The Drill Stem Component Description Engineering Essay

The Drill Stem Component Description Engineering Essay Section 3 Presentation This section presents general strategies for drill string structure. The plan parts of basic significance and elements controlling drill pipe determination are featured. The term Drill Stem is utilized to allude to the blend of tubulars and embellishments that fill in as an association between the apparatus and the boring apparatus (RGU address slides). It comprises for the most part of Drill Pipe, Drill Collars (DC) and Heavy Weight Drill Pipes (HWDP) and frill including bit subs, top drive subs, stabilizers, containers, reamers and so on. Drill stem is regularly utilized reciprocally with the term Drill String which really alludes to the joints of drill pipe in the drill stem. With the end goal of this report, Drill String will be utilized to allude to the string of drill pipes that along with drill collars and overwhelming weight drill pipe make up the drill stem see fig 3.1. 3.1 DRILL STEM COMPONENT DESCRIPTION 3.1.1 Drill Pipe The drill pipes are consistent channels generally produced using distinctive steel evaluations to various widths, loads and lengths. They are utilized to move rotational torque and penetrating liquid from the apparatus to the base opening gathering (drill collars in addition to adornments) and boring tool. Each drill pipe is alluded to as a joint, with each joint comprising of a funnel body and two associations (see fig 3.2). Drill pipe lengths shift, and these various lengths are named ranges, the accessible or progressively regular reaches include: Range 1: 18 22 ft Range 2: 27 30ft Range 3: 38 40ft. Drill Stem. Fig 3.1: Drill Stem with parts. (Heriott Watt University address Notes: Drilling Engineering) Drill pipes are additionally fabricated in various sizes and loads which mirrors the divider thickness of the drill pipe. Some basic sizes and their comparing loads incorporate 31/2 in. 13.30 lb/ft and 4 1/2in. 16.60 lb/ft. The demonstrated weight is the ostensible load in air (pipe body weight barring instrument joints) of the drill pipe. A total posting of API perceived drill pipe sizes, weight and grades are distributed in the API RP 7G. The drill pipe grade means that the base yield quality of the drill pipe which controls the burst, breakdown and pliable burden limit of the drill pipe. The normal drill pipe grades are introduced in the table underneath Evaluation Yield Strength, psi Letter Designation Exchange Designation D D-55 55,000 E E-75 75,000 X X-95 95,000 G G-105 105,000 S S-135 135,000 Table 3.1: Drill Pipe Grades. Drill pipes are regularly used to bore more than one well, accordingly much of the time the drill channel would be in a ragged condition bringing about its divider thickness being short of what it was the point at which the drill pipe was fresh out of the plastic new. So as to recognize and separate drill pipes, they are gathered into classes. The various classes are a sign of the level of wear on the divider thickness of the drill pipe. The classes can be summed up as keeps as per API guidelines: New: Never been utilized, with divider thickness when to 12.5% underneath ostensible. Premium: Uniform wear with least divider thickness of 80%. Class 2: Allows drill pipe with a base divider thickness of 70%. It is basic that the drill pipe class be distinguished in drill pipe use or plan, since the degree of wear influences the drill pipe properties and quality. While determining a specific joint of drill pipe, the class, grade, size, weight and range must be recognized, the particular could subsequently show up along these lines: 5 19.5 lb/ft Grade S Range 2 Fig 3.2: Parts of Drill pipe. (Handbook for Petroleum and Natural gas) 3.1.2 Tool Joints Instruments joints are screw type associations welded at the closures of each joint of a drillpipe. The device joints have coarse tightened strings and fixing shoulders intended to withstand the heaviness of the drill string when it is suspended in the slips. Device joints are of two sorts; the pin (male area) and the crate (female segment). Each drill pipe has a pin joined to one end and a crate connected at the opposite end. This makes it feasible for the pin of one joint of drill channel to be cut into box of a past drill pipe. There are a few sorts of hardware joints generally utilized: Joint Type Chart Portrayal Inside Upset (IU) Device joint is not exactly the channel. Instrument joint OD is around equivalent to the channel. Interior Flush (IF) Instrument joints ID is roughly equivalent to the funnel. The OD is vexed. Inside/External Upset (IEU) Instrument joint is bigger than the funnel with the end goal that the device joint ID is not exactly the drill pipe. The device joint OD is bigger than the drill pipe. Table 3.2 Types of hardware joints. (The Robert Gordon University Lecture Notes: Drill String Design) 3.1.3 Drill Collars Drill collars are thick walled tubes produced using steel. They are ordinarily the overwhelming piece of the base opening get together (BHA) which gives Weight on Bit (WOB). Because of the huge divider thickness of the drill collars, the association strings could be machined legitimately to the body of the cylinder, along these lines dispensing with the requirement for instrument joints (see fig 3.3). Drill collars are produced in various sizes and shapes including round, square, triangular and winding furrowed. The smooth and winding furrowed drill collars are the most widely recognized shapes utilized at present in the business. There are drill collars produced using non-attractive steel used to confine directional overview instruments from attractive impedance emerging from other drill stem segments. The steel grade utilized in the assembling of drill collars can be a lot of lower than those utilized in drill pipes since they are thick walled. Capacities Give weight on bit Give solidness to BHA to keep up directional control and limit bit soundness issues. Give solidarity to work in pressure and forestall clasping of drill pipes. Fig 3.3: Carbon Steel Drill Pipes. 3.1.4 Heavy Weight Drill Pipe Substantial weight drill pipes (HWDP) are regularly produced by machining down drill collars See fig 3.4. They generally have more noteworthy divider thickness than ordinary drill pipe. HWDP are utilized to give a steady traverse when making progress between drill collars and drill channels to limit pressure fixation at the base of the drill pipe. These pressure fixations regularly result from: Distinction in solidness because of the distinction in cross-sectional territory between the drill neckline and drill pipe. Bit ricocheting emerging from turn and cutting activity of the bit. HWDP can be utilized in either compressive or pliable help. In vertical wellbores it is utilized for progress and in exceptionally veered off wells, it utilized in pressure to give weight on bit. Fig 3.4: Heavy Weight Drill Pipe. (Heriott Watt University address Notes: Drilling Engineering) 3.1.5 Accessories Drill Stem adornments include: Stabilizers: these are made of a length of funnel with cutting edges on the outer surface. The sharp edges are winding or straight, fixed or mounted on elastic sleeves to permit the drill string pivot inside. Elements of the stabilizer include: Settle the drill collars to lessen clasping and twisting Guarantee uniform stacking of tricone bits to decrease wobbling and increment bit life. To give important divider contact and solidness behind the bit to actuate positive side power to construct point when penetrating digressed wells. Reamers: utilized in the BHA to extend the very much bore distance across and ream out doglegs, key seats, edges. Boring Jars: joined in the BHA to convey a sharp blow and help with liberating the drill string should it become stuck. 3.2 DRILL STRING DESIGN The drill string configuration is done so as to build up the most effective mix of drill pipe size, weight, and grades to satisfy the penetrating goals of a specific gap segment at the least expense inside satisfactory security measures. So as to structure a drill string to be utilized in a specific opening segment, the accompanying boundaries should be set up: Opening area profundity Opening area size Expected mud weight Wanted wellbeing factors in pressure and overpull. Wanted wellbeing factor in breakdown Length of drill collars required to give wanted WOB including OD, ID and weight per foot. Drill pipe sizes and assessment class The drill string configuration needs to meet the accompanying prerequisite: The working burdens (pressure, breakdown, burst) on the drill string must not surpass the appraised load limit of every one of the drill pipes. The drill collars ought to be of adequate length to give all required WOB to forestall clasping loads on the drill pipe. The drill pipes utilized need to guarantee the accessibility of adequate liquid stream rate at the boring tool for opening cleaning and great pace of infiltration. 3.2.1 Design Safety Factors Plan wellbeing factors are applied to determined working burdens to represent any sudden help load on the drill string. They are utilized to speak to any highlights that are not considered in the heap computations for example temperature and consumption, along these lines guaranteeing that administration loads don't surpass the heap limit of the drill pipe. Plan security factor esteems are frequently chosen dependent on experience from working inside a specific territory, the degree of vulnerability in the working conditions for example while working in HPHT conditions, a bigger security factor is applied than while working in less brutal conditions. Some generally utilized plan wellbeing esteems are represented in the table beneath Burden Structure Safety Factor Value Strain 1.1 1.3 Edge of overpull (MOP) 50,000 100,000. MOP of 400,000 have been utilized in ultra profound wells Weight on Bit 1.15 or 85% of accessible Weight on bit to guarantee nonpartisan point is 85% of drill neckline string length measures from the base (API RP 7G) Torsion 1.0 (in light of the lesser of the funnel body or device joint quality) Breakdown 1.1 1.15 Burst 1.2 3.2.2 Drill Collar Selection The drill collars are chosen with the point of guaranteeing that they give adequate WOB without clasping or putting the lower segment of the drill string