Which way the drill can be used?. Bullet perforation.
Design and principle of operation of hydraulic torches.
One-piece (integral) and compound drills (rods) are used for drilling boreholes. The first bit is forged at the same time with the body of the drill, which allows you to drill blanks with a reduced diameter of 24-38 mm, the second bits are removable, attached to the rod cone or thread connection.
According to GOST R 51681-2000, drills with hexagonal size of 19, 22, 25 mm and taper angle of 7°±8 are used for portable perforators. ° (booms with taper angle α=2°23., 3°30., 4°46., 11° and 12°) or with 22, 25 and 28 mm threads. Diameter of the inner channel of 6-7 mm for flushing water (in the case of a dust collector, the diameter of the channel is usually 12-17 mm). Bores (rods) are made of different length of high-alloy hollow. 18Х2Н4МА, 18Х2Н4ВА, 20Х2Н4А, 28ХНЗМ, 35ХГСА or 38ХНЗМФА (X. Chrome, G. manganese, T. titanium) with heat treatment: case hardening and nitro case hardening with subsequent tempering and tempering. To protect from corrosion, the internal channel for rinsing water is phosphatized.
round rods are usually used for rotary rods on mining rigs and drilling rigs.
Drill bit shanks are shaped and sized to match the end-bolt of the used rotary tool.
When drilling, a set of augers is used: auger length 0.7-1 m, and each subsequent auger has a length by 0.5-0.7 m longer than the previous one. The use of this set allows to avoid drill bit breakage while drilling, providing safe working conditions.
Drill bit selection is influenced by the following: Monolithic or fractured; ductile or brittle; abrasive or non-abrasive.
Drill bits for peorators as well as for percussive-rotary drilling heads, depending on the number of blades on them, are produced of several types:. chisel bits (designated by the letter “D” in the marking) are used when drilling low-abrasive only monolithic rocks, where it is practically impossible to drill through the bit’s blades while jamming;. Cross bits (letter.K) are used in drilling highly abrasive fractured formations;. three-periods (letter.T) are used when drilling both fractured and monolithic rocks of medium and high abrasiveness.
It should be taken into account that the less blades on the bit increases the drilling efficiency, and cross bits provide for better circular section of the borehole or hole, which creates favorable conditions for the charge. Teeth are made of 35KhGSA, 30KhGT steel. All teeth are either reinforced with tungsten carbide plates or cylindrical carbide inserts (pins). Drill bits reinforced with plates (marked with the letter.P in the marking of the drill bit) are recommended when drilling ductile rocks, pins (letter.S). when drilling brittle rocks. Deciphering of designation of drill bits:
For example, KDP 40-25-2M. Chisel bits, reinforced with 40 mm diameter plates and 25 mm seating size, second modification.
Bits (K) are chiseled (D), reinforced with tungsten carbide plates (type P) or pins (type S) (d=32, 36, 40, 43, 46 mm)
Drilling of low-abrasive viscous (П) or brittle (Ш) monolithic rocks
Teeth (K) cross (K), reinforced with tungsten carbide plates (type P) or pins (type S) (d=40, 43, 46, 52 and 60 mm)
Drilling in viscous (P) or brittle (H) highly abrasive fractured formations
Three-pronged bits, reinforced with plates (type P) or pins (type S) of hard alloy (d=40, 43. 46, 65 mm)
Drilling viscous (P) or brittle (S) monolithic and fractured rocks of medium to high abrasiveness
Non-perforated teeth, reinforced with pins with a hemispherical apex
Drilling in highly abrasive brittle formations
Bits of KNSH type have an advantage over other types, because of their improved durability and, therefore, less time loss for blunt tools replacement (during drilling they are practically self-sharpening).
Domestic drill bits are available in the following diameters (GOST 17196-77): D=32; 36; 40; 43; 43; 46; 52; 56; 60; 65; 70; 75 mm. Height of drill bits.H varies depending on the diameter (D) from 65 to 115 mm.
Crown plates and pins are made of metal-ceramic hard alloys of BK-8B, BK-11B and BK-15 types. These alloys are made by sintering a mixture of tungsten monocarbide powders and cobalt at 1350-1480 C (depending on the composition). Tungsten monocarbide (WC) is present in the alloys in the form of 1-5 micron grains, Cobalt in the alloy being the cementitious base. The number in the alloy designation indicates the percentage of cobalt in the alloy; increasing the cobalt content increases the toughness of the alloy, and the alloy withstands shocks better but performs poorly against abrasion. For example, hard-alloy BK-15 is rational to use when drilling hard rocks, although the bits wear out faster; BK-8B. when drilling medium-hard rocks (f10), т.е. The holes are connected to the teeth with lower impact loads, increasing the resistance to wear and tear.
Structurally the ceramic-metal alloys are divided into: fine-grained (index.M in the bit designation, grain size up to 1 micron), medium-grained (no index in the designation, grain size 1-2 microns) and coarse-grained (index.B, grain size 2-5 microns). In mining medium- and coarse-grained alloys are widely used. Due to insufficient strength, fine-grained alloys are practically never used.
The inserts and pins are inserted into the corresponding grooves in the body of the bit and soldered with brass solder. The solder is used in the form of a sheet thickness of 0.3. 0,6 mm or wire of 1,5. 2,5 mm; technical borax is used as a flux. The crown body is usually heated with high-frequency currents.
tapered connection of the core bit and drill rod ensures tight fit of the seating surfaces of the core bit and rod, reducing the possibility of premature wear and breakage of the core bit body and the tapered end of the drill rod.
The threaded connection of the core bit with the drill rod is used for powerful rotary and percussive drilling heads and rotary-impact drill heads. Special round thread is used, which provides increased strength due to absence of sharp angles on coils and ease of screwing and unscrewing after drilling at the expense of a large angle of elevation of the screw line.
By the type of rock destruction tool used there are screw drilling, roller cone drilling, diamond drilling, shot drilling and so on, by the type of drilling machine. rotary drilling, pneumatic impact drilling, water hammer drilling, rotary drilling, turbine drilling and so on, by the direction and method of drilling. cluster drilling, vertical drilling, directional drilling, multibranch drilling and so on. Drilling develops and specializes in three main areas of mining: the extraction of liquid and gaseous minerals, prospecting and exploration of minerals, the extraction of solid minerals by explosion. Such a historically formed division is rather conventional, but methodologically convenient for a brief presentation of such a multidimensional concept as “drilling”.
Drilling for liquid and gaseous minerals. There is information that in China more than 2,000 years ago by shock drilling method wells with diameter of 12-15 cm and depth up to 900 m were drilled for extraction of brine. Drilling tools (bits and bamboo rods) were lowered into the hole on ropes 1-4 cm thick, twisted from reeds. Impact drilling before the end of the 19th century. rotary drilling practically remained the only.
In Russia, the first holes were drilled in the 9th century. and is related to the extraction of table salt solutions in Stara Russa. Then the salt mines developed in Balakhna (12th century).) and Solikamsk (16th c.). Appearance of new drilling methods and techniques belongs to the 19th century. due to the increasing need of supplying large cities with drinking water. In 1831 in Odessa “Society of artesian fountains” has been formed and 4 chinks in depth of 36-189 m are bored.
In the U.S. the first well was drilled for brine near Charleston, West Virginia (1806), the first oil from the well was obtained in 1826 in Kentucky by accident while searching for brines. In 1834, the German engineer Eighausen proposed the use of a shifting pair of links in rod impact drilling. The idea of discharging a drill bit connected to a rod was realized in France by K. Г. Kind (1844) and Fabian (1849), who invented the free-falling drilling tool (Freifal). In 1846 French engineer Fauvel successfully drilled the first well in Perpignan with bottom-hole cleaning by a jet of water pumped from the surface into the hollow rod.
In the middle of the 19th century. Impact manual drilling began to be replaced by portable mechanical rigs. In Russia, G. Д. Romanowsky in 1859 for the first time mechanized work, using a steam engine to drill a well near Podolsk. The first oil well drilled by a percussion drilling rig was drilled by Drake in 1859 (USA, Pennsylvania).
The first oil well in Russia was drilled in 1864. Anapa. The development of drilling techniques is connected with the formation of the oil industry. At the oil fields of Baku the first steam engines appeared in 1873, and in 10 years they replaced the horse traction almost everywhere. In drilling wells for oil, the first stage was the development of the percussion method (drilling by rod, rope, quick-impact drilling with bottom-hole flushing). At the end of the 80-ies the development of the drilling technique is connected with the formation of the oil and gas industry. 19 в. In the USA, rotary drilling for oil is introduced in New Orleans (Louisiana) with the use of paddle bits and flushing with clay mud. In Russia, the rotary method with bottom-hole flushing was first used in 1902 in Grozny. The oil well drilled to a depth of 345 m was drilled in Grozny. A well was drilled to produce gas in Surakhani (Baku) in 1901. A year later, gas was produced from a depth of 207 meters, which was used for heating the plant. In 1901 the first electric engines, which replaced steam engines, appeared in Baku oil fields. At the beginning of the 20th century. In the United States, a method of directional rotary drilling with small-diameter drill bits was developed for drilling wells with subsequent reaming.
An offshore well was first drilled in 1897 in the Pacific Ocean off Somerland Island (California Peninsula shelf, USA), later the offshore drilling became widespread. In the USSR offshore drilling started in 1924 (near Baku).
At the beginning of the 20th century. in Russia by the Polish engineer W. Volsky created a hydraulic quick-impact motor (Volsky ram), a prototype of today’s hydraulic shocks. In 1924 the Soviet engineers M. А. Kapelyushnikov, S. М. Volokh and N. А. Kornev designed a geared turbodrill that was used until 1934 to drill wells up to 1000 m deep. In 1935-39 the Soviet engineers P. П. Shumilov, R. А. Ioannesyan, E. И. Tagiev and M. Т. Gusman proposed the gearless multistage turbodrill, after which the turbine method of drilling became mainstream. In 1941 they also developed a method of directional drilling with normal-diameter drill bits without subsequent reaming, which became widespread because it allowed several wells to be constructed on a single base. In 1940 in Baku the first well was drilled with an electric drill designed by A. S. Ostrovsky. П. Ostrovsky and N. В. Aleksandrov. In 1941 the Soviet engineer N. С. Timofeev suggested the use of multibranch drilling in stable rocks.
In the early 50’s Timofeev proposed the use of multibranch drilling. at the suggestion of R. А. Ioannesian, M. Т. Gusman and G. А. Bulakh in Makhachkala a large diameter (about 1 m) reactive-turbine well was drilled for the first time, which made it possible to begin constructing mine shafts.
In the early 60’s Ostrovskiy and N.T. Ostrovskiy drilled the first well with an electric drill. Harrison in the USA used the Moano gerotor screw pump to create a volumetric motor, which is used to curve the well in directional drilling. In the USSR, for drilling for oil and gas from the end of the 60s the perpetual grease has been used as a lubricant. A gerotor motor with a screw pair with a considerably large number of trips is used, which allows to increase the torque and decrease the rpm. It is used to drill the whole well, not just the curvature areas (see “Drilling the first such well” on page 54). Screw downhole motor).
In the USA, one of the deepest wells in the world. 9583 m. was drilled in 1975 with the rotary drilling method. Superdeep drilling). In the USSR, according to the program “Upper Mantle of the Earth” several wells down to 15 km depth are to be drilled. Drilling of the first such well started on the Baltic Shield with turbo-drills (by 1981 the depth reached 11 km).
Modern oil and gas drilling is characterized by greater depth of penetration, a sharp increase in the total volume of drilling. The average depth of wells in the USA in production drilling is about 1300 m, in exploration drilling. about 1700 m; in the USSR in production drilling. about 1900 m, exploration drilling. about 3000 m. Most of the drilling in the USSR was done with turbine drilling (about 80% of the total penetration, 1975-78). There are plans to increase the volume of rotary drilling and expand the use of gerotor motors. In the United States, the main method of drilling for oil and gas is rotary; and the percentage of drilling with downhole motors is expected to increase. The main directions of drilling improvement are related to improving bit, motor and drillstring designs, increasing bit penetration per run, using effective flushing fluids, automating the drilling process, improving well designs and quality of their anchoring.
Classification of Drill Sticks [ edit ]
Core drill rig feeders with certain axial force (up to 6000 N) are delivered to the bottomhole by screw, rope or piston-type automatic feeders. Drilling carriages are equipped with long-stroke automatic feeders, which provide continuous feeding of drill bits by 3-4 m in length. The telescopic handpiece consists of the actual hammer and a telescopic piston rod feeder (feed length up to 650 mm, force up to 1,600 N). The most common are pneumatic gauges, less common are hydraulic, gasoline, electric. Pneumatic gimbals operate on compressed air (pressure 0,5-0,6 MPa; powerful gimbals up to 1,5-2,0 MPa are being developed abroad). Air consumption (m3/min) is 2.5-3.5 for manual gears, 3.5-5.5 for telescopic gears and 9-13 for core gears. Impact power (kW) is 1.6-2.1 and 1.9-3.7 respectively;.4-5; torque (J) 12-18; 20-29; 175-245. With the increase of percussive power of peorator and torque, the speed, depth and diameter of boreholes and blast-holes have increased.
Drilling speed with increasing rock hardness decreases from 1-2 to 0.15-0.2 m/min. Since the end of the 1970s the pneumatic gears have been used. hydraulic percussive drilling machines which have more weight (than pneumatic ones), specific impact energy 20-30 J per 1 cm of bit diameter, torque up to 250 J, work with oil under pressure up to 30 MPa are increasing their drilling capacity. Hydraulic torches are installed on self-propelled drilling carriages for drilling blast holes with a diameter of over 44 mm.
Mobile pneumatic torches are designed for blast-hole drilling and are mainly used with pneumatic carriers as feed and support devices. Peorators have three modes of operation: drilling, full operation, intensive blowing of the borehole. The torches are equipped with anti-vibration carriages and noise mufflers, as well as systems for vacuum suppression and hole cleaning from drilling sludge.
Noise and vibration occur during the operation of the gun, to reduce which protective devices are used (spring vibration protective handles, gloves with polyvinyl chloride inserts, silencers and mufflers, headphones).
ROTARY DRILLING MACHINES
Impact drilling machines are designed for drilling blast holes up to 52 mm in diameter and depth of up to 5 m and wells up to 150 mm in the rocks of medium hardness and strong.
Drilling hammers (peorators) and percussive drilling machines are referred to as rotary drilling machines.
by type of power input. pneumatic, electric and hydraulic;
how the drill fines are removed from the borehole or well. with flushing, blowing and sucking out;
by frequency of blows. normal and high-speed (up to 2000 blows per minute and more, respectively);
by method of air distribution. with valve, spool, self-distribution and combined air distribution;
by method of installation and support of a hammer when drilling. into manual, core and telescope ones.
In addition, a distinction is made between conventional hammers located outside the borehole or well, and coming into the borehole (submersible hammers), and by weight a conventional distinction is made between light, medium and heavy hammers. To the medium weight the manual hammers of 20-25 kg, core hammers of 40-50 kg, telescope hammers of 35-45 kg and submersible hammers of 20-30 kg belong.
When drilling, the hand-held slides with a weight not exceeding 12.5 kg are held in hands, and if their weight is greater they are set on special devices. pneumatic slides. Telescopic rotators are equipped with pneumatic supporting and feeding telescopic mechanisms. String orbits are the heaviest ones and for drilling they are installed on helical spreader bars, manipulators or a drilling carriage equipped with automatic feeding mechanisms. feeders. Submersible peorators enter directly into the borehole to be drilled and are attached to the end of the rod fixed in the cartridge of the feeding mechanism.
In general case, a drilling hammer consists of a housing and a shock-swivel mechanism installed in it, air dispenser, control mechanism and a device for cleaning blast holes (boreholes) from drill fines.
The body of the hand-held geodrill, in its turn, consists of the head 1 (Fig. IV.36), cylinder 4 with guide sleeve 8 and chuck 9 with a drill bit holder 11. rotary-kick mechanism serves for striking and rotating a drilling tool. It consists of a striker piston 7 with a swivel nut 13, rotary screw 6 with a ratchet device 5, rotary bead 10 and grandbouquets 12. Air distribution device 3 designed for alternate supply of compressed
air into the outer or rear cavity of the perforator cylinder. Control mechanism is mounted in the rotary table head and consists of starting valve 14 with handle. Device 2 Serves for removal of drilling fines and dust suppression. The essence of gator functioning is that the compressed air with the help of air distributing device is supplied to right or left cylinder cavity providing reciprocating motion to striker piston 7.
The hammering piston strikes the drill bit when it moves forward (stroke) 15, and in reverse (idle) stroke rotates by a certain angle around the screw 6, by rotating through the axle 10 and grubber 12 drilling tool.
Working tool.As a working tool for rotary drilling one uses augers or drill rods with heads or teeth. In this case the drills may be one-piece and composite.
The choice of the type of drill bit and teeth is determined by the physical and mechanical properties of the rock and the drilling conditions.
The most widespread in the mining industry are single-bit and cross bits, which are used for drilling homogeneous monolithic and fractured formations, respectively. Bits and drills are connected by tapered 3° 30′ or threaded. The set of core bits for drilling is selected in such a way that each next core bit has a diameter 1-3 mm less than the previous one.
The core drill bit consists of the body / (Fig. IV.37, a), which is made of U7A or U8A steel and reinforced with hard alloy 2 in the form of plates or pins. For flushing the borehole the core bit has a hole 3. Blade of the crown is sharpened at an angle of 90-120°.
Flail crowns (Fig. IV.37, a, b) The shells for peoratorial drilling usually have a diameter of 300 mm D, equal to 32-65 mm, and the cross ones. up to 85 mm.
Cross crowns (Fig. IV.37, в–д) usually have a central flushing port.
Teeth with an advanced blade (Fig. IV.37, ё) They are used for drilling with heavy core and telescope, as well as with submersible perforators.
is carried out by apparatus lowered on a cable, and differs from bullet perforation in that a bursting projectile equipped with a delayed-action detonator is used for the shot. Weight of internal explosive charge of one projectile equals 5 g. The apparatus consists of sections, each with two horizontal shafts. The projectile is equipped with an incandescent detonator. When the projectile stops, there is an explosion of the internal charge, which results in cracking of the surrounding rock. Weight of explosive material in one chamber. 27 g. The depth of the channels according to the test results is 100-160 mm, the channel diameter. 22 mm. Not more than four holes per 1 m of filter length are usually penetrated, because casing failure is not uncommon in torpedo peonization.
The projectile is carried out by firing perforators with no bullets or projectiles. The penetration of the obstacle is achieved by a focused explosion. This is the result of the conical shape of the explosive charge surface, which is clad with a thin metallic coating (copper sheet of 0.6 mm thickness). The energy from the explosion in the form of a thin beam of gases. of the cladding products penetrates the channel. Cumulative jet gets speed up to 6-8 km/s in the head and creates pressure on the obstacle (0,15-0,3) 106 MPa. When shot in an obstacle they create a narrow peoria channel up to 350 mm deep and 8-14 mm in diameter in the middle part. The size of the channels depends on the strength of the rock and the type of torator. Shaped charge materials can be either corpuscular or taped. Hull gauges are reusable after their recharge. Cordless. single-action. The perforators are run on a cable (there are some small-sized perforators run through the tubing), as well as through the tubing. In the latter case, instead of an electrical impulse, the explosion is triggered by dropping a rubber ball into the tubing, which acts like a piston on the explosive device. Weight of a single shaped charge (depending on the type of shaped charge) is 25-50 grams. The use of different types and designs of orators depends on the density of breeds to be broken through. Cumulative perforation is recommended for hard rock formations, but for less dense and low-permeability formations. shell-shaped, in loose rocks and weakly cemented sandstones. bullet. Maximum thickness of the interval to be penetrated by the cumulative perforator reaches. 30 m, torpedo. 1 m, bullet. up to 2,5 m. This. one of the reasons for the widespread use of cumulative perforators. Ribbon pehorators are much lighter than hulled ones, but their use is limited by downhole pressure and temperature, since their explosive cartridge and detonating cord are in direct contact with the borehole fluid. In such perforators, the charges are mounted in glass (or other material) hermetically sealed cups, which are placed in the holes of a long steel band with a weight at the end. The entire garland is lowered on a cable. Usually the tape is not completely destroyed in a salvo, but it is not used for reuse. The head, weight, tape after firing are removed to the surface together with the cable. One of the disadvantages of bare body torches is impossibility to control the number of failures, while with shell torches it is easy to do so when inspecting the body extracted from the borehole. Cumulative perforators are the most widespread. By selecting the necessary explosives, their thermal and pressure sensitivity can be adjusted over a wide range, thus expanding the possibilities of perforation in wells with abnormally high temperatures and pressures.
WELL PEORATION (from Latin. perforatio. drilling a. well perforation; n. Durchschie ß ung der Erdolbohrlocher; f. perforation des puits; and. perforacion de sondeos). punching holes in the walls of a borehole against a given section of the productive formation in order to obtain or enhance the flow of water, oil, gas into a production well or reservoir. Explosives are used for well perforation (cumulative, bullet and projectile well perforation) and, less frequently, fluid flow with abrasive materials (sand jet well perforation).
Cumulative borehole peoriaa tion is the most used (cf. Cumulative Peorator). In bullet perforators, it is the powder gases that propel the bullet. A good penetration ability has a vertically directed peorator. PVN (Fig.).
The bullet, moving along the channel (bore) of the peorator, located parallel to the axis of the well, at the deflecting section changes its direction of flight and goes into formation. The vertical positioning of the channels in the case ensures that they are long enough to achieve a projectile velocity of up to 900 m/s, which, combined with a high gas pressure of the propellant charge. Horizontal bore bullet perforators are of limited use and do not always provide the required penetration, t.к. The channel length is short. Shell peoria, which is carried out in the same way as the bullet peoria, but not by a bullet, but by a projectile, is practically never used. In rare cases, the boreholes are blasted with cylindrical high-explosive charges, creating cracks in the string, cement ring and rock.
Hydroblasting is based on abrasive and hydromonitoring destruction of obstacles. Deep clean cavities and canals are created in the form of high-pressure jets of fluid with sand, pumped into the well from the surface by the pipes and coming out of the nozzles. The method is complicated.
The choice of well perforation method is made taking into account the geology of the reservoir, well design, drilling conditions, technical data of the perforators, side effects accompanying the perforation and other factors. It determines the type of perforator, the density of penetration and the technology of subsequent operations. The nature of the perforation is studied at special test rigs, where the channel sizes and peculiarities of fluid or gas flow in the sample before and after perforation are determined under conditions close to downhole. The quality of well perforation is one of the most important factors that determine the efficiency of well operation.
Bits for rotary drilling are produced of two basic types. chisel and roller cone.
Cutting bits have two basic varieties with removable and nonremovable cutting elements, reinforced with carbide plates or teeth or, in special-purpose bits, with artificial monocrystals and natural diamonds.
The main chisel type chisel sizes are made in the range of 149.2. 444.5 mm. Sands 1/2², 3/4², 7/8² Main manufacturers are Sandvik (Sweden), General Electric, Sekuryti (USA), etc.
Structurally, a distinction is made between paddle, peak and auger bits (see bit design). Fig. 3.5.). Blades are reinforced with hard alloy for better durability
Cone chisels are manufactured by companies: “Securiti, Baker-Hughes (USA); Sandvik Rock Tools (Sweden), etc. In the former USSR there were 13 types of roller cone drill bits with 46-508 mm diameter (GOST20692-75)
Cone cone (Fig. 3.6). tool sitting freely on its axis and destroying the borehole bottom as it rolls over its surface. Depending on the type of cutting structure there are cutters: toothed, pinned, disk-shaped and combined. By form. conical and cylindrical. On the principle of the impact on the bottomhole. crushing. shearing.
Crushing action cones are characterized by minimum sliding of teeth while rolling over the bottomhole and absence of milling action on the borehole walls by peripheral teeth. There are the following types: T. for drilling hard rocks; TZ. for hard abrasive rocks; TK. hard rocks with interlayers of strong TKZ. hard strong abrasive rocks; K. strong rocks; OK. very strong rocks.
Perforated Well part 1Classroom Activity
Crushing and shearing cones are characterized by increased sliding of teeth while rolling along the bottomhole face and walls of the well. We distinguish the following types: M. for drilling soft rocks; MZ. Soft abrasive rocks; MC. CC. abrasive medium-hard rocks; ST. abrasive medium-hard rocks with interlayers of hard rock; MSZ. soft rocks with interlayers of medium-hard rocks; WS. abrasive medium-hard rocks; E. soft abrasive rocks with interlayers of medium-hard rocks; C. medium-hard rocks; NW. medium-hard abrasive rocks; ST. medium-hard abrasive rocks with interlayers of hard.
BLASTING OF BOREHOLE CHARGES
The borehole charge method consists in placing an explosive material in a slant or vertical well and filling the upper part with inert materials such as sand, drill fines or bottom hole material of special composition.
Wells within the blast block are arranged in one or more rows parallel to the top edge of the ledge and are placed from each other at a calculated distance on a rectangular grid or in staggered order. the distance from the first row of holes to the top edge of the ledge should ensure the safety of the machine position on the ledge and workers on loading holes. The distance between the wells is chosen so that the fractures in the massif from each well overlap each other, without forming “thresholds” at the base of the scarp.
The explosive block in case of single-row arrangement of wells is blasted instantly or with an interval through the well, in case of multi-row arrangement. with an interval between series, which are designed depending on the selected method of forming the scarp (Fig.). The volume of simultaneously blasted block is taken depending on the mode of blasting in the opencast pit (once per shift, day, week and month) and the excavator capacity in the face.
The main parameters of blasting operations in the borehole method of mass destruction are: the diameter of the charge d; line for the resistance trimmer at the bottom W, which is the distance from the bottom of the ledge to the axis of the charge; the distance between the charges in a row a ; the distance between the rows b ; the distance between the top of the ledge and the first row of holes c; hole depth l; the depth of overburden Іn ; length of the bore Іz ; length of the charge Іzar; charge size P kg; width bp and height of the slump hp.
The greatest influence on the degree of rock fragmentation has a specific consumption of explosives.
Empirical relationship between rock flow rate and degree of crushing
Distance between the rows in a staggered arrangement of charges b = 0.85a and in a square grid b = a.
The minimum value of the resist line on the bottom is determined by the geometric parameters of the bore
Depending on the line of resistance on the bottom, the distance between boreholes and rows, and the weight of charges are calculated.
Re-drilling is carried out for the purpose of working out the bottom line. Currently, it is determined by empirical relationships, taking into account the resistivity line at the bottom and the specific consumption of explosives
In the practice of drilling and blasting the distance between charges is calculated on the basis of empirical data, in which the quality indicator (bad, satisfactory or good crushing) is taken as the criterion of the effect of the explosion. Calculated dependences for determining the distance between the wells and the rows are as follows: a = (0.8÷1.4)W; b = (0.91)W for short-delayed blasting; b = 0.85W for instantaneous blasting and staggered arrangement of wells. The number in front of W is the proximity ratio (relative distance between the charges), which is indicated by m. Its value depends on the properties of the mass, the required degree of fragmentation, the sequence of blasting charges, etc. п. Smaller values of m are used for hard-to-explode formations.
Types of perforators that are used for productive horizons in oil and gas wells
Slug submersible perforator (PP) is a tube of 1 m length and 100 mm diameter, which is loaded with compressed powder and 10 steel bullets. On a logging cable, a bullet peorator is lowered into a borehole filled with clay mud, set against a given interval of the productive formation and shots are taken. The depth of the holes in the rock does not exceed 5-7 cm. Many bullets get stuck in the production pillar, in the cement stone, and only a small number of them pierce the pillar and cement stone. Practically does not find any application at the moment.
Torpedo peorator (TP). Torpedo peening is carried out by apparatus lowered on a cable and firing bursting projectiles of 22 mm in diameter. The apparatus consists of sections, each with two horizontal shafts. When the projectile stops, the internal charge explodes and the surrounding rock cracking takes place. According to test data, the depth of channels is 100-160 mm, channel diameter is 22 mm. On 1 m of the productive part of the formation is made no more than four holes, as at torpedo peoo torpedoing often occurs destruction of the casing. Similar to gunfire, torpedo peoria is used very narrowly.
At the present time the following methods are mainly used cumulative perforation (PC). Shaped charge perforators have cone-shaped charges, which focus explosive gas streams and direct them at high velocity perpendicularly to the borehole walls (Fig. 8.1).
Schematic diagram of shaped charge hole formation: 1. charge, 2. detonator, 3. cable, 4. zone of charge combustion propagation, 5. metal cladding, 6. collector, 7. a hole in the collector, 8. cement stone, 9. casing pipe
The cumulative peorator has a cone-shaped notch, lined with a metal plate, which is made of a compacted powdered explosive.
Cumulative perforation is carried out by firing perforators with no bullets or projectiles. The blast of the column, cement stone, and rock is achieved by a focused explosion. This focus is due to the conical shape of the surface of the explosive charge (EO), lined with a thin metal coating (0.6 mm thick sheet copper). Explosive energy in the form of a thin beam of gases. cladding products. penetrates a channel. Cumulative jet has a velocity at the head up to 6-8 km/s and generates a pressure of 3-5 thousand. mPa.
When fired with a shaped charge in the column and cement stone, a narrow perforation channel up to 350 mm deep and 8-14 mm in diameter in the middle part is formed. All shaped perforators have horizontally placed charges and are divided into hull and housingless. Casing pehorators, once recharged, are used multiple times. Shellless. disposable. In shaped charges are fired by closing an electrical circuit in the rig. Fire 10-12 rounds in one go. For frameless peoria, shaped charges are made in glass or plastic casings and placed in round through-holes of aluminum tape.
Hull-less peorators Run into the borehole on a logging cable. Glass or plastic casings are completely destroyed by the shot. Casingless blasting heads allow to increase significantly the weight of shaped charges and, consequently, their penetration ability.
Sand jet perforator: 1. feather shank; 2. body; 3. ball valve; 4. nozzle holder; 5. nozzle; 6. plug.
In the oil fields they also use Sand jet perforator (BOP). Sand jet perforator (Fig. 8.2) consists of a thick-walled body, into which is screwed up to ten nozzles from abrasive-resistant material (ceramics, hard alloys) with hole diameter 3-6 mm. The jet perforator is lowered into a well by the tubing. Before perforating a well, a ball is thrown from the surface into the tubing to bridge the perforation hole of the perforator. After that with the help of pump units AN-500 or AN-700 the liquid with sand is pumped through the tubing into the well. Injected fluid with sand only comes out through the nozzles. The concentration of sand in the fluid is usually 80-100 kg/m, diameter of quartz sand particles is 0,3-0,8 mm. Huge abrasive jet velocities develop as it leaves the nozzles. As a result, holes in the casing, cement stone and rock are punched in a short time and the wellbore is connected to the productive formation. Depending on nozzle diameter, their number and speed of fluid injection the depth of perforation holes is up to 40-60 cm. At the same time the tightness of cement stone behind the string is preserved .
What are the effective geophysical methods to control water encroachment of oil formations in wells cased with steel pipes?? Gas reservoirs?
Thermometry is one of the basic methods in a complete set of well surveys to study reservoir performance. In perforated reservoirs, thermometry is used to determine inflow intervals (injectivity), to determine outflow (intake) reservoirs and to establish water encroachment intervals. In unperforated formations, thermometry is used to trace the location of the temperature front of injected water.
At a certain stage of development the oil reservoirs start to be watered by injected water. If water is flowing into the well, it indicates the approach of the injection water front or a breakthrough of the injection water. The water encroachment of the pay zone with saline water is relatively easy to establish in cased-hole wells using data from Radioactive methods. NGM,NNM-T.
Electromagnetic location method The use of water shutoff couplings is used to determine casing collar positions, the current bottomhole assembly, and, under favorable conditions, to determine the penetration interval and locate casing fractures and cracks.
Electromagnetic flaw detection and thickness gauging method
identifying the location of the casing shoe and sleeves (conductor, technical) placed behind the casing in which the research is carried out;
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PURCHASE DRILLING (a. percussive-rotary drilling; n. Drehschlagbohren; f. forage rotopercutant, perforation roto-percutante, forage par rotary-percussion; and. perforacion giratoropercusivo, sondeo giratoropercusivo, taladrado giratoropercusivo). is a drilling method, in which rock destruction is performed by striking a continuously rotating rock destruction tool. Used in mining operations for borehole and blast-hole drilling to a depth of 25-50 m, diameter between 40 and 850 mm and for prospecting and exploration to a depth of 2000 m, diameter 59-151 mm. For percussive-rotary drilling of boreholes, heavy pneumatic drill hammers on carriages are used in mining operations; surface pneumatic and hydraulic percussion machines are used for drilling exploration boreholes; submersible hydro- and pneumatic percussion machines. The axial load and torque are transferred from the surface through the drill string to the rock destruction tools (core bits and bits with bladed and pinned carbide inserts, roller cone bits and bits reinforced with super-hard materials and diamonds).
In percussive drilling, the rock is broken by shearing and crushing it by striking the rock destruction tool. The ledges formed on the face are partially cut off by the blades of a rock destruction tool when turning between blows. Energy of a single blow mainly 1-2 J per 1 mm of the blade length (pneumatic hammers, pneumatic hammer) and 0.1-0.15 J per 1 mm of the core diameter (hydraulic hammer), the distance between the blows along the hole or well contour from 2 to 8 mm (depending on the rock hardness), impact frequency from 1000 to 3000 beats/min, axial load 150-400 N per 1 cm of the hole or well diameter.
A distinction is made between percussive-turning (t.ч. percussive drilling) percussive-rotary drilling and rotary-impact drilling and its variants (water-impact drilling). Shock-rotary drilling is characterized by high values of single impact energy (2-3 J per 1 mm of blade length) and small rotary angle between impacts (2-3°), t.к. Breaking of the rock (shear, crushing) is done only by blows, with no contact between the tool and the rock. Breeding tools are drill bits and bits reinforced with tungsten carbide inserts with symmetrical angle at top (90-110ºC) or cylindrical with spherical working surface. This method is most effective when drilling hard abrasive formations.
Impact-rotary drilling was first used in Russia in 1905-07 by engineer V. В. Volsky during oil and gas drilling in Caucasus. For drilling wells for solid minerals, percussive-rotary drilling was first used in the CCCP in the Urals in 1930 by engineer V. Н. Komarov. The first experimental and theoretical work on percussive-rotary drilling as applied to drilling boreholes and blast holes performed in 1934-37 at the Dnepropetrovsk Mining Institute, Professor E. Ф. Epstein.