Задания 4 этапа итоговой Контрольной работы по ПАЯ Очное обучение 3 курс 5 семестр
1. The first planned oil well was drilled in 1859 by Colonel Drake at Titusville, Pennsylvania USA.
2. The term cabletool drilling is used to describe the technique in which a chisel is suspended from the end of a wire cable and is made to impact repeatedly on the bottom of the hole, chipping away at the formation.
3. When the cement has set hard the BOP stack is removed and a wellhead spool is mounted on top of the wellhead housing.
4. The drill string is pulled out and tools which can measure for instance: the electrical resistance of the fluids in the rock (indicating the presence of water or hydrocarbons).
5. About 25% of the world’s oil and gas is currently being produced from offshore fields (e.g. North Sea, Gulf of Mexico).
6. In the North Sea, exploration wells are drilled from a jack-up or a semisubmersible drilling rig.
7. Semi-submersibles can operate in water depths of up to 3500 ft.
8. In very deep waters (up to 7500 ft) drillships are used to drill the well. Since the position of floating drilling rigs is constantly changing relative to the seabed special equipment must be used to connect
9. the rig to the seabed and to allow drilling to proceed.
10. A well drilled from an offshore rig is much more expensive than a land well drilled to the same depth.
11. The specialised equipment which is required to drill from an offshore drilling rig will be discussed in a subsequent chapter. 12. The hoisting system is a large pulley system which is used to lower and raise equipment into and out of the well.
13. The drawworks consists of a large revolving drum, around which a wire rope (drilling line) is spooled.
14. The drilling line is threaded (reeved) over a set of sheaves in the top of the derrick, known as the crown block and down to another set of sheaves known as the travelling block.
15. A set of clamps, known as the elevators, used when running, or pulling, the drillstring or casing into or out of the hole, are also connected to the travelling block.
16. The circulating system is used to circulate drilling fluid down through the drill string and up the annulus, carrying the drilled cuttings from the face of the bit to surface.
17. Drilling fluid (mud) is usually a mixture of water, clay, weighting material (barite) and chemicals.
18. The mud is pumped through the standpipe, kelly hose, swivel, kelly and down the drillstring. At the bottom of the hole the mud passes through the bit and then up the annulus, carrying cuttings up to surface.
19. When the mud pumps are switched off, the mud will stop flowing through the system and the level of the mud inside the drillstring will equal the level in the annulus.
20. The rotary system is used to rotate the drillstring, and therefore the drillbit, on the bottom of the borehole.
21. The kelly is the first section of pipe below the swivel. It is normally about 40' long, and has an outer hexagonal cross-section.
22. Slips are used to suspend pipe in the rotary table when making or breaking a connection.
23. The function of the well control system is to prevent the uncontrolled flow of formation fluids from the wellbore.
24. The term drill string is used to describe the tubulars and accessories on which the drill bit is run to the bottom of the borehole. 25. The drill string consists of drill pipe, drill collars, the kelly and various other pieces of equipment such as stabilisers and reamers, which are included in the drill string just above the drill bit
26. Drill pipe is the major component of the drill string It generally constitutes 90-95% of the entire length of the drill string.
27. Heavy wall drill pipe (or heavy weight drill pipe) has a greater wall thickness than ordinary drill pipe and is often used at the base of the drill pipe where stress concentration is greatest.
28. Drill collars are tubulars which have a much larger outer diameter and generally smaller inner diameter than drill pipe.
29. A roller reamer consists of stabiliser blades with rollers embedded into surface of the blade.
30. A shock sub is normally located above the bit to reduce the stress due to bouncing when the bit is drilling through hard rock.
31. Subs are short joints of pipe which act as crossovers (i.e. connect components which cannot otherwise be screwed together because of differences in thread type or size).
32. The purpose of these tools is to deliver a sharp blow to free the pipe if it becomes stuck in the hole.
33. A drilling bit is the cutting or boring tool which is made up on the end of the drillstring. The bit drills through the rock by scraping, chipping, gouging or grinding the rock at the bottom of the hole.
34. A drag bit consists of rigid steel blades shaped like a fish-tail which rotate as a single unit. These simple designs were used up to 1900 to successfully drill through soft formations.
35. Roller cone bits (or rock bits) are still the most common type of bit used world wide. The cutting action is provided by cones which have either steel teeth or tungsten carbide inserts. 36. A new generation of diamond bits known as polycrystalline diamond compact (PDC) bits were introduced in the 1980’s.
37. A casing string consists of individual joints of steel pipe which are connected together by threaded connections.
38. The production casing is either run through the pay zone, or set just above the pay zone (for an open hole completion or prior to running a liner).
39. The conductor is the first casing string to be run, and consequently has the largest diameter.
40. A liner is a short (usually less than 5000ft) casing string which is suspended from the inside of the previous casing string by a device known as a liner hanger.
41. Drilling fluid’s primary functions are to remove the drilled cuttings from the borehole whilst drilling
42. and to prevent fluids from flowing from the formations being drilled, into the borehole.
43. The cost of the mud can be as high as 10-15% of the total cost of the well.
44. The rock cutting process will, in particular with PDC bits, generate a great deal of heat at the bit.
45. These muds will be discussed in detail in Section 3 and 4 below but as a general statement, Water-based muds (WBM) are those drilling fluids in which the continuous phase of the system is water (salt water or fresh water) and Oil-based muds (OBM) are those in which the continuous phase is oil.
46. Primary control over the well is maintained by ensuring that the pressure due to the colom of mud in the borehole is greater than the pressure in the formations being drilled i.e. maintaining a positive differential pressure or overbalance on the formation pressures.
47. The first recorded instance of a well being deliberately drilled along a deviated course was in California in 1930. 48. Multi-well Platform drilling is widely employed in the North Sea. The development of these fields is only economically feasible if it is possible to drill a large number of wells (up to 40 or 60) from one location (platform).
49. If a blow-out occurs and the rig is damaged, or destroyed, it may be possible to kill the “wild” well by drilling another directionally drilled well (relief well) to intercept or pass to within few feet of the bottom of the “wild” well.
50. The trajectory of a deviated well must be carefully planned so that the most efficient trajectory is used to drill between the rig and the target location and ensure that the well is drilled for the least amount of money possible.