SUSTAINABLE DRILLING OF OIL & GAS WELLS

INTRODUCTION The purpose of drill rig is to drill a hole in the ground. The hole purpose is to tap an oil and gas reservoir.Rigs operate both on land and sea offshore . Drilling rigs are large and noisy and it has many pieces of equipments and most of its are huge.

FORMATION OF OIL Oil and gas are naturally occurring hydrocarbons. Hydrocarbons and their associated impurities occur in rock formation that are usually buried thousands of feet or meters below the surface.

EXPLORATION OF OIL

FINDING OIL Examine the surface rocks and terrain with the help of satellite images. Use sensitive gravity meters to measure tiny changes in earth’s gravitational field that could indicate flowing oil. Use sesimology,creating shock waves that pass through hidden rock layers and interpreting the waves that are reflected back to surface.

THE DRILL SITE Once the location for the site has been established ,the area is prepared for drilling with following steps: Site preparation Conductor – rathode Transport equipments

HORIZONTAL DRILLING VERTICAL DRILLING DRILLING TECHNIQUES HORIZONTAL DRILLING VERTICAL DRILLING

RIGS ONSHORE OR LAND RIGS MOBILE OFFSHORE RIGS LIGHT DUTY MEDIUM DUTY HEAVY DUTY VERY HEAVY DUTY BOTTOM SUPPORTED SUBMERSIBLE JACKUP FLOATING UNITS SEMI SUBMERSIBLE DRILL SHIPS

POWER SYSYTEM HOISTING SYSTEM ROTATING SYSTEM CIRCULATING SYSTEM RIG COMPONENTS POWER SYSYTEM HOISTING SYSTEM ROTATING SYSTEM CIRCULATING SYSTEM

POWER SYSTEMS Large diesel engines-every drilling rig uses internal combustion engine as a prime power source and diesel is used as fuel in that. Electrical generators –powered by diesel engine to provide electrical power.

HOISTING SYSTEM

ROTATING SYSTEMS Rotating equipment turns the bit. The rotating system consist of 3 equipments: A rotary table & Kelly A top drive , and A down hole motor

ROTARY TABLE SYSTEM The turnable in the rotary table rotates the master bushing ; the kelly drive bushing rotates the attached Pipe and swivel suspends the pipe allows it to rotate and has a passage for drilling mud to enter the kelly and pipe

TOP DRIVES Top drive is a device with a powerful built in motor that turns the pipe and bit. The motor turns a threaded drive shaft , which the crew inserts in to top of the drill string , it rotates the drill string and the bit.

DOWN HOLE MOTORS A down hole motor rotate the bit without rotating the entire string of pipe. Rig often use down hole motor to drill directional holes

HORIZONTAL DRILLING

THE DRILL STRING The drill string consist of drill pipe and heavy walled pipe called drill collars, are metal tubes through which the drilling fluid is pumped. Drill collars are heavy because they are used in the bottom part of string to put weight on the bit. This weight presses down the bit so the bit cutters can bite in to the formation and drill it.

DRILL BIT A bit has teeth or cutter which removes rocks as bit drills Tricone or three roller bit Fixed head bits Steel teeth Tungsten carbide inserts Natural diamond Poly crystaline diamond type

CIRCULATING SYSTEM

HOW DRILLING IS DONE??

RUNNING AND CEMENTING CASING Casing that is cemented has following advantages in drilling purpose: Prevent contamination of fresh water well zones. Seals off high pressure zone from the surface , avoiding potential for blow out. Provide a stronger upper foundation to use high density drilling fluid to continue drilling deeper.

HOW CEMENTING THE CASING IS DONE ??

FORMATION EVALUVATION Examining cutting & drilling mud Well logging Drill stem testing Coring

COMPLETING THE WELL The operating company carefully considers the data it obtains from the test. Then it decides weather to set production casing or liner and complete the well or to plug and abandon it.

SETTING PRODUCTION CASING The casing and cementing crew runs cement a string of casing in the well almost to the bottom of the hole.The production casing and cement actually seals off the production zone.

PERFORATING To provide a way for oil and gas to get from the formation and into well, a special gun shoots several relatively small hole in the string . These holes or perforation , pierce the casing and cement around the casing. Formation fluid which include oil & gas , flow through this perforation and in to well.

RUNNING TUBING AND INSTALLING CHRISTMAS TREE The completing rig crew places small diameters pipe called tubing inside the well. Then the crew install a collection of fitting and valves called a cristmas tree on top of the well . Valves on the cristmas tree allow the operator to control the amount of production. Usaually , once the crew installs the cristmas tree , the well is complete.

EXTRACTION OF OIL After the rig is removed , a pump is placed on the well head . In the pump system an electric motor drives a gear box that moves a lever. This pushes and pulls the polishing rod up and down. The polishing rod is attached to the sucker rod , which attached to a pump. This system forces the pump up and down creating a suction that draws oil up through the well.

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