Stuck Pipe PreventionPrentice & Hill, LLC First Day

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Hydrostatic PressureWhere:

MW = Mud Weight (ppg)TVD = True Vertical Depth (ft)P = Hydrostatic Pressure (psi)

MEMORIZE THIS EQUATION!!

Hole VolumesV = Hole Volume in BBL/FTD = Hole Diameter in INCHES

Pressure - Area ForcesF = Force (lbs)P = Pressure (psi)A = Area (sq-in)Ff = Force Due to Friction (lbs) = Coefficient of Friction or Friction FactorFn = Normal Force (lbs)

Stuck PipeMost Common Trouble in Overspent WellsAvoiding Stuck Pipe

Understand Different MechanismsPlan to Avoid ProblemsRecognize Symptoms Real TimeTake Proper Actions While DrillingUse Recovery Procedures, if necessary

Solids Induced Pack-off

Formation Movement

Inadequate Hole CleaningCAUSES

Solids Induced Pack-offFormation Loose w/ Little or No Bonding Insufficient Hydrostatic to Hold Back Formation

UNCONSOLIDATED FORMATIONSCauses

Pack-off Due to Unconsolidated FormationsPreventionGel up Mud / Run Hi Vis SweepsControl DrillSpot Gel Pill Prior to TOH

Plan / Anticipate:

Solids Induced Pack-offIncrease Mud Weight, if possibleUse Under-saturated Water Base MudPump Fresh Water SweepsDesign Casing to Handle Collapse Loads

CausesMOBILE / PLASTIC FORMATIONSFormation Extrudes Into Well Bore Due to Overburden Forces.PreventionProper Well Planning:

Solids Induced Pack-off

CausesControl Drill & Ream ConnectionsAnticipate Reaming on Trips

FRACTURED / FAULTED FORMATIONSPreventionLoose Chunks of Rock Fall into Well BorePlan / Anticipate

Solids Induced Pack-off

CausesRaise Mud Weight, if possibleSet Casing Appropriately

OVER-PRESSURED SHALE COLLAPSEPreventionShale Pops Off Wall Due to PressurePlan / Anticipate

Solids Induced Pack-off

CausesUse Inhibited Mud SystemMinimize Exposure TimeBe Prepared for Gumbo Attack

REACTIVE FORMATIONSPreventionMud Filtrate Reacts Chemically with FormationPlan / Anticipate

Solids Induced Pack-off

CausesIncrease Annular VelocitiesBetter Mud Properties

Subject of another section

POOR HOLE CLEANINGPreventionNot Removing Cuttings From Well Bore

Differential StickingCausesHigh Differential Pressures

Excessive Mud WeightDrawn Down FormationsPoor Well PlanningWell Bore ContactPoor Filter CakeLittle or No Pipe Motion

Bad Filter Cake

Differential Sticking - Prevention Minimize Mud WeightImprove Filter CakeSelect Proper Casing SeatMinimize Contact Area

StabilizersHeavy Weight Drill PipeSpiral Drill CollarsKeep Pipe Moving

Plan / Anticipate

Mechanical / Wellbore Geometry Sticking Causes KEYSEATINGMinimize Dog Leg SeverityCase Off Curves Soon After BuildingUse Keyseat WiperMake Frequent Wiper TripsBack Ream Out of Hole

Abrupt Change in Well Bore Path (Dog Leg) Long Hole Section Below Dog Leg

Prevention

Mechanical / Wellbore Geometry Sticking Causes UNDERGAUGE HOLEAlways Gauge Bit & Stabilizers IN and OUTRun Gauge Protected Bits & StabilizersReam Suspected Undergauge Sections

Undergauge Bit and/or Stabilizers Coring (Core heads slightly U.G.)

Prevention

Mechanical / Wellbore Geometry Sticking Causes LEDGES & DOGLEGSRun Packed Hole AssembliesReam on Trips Through Problem Zones

Limber BHAs Hard - Soft Interbedded Formation

Prevention

Mechanical / Wellbore Geometry StickingCausesSHOE JOINT BACKS OFFDo Not Overdisplace CementThread Lock Bottom 3 Joints of CasingDrill Out Carefully

Prevention

Mechanical / Wellbore Geometry Sticking Causes GREEN CEMENTWash Down Carefully to Top of CementPre-Treat Mud Before Drilling Green Cement

PreventionRun BHA Into Un-set Cement

Mechanical / Wellbore Geometry Sticking Causes JUNKGood Housekeeping on Rig FloorKeep Hole CoveredInspect Equipment Frequently

PreventionSomething Manmade is Loose in the Hole

Mechanical / Wellbore Geometry Sticking Causes CEMENT BLOCKSSet All Casing As Close To TD As PossibleReam Casing Shoe & Open Hole Plugs Before Drilling Ahead

Hard Cement Falls In From Casing Shoe or FromOpen Hole Cement PlugPrevention

Mechanical / Wellbore Geometry Sticking Causes LINER & SQUEEZE CEMENTINGHazards in Liner Cementing

Too Much ExcessOverdisplacementSqueeze Cementing

Hold Pressure on Back Side, If PossibleUse Cement RetainersDO NOT Cement Up a Squeeze Packer (RTTS)Cementing Yourself in the Hole

MUD Mud Types / Constituents

Water Base MudOil Base MudSynthetic Base MudPrimary Functions (Review)

Remove CuttingsLubricate and Cool BitProvide Hydrostatic

Mud (continued)Filter Cake 2/32Fluid Loss

API Fluid LossRoom Temperature 100 psi differential

Mud Filter Press

Mud (continued)Filter Cake 2/32Fluid Loss

API Fluid LossRoom Temperature 100 psi differentialHigh Temperature, High Pressure (HTHP)300 F or as specified500 psi differential

Mud (continued)Rheological Properties

Measured with Fann Viscometer Funnel ViscosityPlastic ViscosityYield Point

Mud (continued)Mud Additives

Gel (Wyoming Bentonite)BariteChemicalsLost Circulation / Stuck Pipe PreventativesSized Particulate MatterFibrous MaterialAsphalt Snake Oil

Influence of Mud Properties on Various Stuck Pipe Mechanisms

Inadequate Hole CleaningNear Vertical Wells (Incl < 30 deg)

Stabilize HoleMaintain Good Annular VelocityKeep Low Shear Rate Viscosities HighYield Stress = 2 (6 - 3)Gel StrengthDo Not Overload Hole Due to Too High ROPClean Hole Prior to Trip

Inadequate Hole CleaningMost Difficult Angle to Clean Hole

Unstable Cuttings Beds FormBeds May Avalanche Even With Pumps OnRaising Mud Viscosity Alone Will Not SolveM-I Video of Hole CleaningModerate Angle Wells (30

Inadequate Hole Cleaning Moderate Angle Wells (30

Inadequate Hole Cleaning Moderate Angle Wells (30

Inadequate Hole Cleaning High Angle Wells (Incl > 60) Cuttings Beds Form, But Are Stable

Hole Cleaning Usually Not A Problem in High Angle SectionCuttings Beds Potential Problem on TripsBack Ream Out of High Angle SectionReminder - All High Angle Wells Have a Moderate Angle (Problematic) SectionProblem Prevention

Inadequate Hole CleaningCauses

Inadequate Mud Flow PropertiesToo Low an Annular VelocityCuttings Beds in Directional HolesAngle < 30 - Minimal ProblemsAngle > 60 - Minimal Problems30 < Angle < 60 Problem Area

Inadequate Hole CleaningPrevention

Keep Mud in Good ShapeWatch Shale Shaker for Too Few CuttingsPump More Fluid (Increase AV)Run High / Low Viscosity SweepsUse Larger Drill PipeAvoid long 30 to 60 Angle SectionsMake Wiper Trips (Ream Out w/ Top Drive)

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