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 plan. The plan parts of basic significance and elements controlling drill pipe determination are featured. The term Drill Stem is utilized to allude to the mix of tubulars and extras that fill in as an association between the apparatus and the bore (RGU address slides). It comprises for the most part of Drill Pipe, Drill Collars (DC) and Heavy Weight Drill Pipes (HWDP) and embellishments including bit subs, top drive subs, stabilizers, containers, reamers and so on. Drill stem is frequently 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 substantial 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 funnels generally produced using distinctive steel evaluations to various widths, loads and lengths. They are utilized to move rotating torque and penetrating liquid from the apparatus to the base gap get together (drill collars in addition to adornments) and boring tool. Each drill pipe is alluded to as a joint, with each joint comprising of a channel body and two associations (see fig 3.2). Drill pipe lengths fluctuate, 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 segments. (Heriott Watt University address Notes: Drilling Engineering) Drill pipes are likewise made in various sizes and loads which mirrors the divider thickness of the drill pipe. Some regular sizes and their relating loads incorporate 31/2 in. 13.30 lb/ft and 4 1/2in. 16.60 lb/ft. The showed weight is the ostensible load in air (pipe body weight barring apparatus 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 regular 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, subsequently 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 box new. So as to recognize and separate drill pipes, they are assembled 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 measures: New: Never been utilized, with divider thickness when to 12.5% beneath ostensible. Premium: Uniform wear with least divider thickness of 80%. Class 2: Allows drill pipe with a base divider thickness of 70%. It is fundamental that the drill pipe class be recognized in drill pipe use or plan, since the degree of wear influences the drill pipe properties and quality. While indicating a specific joint of drill pipe, the class, grade, size, weight and range must be recognized, the particular could accordingly show up in this way: 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 Devices 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 case (female segment). Each drill pipe has a pin joined to one end and a crate appended at the opposite end. This makes it feasible for the pin of one joint of drill funnel to be cut into box of a past drill pipe. There are a few sorts of hardware joints generally utilized: Joint Type Outline Portrayal Interior Upset (IU) Instrument joint is not exactly the funnel. Apparatus joint OD is roughly equivalent to the channel. Inside Flush (IF) Instrument joints ID is roughly equivalent to the funnel. The OD is vexed. Inward/External Upset (IEU) Device joint is bigger than the channel with the end goal that the apparatus joint ID is not exactly the drill pipe. The apparatus 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 dominating piece of the base gap gathering (BHA) which gives Weight on Bit (WOB). Because of the huge divider thickness of the drill collars, the association strings could be machined straightforwardly to the body of the cylinder, in this way taking out the requirement for device joints (see fig 3.3). Drill collars are produced in various sizes and shapes including round, square, triangular and winding scored. The smooth and winding notched drill collars are the most widely recognized shapes utilized presently in the business. There are drill collars produced using non-attractive steel used to detach directional overview instruments from attractive obstruction emerging from other drill stem parts. 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 Overwhelming weight drill pipes (HWDP) are frequently fabricated by machining down drill collars See fig 3.4. They ordinarily have more noteworthy divider thickness than normal drill pipe. HWDP are utilized to give a slow traverse when making progress between drill collars and drill funnels to limit pressure fixation at the base of the drill pipe. These pressure fixations frequently result from: Distinction in firmness because of the distinction in cross-sectional territory between the drill neckline and drill pipe. Bit skipping emerging from turn and cutting activity of the bit. HWDP can be utilized in either compressive or elastic assistance. In vertical wellbores it is utilized for progress and in exceptionally strayed 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 frill include: Stabilizers: these are made of a length of channel with cutting edges on the outer surface. The cutting 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 diminish clasping and bowing Guarantee uniform stacking of tricone bits to decrease wobbling and increment bit life. To give fundamental divider contact and solidness behind the bit to initiate positive side power to manufacture point when boring digressed wells. Reamers: utilized in the BHA to broaden the all around bore distance across and ream out doglegs, key seats, edges. Penetrating 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 proficient mix of drill pipe size, weight, and grades to satisfy the penetrating destinations of a specific gap area at the least expense inside worthy security measures. So as to structure a drill string to be utilized in a specific gap area, the accompanying boundaries should be set up: Opening area profundity Opening area size Expected mud weight Wanted security factors in strain 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 necessity: The working burdens (strain, breakdown, burst) on the drill string must not surpass the evaluated 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 bore for gap cleaning and great pace of infiltration. 3.2.1 Design Safety Factors Structure wellbeing factors are applied to determined working burdens to represent any sudden assistance load on the drill string. They are utilized to speak to any highlights that are not considered in the heap estimations for example temperature and consumption, in this way guaranteeing administration loads don't surpass the heap limit of the drill pipe. Plan wellbeing factor esteems are frequently chosen dependent on experience from working inside a specific zone, 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 unforgiving conditions. Some regularly utilized structure security esteems are delineated 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 impartial 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 instrument 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