Overview of Petroleum Industry Chapter 4B – Drilling Operations PTRT 1301 Overview of Petroleum Industry Chapter 4B – Drilling Operations

Rotating system Main motive force rotary table (unless top drive in use) generates torque Rotating equipment starts with the swivel Swivel does not rotate, but allows everything beneath it to rotate Kelly drill string drill collars Drill bit Top drive eliminates much of this system

Rotary table Master bushing - Transfers drive power (torque) to kelly bushing Kelly bushing - Transfers torque to kelly Slips engage the drill pipe when kelly is removed Teeth-like gripping elements called Dies The dies grip the drill pipe to prevent slippage when kelly is disconnected

Kelly Square or hexagonal - Why? Round relies only on friction to cause rotation Flat surface allows strength of steel to support the rotation. Think of using pliers to remove a broken bolt vs wrench on the head.

Top drive On large rigs conventional swivel is replaced with a powered swivel. Replaces kelly bushing & master bushing Rotary table retained for slips to engage Advantage Safer and more efficient Disadvantage $ $

Slips and Connections New section of drill pipe being installed Slips support drill string while disconnected from kelly

Drill pipe & collars Most are steel tubes. Drill collars Sections (joints) ~ 30’ long 4 ½” drill pipe 16.6 lbs/foot 30’ length weighs 498 lbs Drill collars extra weight on the bit larger diameter & thicker 7” diameter 125 lbs/foot 30’ length = 3750 lbs Sections are assembled with threaded “tool joints” Short section of threaded tube welded to the end allows for threads.

Roller Cone Bits 3 ¾” ----26” diameter Most common 17 ½” , 12 ¼”,7 7/8”, 6 ¼” Roller cone bits roller bearings Sealed-keep mud out, & protects from other abrasions Unsealed—drilling mud lubricates Journal bearings Sealed Most roller cone bits are jet bits driller fluid exits through small nozzles between the cones. These jets of fluid sweep cuttings up & out of the hole.

Diamond Bits Diamond Bits Not compatible with highs T Fixed head of natural or industrial diamonds embedded in the surface Diamond-coated Tungsten Carbide Not compatible with highs T Single outlet for fluid & channels to direct the flow along the rows of diamonds for cooling. Hybrid bits combination

Circulating System Conditions and supplies drilling fluid (drilling mud) to the drill bit. (fig.4.34) Mud pump Into Stand pipe into rotary hose Pressure & flow rate provided by mud pump. Rotary hose is flexible to allow vertical motion. Does not rotate. Mud returns with cuttings via the annulus and out through mud return line. Cuttings removed via shale shaker go to reserve pit. Mostly a disposal area but can be used to allow suspended solids to settle out. If settling doesn’t work you can add equipment to clean the mud Desander Degasser Desilter

Drilling Mud Water, clay, other minerals Properties of mud Removes cuttings Cools and lubricates the bit Exerts pressure inside the hole Create wall cake that stabilizes the surface (fig.4.39) Properties of mud Viscosity (support solids) Weight (density) (pressure control) Filtration rate (water loss) Solids content (degrades bit performance)

Power System “Prime movers” Power transmission Internal combustion engines 2 or more 1000-3000 hp. Diesel engines 500-1000 hp. Circulation & hoisting 100-500 hp auxiliary &lighting Power transmission Electric drive- generators Cables transfer power to electric motor to power all other equipment Versatile since extra power can be supplied simply via control & switches Mechanical drive Belts, pulley's, & chain drive are used to transfer power from engines to various systems.

Review EnCana Rig Tour Photos