, UDM: Chapter 1
Introduction • What is UBD • Why drill underbalanced • Techniques and Limitations • Historical perspectives 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 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 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. 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 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 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 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 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 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 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 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. 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 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 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 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 Harold Vance Department of Petroleum Engineering
Historical perspectives Natural Gas drilling in West Texas Harold Vance Department of Petroleum Engineering
Historical perspectives Early Air Compressors used in air drilling 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 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 Harold Vance Department of Petroleum Engineering
Historical perspectives Mid 1980’s Horizontal Drilling Became Fairly Common (Plot is for three companies) Harold Vance Department of Petroleum Engineering
Growth in Horizontal Drilling spurred the resurgence in UBD (US operations) Harold Vance Department of Petroleum Engineering
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 Rotating control Devices Harold Vance Department of Petroleum Engineering
More equipment development • 1995 Varco-Shaffer introduced an RBOP with a rated to 3000 psi Harold Vance Department of Petroleum Engineering
Closed loop system Allows re-use of the drilling fluids in foam systems environmentally friendly Harold Vance Department of Petroleum Engineering
Nitrogen Generation System Harold Vance Department of Petroleum Engineering
Electromagnetic MWD Tools Harold Vance Department of Petroleum Engineering
Hollow Glass Spheres Harold Vance Department of Petroleum Engineering
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 Factors leading to increased UBD Harold Vance Department of Petroleum Engineering
End of Lesson 8a Harold Vance Department of Petroleum Engineering