DrillSafe Forum Jun08 KEEP DRILLING Ken Muir Managed Pressure Drilling Talk

7/28/2019 DrillSafe Forum Jun08 KEEP DRILLING Ken Muir Managed Pressure Drilling Talk

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Managed Pressure Drilling (MPD)Systems & Applications

Ken MuirVP, EngineeringKeep Drilling Pte. Ltd.

www.keepdrilling.com


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Managed Pressure Drilling WHY? Conventional Drilling hasnt changed much in over 100

years its still an Open to Atmosphere system The easy drilling is behind us drilling problems are

increasing and its getting worse Drilling performance curve is flat - technology advances

are cancelled out by increased drilling problems

Independent studies reveal that 25 33% of new wellscant be drilled conventionally Drilling costs are now higher

than facilities costs (used to

be the other way round) MPD is a safer drilling

method

We need a better way to drill

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Drilling MethodsOVERBALANCED DRILLING: Drilling with BHP higher thanformation pressure = CONVENTIONAL DRILLING.

Objective: To minimise the chance of an influx.PERFORMANCE DRILLING: Drilling with low BHP to enhance ROP &bit life. Used in well construction = AIR or GAS DRILLING.

Objective: To enhance penetration rateUNDERBALANCED DRILLING: Drilling with the BHP below reservoirpressure naturally lower or induced = UBD.Objective: To minimise reservoir damageMANAGED PRESSURE DRILLING: Drilling with precisely controlledBHP to avoid influx, fluid loss or borehole instability. Pressureprofile managed by addition of surface pressure or by change inhydrostatics or friction pressure.

Objective: To minimise pressure related drilling problems3


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MPD AdvantageConventional Drilling:

BHP = MW + Annulus Friction PressureBHP control = only pump speed & MW change,because its an Open to Atmosphere System.

Managed Pressure Drilling (MPD):BHP = MW + Annulus Friction Pressure + BackpressureBHP control = pump speed change, MW change &

application of back-pressure, because its anEnclosed, Pressurized System.

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IADC Definition:The objectives are to ascertain the downholepressure environment limits and to manage theannular hydraulic pressure profile accordinglyMPD does not change the downhole pressurewindow pore pressure and fracture gradient remainunchangedbut MPD helps us to remain in the window

MPD Advantage


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Source James K DodsonCompany Studyirectional & Completion5%

Chemical Problems3%Stuck Pipe11%

Sloughing Shale3%

Wellbore Instability1%

Cement squeeze9%

Twist Off3%

Wait on Weather13%

Casing or WellheadFailure5%

Rig Failure21%

Other1% Kick9% Gas Flow


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Who is using MPD?

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MPD System Components

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Conventional BOP & Choke Manifold (no change)


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Automated MPD System


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Step Choke

Pressure

(psi)

Pump

Rate

(gpm)

Pump

(spm)

Pump

Press

(psi)

Friction

DP (psi)

BHP

(psi)

Pump Rate while drill ing 20 196 70 2995 393 1566

Increase choke pressure 48 197 70 3003 393 1617

Decrease pump rate 48 183 65 2646 345 1566



Increase chore pressure 155 170 60 2397 258 1608


And continue with s teps unt il pumps are stopped








Make a connection and keep BHP within a 50psi window

50psirange

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Manual CBHP System


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Types of MPD Returns Flow Control (Enclosed wellbore vs. open-to-atmosphere) Pressurized or Floating Mud Cap Drilling (PMCD) Constant Bottom Hole Pressure (CBHP) Dual gradient (DG)

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MPD allows the BHP to beadjusted to penetrate the

Windows between PorePressure & Fracture

Pressure

PorePressure

FracturePressure

MW MW + ECD


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Pore Fracture Pressure WindowEasy to drill wells in a large Drilling Window

CollapsePressure PorePressure

FracturePressure

OverburdenPressure

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Narrow Drilling Windows are not easy to drillPore Fracture Pressure Window

CollapsePressurePorePressure

FracturePressure

OverburdenPressure

NarrowDrillingWindow

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Constant Bottom Hole Pressure CBHP

BomHeCrcuanPeue

Time

FracturePressure

ReservoirPressure

Fluid Losses Fluid LossesBottom Hole Pressure

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Constant Bottom Hole Pressure CBHP

BomHeCrcuanPeue

Time

FracturePressure

ReservoirPressure

Bottom Hole Pressure

Kick Kick

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Tool Joints

Automated MPD System Reaming to Bottom


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Kick Tolerance is greatly reduced


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409 psi = 73 gpmof mud loss

339 psi = 5 gpmof mud loss

Accurate determination of the fracture gradient


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Low Pressure RCD

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Low pressureRCD with spareseal elementsand components

for pressuretesting andlogging.

Pressure Rating:Rotating and/orStripping:500psiStatic: 1,000psi

Over 600 wells are drilled with Rotating ControlDevices (RCD) every day in the US & Canada


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High Pressure RCD

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Pressure Rating:Rotating and/orStripping:2,500psiStatic: 5,000psi


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PMCD System Floating Rig

4 Annulus Injection Linefrom Mud Pump

6 HCR

4 Bleed-off Line toChoke Manifold

2 Fill-up Line fromTrip Tank Pump4 HCR

4 HCR

Riser tensioner linessupport the full riserweight and PMCDequipment

Rotating ControlDevice

6 Line Flow Line

Riser Slip Joint used inthe collapsed position

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PMCD System Floating RigsSemi-submersible Drillship

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MPD has already been performed on Drillships, Semi-subs,Jack-ups & Platform Rigs


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Automated MPD Floating Rig

Full Automated MPD System forfloating rig applications in harshenvironment conditions

Project due to commence July 2008


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MPD Applications

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Kick Control (Influx Control) Severe Drilling Fluid Loss Fractured orVugular Formation Differential Sticking Stuck Pipe Twist-off Tight Pore Pressure Fracture PressureWindows Depleted Reservoir Drilling HPHT Drilling Unknown Pore Pressure


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MPD Applications contd.

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Unstable Wellbore (Wellbore Instability) MPD + ERD (Extended Reach Drilling) Low ROP Drilled Gas (Nuisance Gas) High H2S Levels High ECD Ballooning / Breathing formation


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KICK CONTROL Advantages of MPDSafety Response and influx size reduced using an enclosed system

Enclosed wellbore is safer than open to atmospheresystembecause back-pressure can be applied immediately

The majority of kicks are low pressure events that can easilybe handled by an RCD

Lower risk of exceeding MAASP with MPD (because of thesmaller influx) and consequently lower risk of breaking downthe casing shoe

Lower risk of taking second influx with MPD (longer criticalchoke control needed while circulating out the larger influx)

Time &Cost

The drillstring can be moved all the time, reducing the risk ofdifferential sticking potential huge cost saving

One full circulation at slow circulating rate can take hours,plus time to weight up the kill mud. Typically 12 24 hourscan be saved (the time loss varies GOM deepwater theaverage time loss due to taking a kick is 10 days)

Reduces wear & tear on BOP and rig choke system

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PMCD Advantages & DisadvantagesAdvantages Permits safe and efficient drilling through severe or total

loss zones highly cost effective compared toconventional drilling

Well can be drilled to TD with virtually no loss of rig time

no major AFE Overruns

Limits damage to the reservoir caused by LCM, gunkand cement

Very good technique for H2S environments because the

gas is pushed back into formation no gas to surfaceDisadvantages There are no returns to surface Geologists dont like

this technique no samples

At TD, or for intermediate trips, there still remains the

issue of how to get out of the hole with total losses casing valve or pumping technique

PMCD uses large volumes of fluid a week of drillingcould require 120 150,000bbls of fluid includingdrillpipe & annulus injection

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Case HistoryRan 7 casing tie-back string to

top of liner hanger with casingvalve to allow drillstring recovery

Changed to PMCD

Injected water in annulus withhigh surface pressure on RCD(1,400psi)

Drilled out tie-back shoe, gunk

plug plus 3m of new formation.POOH closing casing valve toisolate reservoir pressure

Reservoir section drilled in two

further trips SPP range 1,900 2,100psi CP range 1,250 1,400psi ROP ~ 4 5 metres/hour

7 Tie-backcasing stringCasing Valve

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MPD + ERDPROBLEM: Compare twowells of 3,500mMD. Avertical well with APL of478psi and 10.6ppg ECDusing 9.8ppg mud, andan ERD well with TVD of2,000m. The ERD wellwould have the same APLbut an ECD of 11.2ppg.

X Greatly increased ECDX At reduced depth weaker formationMPD SOLUTION: Drill with9.3ppg mud giving a10.6ppg ECD and trapannulus pressure duringconnections to controlany influx or maintain

wellbore stability

ECD (ppg) = Annular Pressure Loss (psi) / 0.052/ TVD (ft) + Current Mud Density (ppg)

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High ECDPROBLEM: While drilling a 6-1/8 hole at 3,064mTVD with 13.2ppg mud and

an APL of 575psi, ECD is so high that losses are being caused. Thepump rate must be reduced and ROP controlled to avoid holecleaning problems and stuck pipe

Circulating BHP adds 1.1 1.6ppg, so ECD = 14.3 14.8ppg

PorePressure

FracturePressure

MW MW + ECDPD SOLUTION: Drill with a light fluid. Can bestatically balanced but with the

MPD system for additionalsecurity

Eliminate the 0.5ppg drillingmargin enclosed wellbore

Or go statically underbalancedwith a 12.1ppg MW and trap575psi in the annulus on thechoke during connections (ECD= 13.2ppg)

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Ballooning / Breathing FormationPROBLEM: The formation charges up with fluid and pressure while drilling

and releases this fluid pressure back into the wellbore whenthe pumps are shut down

The drilling supervisor thinks the well is flowing and orders themud weight increased which increases the BHP whichcharges up the formation even more so it flows even more at

the next connection

MPD SOLUTION: If the well is flowing due to an influx the flow trend will be

gradually increasing but if the problem is ballooningformation then the flow trend will be decreasing

An Automated MPD System, with highly accurate flowmeasurement can clearly identify what is happening.

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Ballooning Formation decreasing trend


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Ballooning Formation


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Ballooning Formation a Clear Picture


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MPD - Conclusions MPD forces Drilling Engineers & Supervisors to

change their ideas there is a better way.

Conventional methods are often used well past the

time that economics dictate a new approach isrequired often wasting US$ millions on a well.

Enclosed wellbore solutions are inherently safer

and more efficient than conventional Open toAtmosphere systems - a well in MPD Mode is awell in Safe Mode).

Many examples exist where MPD delivered a wellwhen conventional methods failed in fact this isthe target market for MPD

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DrillSafe Forum Jun08 KEEP DRILLING Ken Muir Managed Pressure Drilling Talk

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