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Lesson 17. Flow Drilling Mudcap Drilling Snub Drilling Closed Systems Read: UDM Chapter 2.8-2.11 pages 2.180-2.219. Flow Drilling. Flow drilling refers to drilling operations in which the well is allowed to flow to surface while drilling.
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Lesson 17 Flow Drilling Mudcap Drilling Snub Drilling Closed Systems Read: UDM Chapter 2.8-2.11 pages 2.180-2.219
Flow Drilling Flow drilling refers to drilling operations in which the well is allowed to flow to surface while drilling. All UBD operations are really flow drilling operations, but the term is usually applied to drilling with a single phase mud, and no gas is injected except by the formation. Harold Vance Department of Petroleum Engineering
Drilling fluid selection • Density is determined by: • maximum pressure <= to formation pressure • minimum pressure dictated by wellbore stability • Pressure limitations of diverter and BOP equipment Harold Vance Department of Petroleum Engineering
Surface Equipment Harold Vance Department of Petroleum Engineering
Surface Equipment Harold Vance Department of Petroleum Engineering
Surface Equipment Harold Vance Department of Petroleum Engineering
Surface Equipment - RBOP Harold Vance Department of Petroleum Engineering
Surface Equipment - RBOP sealing element Harold Vance Department of Petroleum Engineering
Surface Equipment Harold Vance Department of Petroleum Engineering
Sizing Flare line Harold Vance Department of Petroleum Engineering
Sizing Flare line Harold Vance Department of Petroleum Engineering
Sizing Flare line Harold Vance Department of Petroleum Engineering
Sizing Flare line Harold Vance Department of Petroleum Engineering
Surface Pits • Primary Oil Separation Pit • Secondary Oil Separation Pit • Skimmer System Safety • Drilling Fluid Pit • Oil Transfer Tank Harold Vance Department of Petroleum Engineering
Operating Procedures • Mechanical objective is to control the well at the surface to maintain underbalanced conditions. • Maximum tolerable surfaces pressures should be established before drilling starts. Harold Vance Department of Petroleum Engineering
Mudcap Drilling • Utilized with uncontrollable loss of circulation during flowdrilling operations. • Higher pressures than can be safely handled with the rotating head or RBOP. • Not necessarily underbalanced. Harold Vance Department of Petroleum Engineering
Mudcap Drilling • Driller loads the annulus with a relatively high density high viscosity mud and closes the choke with surface pressure maintained • Drilling is then continued “blind” by pumping a clear non-damaging fluid down the drillstring through the bit and into the thief zone. Harold Vance Department of Petroleum Engineering
Mudcap Drilling • Applications: • Sustained surface pressures in excess of 2000 psi • Sour oil and gas production • Small diameter wellbores Harold Vance Department of Petroleum Engineering
Mudcap drilling Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements • Annular volumes will depend upon whether the operator desires continuous or periodic injection of annular fluids or whether a floating mudcap is to be used. Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements Harold Vance Department of Petroleum Engineering
Fluid Volume Requirements Harold Vance Department of Petroleum Engineering
Snub Drilling • UBD operation utilizing a snubbing unit or coiled tubing unit. • Expense is justifiable if very high formation pressures are anticipated, and uncontrollable loss of circulation is expected. Harold Vance Department of Petroleum Engineering
Closed Systems • Refers to UBD operations with a specific surface system. • A pressurized, four phase separator and a fully closed surface system, is used to handle the returned fluids. Harold Vance Department of Petroleum Engineering
Fig. 2.70 Harold Vance Department of Petroleum Engineering
Fig. 2.71 Harold Vance Department of Petroleum Engineering
Fig. 2.72 Harold Vance Department of Petroleum Engineering
Other Surface Equipment • Cuttings Filter • Heater • Degasser • Flare Stack/Pit • Production Tank • Water Tank • Solids Tank • Instrumentation Harold Vance Department of Petroleum Engineering