A.Fresh Water Muds B.Inhibited Muds C.Water Base Emulsion D.Oil Base & Synthetic Muds I- MUD SYSTEMS
((is that mud with water as its continuous phase.)) 1- Spud mud. 2- Low solids mud. 3- Lignite mud. 4- Lignite surfactant systems. 5- Lignosulfonate mud. 6- Lignite/ Lignosulfonate mud. A- Fresh water Base Mud
B- Inhibited Mud ((Is that mud which repress the hydration and subsequent dispersion of clay into the mud)). 1- Lime mud. 2- Low lime mud. 3- Gypsum mud. 4- Sea water mud. 5- Saturated salt water mud. 6- K-plus mud.
Advantages over conventional water base mud:- 1- will Telerate a higher concentration of clays before developing high viscosity, 2- less drastic effects by contaminants such as cement, anhydrite,.. 3- can be raised to a higher mud weights before developing excessive viscosity, 4- less progressive gelling tendency. B- Inhibited Mud (continue)
C- Water Base Emulsion Mud ((Is that mud with oil & water being emulsified together)). Advantages over conventional water base mud:- 1- Reduction of pipe torque & drag. 2- Increased ROP & bit life. 3- Reduction of bit balling. 4- Alleviation of differential sticking. 5- Better filtration control & production zone.
((Is that mud with oil as its continuous phase with not more than 1 – 5% water)). Advantages of oil base mud:- 1- protection of production horizon, 2- drill water sensitive formations; salt, clays.. 3- allowing longer bit runs than water base mud of the same weight. 4- less viscosity problems in deep hot holes. D- Oil Base & Synthetic Mud
(( Any accepted terminology that indicates the weight per unit volume of drilling fluid)) - Pounds per gallon (ppg). -Pounds per cubic feet (pcf). -Gram per cubic centimeter (g/cc). -Kilogram per liter (kg/l). 1- DENSITY
VISCOSITY ((Viscosity is a measure of the internal resistance of a fluid to flow)) 1- Funnel Viscosity Apparent Viscosity (vis) is the measured times it takes for one quart of mud to gravity feed through a hole of a specific diameter.
viscosity 2- Multi Speed rheometr relates viscosity to shear rate and shear stress. i.Newtonian fluids ii.Non Newtonian fluids
b-Plastic viscosity (Pv) is that part of flow resistance in a mud caused primarily by the friction between the suspended particles and by the viscosity of the continuous liquid phase. i.e. it is a representation of the concentration, size and shape of the solid particles. c-Yield point (Yp) is a measurement under flowing conditions of the forces in the mud which cause gel structure to develop when the mud is at rest. 2- RHEOLOGY ((continue))
Gel strength d-Gel strength (Gel) is a measurement under static conditions of the forces in the mud which cause gel structure to develop when the mud is at rest.
e- pH is a measure of acidity or alkalinity of drilling mud as expressed in the hydrogen ion concentration. It is used as an aid in determining for type of mud treatment and as indication of contaminants such as cement, gypsum. f- Filtration (Wl) is a measurement liquid filtrate of the drilling mud. It measure the ability of the solid components to form a thin, low permeability filter cake. 2- RHEOLOGY ((continue))
III- HYDRAULICS ((Deals with the behavior of mud with specific Rheology in moving)) a- Flow PATTERN. b- PRESSURE DROP. c- ECD. d- SLIP VELOCITY d- SURGE & SWAP. e- BIT HYDRAULICS.
a- Flow Pattern ((Refers to the relation between the different layers to each other in moving)) 1- Plug flow. 2- Laminar flow. 3- Turbulent flow. This depends on the relation between the Fluid Velocity & the Critical Velocity i- Fluid Velocity. ii- Critical Velocity.
b- Pressure Drop ((Refers to the pressure required to overcome the friction between the drilling fluid and specific system section)) 1- Drill String Pressure Drop. 2- Annulus Pressure Drop. 3- Bit Pressure Drop.
1- Drill string pressure drop ((Refers to the pressure required to overcome the friction between the drilling fluid and drill pipe))
2- Annulus Pressure Drop ((Refers to the pressure required to overcome the friction between the drilling fluid and annulus)) ECD (Equivalent Circulating Density):- is the combined pressure being exerted hydrostatically by the mud and the mud pump when the system is circulating. Slip Velocity:- is the rate at which cuttings fall back toward bottom.
((Reology in Bingham model concerned with PV & YP)) PV = C 600 – C 300 YP = C 300 – PV It is more accurate in Oil Base Mud than in Water base mud. BINGHAM PLASTIC
It allows for more plastic or pseudo – fluid behavior. Power law slip velocity is generally less than Bingham one. Calculating slip velocity by Bingham provide adequate hole cleaning More accurate in water base mud. POWER LAW
Swap pressure is a negative value produced by pipe movement up ward. Surge pressure is a positive value produced by pipe movement down ward. 3- Swab & Surge Pressure
4- Bit Hydraulics Bit Pressure Drop. Jet Velocity. Hydraulic Horse Power. Impact Force