Drilling Fluids FunctionsTypes of Drilling Fluids - Water-base - Oil-base - Emulsions - Air, Foam, & Aerated FluidsCompositionAdditivesTestingEngineering Calculation

Drilling Fluids Functions of Drilling Fluid: To remove cuttings from the bottom of the hole and carry them to the surface. To cool and Lubricate the bit and drill string To coat the hole with low permeability cake To hold cuttings and weight material in suspension when circulation is interrupted

Drilling FluidsDrilling fluids should: Release sand and cuttings at the surface Minimize formation damage Insure maximum information about formation penetrated. Transmit hydraulic horsepower to the bit Control corrosion

Water Base MudTypes of water base mudGel MudGel Polymer MudLignosulphonate MudLignite MudLime base MudGypsum Mud

Water Base Mud7.PHPA Mud8.Glycol Mud9.Salt Saturated Mud 10.Sized salt Mud11.Sized carbonate Mud

Oil Base Mud Types of Oil Base Mud:

Diesel baseLow Aromatic base.Synthetic base.

Water Base Mud Formulation

Gel MudBentonite 20-30 ppbfor viscosity and filter cake.Caustic Soda .25-1 ppbto remove mg++Soda Ash .25-1 ppbto remove ca++

Water Base Mud Formulation2.Gel Polymer

Gel Mud + PolymerPolymers:1- Starch, CMC ,PAC: for filtration control 2- Guar Gum, Xanthan Gum: Rheology3- PHPA : Shale inhibition

Water Base Mud Formulation3.Lignosulphonate or Lignite mud It is called Dispersed mud for drilling massive clay and shale sections. Bentonite : 6-10 ppb Caustic Soda : .1-1.5 ppb Soda Ash : .5-1.0 ppb Lignosulphonate : 4-8 ppb

Water Base Mud Formulation4.Lime or Gypsum mud for drilling active shale sectionsCa++ Replaces Na+ on clay surface and reduces hydration and swelling.Lime : source of Ca++Caustic : pHPolymer : filtration control

Water Base Mud Formulation5.Salt Saturated MudTo drill salt sectionsTo eliminate washout of salt sections.To inhibit shale.NaCl : 110 ppbCaustic Soda : 1-1.5 PPBPolymers : Viscosity and Filtration control

Water Base Mud Formulation6.PHPA MudPartially Hydrolyzed Poly acrylamide Long chain polymer with molecular weight more than 5 M.For shale inhibition by coating effect.

Water Base Mud Formulation8.GlycolDiffer from Alcohols by having more than one OH group.Shale inhibition by emulsion blocking through cloud point.Cloud point is the temperature at which Glycol becomes insoluble.

Water Base Mud Formulation9. Non Damaging MudSized salt in saturated brine systemSized carbonates with non damaging polymers.

Mud Properties Mud WeightField units are: specific gravity ,ppg, Ib/ft3 ppg/ 8.33 = specific gravitymeasured by mud balance Hydrostatic pressure, psi = .052 X Mud Weight (ppg) x Depth (ft)

Mud Properties 2. RheologyHole cleaning propertyMarsh funnel is used to measure funnelviscosity.V.G. Meter is used to measure:plastic viscosity, yield point & gel strength

Mud Propertiesplastic viscosity= R600 - R300 cpyield point = R300 - PV lb/100ft2Gels = 10 sec & 10 minApparent viscosity= R600/2 cp

Mud Properties3. Fluid LossMeasures fluid invasion into formationFilter press is used to measure it in ml/30 min.HTHP filter press is used to measure it at 200-350 deg. F & 500 psi Differential pressure.Also measures cake thickness in 1/32 in.

Mud Properties4. RetortBy evaporation and condensation.Gives % Solids, % Water & % Oil

5.pHMeasured by pH meter or pH paper strips Important for: corrosion, solubility, activity

Mud Properties6. MBTMeasures clay & bentonite content

7. Ions TitrationCa++, Mg++, CI- & k+