Drilling Operations Report Pakistan Petroleum Limited, (PPL)
Submitted by Mustafa Fareed (Intern – Drilling Department)
INTRODUCTION TO DRILLING: Chronological order of operations
Well drilling is the process of drilling a hole in the ground for the extraction of a natural
resource such as ground water, brine, natural gas, or petroleum, for the injection of a fluid from surface to a subsurface reservoir or for subsurface formations evaluation or monitoring. Drilling for the exploration of the nature of the material underground (for instance in search of metallic ore) is best described as borehole drilling, or 'drilling.
The drilling hole is drilled by various mechanism from which most applied technique is Rotary Drilling, in which a drill string (combination of series wise drill pipes and bits etc) Is forced down with rotation to perform the drilling process and the cuttings are extracted through the circulating mud from hole bore. As the depth increases drill pipes are connected over one another to provide the length to drill string. After each specific formation of earth (prognoses by experts) the casing is run in the hole to support the well bore and cemented within the volume of bore’s internal diameter to casing’s outer
diameter until the reservoir (oil or gas) is reached.
As the total depth is achieved the liner is run in the hole to protect the open well hole and cemented, through which the bullet perforator is run in the hole at bottom which on blast creates the perforation on liner which serves as a gateway for the trapped oil or gas extraction. The trapped oil or gas is extracted on the principle of pressure difference flow. The formation pressure at bottom is higher than the atmospheric pressure which causes the oil or gas to flow outward the hole. A Christmas tree structured combination of valves, pressure gauges, and chokes are assembled at the top of well opening to control the flow. Also a pump is set at the opening to increase the pressure difference. The extracted oil or gas is then separated on the basis of compositions and purified through various plants.
Drilling Rig Components The Drilling rig present at Adam West X-1 the CCDC-34, was operated by the CNPC Chuanqing Drilling Engineering Company Limited. The Rig comprises of a derrick, the draw works with its drilling line, crown block and the travelling block and a Mud circulation system including the stand pipe, swivel, Mud pits and pumps. While drilling a stand is connected to the Top drive System and the swivel. The Top drive System and the swivel are suspended from a hook beneath the travelling block. The TDS rotates the drill string while the Swivel allows the drill string to rotate and allowing the drilling fluid to pass into the borehole.
The 5 major systems: 1. Hoisting System 2. Rotatory System 3. Circulation System 4. Blowout Prevention System 5. Power System
1. Hoisting System:
The Hoisting System consists of the Derrick, elevator, travelling block, drilling line, crown block and the draw works. Mast or Derrick:
Used for elevating and placing the drilling string and piping above the well bore, and containing the machinery for turning the drilling bit around in the hole.
Draw works:
The draw work is the main hoisting equipment which is powered by a series of prime movers. The operation of the draw work is controlled by the driller using a series of clutches, gears and brakes.
Travelling Block, Crown Block, Drilling Line and Hook:
The travelling block, crown block, drilling line and the hook are all connected to the derrick. The drill string is lowered down into the borehole or pulled out of the hole using all these equipment. The drilling line is connected to the draw works.
2. Rotary System: top Drive System:
The modern drilling rigs use Top drive system for Rotating the drill string. The TDS is present below
Travellin Block
the Swivel. In such a system the Kelly and the Kelly bushing are not required therefore stands are Used instead of joints. Each stand is a
Swivel Top Drive System
Combination of Three drill pipes. Hose Pipe
Drill Stem: Swivel:
The swivel is present above the top drive system. The Swivel does not rotate by itself but allows the drill pipe to rotate. Mud is pumped into the drill string from the goose neck which connected to the swivel.
The old Kelly – turntable system
Drill String:
The drill string comprises of drill pipes and the bottom-hole assembly.
Drill Pipe:
Each drill pipe has a particular OD which is always the same the OD might change depending upon the strength and weight of the drill pipe. The OD and ID of drill pipe is important to be noted properly as it is used in various calculations that are carried out during different drilling operations. Heavy Weight Drill Pipe
The HWDP has the same OD as that of the drill pipe but has a smaller OD thus giving it more strength. HWDP has two major functions; one that it adds load to the drilling Bit and second as we have heavy drill collars, jars and bit below therefore sudden change in pipe strength will break the string even with a slight increase in torque the HWDP provides a gradual shift in weight and strength. Drill Collars:
Drill collars have a larger OD and a smaller ID. The drill collar performs the following major functions.
Adds weight to the bit while drilling
The weight of collar keeps the drill string in tension
The drill collars has outer spirals that helps in penetration
The number of drill collar depends upon the mud weight, the greater the mud weight the greater will the buoyancy and more drill collars will be needed to provide sufficient weight to the drill string.
Jars: The jars are similar to the HWDPs having a shock absorber in the middle. They absorb the shock in case of sudden jerk to the drill string .
Stabilizers:
Stabilizers are short length pipe having Ribs that have diameter equal to the hole size. The Ribs are either straight or spiral. Stabilizers keep the string straight protecting it from vibration plus they help to maintain hole diameter. Cross-Over Subs: Cross over subs link two pipes of different diameter.
3. Circulation System: This system circulates the drilling mud to the bit & back to the surface for cleaning and circulation. It consists of the following:
Mud pumps They provide sufficient pressure required for the movement of mud from mud pit to drill bit. A drilling rig usually has two or three Mud pumps. Mud Pumps are the heart of the rig circulating the drilling fluid through the borehole. The function of the pumps is to circulate the mud from a mud pit at the surface through the drill string into the bore hole, out of the bit bringing it up the annulus, back to the Mud tanks.
Mud pumps present at Adam West X-1, were triplex single acting pumps
Stand pipe
It delivers the mud from the mud pumps up to the swivel via the goose neck. Rotary hose
It provides a passage war for drilling mud.
Swivel/top drive
It provides a pressure tight passage way for the drilling mud
Drill string
It consists of drill pipe and drill collar through which mud is pumped.
Bit
Mud is pumped through the nozzles and lifts the cuttings back to the surface via annulus.
Mud return line/flow line
Mud returns to the mud tanks via these lines.
Mud tanks
It provides mud and circulates it. It contains agitators that provide continuous mixing of the mud.
Shale shaker
It removes solid particles from the mud.
4. Power system:The power system of a rotary drilling rig has to supply power to the main components such as rotary system, hoisting system and drilling fluid circulation system. In addition, auxiliaries like the blowout preventer, boiler-feed water pumps, rig lighting system, etc. have to be powered. Since the largest power consumers on a rotary drilling rig are the hoisting and the circulation system, these components determine mainly the total power requirements. At ordinary drilling operations, the hoisting (lifting and lowering of the drillstring, casings, etc.) and the circulation system are not operated at the same time. Therefore the same engines can be engaged to perform both functions. The power itself is either generated at the rig site using internal-combustion diesel engines, or taken as electric power supply from existing power lines. The raw power is then transmitted to the operating equipment via mechanical drives, direct current (DC) or alternating current (AC) applying a silicon-controlled rectifier (SCR). Most of the newer rigs use the ACSCR systems. As guideline, power requirements for most rigs are between 1000 to 3000 hp.
Following are the important components of power system:
Prime mover
It provides basic source of electricity.
Drives
It transfers electricity to other components of the rig
Adam West X-1 had a capacity of 1500 hp, 4 generators contributing equally.
Well control System:Well control system consists of a series of stacks that are used to isolate the borehole from the surface in the event of flow of formation fluid into the borehole. The increase in pressure is term as “kick” or “blow -out” in the drilling terms.
Following are the important components of well control system.
BOP
It assists in controlling a kick before it becomes a blowout.
Annular Preventer
It seals the annulus between the Kelly, drill pipe or drill collars.
Pipe Ram
It closes on the drill pipe.
Blind Ram
It closes on an open hole.
Shear Ram
It cuts the drill pipe & seals the hole.
Services provided by companies at Adam West X-1 Well:1. CCDC:Utilize CCDC Rig 34 for well Adam West X – 1.
2. Mud Engineering:M/s Halliburton (Baroid) will provide Mud Engineering Services and Chemicals on Consignment Basis at the well site.
3. Cementing:Halliburton unit along with crew will be available at site. 4. Mud Logging Unit:-
Shenkai complete with unit, mud loggers, pressure engineer and equipment will be available at site. 5. Fishing:-
Fishing tools for 17 ½”, 12 ¼”, 8 ½”, 6” and 4 1/8” holes will be provided by Weatherford. 6. Schlumberger:-
Mud motors and MWD for directional drilling would be provided by Schlumberger which is the primary directional/performance drilling contractor for PPL. 7. Wire line Logging:-
Schlumberger / Weatherford Wire line services logging unit with personnel and necessary logging tools will be available at site. 8. BHA Tools:-
ITS (International Tubular Services) will provide all BHA tools including drilling Jars. CSR to coordinate with Drilling Engineer for BHA tools.
9. Casing/ Tubing Running Services:-
Weatherford can be called along with equipment and personnel for casing/ tubing runnin g services as and when required. 10. Tubular Inspection Services:-
PTIS can be called along with equipment and personnel for the services as and when required. 11. Well Head Services:-
M/s AKER SOLUTION personnel can be called (if required) for the services as and when required. 12. Liner Hanger Engineer / Setting Tools etc:-
Smith Schlumberger Liner Hanger Services. CSR to coordinate with ED for Service engineer, liner hanger setting tools and polish mill. These tools are on daily rental from Smith Services. 13. Coring :-
BHI Coring Services will provide Coring tools & services.
Fishing Job as seen on Adam West X-1: Tool sticking occurred in the wire line tool during the process of logging, this posed a major problem as the source present in the tool is radioactive in nature, obviously due to health and safety concerns, a safe method of retrieval was needed. Decisions were made to fish the tool and continue logging during pull out. Schlumberger was in charge of the fishing job.
Steps taken.
Wire was cut, thereby disabling current to the tool. Held in place with T clamp.
Wire sockets were made
Fishing assembly was attached to pipes and wire, both.
Assembly run in hole
Process of cutting and joining the wire again after each section of pipe until the tool depth was reached.
Grapples present in over shot assembly latch the tool automatically grabs on tool head.
Pull out of hole while logging.
Wire line cut to expedite pull out from hole.
TLC for XPT run.
