Cementing

cementing By Karwan saeed Ibrahim

1Cementing

# 1 1.1.Functions of cement 1.2.Cement type and Cement additives1.3.Slurry testing1.4. 2.1.Casing and Cementing hardware

#22.1. Cementing Mechanics2.2.Displacement Theory2.3. Washes and Spaces2.4. 3.2.Cement Calculations

#33.1.Cement plugs3.2.Cement squeezing.3.3.Cement Problems.3.4.Cement Evaluation3.5.Cement failures and problems

1.1.Functions of Cementing

Cement Functions:-

Completes the isolation step that was started with casing. Pressure isolation Pipe support and protection Exterior corrosion Pressure control Load and force application support Leakoff control prevents crossflow? Water influx control 1.2.Cement Type

1.2.Cement Additives-Nut Shells (cellophane)-Barite,Baso4-Hydrocarbons(Diesel,Oil,Kerosene)-Bentonite -Lost circulation control agents-Fluid loss additives -Dispersants-Miscellaneous Agents-Weighting Agents-Extenders-Retarders-Accelerators

additivesType of additives useChemical compositionbenefitacceleratorsReducing WOC timeCalcium chlorideSodium chloridegypsumAccelerated setting ,high early strenghtretardersIncreasing thickening time for placement ,reducing slurry viscosityOrganic acidsLignosulfonatesIncreased pumping timeWeight reducing additives Reducing weightBentonitegilsoniteLighter weight economyHeavy weight additivesIncreasing slurry weightHematitedispersantsHigher densityAdditives for controlling lost circulationbridgingWalnut hullsGypsum cementLighter fluid columnsSqueezed fractured zoneFiltration-control additives Squeeze cementing ,setting long linerspolymersReduced dehydrationThere are five steps required to obtain successful cement placementAnalyze the well parametersCalculate fluid (slurry)compositionUse necessary hardwareMonitor the treatment in real time Evaluate the results .compare with the design in first step1.3.Slurry Testing -Thickening time(consistometer)-Free water and Sedimentation(2hrs)-Fluid loss-Compressive Strength-Rheology (Temp. 80F ,reading should be reported at 200 ,100, 60, 30,6 and 3rpm)In summary slurry testing is a major requirement for successful oil well cementing especially in high angle or horizontal wells.2.1.Casing and Cementing hardware-Guide shoe(a simple guide ,a ball valve or flapper).-Float collars-Baskets &Centralizers-Cement plugs-Multi stage collarCasing guide shoe

Float collars

Baskets & centralizers

Cement plugs :separate fluids with wiping casing

Multi stage collar : reduce total pumping pressure and hydrostatic pressure on weak formations ,allow entire length of casing to be cemented.

Multistage cement collar is used for : .Reduce total pumping pressure.Reduce total HP on weak formations.Allow entire length of casing to be cemeneted2.2.Cementing MechanicsConditioning the drilling mud :

Hole sectioninches PV cpYPIbf /100f^2Gel strenght10s/10min17 1/2