Squeeze Cementing Brett W. Williams Cementing Technical Advisor January 2016 Tulsa API Meeting
Definition Squeeze Cementing is the process of applying hydraulic pressure to force or squeeze a cement slurry into the desired perforations, fractures, channels, or voids and force filtrate water from the slurry to create a solid mass which will harden to provide the desired seal.
Slurry Enters the Void
Slurry Seals the Void
Squeeze Cementing is as much an Art as it is a Science. Area experience is essential.
First Question to Ask Why are we squeezing? Repair casing leak Insufficient top of cement on primary job Seal off troublesome zone during drilling Repair mud or gas channel Isolate a formation prior to perforating Shut off unwanted production Abandonment of non-productive zone Modify an injection profile
Second question to ask How do we know where to squeeze? Sonic evaluation logs Hunting holes Primary cement job design Primary cement job performance Mud returns Formation Integrity Test Experience Offset well data
Third question to ask Do we need to squeeze now or wait? Cost considerations Equipment Time delays for after-the fact squeezes Well construction plans Regulatory requirements
Fourth question to ask Will a squeeze job accomplish what we want it to do? Is it hindering the well s performance? Can we pump into it? Will it hold up? Am I going to have to breakdown formation to squeeze? What future operations will the well see?
SQUEEZE TECHNIQUES
Squeeze Techniques Pressure to squeeze High pressure squeeze Low pressure squeeze Pumping technique Hesitation squeeze Running or walking squeeze Placement technique Squeeze packer Bradenhead (including coiled tubing)
High Pressure Squeeze Surface pressure + Displacement fluid hydrostatic + Cement slurry hydrostatic = Total bottom hole pressure Greater than Formation fracture pressure
High Pressure Squeeze
Low Pressure Squeeze Surface pressure + Displacement fluid hydrostatic + Cement slurry hydrostatic = Total bottom hole pressure Less than Formation fracture pressure
Low Pressure Squeeze
Squeeze Techniques Pressure to squeeze High pressure squeeze Low pressure squeeze Pumping technique Hesitation squeeze Running or walking squeeze Placement technique Squeeze packer Bradenhead (including coiled tubing)
Hesitation Squeeze
Running/Walking Squeeze
Squeeze Techniques Pressure to squeeze High pressure squeeze Low pressure squeeze Pumping technique Hesitation squeeze Running or walking squeeze Placement technique Squeeze packer Bradenhead (including coiled tubing)
Squeeze Tool Method Retrievable or drillable squeeze packer set above injection point Isolates casing above packer from squeeze pressure Higher squeeze pressures possible Annulus pressure applied to help prevent casing collapse
SQUEEZE SLURRY DESIGN
Primary Cement Cement node development Perforation tunnel Permeable rock matrix
Fluid Loss Control Vs. Filter Cake Development 1000 cc - Neat Cement Slurry 300 cc Fluid loss Slurry 75 cc Fluid loss Slurry 25 cc Fluid loss Slurry
Effect of Hesitation on Thickening Time
Gel Strength Development High pump pressures False indication of squeeze Difficult reversing out High pump pressures Formation breakdown Pump hole through slurry during hesitation squeeze
CEMENTING SYSTEMS
Conventional Cement Systems Co-polymer fluid loss control Reduced node acid solubility rate Low fluid loss FineCem TM Cement Low injection rates Casing collar leaks
LOCATION OF SQUEEZE PACKERS
Tool Location Recommendations Set in supported casing when possible As close to zone as possible to minimize cement drillout But far enough away from perforations for staging volume Displace tubing volume before staging Safe distance from perforations to prevent casing collapse (Next slide will illustrate this)
SQUEEZE APPLICATIONS
Block Squeeze Process Performed to isolate zone Perforate & squeeze below and above zone Drill out & test Disadvantages Difficult to clean flow path of cement Must avoid fracturing formation
Bradenhead Method Process Spot cement across squeeze interval Pull workstring above cement top Close BOP/Bradenhead & reverse tubing clean Apply squeeze pressure Disadvantages Casing exposed to squeeze pressure Limited squeeze pressure advantages Cost reduction Wash cement out of casing
Circulating Squeeze Process Suicide Squeeze Drillable tool set between perforations Cement circulated through lower perforations and back out upper ones Sufficient spacer to clean annular flow path Disadvantages Probability of sticking Casing collapse possible NOT a recommended practice!!
Channel Squeeze Channel must be void of mud Allow production to clean channel if possible Clean channel with acid or chemical washes Perform low pressure squeeze Inject into production perforations or adjacent to problem zone
Squeezing Corrosion Holes Often occur above cement top May require multiple stages Caution with tools due to weak or enlarged casing New holes often created during squeeze Use low pressure squeeze
Squeezing fractured or vugular zones Multiple stages likely Tail First stage - possible solutions Lost circulation material High fluid loss cement Thixotropic cement Foam cement Lead Quick setting cement Reactant preflushes Second stage Low fluid loss cement
Casing Shoe Squeeze Formation in shoe area unable to support hydrostatic during continued drilling Moderate to high fluid loss cement Reactive preflush Channel to nearby weak formation above shoe Clean channel with preflush fluids Perform low pressure squeeze to prevent creating fracture and increasing problem Pressure test may fracture, so use high pressure squeeze to fill fractures
JOB EXECUTION
Job Execution Well Preparation Well fluid clean and free of debris Perforations open Pressure test surface treating lines, workstring, and tools to maximum expected pressure Use clean workover fluids for injection Solids in workover fluid may clog perforations Avoid/minimize fracturing Control squeeze pressures Use low fluid loss cement slurries
MYTHS IN SQUEEZE CEMENTING
Myth Cement slurry enters the formation matrix Cement average particle size 20-50 microns > 2000 md formation permeability required Fact - Cement particles are too large to enter the matrix of most formations except in cases of extremely high permeability or fractures Fact - Filtrate enters formation Berea Sandstone - 350 md
Myth Squeezing produces a horizontal pancake of cement Facts Fracture orientation is normally vertical rather than horizontal Fracture may be at an angle to the wellbore in deviated wells
Myth All perforations are open during injection Facts Perforations may be partially plugged Injection pressure of perforations varies Cement will take path of least resistance Solids laden injection fluid should be avoided
Myth High final squeeze pressure is necessary Facts Final squeeze pressure does not need to equal future working pressure. Squeeze pressure is applied across node before cement develops compressive strength Fractures may be created Productivity may be damaged High pressure does not ensure placement in desired location