Drilling Engineering 1 PDF

Drilling Engineering 1  DRILLING ENGINEERING I PET314 Module 2:TECHNIQUES FOR OIL-WELL DRILLING ENGR DIKE, H.N Ph.D  COURSE  OUTLINE Introduction/ Overview  Int. to Oil-well Drilling;Techniques, Component and operations of Rig System: Dri...

Drilling Engineering 1  DRILLING ENGINEERING I PET314 Module 2:TECHNIQUES FOR OIL-WELL DRILLING ENGR DIKE, H.N Ph.D  COURSE  OUTLINE Introduction/ Overview  Int. to Oil-well Drilling;Techniques, Component and operations of Rig System: Drilling rigs; Equipment, Rotary, Hoisting, Circulation Systems, Drill String, Drill Bits,, Casing & Casing Shoe, Tubing, Packers and Basket.  Techniques for Oil-well Drilling 2  Drill bits technology, Offshore Drilling rigs  Int.- Drilling Fluids, and Types  Well Head Equipment, Drilling and Casing Programs, Drilling Performance.  Basic Rig Maths  Drilling Performance and Drilling Hydraulics  Drilling Problems, Detection and Control  Fundamental of Pore Pressure and Fracture Gradients  Overview of Oil Well Drilling Well planning.Technology Drilling method. Drilling rigs operating systems. Drilling fluids function and properties. Drilling fluid maintenance equipment. Oil & gas well cementing operations. Drill bit types and their applications. Drill string & Casing string function, operations, selection & design. Drilling problems, their control & remedies. Directional drilling tools. Directional survey. Application of horizontal, multilateral, extended reach, slim wells.  LEARNING OBJECTIVES Upon the completion of this lesson, the students should be able to: Explain briefly the history of oil well drilling and Various techniques of drilling Classify Wells and State their Purpose(s) Describe Drilling rigs. Describe the Types of Drilling rigs, Drilling tools & Equipment Offshore/Marine Rigs, their Advantages and Disadvantages. Describe the design criteria used in selecting Offshore/Marine rigs. Describe the differences between Oil rigs and Oil Platforms.  INTRODUCTION Drilling is one of the stages of oil exploration, carried out after the prospecting phase It involves all the operations done since the beginning of the well to its delivery (to the production team) The problem is that, with this increased consumption, more accessible oil reserves are depleted at a fast pace and it becomes necessary to explore new areas where the complexity and the risk of operations are larger, requiring knowledge, technologies and personnel There are also further questions about the impact caused on an environment, which makes the challenge of the oil industry to not only overcome the structural complexity of the areas explored, but to also be, produced in a sustainable way Thus, the analysis of operations conducted during the drilling of an oil well is extremely important, and contribute to the improvement of the technology used and the implementation of best practices in future operations  WHAT IS DRILLING? Drilling and well engineering is an aspect of a broader field of Petroleum engineering Defined as the boring of hole into the subsurface to access the location of the hydrocarbon in place ( a subsurface strcture beneath the earth) It provides communication channels between the surface and subsurface fluids  WHY WE DRILL WELLS!!! To gain information (e.g. Exploration & Appraisal wells) To produce hydrocarbons or support their production through the injection of gas and liquids Drilling a well is the only way to access a Reservoir and establish what “lies beneath” Each well is a multi million dollar project involving multi disciplines and each well is as unique as each individual person  Types of wells  wildcat wells: drilled outside of & not in the vicinity of known 26 oil or gas fields.  exploration wells: drilled purely for exploratory (information gathering) purposes in a new area  appraisal wells: used to assess characteristics (such as flow rate) of a proven hydrocarbon accumulation  development wells: drilled within the boundaries of a known producing reservoir to increase the production in the field  offset well: a type of development well that is drilled near a well that is producing or had previously been productive  production wells: drilled primarily for producing O & G, once the producing structure & characteristics are determined  disposal well: used to dispose of produced water, drilling cuttings or any other unwanted fluid  water or gas injectors: drilled to inject (water or gas) into the reservoir to maintain reservoir pressure  storage well: drilled to store hydrocarbons for later  Well Classification Oil and gas wells are commonly classified based on their total vertical depth (TVD), which is broadly divided into three main categories: Shallow well: represents the conventional oil and gas reserves. Its less than 3000 m [≈10000 ft] deep Deep well: Deep wells enclose most of the newer fields in production today. Deep wells refer to wells with depths ranging from 3000 to 6100 m (10 000−20 000 ft). Ultra-deep well: Ultra-deep wells are wells deeper than 6100 m (20 000 ft) Well Classification  WHO DRILLS THE WELL? Functions of a Driller/Well  Engineer To prepare drilling programs; modified drilling program cost estimates including AFEs (Authorization for Expenditure); bid specification for drilling contractor; drilling contracts.  There are various drilling contracts: daily rate, turnkey, footage rate, and incentive.  To work with a geologist (on the logging program), and other specialists such as directional engineers, mud engineers, service and supply personnel.  RESPONSIBILITIES OF A WELL ENGINEER The well Engineer is the architect and planning coordinator for the project and is responsible for:  estimating overall well cost(AFE)  collecting and reviewing available data on all offset wells in the area  designing all drilling programs (drilling fluids, bits, etc)  anticipating drilling problems and planning contingencies selecting the drilling rig and its specifications  preparing drilling cost and drilling time curves  coordinating bid requests and evaluating contractors to ensure optimum rig selection/personnel efficiency and safety records  coordinating the activities of purchasing, environmental, regulatory and other engineering groups to ensure that all phases of the program are completed economically, safely and on schedule THE DIFFERENT WELL PHASES ENGR. DR. DIKE, H. N.  THE WELL LIFE CYCLE Design: Agree the well objectives, schedule, costs, order equipment, place contracts for the rig and services, prepare the site Construction Drill: The well is created by drilling a hole, isolating with casing and cement and repeating this process until the target depth and location are reached Test: A well may be produced temporarily to establish the Reservoir potential Complete/Suspend: If the well is to be put on production/injection it is completed with tubing and flow control equipment: otherwise downhole plugs are installed Commission: The well is handed over to operations and connected to the process facilities  THE WELL LIFE CYCLE CONT’D Operation: Well performance and integrity are continually monitored. Routine maintenance is performed Workover: The well is handed back to the wells team to perform downhole surveillance, improve the well performance or repair/replace downhole equipment. The well may also be “sidetracked” i.e. a new hole is drilled from the existing wellbore to a new target Abandonment: When a well becomes uneconomic the wells team return to install downhole cement plugs to isolate hydrocarbon zones and the wellhead is removed.  DRILLING: BRIEF HISTORY The Chinese have used oil and gas for many centuries There is no record of when Chinese began using natural gas, but clearly in Szechuan the local people were drilling down hundreds of feet into the earth to get natural gas and brine The Chinese used bamboo pipelines to carry natural gas and mix it with air to yield a usable source of fuel for fires The initial discovery of natural gas may have come as an unexpected by-product of the search for brine and salt Edwin Drake is often mentioned for digging a modern oil well in Pennsylvania in 1859, starting a boom in petrochemical and mining industry DRILLING FOR BRINE IN CHINA  ADVANCEMENT OF CHINESE DRILLING The first drilling technique developed in China was the Spring Pole Technique, which harnessed the motion of a wooden pole to lower and raise a drill bit into the ground By the first century B.C., the technology of well-drilling had advanced to the use of a derrick and cable tools Chinese engineers were able to dig down over 800 feet and commonly did so as part of a brine industry in Szechuan EXAMPLE OF SPRING POLE TECHNIQUE  DEVELOPMENT OF EARLY DRILLING TOOLS The striking drilling method on its own is impressive, especially when considering that the rest of the world had nothing comparable in the earlier centuries More impressive are all the techniques the Sichuan drillers developed to overcome common drilling problems such as cave-ins, lost tools and so on They also developed a huge variety of tools and techniques to handle well repair issues Many different drill bits were also developed, with different sizes, shapes and compositions to deal with the different rock types encountered and the many different drilling requirements  TRADITIONAL FISH TAIL BIT TRADITIONAL CHINESE DRILLING EQUIPMENT THE DEVELOPMENT OF SPRING POLE DRILLING IN THE USA Drilling knowledge which started in China eventually made its way to the rest of the world In the United States the Spring Pole technique was being used successfully to drill for “Brine” so that salt could be extracted In 1802 in what is now West Virginia, salt brine drillers David and Joseph Ruffner took 18-months to drill through 40 feet of bedrock to a total depth of 58 feet using a Spring pole The well’s historic significance rest on the “development of well drilling tools and practices, which became almost immediately standard equipment used by many other well drillers in the industry The rainbow sheen and pungent smell of oil was bad news to brine drillers DEVELOPMENT OF SPRING POLE THE WORLD STRUGGLE FOR OIL IN USA 1802 FILM 1924  THE DERRICK AND CABLE TOOL DRILLING The advent of cable-tool drilling introduced the wooden derrick into the changing American landscape Using the same basic notion of chiseling a hole deeper and deeper into the earth, with frequent stops to remove the chipped-away rock, bail out water and sharpen the bit Bull wheels and hemp rope repeatedly hoisted and dropped heavy iron drill strings and variety of bits deep into the borehole Oil was still an adversary to those in search of either fresh water or brine; when Yale chemist, Benjamin Silliman found that oil could be distilled into a kerosene illuminant, the world changed forever Inspired entrepreneurs with the idea of using cable tool drilling to extract oil quickly got to work CABLE TOOL DRILLING WITH STEAM ENGINE  THE DRAKE WELL Edwin L. Drake’s 1859, discovery of commercial quantities of oil at 69.5 feet in Titusville, Pennsylvania brought America’s first drilling boom and virtually created an industry over night Soon, cable-tool rigs were everywhere, pounding into the earth, searching for oil In 1860 steam engines were introduced to power rigs and the drilling operation became much more efficient As wells got deeper, some drilling experts found resistant rock strata that made progress far more difficult using the percussion drilling method Sometimes the drilling tools got stuck threatening the well  DEVELOPMENT OF ROTARY DRILLING Instead of the repetitive lift and drop of heavy cable-tool bits, rotary drilling introduced the hollow drill pipe that enabled drilling fluid to be circulated down through the drill pipe Then cuttings would be washed out of the borehole while the rotating drill bit cut deeper By applying downward pressure, the drilling fluid also stops an oil well from kicking unexpectedly by using a mud weight that is greater than the anticipated reservoir pressure Archaeological records show that as early as 3000 BC the Egyptians may have been using a similar technique Leonardo Di Vinci, as early as 1500, developed a design for a rotary drilling mechanism similar to today’s technology INTRODUCTION OF ROTARY DRILLING CAPTAIN ANTHONY LUCAS & PATILLO HIGGINS SPINDLETOP GUSHER  History of oil well drilling 8  First use of oil (1000+ yrs. ago) was for lighting purposes  Oil was known to exist but extraction was the issue  Edwin Drake, hired by Seneca Oil Co. to study potential oil deposits in Titusville, PA. Drilling started in summer 1859  Well was dug on an island on the oil Creek (Allegheny river) – Drilled in the manner as salt well Cable Tool drilling – Steam engine to power the drill – Progress was about 3 feet/ day  On August 27, depth was 69.5 ft. – Billy Smith (driller) saw oil rising up – 25 Bbls of oil were collected in a bath tub on day  History of drilling 9  Drake pioneered a new drilling method for producing oil – Using piping to prevent borehole collapse, allowing for the drill to penetrate further into the ground – A 32’ iron pipe was driven into the bedrock – The principle is still employed today  Drake’s method were imitated by others along Oil Creek – Several oil boom towns along the creek were born  Drake's well produced 25 barrels (4.0 m3) of oil a day – 1872, the area produced 15.9K BOPD (2,530 m3)  Drake did not possess good business acumen. He  First Producer 10 Wells 1 2 Overproduction became an 1) Phillips well: 4K BOPD , Oct. 1861 issue Market was over flooded 2)Woodford well: 1500 BOPD, July and price dropped from few $ 1862 Empire well: 3000 BOPD, to 10 cts a barrel Sept. 1861  Oil Well Drilling Methods There are two drilling methods used in the petroleum industry: The cable tool method, by which the first oil well was drilled in 1859 to a depth of 65 ft, was first employed by the early Chinese in the drilling of brine wells. The rotary drilling method, started by a French civil engineer in 1863, is the most common method that performs a rotary grinding action; some cable tool rigs are still working in parts of Europe as well as in the USA.  Cable Tool Method The cable tool method is one of the oldest methods of drilling used in the oil industry. It was developed in China. some of the unique factors are:  lower initial equipment cost ·  lower daily operating expenses.  lower transportation cost ·  lower rig-up time and expense  drilling rates somewhat comparable to those of rotary rigs in hard, shallow areas ·  more precise sample (cuttings) data ·  reduced formation damage from drilling fluids  Cable Tool Method The cable tool method is used in drilling unconsolidated, soft rock formations, or shallow depth wells. It has slow penetration rate. The methods of casing advancement used in cable tool method are the drive cap and drive block It also uses a drilling string where the bit goes up and down performing drilling functions such as penetrating the material, reaming the sides of the hole, crushing the geology into fine particles, mixing this materials with water.  The cable tool method The cable tool drilling process consists of drilling, removing cuttings, identifying the geology, monitoring water flow if present, and advancing the casing. Drilling with a cable tool rig is accomplished by raising a special drill bit and dropping it on the formation. The drillstring is composed of the bit, the drillstem, jars, and  DRILLING RIGS Drilling rigs are used to drill the hole, lower and cement casing in the well, and provide a means to perform various auxiliary functions such as logging and well testing. Many companies are applying more effort in rig selection since it is important for the safety, efficiency, and cost of the well. The proper procedure for rig selection is to size or design the various loads that will be placed on the equipment and to select the most cost-effective rig that will satisfy these requirements.  FACTORS DETERMINING OFFSHORE RIG SELECTION  Major criteria are as follows:  Water depth rating  Derrick and Substructure capacity  Physical Rig size and weight  Deck load capacity  Stability in rough weather  Duration of drilling program  Rig rating features such as horsepower, pipe handling capabilities, mud mixing capacity  Exploratory vs development drilling availability  Cost  Rig mobilization costs must be considered when selecting marine rigs. These costs can be significant and greater than the differences in daily operating rates between comparable rigs. In many cases, the number of wells involved in the contract will influence the selection decision due to high initial mobilization costs.  FACTORS FOR THE SELECTION OF PLATFORMS 1. Water depth 2. Environmental criteria (wind, wave and current movement) 3. Type and density of sea water 4. Drilling Depth 5. Operational limitations 6. Rig move.  Type of Rotary Drilling Rigs  All rigs have the same basic components.  Land rigs: jackknife or cantilever rigs and portable-masts.  Main design features are portability and maximum operating depth. Derricks are built on locations.  Marine (or offshore) rigs: bottom-supported offshore rigs, semi-submersible floating rig, drill- ship floating rig.  Main design features are portability and maximum water depth (WD) of operation.  Type of Rotary Drilling Rigs Drilling Rigs Land Marine Rigs Heavy Land Rigs Rig Light Floating Bottom Supported Land Rig Helicopter Rigs Rigs Semi Jackup Portable Rig Submersible Drill Ship Drilling Platfor Submersi Barge ble m A typical classification of rotary drilling rigs  Offshore Drilling Rigs  Two main types:  floating  bottom-supported unit  Floating unit include: semisubmersible (bottle-type, column stabilized), barge rig and drill ship.  Bottom-supported unit include: submersible (posted barges, bottle-type submersibles, arctic submersibles), jackups and platforms.  Functions of Drilling Rig Formation Fracturing with a Bit Cleaning of the drilled Hole with Circulating Mud Control of drilling Process o Arresting Caving in Tendency o Sealing Borehole Wall (Mud Cake) o Prevention of Kick o Prevention of Underground Blow-out o Maintaining Drilling Fluid Quality Hoisting of Tubular Members and all Materials Provision of Power Required for all Operations Provision of Storage Facilities (Consumables and Reusables) Provision of Waste Handling Facilities Provision of Accommodation Provision of Health Facilities  TYPES OF DRILLING RIGS Land Rigs Land rigs are generally either wheel-mounted portable types or a component system that must be moved by trucks and cranes. The drilling floor generally sits on top of a steel substructure that could be 30 feet high or more. A drilling mast (derrick) is attached to and raised above the floor. In general, the deeper wells need a larger, taller rig. The mast must be capable of supporting the vertical load and weight of the stacked drill pipe. It must also withstand wind loads of 100 to 130 miles per hour. Shallow wells and wells being completed or repaired will probably use a portable rig. This rig can be driven to the well site, raised up  TYPES OF DRILLING RIGS Offshore Rigs Drilling rigs used offshore are termed marine rigs. A common grouping system for marine rigs is based on the bottom support of the rig on the seafloor. A bottom-supported rig rests on the seafloor or on pads built on the seafloor. Floating rigs rely on ballast systems similar to shipping vessels for support and do not rest on the seafloor. The environment also determines which type of marine rig will be used. Each rig has advantages and disadvantages when used in different water depths and weather conditions. The type of marine rig also can depend on problems involved in getting the rig on location and keeping it stationed in the desired position. Some of the marine rigs are: Jack up Rig Semi-submersible Rig Drillship Platform rigs Inland barge rig Marine Rigs  (1). Semi Submersible  This floating drilling unit has columns when flooded with seawater, cause the structure submerge to a predetermined depth.  Although it is moved by wave action, it sits low with a large part of its structure under water combined with eight huge mooring anchors, make it a very stable installation.  This type of rig drills a hole in the seabed then it moves to the next location.  With advancing technology some semi submersibles can drill in water depths over five thousand feet. Semi Submersible  SEMI- SUBMERSIBLE RIGS Semi-Submersible Rigs  SEMI- SUBMERSIBLE RIGS Semi-Submersible Rigs Semi-submersible rigs are floating rigs supported on pontoons. A common design consists of four, five, or six legs. Older semi-submersibles are kept on location by means of anchors and chains, whereas some of the newer ones are kept on location by means of thrusters. The pontoons can be re-floated to change locations. They can be towed easily or even self-propelled to the new location. The semi-submersible rig evolved from the older submersible rigs. It can provide a relatively stable drilling platform. It can operate under more severe weather and sea conditions and in water depths from 600 to 4,000 feet. The semi-submersible rig contains a normal working deck plus columns and pontoons under the deck. These pontoons are ballasted to a water depth that causes the upper deck to remain high above the water. Semi-submersible rigs are the elephants of the offshore rigs, capable to continue operation in bad weather. Semi-submersible rigs move with the tide and the drilling penetration rate must be corrected for the influence of the tidal heave. The disadvantages of semi-submersible rig types are that they require marine drilling risers and a subsea stack, have limited cargo capacity, and require support vessels.  (2). Platform  This immobile structure can be built from concrete or steel and rests on the seabed.  When oil or gas is located a platform may be constructed to drill further wells at that site and also to produce the hydrocarbon.  OFFSHORE PLATFORMS Oil Platforms An oil platform is a large structure installed in offshore areas, often in deep water, to carry out drilling and production activities. These oil platforms are built with stability and resilience to withstand harsh weather conditions and provide a safe working environment for the crew. An oil platform serves as a base for drilling wells and extracting oil from beneath the ocean floor. It houses specialized machinery, pipelines, and storage facilities necessary for the extraction, processing, and transportation of oil. Once the oil is extracted, it is transported to refineries through pipelines or tankers. Oil Platform is a permanent structure that is fixed to the  PLATFORM RIGS Platform Rigs  Steel Jacket Platform  Most common type of platform  Consist of the jacket, a tall vertical section made of tubular steel members.  Supported by piles driven into the seabed.  Additional sections on top of the jacket provide space for drilling rig, crew quarters, and other equipments. PLATFORM STEEL JACKET PLATFORM  Concrete Gravity Platform  Build from steel reinforced concrete  Tall caissons, or column are the dominant feature of this platform.  Sometime, special concrete cylinder are fixed at the base of the caissons on the sea floor to store crude oil.  Compliant Platform Guyed tower platform Tension Leg Platform (TLP)  (3). Jack up  This is a mobile drilling rig, different from the semi submersible. Instead of floating over its drilling location the Jackup has long leg structures, which it lowers to and into the seabed raising the rig out of the water.  The obvious limitation with this type of installation is the depth of water it can operate in.  The maximum being five  (4). Drill Ship  As the name suggests this is a ship shaped drilling vessel.  Unlike the semi submersible and the Jackup, it does not require tugboats to tow it to location.  Although they are not as stable as semi submersibles they also drill in very deep waters.  DRILL SHIP Drill Ship  5. FPSO  Floating Production, Storage and Offshore Loading  They are attached to a seabed well head and they produce and store the oil until another tanker takes it from them.  They are used to produce from small wells where it would be too expensive to build a platform.  FACTORS DETERMINING OFFSHORE RIG SELECTION Water Depth 8 to 35 ft. Swamp Barges  150 ft. Submersibles  350 ft. Jack-ups  1,000 ft. Fixed Platform  8,000 ft. Semi-submersible  8,000 ft. Drill Ship  Rotary drilling rig Rotary drilling rig power has increased from 1 horsepower (hp) a hundred years ago to the 10,000-hp equipment now used offshore. The essential functions of rotary drilling rigs are hoisting, rotating, circulating and controlling and powering.  Rotary Drilling  Rotary drilling uses a sharp, rotating drill bit to dig down through the Earth's crust.  The spinning of the drill bit allows penetration of even the hardest rock.  The actual mechanics of modern rigs are quite complicated. In addition, technology advances so rapidly that new innovations are being introduced constantly.  A rotary drilling rig with some of its major components identified is illustrated in the next figure. Rotary Drilling  Rotary Drilling The basic rotary drilling system consists of four groups of components.  Prime movers  Hoisting equipment  Rotating equipment  Circulating equipment  BOP  Drilling Line The Monkey Board Derrick Traveling Block Top Drive System Drill Pipe Rig Equipment  Prime Movers  The prime movers in a rotary drilling rig are those pieces of equipment that provide the power to the entire rig.  Recently, while diesel engines still compose the majority of power sources on rotary rigs, other types of engines are also in use.  Some rotary rigs may use electricity directly from power lines. Most rotary rigs these days require 1,000 to 3,000 horsepower, while shallow drilling rigs may require as little as 500 horsepower.  The energy from these prime movers is used to power the rotary equipment, the hoisting equipment, and the circulating equipment.  Hoisting Equipments  The hoisting equipment on a rotary rig consists of the tools used to raise and lower whatever other equipment may go into or come out of the well.  The most visible part of the hoisting equipment is the derrick, the tall tower-like structure that extends vertically from the well hole.  The hoisting system is made up of the drawworks, derrick, crown block, traveling block, hook and wire rope.  If a drill bit needs to be changed, either due to tear or a change in the subsurface rock,  Hoisting Equipments  The hoisting equipment is used to raise all of this equipment to the surface so that the drill bit may be replaced. Hoisting Equipments Typical Hoisting System The fastline is the end of the drilling line that is affixed to the drum or reel of the drawworks. It travels with greater velocity than any other portion of the line. Deadline is the drilling line from the crown block sheave to the  Hoisting Equipments  Derrick or Mast  Whenever the drillstem is suspended by the traveling block and drill line, the entire load rests on the derrick.  The standard pyramid derrick is a structure with four supporting legs resting on a square base.  In comparison, a mast is much more slender and may be thought of as sitting on one side of the rig floor or work space.  The derrick is erected on a substructure which supports the rig floor and rotary table and  Hoisting Equipments: Derrick  The derrick and its substructure support the weight of the drillstem at all times, whenever it is suspended from the crown block or resting in the rotary table.  The height of the derrick does not affect its load-bearing capacity, but it is a factor in the length of the sections of drillpipe that can be removed.  Hoisting Equipments  Travelling Block, Crown Block, Drill Line & Hook  Use to connect the supporting derrick with the load of drillpipe to be lowered into or withdrawn from the borehole. During drilling operations, this load usually consists of the weight of the drillpipe, drill collars and drill bit.  The drill line passes from the drawworks to the top of the derrick. From here is sheaved between the crown block and traveling block to give an eight, ten or twelve-line suspension. It is then clamped to the rig floor by the deadline anchor.  Hoisting Equipment: Blocks, Drill Line & Hook  Suspended from the travelling block, on standard drilling systems, is the hook which when drilling carries the swivel and kelly and when tripping it lifts the drillstring.  Hoisting System- Block The System block-and-tackle system is the primary link between the drawworks and the pipe or casing. It provides the mechanical advantage to assist in lowering and raising heavy strings of pipe. The equipment can include items such as the crown and traveling blocks, elevators, bails, and heave compensators. The wire rope is also an essential part of the block-and- tackle system  Hoisting Equipment 22  Hoisting/ Lifting system: To raise & lower the drillstring into the well. Starts at the deadline anchor point and ends at the drawworks Lifting System components  Hoisting Equipments  The Drawworks  The drawworks is a mechanism commonly known as a hoist. The main purpose of the drawworks is to lift the drillstring out of and to lower it back into the borehole.  The drill line is reeled (spooled) on a drum in the drawworks.  When engaged, the drum turns and either reels in the drill line to raise the traveling block, or lets out the drill line to lower it. Because the drillstem is attached to the block, it is raised or lowered.  One outstanding feature of the drawworks is  Hoisting Equipments: Drawworks  An integral part of the drawworks is the gear (transmission) system. This gives the driller a wide choice of speeds for hoisting the drillstring.  The drawworks also has a drive sprocket that drives the rotary table by means of a heavy- duty chain. In some cases, however, the rotary table is driven by an independent engine or electric motor.  Another feature of the drawworks are the two catheads. The make-up cathead, on the drillers side, is used to spin up and tighten the drillpipe joints. The other, located opposite the driller's  Rotating Equipments  The rotating equipment consists of components that actually serve to rotate the drill bit.  Rotating equipment from top to bottom consists of swivel, a short piece of pipe called the kelly, rotary table/topdrive, drill string and bit.  A component called the swivel, which is attached to the hoisting equipment, carries the entire weight of the drillstring, but allows it to rotate freely.  The drill bit is located at the bottom end of the drillstring, and is responsible for actually making contact with the subsurface layers, and drilling through them.  Rotating Equipment 17  Rotary System: Provides the rotation “RPM’s” (via a rotary table or top drive) to turn the entire drillstring and drill bit Rotary Table  Rotating Equipments  Drill String  The drillstring is made up of the drillpipe, drill collars, and specialized subs through which the drilling fluid and rotational power are transmitted from the surface to the bit.  Drill pipe and drill collar come in sections, or joints, about 30 feet long.  The most commonly used diameters of drill pipe are 4, 4½, and 5 inches OD.  The purpose of drill collars is to put extra weight on he bit, so they are usually larger in diameter than drill pipe and have thicker walls.  Drillstri ng Typical The drillstring is an important part drillstring of the rotary drilling process. It is the connection between the rig and the drill bit.  Rotating Equipments: Drill String  Drill pipe and drill collars have threaded connection on each end.  On drill pipe the threaded connection are called tool joints. Tool joints are steel rings that are welded to each end of a joint of drill pipe. One tool joints is a pin (male) connection, and the other is a box (female) connection.  Specialized Subs: The word “sub” refers to any short length of pipe, collar, casing, etc., with a definite function.  Drillstring Drill pipe is used toComponents- extend the depth of the 1 Box well. Although there are many grades, weights and sizes, there are only 3 lengths ranges. A joint of pipe can be broken down into 3 sections. The Box. Connection Yield Maximu Grad Tube Strength m e psi psi Tensile i Strength The Tube “Body” Min ps OD D Max 55000 -------- 95000 E 75000 10500 10000 0 The Pin Connection X95 95000 125000 10500 0 G-105 105000 135000 11500 0 Pin S-135 135000 165000 14500 0 I D  Drillstring Components- Drill Pipe Sizes 1 3-1/2”, 4”, 4-1/2”, 5”, 5-1/2” and 6-5/8”  Drill strin 41 g Heavy Weight Drill pipe (Heviwates or Com HWDP) pone nts- 2 Hevi-Wate Drill Pipe (HWDP) is a thick-walled pipe that looks just like the DP but weighs a lot more. The internal diameter is smaller. It is used for many reasons: Keeps the transition zone out of the drill pipe Used in high-angled or horizontal wells instead of drill collars Keep tension on the drill pipe while drilling. HWDP can be recognised by the oversized centre and the amount of hard banding that is on the tool joints HWDP can be ordered in two ranges: Range 2 and Range 3 Sizes are the same as those of drill pipes (3-1/2” to 6-5/8”)  Drillstring components- 3 42 Drill Collars (DC’s) Heavy, stiff steel tubulars (much heavier than DP & HWDP). Used at the bottom of a BHA to provide weight on bit and rigidity The primary function is to provide sufficient WOB (Weight on bit) The DC’s also ensures that the DP is kept in tension to prevent buckling. DC can be slick (flush) or spiral DC sizes can be from 3 1/8” to 11”  Drillstring 43 Components- 4. Stabilizers Center/ stabilize the drillstring components in the drilled hole Reduce the are of contact of the components with the borehole Stabilizers are used with any type of drilling assembly Stabs are used to control hole deviation If correctly used, stabs may improve hole quality, rate of penetration and prevent many undesirable drilling issues, including stuck pipe, hole spiraling and harmful vibration  Drillstring Components- 4 44 Types of Stabilizers Welded. Integral String and nearbit Straight Blades/ Spiral blades Replaceable sleeves / non-rotating sleeve Variable gauge/diameters  Drillstring Jar & Accelerator Components- 5 - Used to free stuck drill strings or to recover stuck components  Drillstring Components- 5 Shocks Absorber Subs & Crossovers (XO’s) - Absorbs or dampen axial vibrations - Make up components with different - Prevent failures of other OD & connections/ threads components - Special applications  Drilling Tools- Mud Motors 47 Mud Motors are run right above the drill bit Are used to improve drilling performance in any type of wells Provide rotation to the drill bit without rotating the drillstring In directional drilling, a motor is used to deviate from vertical, build angle & steer the well to its geological/ subsurface target Motors provide additional energy to the bit o Convert hydraulic to mechanical energy Increases the rate of penetration STATOR Main parts of a mud motor Power Section Transmission Section Bearing Section ROTOR  Rotating Equipments  Drill Bit  At the bottom of drillstring is a the bit, which drills the formation rock.  Most common types are roller cone bits and diamond bits.  The bit size: range from 3¾ inches (9.5 cm) to 26 inches (66 cm) in diameters. The most commonly used sizes are 17½, 12¼, 77/8, and 6 ¼ inches (44, 31, 20, and 16 cm).  Roller cone bits usually have three cone- shaped steel devices that are free to turn as the bit rotates. Drilling Tools- Bits 48  Rotating Equipments: Drill Bit  Several rows of teeth, or cutters, on each cone scrape, gouge, or crush the formation as the teeth roll over it.  Two types: milled teeth and tungsten carbide inserts.  Most roller cone bits are jet bits: drilling fluid exits from the bit through nozzles between the cone, thus create high velocity jets of mud. This will help lift cuttings away from the bit.  Applications for PDC bits 49 PDC Cutter sizes PDC material Tungsten Carbide material  PDC= Polycrystalline Diamond Compacts  PDC cutters are manufactured with man made diamond material  Drilling Tools- Bits 50 Advantages Very Fast ROP. Long Life Potential Disadvantages Impact Damage Abrasiveness Stability ROP vs. Durability  Applications for PDC bits 51 what these bits good for?  PDC bits are also know as “Drag Bits” because they shear / drag the rock as they cut it and were originally designed to drill these types of formations: – Soft to medium hardness (strength) – That can be drilled at high ROPs, very fast – Low abrasivity – Lithology type predominantly shale, claystone – Drilling parameters – Rotary/ top drive: low-medium WOB & medium high RPM’s – Mud Motor: high power (high torque) & medium speed (RPMs)  As technology advanced, new materials and processes were developed, today PDC bits can be used to drill much harder and abrasive rocks than before and can drill with much flexible range of parameters (WOB, RPMs, torque) PDC bits after use 52  Natural Diamond Bits Drill Bits Fixed Rolle r Cutter Con e Mill PDC Diamond Inser Toot t h Natural Impregnat Roller Journal TSP ed Diamond Diamon Bearin Bearin d g g Natural diamond bits are almost always run with high speed mud motors or drilling turbines  Natural Diamonds 54 “ND” Bits What are these bits good for?  Hard and abrasive formations where a PDC or tricone will not last very long. These rocks are drilled by a grinding effect of the diamond stones on the formation  ROP are typically low, typically not higher than 10 feet/ hr and as low as less than 1 feet/hr  Can drill for long drilling time, much longer than a PDC  Natural diamond bits can be run with rotary or with a mud motor or turbine. The speed (RPM) depends on the size of the diamond stones. The smaller the stones, the higher the RPMs generally is  Today, ND bits are not very common as most have been replaced by either new PDC designs or impregnated bits  TSP Bits TSP’s resist / stand much higher temperature than a PDC cutter Drill Bits TSP=Thermally Stable Polycrystalline Diamond Fixed Rolle r Cutter Con e Mill PDC Diamond Inser Toot t h Natural Impregnat Roller Journal TSP ed Diamon Diamon Bearin Bearin d d g g 5 5  TSP 56 TSP is a man made diamond which is thermally stable at Bits very high temperature, at which a PDC cutter will generally fail. These high temperatures are reached when drilling hard/ abrasive rocks at very high RPM’s. That’s why a PDC bit cannot be used to drill these types of rocks TSP  bits are good to drill: Hard and abrasive formations at high RPMs where PDC are not suitable due to the high heat (temperature) generated by friction with the formations  Typical rocks, best application: homogeneous sandstone with low % or none shale or clay  ROP’s can be low (less than 5 ft/hr) to medium-low (less than 20 ft/hr) depending on formation strength (hardness) & size of the TSP stones  Can drill for long drilling time, like a ND bit  Like a ND bit, TSP bits can be run with rotary or with a mud motor or turbine. The speed (RPM) depends on the size of the diamond stones. The smaller the stones, the higher the RPMs generally is  Today, TSP bits are not very common as most have been replaced by either new PDC designs or impregnated bits  Impregnated Bits Drill Bits Fixed Rolle r Cutter Con Advantages e Very Durable Mill PDC Diamond Inser Hard Rock Capability Toot t h Low Junk-in-Hole Risk Disadvantages Slower ROP Natural Impregnated Roller Journal RPM Sensitivity TSP Diamond High Cost Diamon Bearin Bearin g g Applications d ROP vs. Durability Impregnated bits are made with very fine grain/ powder Thermally Stable Polycrystalline Diamond  Impregnated 58 bits Impregnated are another type of TSP bits and are made with very fine powder TSP diamond product. Impregnated bits are good to drill:  The hardest and most abrasive formations and rocks where other bits will not last  Are always run with turbines or high speed motors  ROP’s are usually low to very low (5 to less than 1 ft/hr)  A impregnated bit can last several hundreds hours  Drilling Tools- Bits 59 Other names for Roller Cone bits: Rock Bit, Tri-Cone™. Mill Tooth Bit Advantages Fast ROP Good Stability Economic Disadvantages Tooth Wear Rate Bearing Life ROP vs. Durability  Drilling Tools- Bits 60 Insert Bit Advantages. Cutting Structure Durability Range of Formations Interbed Tolerance Steerability and Stability Disadvantages Slower ROP Bearing Life Risk of Junk-in- Hole ROP vs. Durability Other names for Roller Cone bits: Rock Bit, Tri-Cone™  Drilling Tools- Bits 62 Roller Cone Bits Are Versatile Bits can drill a variety of formations Bits can drill variable and interbedded formations Bits can survive intervals (soft-hard; hard-soft) Weight on bit and & RPM are easily adjusted  So,…….. Do you want to be a Drilling Engineer?  So,…….. Do you want to be a Drilling Engineer?  So,…….. Do you want to be a Drilling Engineer?  Assignment 1. Explain the key components of a drilling rig and their functions in the drilling process. 2. Discuss the differences between onshore and offshore drilling rigs, highlighting the unique challenges associated with each 3. Explain the different types of drill bits used in drilling operations, and when each type is typically employed. 4. How does the choice of drill bit design affect the drilling process and efficiency? 5. Discuss the concept of "drill bit wear" and its impact on drilling performance. Standard Derricks A typical Land rig location Jack up and Submersible rig A Drill ship and a Tension Leg Platform(TLP)