RU2500881C1 - Method for initiation of perforators run in with tube string - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: initiation method includes analysis of productive strata inhomogenuity, state of well case in the area of perforation impact, determination of intensity or potential impact of lower and/or upper stratum water in regard to the concerned productive stratum, arrangement of multiple shots in perforator. The method includes determination of potential remoteness or approach degree for charges along the perforator length, degree of charge power difference from each other along the perforator length and sequence of charge outburst and time of its outburst. The method includes design of perforator with at least one unit of uninterrupted power supply and memory for charge blowing in the perforator. Blowing of each multiple shot is envisaged with additional condition of physical events implementation in the well which are pre-programmed on condition of their exclusion as accidental events, the above program is written to the program in memory unit. Then at preset time the pre-programmed events in the well are implemented so that the blasting unit could outburst multiple shot.

EFFECT: increasing efficiency of perforation and well blasting operations.

5 cl

Description

The invention relates to perforating blasting in various wells and, in particular, oil or gas wells of various types - vertical, inclined and horizontal. In this case, one of the important conditions for the successful and technological implementation of perforation is the method of initiation of the applied charges.

Currently known methods of perforation of the reservoir in the well using the following initiation methods:

initiating rod reset [1];

initiating descent of the rod on the cable or flexible pipe [2];

punching the ball through the tubing [3, 4, 5, 6];

the use of hydraulic blasting heads [1, 7];

The first method is used when perforating a reservoir in vertical or deviated wells with a small angle of inclination. In horizontal wells, its use is impossible.

The implementation of perforation of the reservoir in horizontal wells in the second way is time-consuming, expensive and unreliable, as it requires the use of special equipment, such as a rigid geophysical cable or flexible pipe (coiled tubing). In this case, the delivery of the initiating rod to the head of the tube perforator and the initiation of the perforator by the shock method is very difficult.

The perforation of the reservoir in horizontal wells by the third method is possible only by repression, which leads to crushing of the reservoir by the borehole fluid under the action of excessive pressure.

The perforation of the reservoir using hydraulic blasting heads is the most acceptable method of perforation in horizontal wells in the depression [7].

The disadvantage of this method is the high cost of the work, increased requirements for the skills of performers and they are more complex in technology, as they provide for a piping system, and more difficult to fit into the layout with other downhole equipment, also having a hydraulic connection with the wellhead [1].

Known solutions allow the initiation of charges without the use of wired communication channels. A common disadvantage of all of the above methods is the inability to carry out selective - selective perforation.

Selective perforation, as an example, is necessary for cases of a particularly sparing regime of the secondary opening of the formation with minimum impact on the elements of the well attachment, the upper and lower water zones, which are dangerous for the undesirable watering of the extracted useful production of the formation, while at the same time a powerful effect is necessary on the central zones of the opened formation with heterogeneous filtration properties.

At the same time, other possible options that require the need for selective well perforation up to options with consideration of the order, time and sequence of operation of each of the charges and / or groups of charges of the punch, ensuring reliability of operation according to the chosen scheme, with the prevention of any possibility of unauthorized operation, are not excluded charges and / or groups of charges.

An involuntary deviation from the selected operating pattern of the charges of the perforator leads to a summation of the loads acting on the protected zones of the well elements and / or geological zones and, consequently, to a violation of the required maintenance regime of the exploited object and a decrease in the volume of extraction of the formation fluid - its useful products.

A known method of perforation of a reservoir in a well, providing the possibility of selective perforation, by spreading out time volleys of charges due to the use of a certain way electrical circuit [9].

The disadvantage of this method is the low efficiency of perforation and the increased risk of premature actuation of charges due to the possibility of pickup random currents in a wire system of initiation, the accidental inclusion of an electric circuit.

The technical result of the invention is to increase the efficiency of perforation due to the possibility of selective initiation of the applied charges with the exception of the possibility of their random initiation and to increase the efficiency of perforating and blasting in horizontal wells due to the possibility of initiating perforators in depression and reducing the time spent on work.

The required technical result is achieved by the fact that the method of initiating perforators run on tubing includes analyzing the degree of heterogeneity of the reservoir, the state of the well support in the zone of influence of perforation, determining the degree of manifestation or possible influence of the lower and / or upper formation waters in relation to the considered productive formation, the arrangement of charge groups in a perforator depending on the above-mentioned studied conditions with a given algorithm, in which, from the conditions for obtaining m ksimalnogo fluid flow with minimal flooding and its gentle regime impact on the well lining, include the establishment of:

the degree of possible separation from each other or approaching each other of individual charges along the length of the punch;

the degree of difference in the power of the charges from each other along the length of the punch;

sequence of operation of charges and time of their operation;

the inclusion in the layout of the puncher at least one node with an independent power source and memory for undermining the charges in the punch with the accepted sequence and time of their detonation, while undermining the charges of each of the groups is provided with an additional condition for the implementation of physical events in the well, which are pre-programmed from the condition of exclusion of their implementation in the form of random events, write the mentioned program in the memory of the node to undermine, and then at a given point in time carry out previously programmed nye events in the wellbore to permit assembly of undermining the actual detonation of charges groups.

Besides:

cumulative charges are used as charges in a perforator;

a perforator is lowered into the well on pipes;

the main type of wells for this method are deviated and horizontal wells;

the method allows for the initiation of a perforator in depression;

as programmable physical events in the well, it is envisaged to create in the well from the wellhead a series of certain excess pressures of a given value for a certain time with predetermined pauses between methods of creating excess pressure;

as programmable physical events in the well, a predetermined order of movement of pipes in the well is provided, including axial displacements and rotations with given speeds for a given time at predetermined time intervals.

The invention:

The present method in accordance with the invention involves the implementation of selective perforation. This concept includes the initiation of different groups of charges of a punch, differing in power, their location and response time. Such a task arises when it is necessary to prevent, for example, the opening of the upper and / or lower formation waters accompanying the reservoir, take into account the properties of the rocks of the reservoir with the exception of excessive sanding of the well, take into account the condition of the lining of the well (casing and cement ring) with the condition of reduction explosive loads on it and preventing its destruction. The charges (groups of charges) of the perforator adjacent to the roof and / or the sole of the reservoir can be selected, for example, of lower power, mounted obliquely relative to the axis of the perforator and oriented in the opposite direction from the roof and / or sole of the reservoir. Moreover, these charges use the minimum power with the lowest explosive effect and are subject, for example, to the initial initiation. Subsequently, charges (groups of charges) can be initiated in the central part of the reservoir, for example, with greater power, which can be compensated by existing (previously created) perforation channels (their cavities filled with a medium of lower density) created by charges of lower power. At the same time, such a system for initiating charges (groups of charges) is provided that excludes their accidental initiation.

The method can be considered as an option for lowering the perforator on the pipes, and using essentially an explosive head with a given algorithm of its operation. At the same time, it is envisaged to use, as the conditions for initiating initiation, the physical processes carried out in the well during various technological operations associated with shooting and blasting operations or specially designed to implement the proposed method. These physical processes create the necessary conditions used as options for the decision-making algorithm associated with the initiation of a punch. As such conditions, it is proposed to use the technological operations used during the perforating-blasting operations. These are, for example, changes in hydrostatic pressure in a well, rotation of tubing, flushing of a well, change in the composition of a well’s fluid, the path of a perforator in a well (well geometry), packing and unpacking of the annular (annular) space of the well, installation of insulating elements in the vertical part of the well membranes and their breaking by a bar, to create a dynamic (short-term) change in borehole pressure. The change in hydrostatic pressure is achieved due to tripping, compression, work of surface units, swabbing and operation of electric centrifugal pumps (ESP). Impulse action on the hydraulic medium of the well can be used. For this, powder pressure generators can be used. Also, as a conducting medium - transmitting information, for example, acoustic, wellbore fluid, tubing or tubing, a well casing, rock mass, certain formations, neighboring wells as a whole can be used. Explosive means, mechanical, seismic, pneumatic, hydraulic, etc. can be taken as a means of acoustic information. At certain stages of technological operations, the use of time delays guaranteed by the performer can be provided. It is supposed to use additional technological operations or processes that are not provided for during perforating and blasting operations. For example, the descent of a cable device to create a telemetric communication channel between the device and the electronic explosive head through a borehole fluid or tubing. In this case, the coded initiation commands generated by the equipment of the geophysical station, or signals from an explosive high-frequency device, are sent from the surface via a cable to the device, and then, after converting the electrical signals into physical processes, through a borehole fluid or through a tubing to an electronic explosive head . As such converters, magnetostrictive transducers, piezoelectric emitters, shock devices, compressors, explosive sources, powder charges, electric dischargers can be used.

Thus, a method is proposed that uses as a communication channel necessary for transmitting initiating commands everything that is connected to or surrounds the well (formations, columns, well fluid, well geometry, neighboring wells), and physical processes are used as signals, accompanying various technological operations. The initiation of the punch is carried out with the coincidence of several, spaced in time, combinations of various physical processes with predetermined parameters. Protection against unauthorized actuation of the perforator is carried out by the selection of such combinations of physical processes that exclude their accidental coincidence when not ready for perforation, with the mandatory presence of borehole pressure (at least 2 MPa). All this is provided for the effective implementation of selective perforation. In that

In this case, each section of the puncher or group of charges is supplied, for example, with its explosive head with a given algorithm of action and various conditions for making a decision — resolution of the explosion — are written into it. For example, in the case of working with a cable device, such a condition may be a unique individual number of the electronic initiating head prescribed in it by the manufacturer.

To implement a selective electronic method of initiating a perforator, an electronic explosive head (EVG) can be used, which is a self-contained head with electronic initiation of a perforator. EVG replaces or supplements the standard blasting heads of perforators on tubing, giving them the function of intelligence. This, in turn, leads to flexibility and simplification of perforating and blasting operations, including in horizontal wells on a depression.

In EVG, an autonomous reprogrammable electronic device is used. To initiate a punch with an electronic initiating head, the predefined conditions specified above must be observed. These conditions are used as options for the decision-making algorithm for initiating a punch and are recorded in the non-volatile memory of the EVG.

The composition of the electronic explosive head.

The electronic explosive head performs the following functions:

remembers in non-volatile memory the sequence of technological operations or processes specified and subsequently reproduced by the contractor;

converts physical quantities into electrical signals;

normalizes and digitizes electrical signals;

compares the recorded and received signals;

decides on whether or not to initiate a punch;

generates a time delay from the moment a decision is made to the generation of a signal to initiate a perforator (at this time it is possible to replace wellhead equipment, for example, installing a lubricator);

initiates a certain group of charges of the punch.

The electronic punch initiator device consists of the following blocks:

power source;

converters of physical quantities into electrical signals (sensors);

normalizing amplifiers;

analog-to-digital converter;

signal comparison devices;

non-volatile memory;

pressure switch;

executive module.

High-temperature batteries are used as a power source. As converters of physical quantities into electrical signals, pressure, temperature, liquid density sensors, accelerometers, seismic sensors, torsion sensors, hydrophones, flow meters, acoustic signal receivers can be used. As normalizing amplifiers, an analog-to-digital converter, and a signal comparison device, a microconverter or microcontroller with appropriate electronic harnesses and software is used.

The signal comparison device compares, in the time and amplitude regions, the processes recorded in the non-volatile memory and the signals received from the sensors. The executive module is designed to generate signals or actions necessary to initiate a punch.

The hardware-software module serves to generate the signal necessary for the operation of an electric igniter of an explosive cartridge of a safety type. The design of the cartridge ensures its protection from exposure to direct current sources of voltage up to 500 V and alternating current voltage of up to 380 V at a frequency of 50 Hz, from stray currents of industrial frequency with virtually no restrictions and charges of static electricity up to 25 kV. The frequency, amplitude and duration of the initiation signal is selected depending on the explosive cartridge used. The signals from the module are fed through the contacts of the pressure switch to the coil of the explosive cartridge. A pressure switch is necessary to block the actuating circuits of the explosive cartridge in the absence of borehole pressure. The pressure switch is configured to close the blocking contacts at a pressure of 5 MPa.

As an executive module, for example, a well-known circuit with a DC motor, a gearbox and a mechanism for converting rotational motion into translational motion of the rod is used. In this case, the blasting head of a tube perforator is used, designed to actuate from the borehole pressure when cutting the safety pins with an initiating bar or ball. When the engine is running, the mechanism rod presses on the head sleeve. The pins are cut off, i.e. the executive module performs the functions of the initiating rod, and the hammer of the head under the influence of pressure in the well initiates a perforator. At a pressure of less than 5 MPa, the initiation of a perforator is not possible.

After a tube puncher with an electronic blasting head is lowered into the horizontal part of the well, a cable powder pressure generator [8] can be lowered into the vertical part of the well, with one or more powder charges, which generate, at each initiation from the surface, a pressure pulse in the well fluid. Then lower the fluid level to achieve the necessary depression. These pressure changes are recorded by an electronic blasting head and, after a time delay necessary to perform a number of technological operations, such as raising the geophysical cable, lowering the hydrostatic level to the required work plan, installing wellhead equipment, etc., the entire perforator or individual sections, if multiple EVGs are used.

Another option involves the use of the unit on the surface. In this case, after the perforation system is lowered into the horizontal section of the well, from the surface of the unit, a predetermined number of times, an overpressure is created in the well. Duration of exposure and pause duration are maintained with a time spread. Then lower the fluid level to achieve the necessary depression. In an electronic explosive head, a special algorithm compares the pressure recorded in memory and real pressure cyclograms. In case of coincidence, a punch is initiated.

The third option is similar to the second, but instead of the unit on the surface, an electric centrifugal pump is used in the well. In this case, create several predetermined cycles of lowering and increasing the level of the well fluid. Then they go into depression mode and initiate a perforator.

In the second and third options, as an additional initiating signal, you can use the rotation of the tubing (if you do not use the annular packer). In all cases, a time delay is provided before initiation (from several seconds to several hours). For the safety of perforating and blasting operations, refusal signals from initiation are provided, in particular, such a signal may be the lifting of a perforator by a predetermined or more tubing pipes.

In the first embodiment, the safety of work is additionally provided by the initiation method, i.e. by supplying an initiating signal from the surface, and using an explosive cartridge of a safety type.

The method is as follows.

First, before the hole punching, the geological conditions are analyzed - the degree of heterogeneity of the reservoir - the presence of unproductive layers and interlayers and their spatial position. They study the condition of the well support in the zone of influence of perforation - the degree of wear of the string, its tightness, and the quality of casing cementing. The degree of manifestation or possible influence of the lower and / or upper formation waters is established in relation to the reservoir under consideration when exposed to multiple explosions. Based on the data obtained, charge groups are arranged according to their power, location and initiation time with a given algorithm. This algorithm is based on obtaining the maximum influx of fluid with its minimum water flooding and gentle treatment of the well support, as well as:

the degree of deviation of the density of the placement of charges along the length of the puncher from uniform, for example, from geological conditions;

the degree of difference in the power of charges from each other along the length of the punch;

sequence of operation of charges and time of their operation. At the same time, at least one unit with an autonomous power supply and memory is included in the layout of the perforator for undermining the charges in the perforator with the adopted sequence and time for undermining them. Undermining the charges of each of the groups is provided with an additional condition for the implementation of physical events in the well, which are pre-programmed from the condition of exclusion of their implementation in the form of random events. The aforementioned program is recorded in the memory of the blasting unit, and then previously programmed events in the well are carried out to permit the blasting unit to actually undermine the charge groups.

As physical events for resolving an undermining, an undermining unit can be used, for example, any of the above physical events. Moreover, these events should also be considered only as an example.

Information sources:

1. Kurtinov V.M., Bozhko G.I., Falk I.B. Opening of productive formations with perforators on pipes Moscow, 1990, p. 7, 17-28, 40.

2. NTF PerfoTech, Perforation systems, Association Neftegaz Service, 2007.

3.Fridlander L.Ya. Shot-blasting apparatus and its use in wells, Moscow, Nedra, 1985, p. 33, 191-192.

4. VNIIGEOPHYSICS, Methodological instruction for opening productive formations with perforators, lowered on tubing, Moscow, 1973, p. 23.

5. V.M. Dobrynin, B.Yu. Wendelstein, R.A. Rezvanov, A.N. Afrikyan, Field Geophysics, Moscow, 2004, p. 316.

6. Shooting and explosive equipment, Handbook, ed. L.Ya. Friedlyander, Moscow, Nedra, 1990.

7. INNICOR Subsurface Technologies, CJSC “Vzryvgeoservis”, Product Catalog, 2008

8. JSC VNIPIvzryvgeofizika, Highly efficient technologies and equipment for perforated blasting operations in wells, 2003.

9. RF patent No. 2065932, 08/27/1996

Claims (5)

1. A method of initiating perforators launched on tubing, including analyzing the degree of heterogeneity of the reservoir, the state of the well support in the zone of influence of perforation, determining the degree of manifestation or possible influence of the lower and / or upper reservoir waters in relation to the reservoir under consideration, grouping charges in the perforator depending on the aforementioned conditions studied with a given algorithm, in which, from the condition of obtaining the maximum fluid flow with its minimum winding tion and gentle treatment of the well support include the establishment of:
the degree of possible separation from each other or approaching each other of individual charges along the length of the punch;
the degree of difference in the power of the charges from each other along the length of the punch;
the sequence of operation of the charges and the time of their operation, the inclusion in the layout of the punch, at least one electronic unit with an autonomous power source and memory for undermining the charges in the punch with the adopted sequence and time of their undermining, while undermining the charges of each group is provided with the additional condition the implementation of physical events in the well, which are pre-programmed from the condition of exclusion of their implementation in the form of random events, record the program in the node memory A blasting and then performed previously programmed events downhole assembly to permit proper detonation of the blasting charges groups. 2. The method according to claim 1, characterized in that it can be considered as an option for lowering the drill on the tubing to work in vertical, deviated or, most importantly, horizontal wells, and using an electronic blast head with a given algorithm for its operation, while it is envisaged to use as conditions for permitting the initiation of physical processes carried out in a well during various technological operations associated with perforating and blasting operations or specially designed for implementation the proposed method. 3. The method according to claim 1, using as the communication channel necessary for transmitting the initiating commands, everything that is connected with the well or surrounds it (formations, columns, well fluid, well geometry, neighboring wells), and physical signals are used processes accompanying various technological operations; the initiation of the perforator is carried out when several combinations of different physical processes spaced in time coincide with predetermined parameters. 4. The method according to claim 1, characterized in that as a programmable physical event in the well, it is envisaged to create in the well from the wellhead a series of certain excess pressures of a given value for a certain time with predetermined pauses between methods of creating excess pressure, with a further decrease in pressure and initiating a perforator on depression. 5. The method according to claim 2, characterized in that the programmed physical events in the well include a predetermined order of movement of the pipes in the well, including axial movements and rotations with given speeds for a given time at predetermined intervals.