Drill pipe design

Drill Collar 716. Drill Pipe 735. Tool Joints 748. Heavy-Weight Drill Pipe 749. Fatigue Damage of Drill Pipe 763. Drill String Design 765. 

The derrick or mast must also be designed to withstand wind loads. Wind loads are imposed by the wind acting on the outer and inner surfaces of the open structure. When designing for wind loads, the designer must consider that the drill pipe or other tubulars may be out of the hole and stacked in the structure. This means that there will be loads imposed on the structure by the pipe weight (i.e., setback load) in addition to the additional loads imposed by the wind. The horizontal forces due to wind are counteracted by the lattice structure that is firmly secured to the structure s foundation. Additional support to the structure can be accomplished by the guy lines attached to the structure and to a dead man anchor some distance away from it. The dead man anchor is buried in the ground to firmly support the tension loads in the guy line. The guy lines are pretensioned when attached to the dead man anchor. 

Tool Joint Designation Reference Drill Pipe Size and Style (All Weights and Grades) Weld On Too) Joints Elev. Marking... 

The tool Joint holds drill pipe together, and the shoulders (similar to drill collars) form a metal-to-metal seal to avoid leakage. The tool Joint threads are designed to be made up with drilling fluid containing solids. Clearance must be provided at the crest and root of threads in order to accommodate these solids. Therefore, the shoulder is the only seal. To keep the shoulders together, proper makeup torque is required. 

The drill string design is to determine an optimum combination of drill pipe sizes and steel grades for the lowest cost of string or the lowest total load (in... 

Normally, based on hole diameter, the designer can select drill collar diameter and drill pipe diameter. Next, specific pipe is chosen the maximum length of that pipe must be determined based on condition 1. For this purpose, the following equation is used ... 

Normally, not more than two sections are designed but, if absolutely necessary, even three sections can be used. To calculate the tensile load capacity of drill pipe, it is suggested to apply Equation 4-58 and use the recommended makeup torque of the weakest tool joint for the rotary torque. 

The drill pipe will not be crushed in the slips. The drill string design satisfies the specified criteria. 

Annulus. From the drill pipe, the drilling fluid is jetted out of the bit nozzles and into the annulus. The jets are designed to remove drilled cuttings away from the drill bit. The pressure drop across the nozzles accounts for about 60% of the total frictional pressures losses during the circulation of the drilling fluid. About 90% of the pressure drop across the nozzles is due to the turbulence at the outlet, with only about 10% due to the flow through the nozzles. 

As previously stated, the blowout preventer (BOP) was designed and manufactured by Cameron International of Houston, Texas. It was owned and maintained by Trans-ocean, the owners of Deepwater Horizon. Failure of the BOP was an absolutely key aspect of the accident this was a multiple-channel high-integrity redundant systan, the sole function of which was, in extremis, to cut the drill pipe within the well bore and seal off the well, and yet it did not work. 

Stress increases corrosion attack and must be controlled through proper design and use of equipment, as well as by reduction of enviromnental corrosives. For example, corrosion pits concentrate stress and are prime initiation points for corrosion fatigue cracks, which are the major cause of drill pipe failure. It is easily understood that corrosion problems become more critical as well depth increases, because among other things, high temperature becomes one of the more critical problems faced in many deep drilling projects. 

This type of batch treatment is usually based on the rule of thumb 5.7 L (1.5 gallons) of inhibitor-oil mixture for each 304 m (1000 feet) of drill pipe in the hole. Spray equipment has been designed to treat the drill pipe while making trips. This technique is preferred for coating the outside of the drill string. 

Mast setup distance The distance from the centerline of the well to a designated point on the mast structure defined by a manufacturer to assist in the setup of the rig. Maximum rated static hook load The sum of the weight applied at the hook and the traveling equipment for the designated location of the dead line anchor and the specified number of drilling lines without any pipe setback, sucker rod, or wind loadings. 

Slant rig Drilling rig specifically designed to drill a wellbore that is nonvertical at the surface. The mast is slanted and special pipe-handling equipment is needed. 

Joshi (1980) modified the pipe impeller design. Holes were drilled near the tip of the impeller and on the hub (Fig. 9b). In this design, the increase in the liquid flow increases the rate of gas induction by 30-60% at practically the same power consumption. Martin (1972) used a flattened cylindrical tube so as to simulate the aerofil design (Fig. 9c). In flotation applications, the Denver and Wamco type of self-inducing impellers has been widely used for several decades. Zundelevich (1979) has modified the Denver design so as to increase the rate of gas induction by about 100% (Fig. 9d). 

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