Underbalanced Drilling and Managed Pressure · PDF fileUnderbalanced Drilling and Managed Pressure Connections 1 ... Bearing Assembly ... Monitoring bottom hole pressure with pressure

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Underbalanced Drilling and Managed Pressure Connections

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June 2012

Summary of Presentation

Rig setup on EWG 103 for Underbalanced Drilling Operations- Designed as a light fluid drilling vertical rig- Converted to do underbalanced air drilling- Airpack & hard lines

Managed Pressure connections

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Rig setup

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Easternwell 103 – Rig Setup for Underbalanced Drilling

Stand-pipeTo Well

Bypass line

Strata float

Blooie line

Test Separator

Choke Line

Choke manifold

Kill LineChoke Line

Mud Tank

Mud Pump #1

M d P #2

Stand-pipe manifold

Compressor Mist Pump

Mud Pump #2

Primary Jet

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Compressor

Compressor

BoosterJet

CFM Meter Killing Well By-pass

P & T transmitter

BOP Stack and Well Head

Rotating head and Bearing Assembly

Annular Rams

Ai C D illiAir Cross Drilling Spool

Pipe Rams

Drilling Spool

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B-Section

A-Section

Air Compressors and Boosters

3 Compressors: 1350 cfm @ 350 psieach (+ one spare)

1 Booster: 1400 psi & ~ 2000 CFM

Monitored in the Air-pack manifold Orifice Plate (CFM)

To booster

Pressure Relief Valves

Mist Pump

CompressorFrom compressors

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Compressor

Compressor

Booster

Air-pack Manifold

mufflers

Psi readingCFM Meter Psi readingCFM Meter

Vent

P & T transmitter

Metering Orifice Plate (CFM di )

Main air flow to stand-pipe

(CFM reading)

Line to spare mist

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Line to spare mist pump (TDC)

Addition of Airpacks in the Circulating System

Mist Pump

Fluid from C /

Air from Air-pack

Cement / Mist Pump

Mist into lineMist into line up to stand pipe

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Blooie Line and Primary Jet

Relief line fromChoke Manifold

Sample Catcher

Blooie Line

Degasser Blooie Line

Primary Jet(from stand-pipeManifold)

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Underbalanced drilling operations

Directional drilling in 75 degree inclination well with motor

Average drilling rate is 10m/hr including connections time Average drilling rate is 10m/hr including connections time

Managed pressure connection time ranges from 10 minutes to 20 minutes20 minutes

Monitoring bottom hole pressure with pressure while drilling subsub

Normal reservoir pressure is 2 – 4ppg, drilling with circulating BHP ranging from 400 – 450 psiBHP ranging from 400 450 psi.

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Managed Pressure Connections

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Formation pressures ranges from 250 – 500.

To minimise bottom hole pressure cycling (of up to 500 psi) between circulating ( ll ) ( ) l f(drilling) and static (connection) modes, a connection procedure was developed for building up and shutting in casing pressure (SICP) before diverting the air flow to the primary jet.

Based data from EM‐MWD package with a Pressure While Drilling sub in the BHA. BHA measurement indicated significant pressure cycling being applied to the coal formations between drilling and connection mode.

This pressure cycling could possibly lead to borehole instability and breakout, resulting in stuck BHA while having static pipe in hole during connections. Cycling of coals could also cause hole issues while running pre‐perforated liner.

Managed pressure connection procedures is developed to reduce BHP fluctuations between drilling and connection modes to below a target of 100 psi.

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First Trial of Managed Pressure Connections - Fairview Concept 10 Wells

Wells Fairview 508 Fairview 509 Fairview 506

Casing

9-5/8” @ 129.5m (MD/TVD)

7” @ 1231m / 653m

9-5/8” @ 130.2m (MD/TVD)

7” @ 1250 5m / 658 8m

9-5/8” @ 130m (MD/TVD)

7” @ 1252m / 648 6mCasing Policy

7 @ 1231m / 653m (MD/TVD)

6-1/8” Production Hole to TD

7 @ 1250.5m / 658.8m (MD/TVD)


7 @ 1252m / 648.6m (MD/TVD)


W ll TD1544.5m MDRT 1613m MDRT 1630m MDRT

Well TD734.5m TVDRT 738.4m TVDRT 745.9m TVDRT

Survey at Well TD

Inclination = 64°Azimuth = 346.4°

Inclination = 76°Azimuth = 34°

Inclination = 73.8°Azimuth = 331°

Formation Pressure 275 psi (2.4 ppg EMW) 225 psi (1.94 ppg EMW) 264 psi (2.28 ppg EMW)

Target Formations TVD

673 1 t 673 7 (0 6 ) 674 t 675 (1 ) 656 t 656 9 (0 9 )A Coal 673.1m to 673.7m (0.6m) 674m to 675m (1m) 656m to 656.9m (0.9m)

B Coal 681.3m to 687m (5.7m) 684m to 688.3m (4.3m) 686.4m to 692.8m (6.4m)

D Coal 707.6m to 711.1m (3.5m) 710.1m to 715m (4.9m) 714m to 717.5m (3.5m)

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E Coal 728.8m to 729.5m (0.7m) 732.8m to 733.9m (1.1m) 740m to 740.2m (0.2m)

Bottomhole Pressure Behaviour in Air Drilling

Pf = Friction Pressure

Phyd = Fluid hydrostatic Pressure

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Connection after Drilling Phase (A) – Performed without locking SICP

Connection after Drilling Phase (B) – Performed with locking SICP

Procedure for minimizing BHP fluctuations

Determine hydrostatic pressure of fluid in annulus (Phyd)Phyd = BHP – SICP (assume formation P of around 250 psi)

Phyd = 264 – 130 = 134 psi

Based on the pumping rates and the drilling fluid properties,

Circulating BHP while drilling production hole in Fairview 506 = 440 psig g p p

SICP to be locked in connections = Circ. BHP – Phyd

= 440 psi – 134 psi

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= 306 psi


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Air Drilling Setup – Drilling 6-1/8” Production Hole

Fl th f i / i t / f

Standpipe Manifold

Flow path of air / mist / foam through standpipe manifold (highlighted in RED) while drilling 6-1/8” Production holedrilling 6 1/8 Production hole

Valves 1, 2, 5 – CLOSED

Valves 3 & 4 – OPEN

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Air Drilling Setup – Making a Connection

Standpipe Manifold

Flow path of air / mist / foamFlow path of air / mist / foam through standpipe manifold (highlighted in RED) while making connection.

Pressure trapped in the drill string is released through secondary jetis released through secondary jet (highlighted in GREEN)

Valves 1, 3, 5 – OPEN

Valves 2 & 4 – CLOSED

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BHP behaviour in Fairview 508 well


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BHP behaviour in Fairview 509 well


Formation Pressure

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BHP behaviour in Fairview 506 well – Adopted procedure to lock in SICP during connections

Thank you

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Underbalanced Drilling and Managed Pressure · PDF fileUnderbalanced Drilling and Managed Pressure Connections 1 ... Bearing Assembly ... Monitoring bottom hole pressure with pressure

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