Stuck Pipe Prevention

Prentice & Hill, LLC

First Day

Hydrostatic Pressure

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

MEMORIZE THIS EQUATION!!

TVDMWP 052.

Hole Volumes

1029

2DV

V = Hole Volume in BBL/FT

D = Hole Diameter in INCHES

1029

22io

Annulus

DDV

Pressure - Area Forces

F P x A

F = Force (lbs)P = Pressure (psi)A = Area (sq-in)

F Ff n

Ff = Force Due to Friction (lbs) = Coefficient of Friction or Friction FactorFn = “Normal” Force (lbs)

Stuck Pipe

Most Common “Trouble” in Overspent WellsAvoiding Stuck Pipe

Understand Different Mechanisms Plan to Avoid Problems Recognize Symptoms Real Time Take Proper Actions While Drilling Use Recovery Procedures, if necessary

Solids Induced Pack-off

Formation Movement

Inadequate Hole Cleaning

CAUSES

Solids Induced Pack-off

Formation Loose w/ Little or No Bonding Insufficient Hydrostatic to Hold Back

Formation

UNCONSOLIDATED FORMATIONS

Causes

Pack-off Due to Unconsolidated Formations

Prevention

Gel up Mud / Run Hi Vis SweepsControl DrillSpot Gel Pill Prior to TOH

Plan / Anticipate:

Solids Induced Pack-off

Increase Mud Weight, if possibleUse Under-saturated Water Base MudPump Fresh Water SweepsDesign Casing to Handle Collapse Loads

Causes

MOBILE / PLASTIC FORMATIONS

Formation Extrudes Into Well Bore Due to Overburden Forces.

Prevention

Proper Well Planning:

Solids Induced Pack-off

Causes

Control Drill & Ream ConnectionsAnticipate Reaming on Trips

FRACTURED / FAULTED FORMATIONS

Prevention

Loose Chunks of Rock Fall into Well Bore

Plan / Anticipate

Solids Induced Pack-off

Causes

Raise Mud Weight, if possibleSet Casing Appropriately

OVER-PRESSURED SHALE COLLAPSE

Prevention

Shale “Pops” Off Wall Due to Pressure

Plan / Anticipate

Solids Induced Pack-off

Causes

Use Inhibited Mud SystemMinimize Exposure TimeBe Prepared for “Gumbo Attack”

REACTIVE FORMATIONS

Prevention

Mud Filtrate Reacts Chemically with Formation

Plan / Anticipate

Solids Induced Pack-off

Causes

Increase Annular VelocitiesBetter Mud Properties

Subject of another section

POOR HOLE CLEANING

Prevention

Not Removing Cuttings From Well Bore

Differential StickingCauses

High Differential Pressures• Excessive Mud Weight

• Drawn Down Formations

• Poor Well Planning

Well Bore ContactPoor Filter CakeLittle or No Pipe Motion

Differential Sticking - Prevention

Minimize Mud WeightImprove Filter CakeSelect Proper Casing SeatMinimize Contact Area

Stabilizers Heavy Weight Drill Pipe Spiral Drill Collars

Keep Pipe Moving

Plan / Anticipate

Mechanical / Wellbore Geometry Sticking

Causes KEYSEATING

Minimize 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 HOLE

Always 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 & DOGLEGS

Run Packed Hole AssembliesReam on Trips Through Problem Zones

• Limber BHAs• Hard - Soft Interbedded Formation

Prevention

Mechanical / Wellbore Geometry StickingCauses

SHOE JOINT BACKS OFF

Do Not Overdisplace CementThread Lock Bottom 3 Joints of CasingDrill Out Carefully

Prevention

Mechanical / Wellbore Geometry Sticking

Causes GREEN CEMENT

Wash Down Carefully to “Top of Cement”Pre-Treat Mud Before Drilling Green

Cement

Prevention

Run BHA Into Un-set Cement

Mechanical / Wellbore Geometry Sticking

Causes JUNK

Good Housekeeping on Rig FloorKeep Hole CoveredInspect Equipment Frequently

Prevention

Something Manmade is Loose in the Hole

Mechanical / Wellbore Geometry Sticking

Causes CEMENT BLOCKS

Set 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 Plug

Prevention

Mechanical / Wellbore Geometry Sticking

Causes LINER & SQUEEZE CEMENTING

Hazards in Liner Cementing Too Much Excess Overdisplacement

Squeeze Cementing Hold Pressure on Back Side, If Possible Use Cement Retainers DO NOT Cement Up a Squeeze Packer (RTTS)

Cementing Yourself in the Hole

MUD

Mud Types / Constituents Water Base Mud Oil Base Mud Synthetic Base Mud

Primary Functions (Review) Remove Cuttings Lubricate and Cool Bit Provide Hydrostatic

Mud (continued)

Filter Cake “2/32”Fluid Loss

API Fluid Loss• Room Temperature

• 100 psi differential

Mud (continued)

Filter Cake “2/32”Fluid Loss

API Fluid Loss• Room Temperature

• 100 psi differential High Temperature, High Pressure (HTHP)

• 300º F or as specified

• 500 psi differential

Mud (continued)

Rheological Properties Measured with Fann Viscometer Funnel Viscosity Plastic Viscosity Yield Point

Mud (continued)

Mud Additives Gel (Wyoming Bentonite) Barite Chemicals Lost Circulation / Stuck Pipe Preventatives

• Sized Particulate Matter

• Fibrous Material

• Asphalt

• Snake Oil

Influence of Mud Properties on Various Stuck Pipe Mechanisms

Inadequate Hole Cleaning

Near Vertical Wells (Incl < 30 deg) Stabilize Hole Maintain Good Annular Velocity Keep Low Shear Rate Viscosities High

• Yield Stress = 2 (6 - 3)

• Gel Strength Do Not Overload Hole Due to Too High ROP Clean Hole Prior to Trip

Inadequate Hole Cleaning

Most Difficult Angle to Clean Hole Unstable Cuttings Beds Form Beds May Avalanche Even With Pumps On Raising Mud Viscosity Alone Will Not Solve M-I Video of Hole Cleaning

Moderate Angle Wells (30° <Incl < 60°)

Inadequate Hole Cleaning Moderate Angle Wells (30° <Incl < 60°)

Anticipate Problem - Alert for Symptoms Erratic Pump Pressure Reduced Returns at Shaker for ROP Erratic PWD Data Increasing Overpull 5-10 Stands Off Bottom It Is Possible to Get Stuck In Cased Hole

Problem Prevention

Inadequate Hole Cleaning Moderate Angle Wells (30° <Incl < 60°)

Take Preventive Actions Agitate Cuttings Beds

• Rotate DP at 150+ RPM if possible

• Reciprocate & Rotate While Circulating Bottoms Up Maximize Annular Velocity

• Larger Drill Pipe

• Larger Jets Make Wiper Trips Back Ream Out Of Hole - Carefully!

Problem Prevention

Inadequate Hole Cleaning High Angle Wells (Incl > 60°)

Cuttings Beds Form, But Are Stable Hole Cleaning Usually Not A Problem in High

Angle Section Cuttings Beds Potential Problem on Trips Back Ream Out of High Angle Section Reminder - All High Angle Wells Have a

Moderate Angle (Problematic) Section

Problem Prevention

Inadequate Hole Cleaning

Causes Inadequate Mud Flow Properties Too Low an Annular Velocity Cuttings Beds in Directional Holes

• Angle < 30º - Minimal Problems

• Angle > 60º - Minimal Problems

• 30º < Angle < 60º Problem Area

Inadequate Hole Cleaning

Prevention Keep Mud in Good Shape Watch Shale Shaker for Too Few Cuttings Pump More Fluid (Increase AV) Run High / Low Viscosity Sweeps Use Larger Drill Pipe Avoid long 30º to 60º Angle Sections Make Wiper Trips (Ream Out w/ Top Drive)