Power slips are designed to fit around the drill pipe in the rotary table, and serve to prevent its slipping into the hole while making a connection or making a trip. The use of power slips also reduces fatigue, and provides faster performance in making connections and trips.
4 Make a plan to Text 1 and retell it.
5 Learn the meaning of the following words, word-combinations and word groups:
cementing, seal, slurry, truck, squeeze, tank, strata, perforation, attachment, shoe, cementing collar., cementing plug, stop-ring, drillable plug.
6 Read Text 2: Text 2 Casing and Cementing
The «wrapping» for the hole is called casing. It is a heavy steel pipe which seals off the hole from cave-ins, and is in turn wrapped in cement, which protects the casing from corrosion, prevents migration of fluids from one formation to the other, and prevents pollution of the-oil and gas produced.
Placing the cas ng accurately is a job requiring skill and experience. When the casing is set in the proper location, it must be held there, which is the job of the cement. The cement seals the annular space between the casing and the walls of hole. Casing is run in the hole in much the same manner as drill pipe, but it is a great deal larger in diameter.
Casing, like drill pipe, varies in lengths. The number and size of the casing strings used vary with the: area, depth and the choice of the operation. Note that three separate casing sizes are indicated: the surface pipe, the intermediate string and the oil string.
Each casing string is cemented in place by a slurry pumped down the-pipe and up the a rm ulus between the casing and the open hole. The cement is then allowed to set for several hours before drilling or other operations are recommended.
Cementing units, cement mixers, tracks with cement and high pressure line, and cement head are used for pumping and squeezing the cement. The cementing unit is a heavy lead capacity truck with two pumps mounted on it: a high pressure pump for pumping cement and fluid and a second pump for supplying water to the cement mixer.
A cement mixing unit is a truck with a metal container for dry cement mounted on it. Behind this container there is a special tank in which cement is mixed with water, that is the cement slurry is being obtained. The water supply is measured precisely, the result of which is that a slurry of any desirable specific gravity may be obtained.
After the cement sets electrometric, work for determination of the quality of cement behind the siring of casing is carried out.
The string of casing is tested for hermetization after which gusher fitting is mounted on the well head and a series of perforations is made opposite the oil. or gas productive stratum. Casing strings are designed to withstand three principal types of loading: tensile load, collapse pressure and burst pressure.
Before casing is run in the hole, certain attachments may be added to it. They are: the guide plug (shoe), the thick wall cementing collar, the shoe, the cementing plug, the reverse valve, the stop-ring. When all the casing is set, then cementing operations begin, The casing and cementing crew connects a series of hoses to the top of the well, and pumps cement down the hole and up mound the annular space between the casing and the wall of the hole.
A drillable plug is inserted immediately follo wing the last of the slurry and drilling fluid is pumped behind this plug to the bottom of the hole.
This procedure forces the cement into the space between the casing and well wall. The cement is allowed to set and is tested: the plug is drilled through, and drilling operations are again underway.
Threaded joint and welded joint connections are applied to casing. Welded joint casing is usually used in gas wells.
7 Give English equivalents of the following:
проміжна колона труб, експлуатаційна колона груб, цементувальна головка, цементувальний аїрегат, питома вага, фонтанна арматура, розривне зусилля, зминання, тиск розриву, заливочна пробка, нарізне з’єднання, зварне з’єднання.
8 Make a written translation of the following:
Cementing units, cement mixers, tracks with cement and high pressure line, and cement head are used for pumping and squeezing the cement. The cementing unit is a heavy load capacity truck with two pumps mounted on it: a high pressure pump for pumping cement and fluid and a second pump for supplying water to the cement mixer.
A cement mixing unit is a truck with a metal container for dry cement mounted on it. Behind this container there is a special tank in which cement is mixed writh water, that is the cement slurry is being obtained. The water supply is measured precisely, the result of which is that a slurry of any desirable specific gravity may be obtained.
9 Describe the processes of casing and cementing using Text 2.
10 Learn the meaning of the following words, word-combinations and word groups:
scratcher, centralizer, spring, filter cake, spud, blowout, preventer, ram, packing, casing hanger, flow line, connection, pressure gauge, flow bean, choke, bypass line, pay zone, perforating gun, jet-type perforator, shaped charge, jet, fire, bullet.
11 Read Text 3:
Text 3
Centralizers and scratchers. Centralizers and scratchers serve as invaluable aids in cementing a well. Centralizers are heavy spring steel guides which fit around the outside of the casing. They serve to keep it centered in the hole, thus permitting a good cementing job If they were not used, then the casing might be lying against one side of the hole and would not be properly centered. As the centralizers aid in centering the casing, so scratchers remove the mud filter cake that has been deposited on the wall of the well bore. If the filter cake were not removed, then it would act as a barrier between the cement and the formation.
Once the scratchers are installed on the casing, they are operated by one of two methods. The casing may be spudded to allow the
scratchers to remove the wall cake, or it may be rotated, which accomplishes the same result when special scratchers are used. The wall cake may also be removed by either hydraulic or chemical means.
Blowout preventers. It is not always possible to predict the exact magnitude of pressures which will be encountered in the drilling of a well. Consequently, it is not uncommon to encounter pressures greater than those imposed by the drilling fluid, with the result that formation fluids flow into the bore hole and eventually to the surface. This effect is called a blowout and is one of the most feared and expensive accidents which can occur in well drilling.
The main function of blowout preventers is to furnish a means of closing off the annular space between the drill pipe and casing. Blowout preventers rnay be universal and ram type with mechanical, electrical and hydraulic drive. Steel rams with rubber packing are the basic elements of blowout preventer.
Christmas tree. When all these operations have been finished: casing set and cemented, then the Christmas Tree is installed. The Christmas Tree is the equipment above ground that controls the flow of oil or gas from the well. Included in the assembly are casing hangers, flow line connections, pressure gauges, valves, and flow- beans or chokes. Bypass line are installed so that the flow of oil or gas may be switched for line repairs and the choke may be changed without interruption of production.
Perforating. When casing and cement have been set in the pay zone, there must be some opening made to allow the oil and gas to pass into the well bore. On some formations, the perforating gun is used, while on others the jet-type perforator is more adaptable. It fires shaped charges which accomplish penetration by jets of high- temperature, high-velocity gases. The perforating gun fires bullets through the casing and cement to open passages for flow of oil and gas. It is fired electrically from the surface through-cable.
12 Make a written translation of the following:
It is not always possible to predict the exact magnitude of pressures which will be encountered in the drilling of a well. Consequently, it is not uncommon to encounter pressures greater than those imposed by the drilling fluid, with the result that formation fluids flow into the bore hole and eventually to the surface. This effect
is called a blowout and is one of the most feared and expensive accidents which can occur in well drilling.
13 Put 5 questions to Text 3.
14 Find, read and translate the sentences in Text 3 in which we learn about Christmas Tree.
15 Learn the meaning of the following words, word-combinations and word groups:
fishing, break down, "etrieve, twist, jamming, cone, wedge, wrench, hammer, loose, taper tap, thread, diengage, overshot, intact, grapple, spear, grasp, junk, barrel, hollow, catcher, deflection, angle, whipstock, rearmer, knuckle joint., concave, groove, inclination, balltype.
16 Read Text 4: Text 4
The term fishing, applies to all operations concerned with retrieving of equipment or other objects from hole. One of the most common causes of fishing is the failure of the drill string. The weight and torque applied to it can cause it to twist in two while in the hole.
Another common cause of fishing is the jamming or loss of a cone on the rotary bit. Occasionally, a bit may fail, or a cone may drop off the bit and be wedged in the bottom of the hole.
A wrench, hammer, or other tool may be accidentally dropped in the hole. Before any more drilling can be done, these tools must be recovered, leaving the hole clean and ready for the bit.
There is always the possibility that the pipe will come stuck in the hole. When it cannot be worked loose, it is necessary to remove the pipe above the tight spot and fish the remainder from the hole with the help of special tool.
Fishing tools. Fishing tools are quite numerous. Among the first fishing fools were rotary taper taps and die collars. The tap is run into the fish and rotated until sufficient threads are cut for a firm hold. Their principal disadvantage was the fact that they could not be disengaged, but remained with the fish.
Overshot. One of the most common tools, used for fishing today is the overshot When a twist-off occurs, the in-tact portion of the drill string is taken from the hole and the overshot is lowered in.
This device fits over the fish in the hole; the grapple engages the pipe and enables it to be removed from the hole. Hole-pipe clearance must be sufficient to accomodate the wall thickness of the overshot. Modem overshots have a releasing mechanism to be used if the fish cannot be pulled.
Spears. These devices pass inside the fish, grasping its inner wall with expending slips, which can be set or released by rotating the •)ipe. Spears are generally used when the hole clearance will not olerate an overshot. Their principal advantage is their releasing (lechanism. Small items of junk such as bit teeth, cones, or other small pieces of steel may be retrieved with a permanent magnet run on the drill pipe.
Junk basket. The junk basket is probably the next most commonly used tool. When a cone is last of a bit or when tools are accidentally dropped in the hole, a junk basket can be used to retrieve them.
I
The junk basket is built with a long hollow inner barrel. The bottom of the basket is built much the same as a core bit, and serves the same purpose. The junk basket is lowered to the bottom of the hole and is set over the article to be recovered. The drill string is rotated, causing the bit to cut a small core in the formation. A catcher brings both the core and the article above it to the surface, enabling drilling to proceed. Fishing magnet can be used for the same purpose.
Directional drilling. Control of the course of a well during the process of drilling is of vital importance. For diverse reasons it is frequently necessary or desirable to finish a well at some point away from a straight line drawn vertically below the rotary table, f or this purpose a technique called “directional drilling” has been developed. The system has been used in starting wells under a derrick location on land and drilling away from a straight hole into a producing sand beneath the sea or to reach points situated some distance away, horizontally, from the starting point. In this event, the well must be lirectionally controlled during the progress of drilling from the iurface location to the point selected for penetration of the producing formation. This will involve use of devices to ach ieve deflection of the well in the desired direction and at a suitable angle from the vertical to reach the point selected for penetrat ion of the reservoir rock. The art of directional drilling has so far progressed that a well may be drilled into a given stratigraphic horizon within a few feet of the point selected and the entire course of the well may be kept within a predetermined hypothetical cylinder of intervening formation not more than 25 ft in diameter.
Directional drilling method has been likewise frequently helpful in straightening crooked holes and in drilling around tools that fishing jobs have been unable to clear out of the hole.
Directional drilling may be used profitably in exploration work in a new field.
The tools that have been developed for the purpose of changing the direction of a well are: whipstocks, knucle joints and special drilling bits and retuners.
Whipstocks. A whipstock is along, slender steel wedge with a concave groove on its inclined face, supported in the well in such a position that the drilling tool is deflected from the previous course of the well towards the direction in which the inclined grooved surface faces.
Whipstocks are of two general types, removable and fixed. The removable one is withdrawn from the hole with the drill pipe, while the fixed type stays in the hole as a permanent installation.
Knuckle joint. A knuckle joint is a special type of drill support designed to deflect tire well without using a whipstock. It incorporates a balltype universal joint, connected to and rotated by the drill pipe, which allows the bit to drill at an angle to the axis of the drill column. The knuckle joint is oriented on bottom so that the tool points in the direction in which it is desired to drill.
17 Give English equivalents of the following:
піднімати інструмент із свердловини, гаєчний ключ, звужене місце, мітчик, ловильний дзвін, поломка бурильних труб, пристосування для розчеплення, клини для захоплення труб, корзина для сміття, колонкове долото, труботримач, з різних причин, направлене буріння, продуктивний пласт, викривлена свердловина, дефлектор, жолобчатий, шарнірного типу.
18 Describe the main fishing tools using Text 4.
19 Find, read and translate the sentences in Text 4 in which we learn about directional drilling.
JO Read Text 5:
Text 5 Offshore Drilling Equipment
'ITie primary difference between land and water drilling installations occurs in the supporting structure for the rig and its auxiliary equipment. Other rig components are similar to those used in land drilling with added emphasis on operational ease.
Drilling for oil under water has introduced many new problems to the industry. To set up a rig in a shallow lake or a marsh, the submersible barge serves as a foundation. The rig is assembled on it, and the entire unit is towed by tug to the location. When it is in place, valves are opened, flooding the barge and causing it to sink in position. Once drilling is completed, the water is pumped from the barge, allowing to be moved to the next location.
The mobile drilling platform with supporting legs is widely used in offshore drilling today. When on location, the legs are lowered to the ocean floor and the floating platform is elevated above the water by means of hydraulic jacks.
A second type of mobile drilling platform consists of a deck section containing the rig elevated above a floating section by means of supporting legs. When the floating section is flooded it will sink to the ocean floor and provide support to the main platform.
After drilling operations are completed, the unit is then refloated and moved to the next drilling site.
Some of these platforms provide sufficient area for living quarters, necessary storage space, and the complete drilling unit. Other platforms of smaller dimension necessitate the use of a floating barge or tender which contains the major portion of the drilling equipment, storage space, and drilling crew accomodations. The mud system is contained on the tender. Mud is pumped from the tender through the circulating cycle and then back to the tender. On the newer drilling tenders, the power source - diesel engine driving electric generators - is located on the tender and power is delivered to the electric motors on the platform by cable.
When drilling on a man-made structure is completed, the drilling equipment is removed, and the platform is used for production equipment to bring the oil to the surface and to control the flow.
When wells were first drilled- off-shore, boats were the sole means of transportation between the land and the rig. This could mean a daily trip for the crews and other personnel sometimes lasting six or seven hours. To this discomfort was added the disadvantage of seasickness when rough weather was encountered. Helicopters are proving to have a permanent place in off-shore drilling, for they furnish a convenient and rapid means of transportation between the shore and the installation at sea.
21 Give English equivalents of t he following:
морське буріння, болото, баржа, що сама занурюється, буксир, тягнути на буксирі, наповнювати водою, стійка, плавучий, домкрат, баркас, забезпечувати.
22 Make a written translation oil* the following:
Some of these platforms pro vide sufficient area for living quarters. necessary storage space, and the complete drilling unit. Other platforms of smaller dimension necessitate the use of a floating barge or tender which contains the major portion of the drilling equipment, storage space, and drilling crew accomodations. The mud system is contained on the tender. Mud is pumped from the tender through the circulating cycle and then back to the tender. On the newer drilling tenders, the power source - diesel engine driving electric generators - is located on the tender and power is delivered to the electric motors on the platform by cable.
23 Make a plan to Text 5 and retell it.
CONTROL TASKS
1 Answer the questions:
1 What are some general methods of drilling oil wells?
2 How are the cuttings lifted from hole in rotary drilling?
3 What are the benefits of the turbine drilling method?
4 What methods of drilling does vibrational drilling combine?
5 In what way does core drilling differ from rotary drilling?
6 What is derrick and what is its function?
7 What are tool joints ued for?
8 What is the Christmas free and what does it control?
9 What does the term “fishing“ apply to?
10 What is directional drilling?
.Give English equivalents of the following: | |
експлуатаційна колона труб | роторне буріння |
обсадні груби | колонкове буріння |
пошукова свердловина | бурова вишка |
продуктивна свердловина ударне буріння | лебідка поломка бу рильних труб |
ловильні роботи у свердловині | піднімання інструменту |
шариковии підшипник | вертлюг |
бурова помпа | робоча груба |
буровий шланг | бурова колона |
головний двигун | гаєчний ключ |
рідкий цемент | пружина |
манометр | кулевий перфоратор |
труботримач | направлене буріння |
морське буріння | забійний двигун |
3 Match the terms with their definitions: | |
1 Christmas Tree | a) a method of drilling that combines rotary and percussion drilling |
2 percussion drilling | b) the connection between the slush pumps and the drill string |
3 rotary drilling | c) the necessary valves and fittings for closing-in or controlling the production |
4 derrick | d) a secial type of drill support designed to deflect the well without using a whipstock |
5 drill string | c) devices that pass inside the fish, grasping its inner wall with expending slips which can be set or released by rotating the pipe |
6 knuckle joint | f) the control centre from which the driller operates the rig |
7 spears | g) the most primitive and the most efficient way of drilling which is implemented by a wedge bit |
8 vibrational drilling | h) an extremely expensive rig component that must be replaced periodically |
9 drawworks | i) a four-sided pyramidal structure of square cross section |
10 swivel | j) the way of drilling when the hole is drilled by a rotating bit to which a force is applied |
4 Tell whether each of the following statements is true or false according to the text. Correct the false statements to make them true:
1 The number of strings of casing and their diameter is controlled by local conditions and by the depth to which the well is to be drilled.
2 In turbine drilling the bit is rotated by a turbodrill attached to the upper end of the drill string.
3 There are two types of vibrators: mechanical with a drive from an electric motor or electromagnetic device and an air or pneumatic vibrator.
4 The function of the derrick is to provide the horizontal clearence necessary to the raising and lowering of the drill string into and out of the hole during the drilling operations.
5 The function of the mud or slush pumps is to circulate the drilling fluid at the desired pressure and volume.
5 Make a written translation of the following:
Directional drilling. Control of the course of a well during the process of drilling is of vital importance. For diverse easons it is frequently necessary or desirable to finish a well at some point away from a straight line drawn vertically below the rotary table. For this purpose a technique called “directional drilling” has been developed. The system has been used in starting wells under a derrick location on land and drilling away from a straight hole into a producing sand beneath the sea or to reach points situated some distance away, horizontally, from the starting point. In this event, the well must be directionally controlled during the progress of drilling from the surface location to the point selected for penetration of the producing formation. This will involve use of devices to achieve deflection of the well in the desired direction and at a suitable angle from the vertical to reach the point selected for penetration of the reservoir rock. The art of directional drilling has so far progressed that a well may be drilled into a given stratigraphic horizon within a few feet of the point selected and the entire course of the well may be kept within a predetermined hypothetical cylinder of intervening formation not more than 25 ft in diameter.
P ART 5 COMPLICATIONS IN THE COURSE OF DRILLING
Unit 19 Circulation Loss
1 Learn the meaning of the following words, word-combinations and word groups:
blowout, lost circulation, tight hole, drill collar, gas cutting, swabbing, quebracho, kelly valve, permeable, fractured, cavernous, fibrous, flaky, reinforcing plug., handling, regain, waiting technique, blind drilling, floating, mud cap.
2 Read and translat e Text 1:
Text 1 Difficulties Encountered in Drilling
Blowout its a dangerous and expensive accident in oil-well drilling operations. Blowouts may result from insufficient drilling- fluid density, caused perhaps by gas-cutting. Or, they may occur as a result of failure to keep the hole full of fluid, a situation created by withdrawing the drill column from the well or as a result of lost circulation.
A “tight” hole or clay “balled up” on the drill collar and bit may create a swabbing, O' suction effect on the format below as the drill column is withdrawn, thus developing an abnormal pressure differential that allows high-pressure gas to enter the well.
To avoid such situations in drilling through high-pressure gas- bearing fonnations, close attention should be given to the physical properties of the drilling fluid, maintaining high density by addition of heavy mineral, low viscosity by addition of quebracho or phosphates, and good wallbuilding properties by addition of bentonite.
Prompt countermeasures should be taken to deal with lost circulation. Additional fluid should be pumped into the well to compensate for displacement as the drill column is withdrawn, maintaining the well full of fluid at all times.
If possible, operations that create high differential pressures between the formation and the well should be avoided.
In drilling into high-pressure formations, the well should always be equipped with a blowout preventer and kelly valve which can be closed in the event that a blowout should occur. Thus, the well may be shut in until appropriate measures may be taken to control it.
3 Put questions to each part of Text 1 and retell it in English.
1 Read Text 2:
Text 2 Lost Circulation
Lost circulation is one of the oldest and most common problems of rotary drilling. It may occur to any depth anywhere, particularly in deep wells. Circulation loss is a common difficulty in drilling through unusually permeable, fractured, fissured, or cavernous formations.
Fluid loss to the formations becomes excessive and in extreme cases will fail to return to the surface so that drill cuttings are not removed from, the well. In general, lost circulation may be divided into two classes: first, losses to highly porous or cavernous formations; and second losses created by poor drilling techniques.
It is important to locate the interval within which circulation loss isoccuring before undertaking remedial measures.
Circulation loss may often be remedied by addition of fibrous, flaky, or coarse granular materials and reinforcing plugs to the drilling luid, perhaps with additional bentonite to increase viscosity, and wall-building properties. The true value of any material can be determined only from its performance in the field.
There are three fundamental approaches to the problem of handling lost circulation: preventive methods, special drilling methods, and attempting to regain circulation after it has been lost.
The waiting technique has been found helpful in preventing and overcoming serious lost circulation. At the first indication of lost circulation, drilling and circulation are stopped. The bit is pulled up to a point of safety, and the hole is permitted to remain quiet for a period of 4 to 8 hours. After such waiting periods, drilling maybe resumed without further loss.
L |
There are areas that have; cavernous and open-fissured zones that simply do not permit conventional rotary drilling. Blind drilling with
no returns at the surface, and cable tools have been used for these conditions. In blind drilling, water is pumped down to cool the bit and to carry the cuttings away but no returns are brought to the surface. Sometimes the cuttings are carried into the loss zone and have been known to cure the loss and get returns.
An important variation of this dry drilling is the use of a floating mud cap to balance the formation fluid pressure with the drilling and hydrostatic pressure. This is done by carefully pumping fluid into both the annulus and the drill pipe.
5 Pick out from Text 2 five sentences containing the verbs in Passive Voice and translate them.
6 Make a plan to Text 2 and retell it.
7 Learn the meaning of the following words, word-combinations and word groups:
showing, caving-in, crumble, stick, drilling string, rend, jointing, clearance, restoration, acceleration, flushing, round trip, balling, adjustment, viscidity, yield point, absorption, fissure, traverse, seal off, plugging material, annulus, plug up, cuttings, slurry, plugging mixture, bed, harden, overlap, packer.
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