Use of Automated MPD to Eliminate Losses and Control Influx in

Use of Automated MPD to Eliminate Losses and Control Influx inEliminate Losses and Control Influx in Hot Fractured Rock Geothermal Wells Eliminate Losses and Control Influx in Hot Fractured Rock Geothermal Wells

Presented during:

Underbalanced and Managed Pressure Drilling:

The SPE Applied Technology Workshop on

O C C

Technologies for Improving Drilling Performance, Enhancing Production, and Reducing Project Risk

© 2008 At Balance All Rights Reserved

12-15 October 2008 • Ho Chi Minh City, Vietnam

Australia Hot Fractured Rock Project

Map showing location of active drilling block GEL 98

Concept

HeatExchanger

Binary GeothermalPower Plant

HeatExchanger

Binary GeothermalPower Plant

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Old dry gas wells

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2InsulatingSedimentaryRocks

Old dry gas wells

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4.5km Granite270 C0

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4.5km Granite270 C0

Energy Production Potential

• HFR potentialDefined resource potential > 10,000 MW2.5 km2 will sustain 275 MWe (net) power station for 30 years

• Reserves Equivalent Thermal equivalent of 50 Bbbls of oilThermal equivalent of 50 Bbbls of oil 12 x greater than NW shelf gas reserves in W.A.

• Near term goal 500 MW b 2015500 MW by 2015

• Long term goal 4,000 MW developed by 203025 percent of new energy generationGreenhouse gas reduction equivalent to 5 million cars

– 30 million tons of CO2

Project Drilling Status

• Four Wells Completed To DateHabanero 1 Conventional 2003Habanero 1 Conventional, 2003

Habanero 2 Main hole UBD / MPD 2004– Main hole UBD / MPD, 2004

– Sidetrack 1 MPD, 2004

– Sidetrace 2-4 UBD, 2006,

Habanero 3 UBD / MPD, 2008

Jolokia 1 UBD / MPD 2008Jolokia 1 UBD / MPD, 2008

Managed Pressure Drilling System

Constant Bottomhole Pressure Method

Habanero 2 Main & ST 1 MPD System

• Manifold rated to 10,000 psi • Experimental control system• High pressure flow meterHigh pressure flow meter• Rig pump #2 for backpressure• HP & LP PRV’s

Habanero 3 Equipment Layout

• Manifold rated to 5,000 psi • State of the art automation

LP flow meter• LP flow meter• Dedicated pump

Connection Plot

BOP & Rotating Control Device

Rotating Control Device

• Used to contain pressure during drilling and connections.connections.

• Two different types used.Smith HOLD 2500 and Weatherford 7100

– Static 5000 psi / Dynamic 2500 psi.

• Pack-off elements changed after each bit trip. • No wear problems.

Habanero 1

• Drilled conventionally with 5kpsi BOP stack.• Started with 11 8 ppg• Started with 11.8 ppg• Weighted up to 15.8 ppg

Over pressured required 10kpsi BOPOver pressured, required 10kpsi BOPAdded to energy potential

• Recurring kicks, H2O, CO2 , Methane Gas.g , 2 , 2 ,• Mud degraded by influxes.• Lost circulation / kicksLost circulation / kicks• Drilling NPT = 60 days

Better method of controlling pressure required

Habanero 2• Drilled w/ MW below pore pressure (UBD).

Maintained BHP at 15.3 ppg with between 75 and 300 psi backpressure.Encountered first fracture and stopped influx by increasing backpressure.M d l f iMud system not tolerant to formation water.Drilled ahead maintaining constant bhp at top fracture.ROP 6 -12 ft/hr.Approx 1.5 days to round trip. Using heavy mud.

• Encountered a second (massive) fractureTotal losses into lower fracture.Unable to establish circulation with LCM and still drill aheadCould not reduce BHP and prevent influx from top fracture.p pDrilled mud cap at reduced pump rate with no apparent plugging.BHA failure, fish left in hole.

• ST- 1MPD to maintain BHP at +/- 14 9 – 15 3 ppgMPD to maintain BHP at +/- 14.9 – 15.3 ppg.Did not intersect fractures. Suspected plugging due to mud cap but directional problems?

Would Prefer Not To Lose Heavy Mud Into Fractures

UBD Pressure GradientST-2,3,4 HP UBD (increase ROP / prevent mud loss into Fractures)

Source: Presentation by Phil FrinkBlade Energy Partners. Managed Pressure Drilling Geothermal applicationsSPE ATW, Phuket Thailand, June 11-14, 2006

Solution To Not Losing Mud Into Fractures

Habanero 2 ST 2,3,4 – UBD

• IADC Risk Class 3• IADC Risk Class 3 > 5000 psi shut-in required.

• ROP 5 – 20 ft / hr M 10 h d illi t• Max 10 hours drilling to reduce risk of bit failure.

• 3 days to round trip.• Borehole stability?• Hole cleaning problems.

Drill string stuck / failures• Drill string stuck / failures.Source: Presentation by Phil Frink, Blade Energy Partners. Managed Pressure Drilling Geothermal applicationsSPE ATW, Phuket Thailand, June 11-14, 2006

High Pressure UBD Did Not Achieve Objectives

Bit Condition on Habanero 2 UBD st

3 ½ Hours Using a High Speed Turbine

Habanero 3

• Drilled 300 feet UBD for kick detection.Minor kicks. Adjusted backpressure to stop influxes.Flow out increased > 500 gpm.1.2 ft bit drop.Increased backpressure to control influx. 16.1 ppg equivalent.1200 psi maximum surface pressure.New bit design ROP 10 – 12 ft / hr.

• Drilled 150 feet MPD.Drilled 150 feet MPD.Mud weight increased to reduce surface pressure.Bottomhole pressure reduced to 15.3 ppg equivalent.New bit design ROP of 6 – 8 ft/hrNew bit design ROP of 6 – 8 ft/hr.No further kicks or losses.

Constant Bottomhole Pressure Effective in Controlling Well

Kick Detection & BHP Control

Flow Out ChangesFlow Out Changes

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Jolokia - 1

• Drilled 3770 ft UBD and MPD• 150 psi minimum / 1000 psi maximum backpressure.p p p• Initial fracture identification via kick then MPD.• Further identification assumed on drilling breaks and gas.• Average ROP of 5 – 8 ft/hr• Well circulated to heavy mud for trips.

B k t d b ff t hil t i i t• Backpressure to reduce swab effects while tripping out.• Approximately 1.5 days to round trip.• No mud losses• No mud losses.• Objectives met without incident.

No NPT but need to improve ROP

Geodynamics Summary

• Identified fractures using UBD.• Initially stopped influxes with backpressure.• Automated chokes with manual bhp setpoint. • Minimized increase in mud weight.• Eliminated NPT due to kicks / losses• Eliminated NPT due to kicks / losses.• HP UBD trips 2x as long as MPD.• HP UBD / borehole stability / hole cleaning problems.y g p• MPD borehole stability maintained.• Short bit life due to granite and temperatures.

Hi h RCD b h l f l• Higher pressure RCD may be helpful.Reduce mud weight / solids.Reduce mud contamination problems.

Thank YouThank You

Special thanks to Geodynamics and Paul Fredericks, At Balance Americas for developing this presentation.

© 2008 At Balance All Rights Reserved