RU2552285C2 - Mechanical slotted reperforation of wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to the sphere of production of liquid and gaseous fluids from bore wells. mechanical slotted reperforation of wells, whereat the perforating gun is positioned at the initial point of the slotted interval in the casing pipe, two diametrically opposed longitudinal wells are rolled simultaneously by rolling discs rotated freely in their axes with plastic deformation of the casing pipe metal and further destruction of its integrity, opening of the crack and its edges flanging towards the borehole annulus under influence of leading edges of the rolling discs in the perforating gun, at that radial efforts of these discs indention to the pipe walls and round trips of the perforating gun are ensured by the ground power units, borehole annulus is treated behind the formed slots by water jets. The slots are rolled with the rate of the perforating gun running in and out that does not exceed two centimetres per second, while round trip movements of the running gun within the slotted interval are made with stops, during which at the first working stroke of the perforating gun the marks are made at its suspension over the well head and injection pressure is relieved in the string temporarily up to its value in the mode of standard washing.

EFFECT: positive effect is guaranteed for reliable hydrodynamic interconnection of the stratum and the well within the perforation interval.

2 cl, 3 dwg

Description

The invention relates to methods for creating a stable (reliable) hydrodynamic communication of a well casing cavity with a producing formation in order to optimize and / or intensify the inflow (injection) during oil production or maintaining reservoir pressure.

The level of technology in this area is characterized by a number of technical solutions known from patent documentation [SU 1668640 A1, 08/07/91; SU 1789674 A1, 01/23/93; SU 2043486 C1, 09/10/96; SU 2151858, E21B 43/114, 2000; RU 2007549 C1, 02.16.94; RU 2030563 C1, 03/10/95; RU 2038527 C1, 06/27/96; RU 2039220 C1, July 9, 1995; RU 2070279 C1, 12/10/96; RU 2070958 C1, 12/27/96; RU 2087683 C1, 08/20/97; RU 2105137 C1, 02.20.98; RU 2129209 C1, 04/20/99; RU 2151858 C1, 07.12.98; RU 2161697 C2, 04/07/99; RU 2180038 C2, 05.22.00; RU 2182221 C1, 04/11/01; RU 2232876 C1, 12/17/02; RU 2247226 C1, 08/15/03; RU 2249678 C2, 06.16.03; RU 2256066 C2, 09/12/03; US 4106561 A, 08/15/78; US 4,119,151 A, 10/10/78; US 4220201 A, 02.09.80; US 4392527 A, 07/12/83; US 4,557,331 A, 10.12.85], the initial motive for creating and improving methods for such perforation of casing strings for wells was the so-called knurling of grooves or grooves of a certain shape and depth on the metal surface due to plastic deformation, that is, without removing material. This process is carried out by rollers or disks with a sharp edge made of a significantly stronger material than the metal being processed. However, when considerable efforts are made to press the rolling element (roller or disk with a sharp edge), the plastic deformation of the metal ends with the destruction of the rolled sheet or pipe section along the groove path. This well-known effect of pipe fracture, first in the mode of plastic deformation of a metal under a rolling (more precisely, under a rolling / rolling) disk element, and then in the mode of local wall rupture and opening of a crack with flanging of its edges and formation of a stable configuration as a result of a longitudinal gap, is recognized as the most effective both during the development of the first commissioned well, and with secondary methods of intensifying the influx of products from the formation or injection into the formation of any technological fluid through the well with long-term operation.

It should be noted that all analogues of the claimed method contain, as a rule, a well-known set of technological operations, for example, the method of hydromechanical slotted perforation according to the patent [RU 2244806 C1, 01/20/05] includes the launch of a perforator on a string of tubing (tubing) in well to the perforation interval, flushing the barrel, creating a radial (bursting) force on the wall of the casing from the side of the rolling element-disk, while providing power contact of the disk with the pipe, exceeding the yield strength of its metal, They reveal the formation of a longitudinal gap in the casing wall by reciprocating movements of the NTK string in the perforation interval, followed by erosion and removal of the cement ring and rock around the formed gap by the hydro-monitor action of the jet, relieving the flushing pressure, and removing the perforator to the surface. Distinctive features of this method from previously known are constant monitoring of the radial force on the casing, flushing the well with at least one and a half times the volume of fluid in comparison with its volume in the tubing, phased / stepwise increase in pressure in the tubing during the formation of a gap with simultaneous control of the tightening and landing forces punch suspension until they disappear completely, which indicates the completion of the formation of the gap.

There is also known a method according to patent [RU 2254451 C1, 06/20/05], in which hydromechanical slotted perforation with a rolling tool (disk) is carried out by reciprocating movement of the perforator. A distinctive feature of the known method is the preliminary, before rolling, removal by cutting part of the metal in the zone of formation of the future gap in the wall of the casing.

The disadvantages of the known analogue methods of hydromechanical slotted perforation of wells include insufficient information content of descriptions of them as inventions, which does not allow a specialist with a higher than average qualification to implement (or reproduce) the process of perforation of a well according to the patent, especially since in normative and technical documentation open to uncertain circle of persons, there is practically no information about their use, about the result achieved, about the cost of work, for example, for 10 meters of perforation of the casing string specific diameter, wall thickness, strength group of metal, etc. (perhaps all of this falls into the applicants ’know-how category).

There is a method of producing perforation slots in a production casing according to the patent [RU 2256066 C1, 07/10/05], adopted as a prototype, the whole difference of which is from the well-known and generally accepted method of forming longitudinal slots in a casing by reciprocating rolling of a roller / disc with a sharp the circumference of the edge is that at the same time a pair of longitudinal slots is diametrically rolled to each other in the casing wall with disks not with a round working (sharp) edge, but with serrated disks, that is, having a perimeter in a series of teeth and cavities.

By rolling the gear roll disks in the pipe, this achieves a local increased concentration of mechanical stresses both in the teeth of the disks and in the wall of the casing during reciprocating movements of the punch, which, however, does not contribute to the reliability and durability of the punch. The use of the “punching” effect in this way in the formation of cracks to some extent increases the efficiency of casing wall destruction, but significantly increases the cost of the punch, and when the “armament” of the rolling disks breaks, it significantly lengthens and complicates the whole range of work on slotted perforation.

The technical task, that is, the required technical result of the proposed method, is to obtain a guaranteed positive effect of ensuring reliable hydrodynamic communication of the formation and the well in the perforation interval while minimizing the time and material resources.

The problem is solved in that in the known method of hydromechanical slotted hole punching of wells, in which the punch is positioned at the starting point of the interval of formation of cracks in the casing pipe, two diametrically opposed longitudinal slots with plastic deformation of the metal are rolled simultaneously rotating on the axes in the punch by rolling disks the walls of the casing with the subsequent destruction of its integrity, the opening of a crack and flanging of the edges of the latter into the annular space under the action of the working edge of the rolled disks of the perforator, and the radial forces of pressing these disks into the pipe wall and the reciprocating movements of the perforator are provided by ground power units, the annular space is cleaned behind the formed slots by the action of a jet jet, the cracks are rolled out with a speed of lifting / lowering the perforator no more than two centimeters per second, and the reciprocating movements of the perforator in the interval of formation of cracks is carried out with stops during which the first working stroke of the perforator on its suspension (above the wellhead) is marked and the discharge pressure in the tubing string is briefly reduced to its value in the normal washing mode.

An additional difference of the proposed method is that they determine the spatial orientation of the diametrical plane of the rolled disks of the perforator relative to the wellbore. This essential distinguishing feature provides, if necessary, guaranteed high-quality additional perforation of the same interval of the wellbore with the orientation of the disks of the drill in a perpendicular (its previous plane) position.

A comparative analysis of the proposed method of slotted hole perforation, as a combination of essential features (including distinctive ones) with solutions known from the regulatory and technical and patent documentation, suggests that the object meets all the criteria of the invention, including the criteria of "novelty" and " non-obviousness. "

The drawings show (fragmentarily), respectively, in FIG. 1, a cross-section of a borehole with a longitudinal (along the barrel) slit formed by a punch of a perforator before the jetting effect of a flushing jet; the fragment in figure 2 is the same fragment of the wellbore, but after the completion of the process, in figure 3 is an optimal arrangement of cracks in the wall of the casing with an interval greater than its length, where 1 denotes the first pair of longitudinal slots diametrically opposite to each other , and at position 2, the second pair of the same slots, but oriented relative to the plane of the first pair is almost perpendicular, which is preferable to any other design. It should be noted that the most preferred and / or optimal design of both the first and second pairs of longitudinal slits is their discontinuity along the length of the formation, and the second pair of slots, the same discontinuous, should be shifted in height relative to the first. Non-rolled (non-perforated) gaps of the pipe body should preferably alternate between each other along its length, which provides the pipe with the maximum possible stiffness and crease resistance in the perforation interval. It is also natural that the punching disks during the implementation of the method should not work on the sleeve joints of the casing; to simplify control over the formation of gaps during the first working stroke of the perforator on its suspension above the wellhead, use any of the well-known methods and / or devices (laser rulers, measuring rulers, LED limiters, curvimeters, etc.) with which the specialist in perforation with accuracy sufficient for practice performs and completes the entire process, including the formation of annular drainage cavities by means of jet washing of cracks in the wall of the casing.

We give a specific example of the implementation of the method in one of the fields of Western Siberia. So, a productive layer with a roof mark of 2030 meters and a sole of 2062 meters, respectively, was drilled by the wellbore. At a density of traditional perforation at the rate of 40 holes per 1 meter of the barrel, the hydrodynamic communication of the formation with the well is carried out through approximately 50 cm ^{2 of the} total area of the holes per meter of perforation of the column. For complete perforation along the barrel interval, at least 2.5 days are required, which, taking into account work to call in the inflow of labor resources and material costs, ranges from 550 to 730 thousand rubles. Hydromechanical slotted perforation of a well with the same initial data on the presented method cost the performer 250 thousand rubles, or - in physical terms - 24 hours were spent, 3 pieces of equipment were involved (A-50 hoist, CA-420 cementing unit, circulation tank truck).

The proposed method for perforating the casing was carried out using a pair of round rolled disks with a diameter of 120 mm. The task provided for the formation of one pair of longitudinal gaps discontinuous in length (i.e., with gaps), based on the assumption that each of the disks is loaded with a radial force of indentation into the pipe wall for 150 seconds based on the condition that the punch speed is 2 cm / s, but without load indentations, that is, without rolling out cracks, the punch is moved within 19 seconds. Thus, a perforation is obtained in the form of a 3-meter gap, alternating with an undisturbed pipe section (gap) of 0.4 meters. Given the total perforation length of 32 meters of this shape, each roll disk worked under a load of approximately 75 revolutions and without a load of 10. The total area of all slots was 175 cm ² , which is more than 3.5 times more efficient than traditional perforation, and it saves time directly its implementation, in comparison with the prototype method, amounted to more than 36 hours, while the perforator was removed with virtually no disruption of its working units and elements.

Thus, the proposed technical solution is a method, according to the applicant, with undoubted industrial implementation and compliance with the criteria of the invention is subject to protection by a title of the Russian Federation.

Claims (2)

1. The method of hydromechanical slotted hole punching of wells, in which the punch is positioned at the starting point of the interval of formation of slots in the casing pipe, two longitudinal slots diametrically opposed to each other are rolled simultaneously by freely rolling axes in the casing pipe by plastic deformation of the metal of the casing wall with subsequent destruction of its integrity , opening the cracks and flanging the edges of the latter into the annular space under the influence of the working edge of the rolled disks perfo an atom, moreover, the radial forces of pressing these disks into the pipe wall and the reciprocating movements of the perforator provide ground power units, clean the annular space behind the formed gaps by the action of a hydraulic jet, characterized in that the gaps are rolled out with a speed of raising / lowering the punch no more than two centimeters per second and the reciprocating movements of the perforator in the interval of formation of the slits are carried out with stops during which during the first working stroke of the perforator the torus on its suspension is marked above the wellhead and the discharge pressure in the tubing string is briefly reduced to its value in the normal flushing mode. 2. The method of hydromechanical slotted perforation of wells according to claim 1, characterized in that before the formation of the cracks, the spatial orientation of the diametrical plane of the punch disks relative to the wellbore is determined.

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