deepwater mpd / pmcd - my-spreadmy- - pres mpd-pmcd supt meeting aug · • plan to drill in mpd...

Download Deepwater MPD / PMCD - My-Spreadmy- - Pres MPD-PMCD Supt Meeting Aug · • Plan to drill in MPD mode

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  • Deepwater MPD / PMCD

    August 21, 2011

  • Managed Pressure Drilling (MPD)

    Pressure held on top of riser while drilling.

    Drill in overbalance condition

    Pressurized Mud Cap Drilling (PMCD)

    Pressure of mud column in riser and wellbore plus surface maintained pressure should equal formation pressure at top of carbonates.

    Drill in at balance condition

  • MPD Objectives - GSF Explorer

    Prevent gas entering riser. Improved riser degassing capabilities. Early kick and loss detection and automated reaction to

    these events. Allows Pressurized Mud Cap Drilling (PMCD) to be

    conducted safely. Ability to quickly manipulate the pressures (up or down)

    within the wellbore without the need for mud weight up and circulation.

  • Plan to drill in MPD mode for kick detection for drilling hole section above carbonates.

    Drill overbalanced with RCD bearing installed and maintain surface applied pressure on the well.

    Pressure on welll maintained by circulating through secure manifold choke.

    Improved kick detection

  • MPD - PMCD Switch Application

    MPD to be used in overbalance mode until the losses in the carbonates become excessive thereafter the system will be changed over to a PMCD (pressurized mud cap drilling) arrangement.

    Will use PMCD while drilling carbonates while experiencing severe fluid losses

    Avoid floating mud cap drilling

    Accurate determination of formation pressures

    Maintain well fluid level at surface

  • GSF Explorer MPD Equipment Requirements

    Rotating Control Device (RCD) 21 2k Riser Annular BOP Riser Flow Spool Drilling Choke Manifold (Secure) Buffer Manifold Two Phase Separator Coriolis flow meter Drill String Floats - Plunger Type (connections

    stripping in/out)

  • Approx. 2000 meters of riser between flow

    spool and BOP

  • General Arrangement MPD Configuration

  • Secure Manifold Two Phase Separator

  • Inline Coriolis Flow Meter

  • Sequential Operations MPD to PMCDStart MPD operations with overbalanced fluid

    Drill ahead MPD mode encounter carbonates with acceptable losses

    Annular

    Kill line filled with base oilprior to drilling ahead

    Close Annular BOP

    Determine reservoir pressure = fracture pressure of carbonates using kill line

    Lighten riser fluid till it is just < top fracture pressure

    Take significant losses in carbonates

    Continue drilling down drill string in PMCD mode with seawater

    Kill Line Choke Line

    Pump down annulus periodically to keep it gas free (bullhead to the top fracture)

    RCD

    Pressure mud column below BOP plus kill line hydrostatic

  • MPD Operations

    GSF Explorer

    Ability to stay within a narrow drilling windows (Pore vs. Frac.) .

    Mitigate against losses:- early warning and ability to react quickly by decreasing back pressure.

    Safe means to drill section :- Increased kick detection sensitivity and reaction.

    Back pressure can be used to quicklysupplement drilling fluid density when required if an influx is detected

    With MPD maintain CBHP

  • PMCD Operations

    GSF Explorer

    Annulus mud weight/press < pore pressure.

    Annulus fluid level at surface casing pressure.

    Pressure monitored at MPD manifold.

    SBM will minimize gas migration as it goes into solution.

    Pump down riser boost with original weight mud

    Pump down drill string with seawater.

  • Constant Bottom Hole Pressure - Example

    Drilling Window

    FRACTURE PRESSURE

    12.4 ppg

    PORE PRESSURE

    11.5 ppg

    Static Mud Weight

    11.5 ppg

    Pumps OnAnnular Friction

    Loss0.25 ppg

    RPM FrictionIncrease0.09 ppg

    Surface Back Pressure0.41 ppg

    Bottom hole Pressure Stays The

    Same

    12.25 ppg

    Make a Connection riser Boost Pump ON

    Stop RPM

    Stop Pumps

  • MPD & PMCD Carbonate Section

    Drill below the 11-7/8 shoe prior to entering the carbonate section. To be drilled in MPD Mode.

    Carbonates are anticipated to be vugular and/or fractured and may lead to severe/total losses with no returns.

    Depending on the loss rate > 20% PMCD will commence.

    There may be further losses as the pore pressure decreases (in PMCD mode) as the carbonates are drilled deeper.

  • 4300m brt

    Shale

    Silt/Sand

    Carbonate

    Sand / Shale /Coal

    Choke Line

    Riser Boost Line

    Kill Line

    MPD Drilling into Carbonateslosses> 20%

    Close in (annular BOP) open kill line to base oil and record

    pressure

    Kill line Pressure

    Drilling in MPD mode

    Kill line pre-filled with treated

    base fluid

    Kill line pressure to balance pore

    pressure in carbonates

    Carbonate section below 11 7/8shoe

    Potential for gas in Carbonate section in

    the Fractures &

    Vugs

  • 4300m brt

    Shale

    Silt/Sand

    Carbonate

    Sand / Shale /Coal

    Choke Line

    Riser Boost Line

    Kill Line

    150100 200

    50 250

    300

    150100 200

    50 250

    300

    Calculate lighter mud in riser to give +/- 300 - 500 psi surface

    annular back pressure displace into well

    Light mud to Riser

    annulus via boost.

    Pump seawater down string establish stable injectivity at

    drilling rate

    4300m brt

    Shale

    Silt/Sand

    Carbonate

    Sand / Shale /Coal

    Choke Line

    Riser Boost Line

    Kill Line

    150100 200

    50 250

    300

    150100 200

    50 250

    300

    Annulus Pressure at MPD Choke

    Kill Line Pressure

  • Drill ahead w/seawater down string, Bullhead +/- 20bbls original weight

    mud down riser boost annulus every hour.

    Seawater carries

    cuttings into loss zone

    Periodic pumping to

    annulus maintains it hydrocarbon free pump in at BOP

    4300m brt

    Shale

    Silt/Sand

    Carbonate

    Sand / Shale /Coal

    Choke Line

    Riser Boost Line

    Kill Line

    150100 200

    50 250

    300

    150100 200

    50 250

    300

    Annulus Pressure at MPD Choke

    Drill ahead w/ seawater, further loss zone encountered. Shut in and assess

    pressures using kill line.

    Possibility of X flow

    between loss zones

    Drop in surface annular

    pressureLighter Riser mud stays in

    the riser annulus

    New loss zone at lower

    pressure

    Monitor Surface annular

    pressure

  • PMCD

    During PMCD the pore pressure may start to decrease this will be noticed by a drop in surface annular pressure.

    Shut in well on upper BOP annular & open annulus again to base fluid in the kill line & recalculate new pore pressure.

    Evaluate whether to change out the riser to lighter mud or to pump more lighter mud below BOP.

  • Drill ahead PCWD Cuttings plugging off loss zone. Pressure increase in

    annulus & DP

    Indications an increase in Pump

    pressure and annular pressure

    Cuttings plugging off the loss zone/s

    Control OptionsDepending on pressures involved:Increase pressure to induce lossesRevert to MPD drilling

  • PMCD

    Should the pump pressure and the surface annular pressure rise together, this is indicative of the loss zone starting to heal over.

    Depending on the pressures seen.

    Induce further fractures and continue in PMCD mode

    Return to MPD mode.