Method for producing a dilatancy effect on producing formations

Abstract

The invention relates to the field of blasting and can be used for more efficiently extracting fossils fuels, metallic and non-metallic minerals, hydrominerals, gemstones and chemical minerals. A method for producing a dilatancy effect on producing formations comprises laying ANFO explosive charges on the surface of the ground or in holes at a distance from one another, and detonating said charges with a delay from one to the next. The number of explosive charges is equal to two or more, and the mass of the individual charges may be the same or different but sufficient to produce a dilatancy effect. If the number of charges laid is more than two, the delays between the detonations may be the same or different. The technical result is that of improving the efficiency of mineral extraction.

Description

[0001] METHOD OF DILATANCE IMPACT ON PRODUCTIVE STRUCTURES

[0002] The invention relates to the field of blasting operations and can be used to increase the efficiency of mining combustible, ore, hydromineral, non-metallic, gemstone and mining-chemical raw minerals.

[0003] Extraction of minerals, which form the raw material base for the vast majority of industries, is one of the most important areas of engineering and technical activity. The range of extracted mineral and organic raw materials includes over two hundred types, accessed through open-pit and underground mining, as well as borehole geotechnology, which focuses on the extraction of underground fluids—water, oil, natural gas, gas condensate, and others—and, since the 1960s, the extraction of uranium, gold, and non-ferrous metals using in-situ leaching (ISL).

[0004] Despite the importance of the IW method, for the sake of simplicity, the claimed invention is explained using the example of its use in oil production. However, it is clear to specialists that increasing the efficiency of water, oil, gas condensate, and crude oil production, as well as uranium, gold, and non-ferrous metals, using the IW method is directly related to factors such as increasing the permeability of the product-bearing formations from which the above-mentioned minerals are extracted and increasing the contact area of ​​the working agent (WA) or leaching agent (LA) with the rock / productive formation containing the above-mentioned mineral or organic raw materials.

[0005] The importance of the production level of such basic fluids as oil and natural gas for the fuel and energy complex, processing industry, petrochemicals, and other industries is obvious. Moreover, the scale of extraction and sale of these types of fossil raw materials has in recent years become an active instrument for regulating interstate relations. Therefore, the desire to increase the scale of extraction operations, speed up technological processes and operations, and reduce their costs has driven ongoing interest in the problem of intensifying oil and gas production. This interest is constantly growing due to the growing shortage of raw materials, associated not only with the growth of industrial production and the application of new, often energy-intensive technologies, but also with the increasing depletion of natural resources, the deterioration of the raw material base, and the limited mineral resources of our planet.

[0006] To date, several approaches to solving this problem have been identified: reservoir pressure management (primarily through injection of buffer fluids into the reservoir), fluid viscosity reduction (steam / steam-gas treatment, use of supercritical fluids, in-situ combustion, injection of surfactants, polymers, etc.), and targeted modification of the permeability of the surrounding rocks and the near-wellbore space through mechanical, physical, chemical influences, or combinations thereof. The latter approach has been reflected in the development of stationary and pulse technologies for influencing the productive zone of the reservoir—hydraulic fracturing, the use of powder generators and pressure accumulators, pulse-cyclic (ultrasonic, electric discharge, implosive) treatment of well bottomhole zones, thermochemical, thermogasbarochemical methods, acid treatment, torpedoing, and many others.

[0007] Despite the impressive arsenal of technologies for intensifying oil and gas recovery, their industrial use is limited due to a number of reasons of a (a) technical, (b) economic and (c) environmental nature:

[0008] (a) the first ones include the use of heavy, expensive and energy-intensive equipment, long duration of operations, the need to use significant material and labor resources, significant downtime of wells during major repairs, the possibility of their damage during processing, etc.;

[0009] (b) all this, naturally, is reflected in the degree of economic efficiency - the profitability of the activities carried out, which is aggravated in a number of cases by the need to use specially manufactured materials (for example, proppants, organometallic compounds, etc.), performing work in difficult climatic conditions, in hard-to-reach areas, irreversible losses of working bodies / working agents, energy carriers and enriched solutions.

[0010] (c) Chemical reagent technologies using certain acids, surfactants, and other compounds that produce harmful and toxic substances during reactions in the well or formation, or that are toxic in their original state, can cause environmental pollution, seriously damage drinking and industrial water supplies, and enrich the recovered product with impurities that reduce its commercial quality. This, in part, likely explains the interest in the simplest and most cost-effective technologies for treating oil and gas wells, based on pulsed explosive action.

[0011] For example, the desire to create safe methods of pulsed action on productive deposits in order to increase the productivity of production wells was reflected in the development of equipment and technology for low-frequency processing of reservoirs using special vibrators from the surface.

[0012] Such vibrators, mainly based on heavy military equipment, were created in France and the Russian Federation (IGD SB RAS).

[0013] For example, Russian Patent RU 2155264 C2, issued August 27, 2000, "Method for Vibroseismic Impact on an Oil Deposit and a Device for Implementing the Same," states, "A source of seismic vibrations generates a longitudinal and, additionally, a transverse wave of varying polarization; the vibration fields formed by the waves are applied simultaneously or sequentially. The device comprises radiating plates connected to a vibration exciter mounted on a frame. A plate is attached to the frame. A rod of the vibration exciter passes through this plate. One of these plates is pivotally connected to said rod. Each of the other radiating plates is pivotally connected to two rods, pivotally attached to the plate. This increases the effectiveness of the impact on the oil deposit."

[0014] A disadvantage of the known invention is that when used in densely populated areas, such low-frequency seismic vibrations cause serious damage to industrial and civil facilities.

[0015] Another, more significant drawback of the known invention is that prolonged vibration exposure to the productive zone leads to the formation of a significant amount of finely dispersed mineral material in the formation, which clogs the hydrodynamic channels created by vibration. This suggests that a single pulsed treatment is preferable, but such technologies or methods for a single pulsed treatment of the productive formation—simultaneously affecting the near-wellbore zone and interwellbore zones—are not yet known.

[0016] The current level of technological development allows for numerous methods of one-time pulsed action from a well only on the well's near-wellbore zone in order to increase the permeability of the near-wellbore zone (NWZ).

[0017] According to industry experts, one of the most effective types of impact on the PZP is dilatancy impact.

[0018] Dilatancy as a physical phenomenon has been known for quite some time. Its essence consists of the expansion of a solid's volume under the influence of shear stress. Problems in the mechanics of dilatant media have been developed primarily for bulk, granular, crushed, and other granular media.

[0019] Dilatancy of rocks, which directly influences changes in their physical state and properties, was studied only under static loading, when a necessary and sufficient condition for its existence was the creation of a stress state in the deformable medium, the intensity of which approaches the limit, and the unevenness exceeds a certain value depending on its properties.

[0020] Systematic research conducted since 1975 has established that under uneven stresses, deformation processes in rocks exhibit a number of specific characteristics that determine structural changes, alterations in their physical state, and geotechnical properties. The cause of this anomalous behavior is the accelerated development of transverse deformations, which can be 8-10 times greater than those predicted by elasticity theory.

[0021] The result of this is a loosening of the rock - dilatancy, which leads to an irreversible increase in the permeability of the productive formation and an increase in the contact area of ​​the RAB and BA with the rock / productive formation containing raw materials of mineral or organic origin.

[0022] Under dynamic loads, dilatancy processes in rocks develop more intensely than under static loads, indicating the preferable application of these processes in the technologies being developed. Calculations show that under dynamic loads of explosive origin, the effective area of ​​change in rock properties caused by dilatancy processes extends over a distance 8-12 times greater than under static loads of the same intensity and covers a volume 1,000-2,000 times greater.

[0023] The degree of dilatancy decompression of rocks depends on the magnitude of rock and pore pressure, which inhibit the development of dilatancy.

[0024] However, these relationships are quite weak: according to preliminary calculations, the influence of dilatancy on the geotechnical properties of rocks may disappear at depths of 12-15 km, which will not soon be within the limits of engineering activity. Thus, dilatancy processes occur only under sufficiently high intensity and uneven stress conditions and are accompanied by an increase in intergranular voids, the occurrence and development of microfractures, a general loosening of the rock structure, which can reach the value of natural porosity and even significantly exceed it (in dense, low-porosity media), and, most importantly for the problem under consideration, an increase in permeability, which under certain loading conditions can increase severalfold.

[0025] It is necessary to emphasize that dilatancy of rocks is capable of changing their properties several times in the desired direction, and, consequently, dilatancy methods of influencing the rock mass are capable of radically intensifying the course of the technological process.

[0026] From patent RU 2705676 C1, issued November 11, 2019, "Method for pulsed treatment of a productive formation during hydrocarbon production and a control system implementing it," the known method "includes generating disturbing dual electrohydraulic pressure pulses with a time delay between these pulses in a wellbore at the level of the productive formation. The delay value is determined a priori using a known model, and the repetition rate of the pulse pairs and their number are set based on the optimal dominant oscillation frequencies of the geoblocks, determined on the basis of known knowledge and / or empirical data. After the treatment process is completed, its effectiveness is determined through testing based on the fluid inflow level and / or its gradient, the composition of the wellbore fluid, and, if necessary, the process is repeated, varying the parameters of the disturbing pressure pulses until the optimal result is achieved. A control system for the pulsed treatment is also disclosed.The technical result consists in increasing the efficiency of hydrocarbon raw material production in low-yield fields and fields with hard-to-recover reserves."

[0027] A drawback of the known invention is that electrohydraulic pulses are not powerful enough, and therefore their use only allows dilatancy stimulation to be limited to the bottomhole formation zone. However, the interwellbore volume of the formation remains unaffected by such dilatancy stimulation.

[0028] Also known from the Russian Federation Patent RU 2060380 C1, 20.05.1996 is the “Method for dilatancy torpedoing of wells and a torpedo for its implementation”, which is the closest analogue to the claimed method.

[0029] According to a known method, a system of dispersed explosive charges is placed within a productive formation interval. They are then detonated with a delay relative to one another. The delay time between detonations of adjacent explosive charges is determined using the formula given in the description of the known method. The device comprises a housing containing the explosive charges and a detonation initiator connected to a small tip. The torpedo has support elements and detonating cord segments (DC). The explosive charges are distributed between the support elements and connected by DC segments. The length of the segments / CD is determined from the expression given in the description. The length of the support elements is minimized to ensure detonation transfer along the / CD in its spiral section.

[0030] Despite the fact that the use of explosives implies a stronger impact on the wellbore zone than the use of electrohydraulic pressure pulses, which leads to an increase in the radius of dilatancy effect, nevertheless, often as a result of the use of explosives in the wellbore at its bottomhole, it leads to damage to the cement stone in the annular space of the casing and sometimes can even damage the metal casing itself - causing its deformation or rupture.

[0031] But the main disadvantage of the known method is that the dilatancy effect is limited to the PZP with a radius of, as a rule, 5 to 7 meters.

[0032] The aim of the invention is to create a method for volumetric dilatancy action (1) on one or simultaneously on several productive layers in a horizontal section, including (2) also simultaneously, (a) both on the bottomhole zones of wells of this productive layer or on the bottomhole zones of wells of several productive layers, (b) and on the interwell space of such a productive layer or on the interwell space of several productive layers in a horizontal section of the horizon, as a whole.

[0033] The purpose of the invention is graphically explained in Fig. 1, where a section of horizon 1 shows a volumetric area of ​​dilatancy effect 2, wells 3, 4, 5 and 6, a charge of explosives 7 consisting of dispersed charges 8, 9 and 10, a first productive layer 11, a second productive layer 12, as well as a vertical section of the horizon 13 and a horizontal section of the horizon 14.

[0034] The goal is achieved by the fact that in the method of dilatancy impact on productive formations, which includes the placement of a system of dispersed charges of explosives (HE) on the daylight surface, their detonation is carried out with a delay in relation to each other and in this case the number of dispersed charges of explosives must be more than two, and the masses of each of the charges can be the same or different.

[0035] If the number of dispersed charges is more than two, then the delay time between their detonations may be either the same or different.

[0036] The goal is also achieved,

[0037] - and the fact that the same type of explosive can be used for explosive charges, as well as types of explosives that differ in their chemical composition, physical properties and state of aggregation;

[0038] - and due to the different geometric configuration of the placement of these dispersed charges on the day surface or at the same or different depths from the day surface, including the same or different distances between them;

[0039] - and the fact that dispersed explosive charges can be located on the surface or can be placed in the ground in various ways and arranged in various ways, for example, in the form of cumulative explosive charges with the same or different specified directions of explosions.

[0040] The claimed method is explained using the example of one of the simplest cases of its use and is implemented as follows (Fig. 2).

[0041] On the day surface 15, two shallow pits 16 and 17 are dug, in each of which one dispersed charge of explosives 8 and 9 is placed. In this particular example, the simplest explosive is used as an explosive - igdanite, well known to specialists as a mixture of granulated ammonium nitrate (for example, "Granulite Igdanite") (94-96 wt%) and diesel fuel (4-6 wt%), which is produced at the site of blasting operations.

[0042] The mass of each charge depends on the target depth of the required dilatancy decompression of the rock and, for example, for dilatancy decompression of a productive hydrocarbon formation located at a depth of 2500-3000 meters, the mass of each charge 8 and 9 can vary from 3000 kg to 10000 kg.

[0043] In this particular example, two dispersed charges of explosives 8 and 9 are used, each weighing 7000 kg; the total mass is 14000 kg.

[0044] The control of the unevenness of the explosive loading is carried out on the basis of the superposition of blast waves in the mode of ultra-short-delayed or other delayed detonation of charges 8 and 9, and the magnitude of the delay can vary from 1 μs to 100 s.

[0045] To ensure the required deceleration value, sections of detonating cord with a calibrated detonation velocity or other technical means are used that provide a deceleration interval with an accuracy of up to ±0.5 μs.

[0046] In this specific example, a section of highly water-resistant detonation cord, type DSh-V 18, with a detonation velocity of 6,500 m / s, is used to slow the explosions relative to each other. The section DSh-V 18 connects the dispersed explosive charge, type 8, with the dispersed explosive charge, type 9.

[0047] The length of the DSh-V segment - the delay between explosions is determined empirically, since above the target productive formation or hydrocarbon formations there are, as a rule, dozens of different types of rocks and various fluids, the speed of wave propagation in which is also different.

[0048] The propagation speeds of waves are determined by the composition, structure and condition of rocks, which, in turn, depend on the granulometric and mineral composition of solid particles, depth of occurrence, age of rocks, degree of metamorphism, density, porosity, fracturing, destruction, weathering, water saturation, oil and gas saturation and other factors, see Fundamentals of Geometric Seismics, https: / / lektsii.org / 4-12333.html [1].

[0049] The lowest velocities are found in loose dry sands (0.5 - 1 km / s), oil (~1.2 km / s), water (~1.5 km / s), clays (1.3 - 3 km / s), and coal (1.8 - 3.5 km / s). Higher velocities (3-6 km / s) are found in sedimentary rocks (limestone, marble, dolomite, salt, etc.). The highest velocities (4-7 km / s) are found in igneous and metamorphic rocks [1].

[0050] In this particular example, a 5 ms delay between explosions is used. To achieve this, a 32.5 meter long DSh-V 18 is used ((6500 m / s / 1000 ms) * 5 ms).

[0051] Charge 8 made of igdanite is initiated by any suitable detonators 19 approved for use by state bodies of the Russian Federation.

[0052] After placing the dispersed charges of igdanite 8 and 9, installing a moderator between them - DSh-V 18 and a detonator 19, charges 8 and 9 are detonated in the ultra-short-delayed detonation mode.

[0053] The method was implemented, and the productive formation or formations located at a depth of 2,500 to 3,000 meters were subjected to dilatancy; their porosity and permeability increased, and the flow rates of wells 3, 4, 5, and 6 increased. An area of ​​approximately 10-15 km was subjected to dilatancy. 2 .

[0054] Moreover, dilatancy effects typically change the phase composition of the recovered fluid. The recovered well product—the oil-water mixture—significantly increases in oil content and decreases in water content.

[0055] The novelty of the claimed method lies in its ability to simultaneously perform dilatancy stimulation on both the bottomhole formation zone (BFZ) and the interwell volume of the productive formation. Furthermore, the novelty of the claimed method lies in its ability to simultaneously perform dilatancy stimulation on multiple productive hydrocarbon formations located at various depths and containing both liquid and gaseous hydrocarbons (and other minerals mentioned above).

[0056] The significant advantages of the claimed method (using the example of its use in oil production) in comparison with known methods of increasing oil recovery, including in comparison with the closest analogue, are:

[0057] - the possibility of changing the reservoir properties of the host rocks in the field as a whole or in its individual parts, contributing to an increase in the flow rate of all production wells or their group;

[0058] - no need to carry out blasting and perforating operations in wells for the purpose of treating the bottomhole formation zone;

[0059] - complete safety of well operations, ensuring the integrity and tightness of casing strings;

[0060] - absence of any technological interruptions in the operation of wells associated with their preparation and repair and restoration operations; no need to use expensive geophysical equipment and, in most cases, expensive and special explosives, since charges can be prepared on site using ammonium nitrate and diesel fuel (igdanite); simplicity, speed of organization and implementation of work, duration of the positive effect (up to 4 years);

[0061] - environmentally friendly operations in terms of possible contamination of the subsoil and underground seepage flows; the possibility of rapid and low-cost scaling of the proposed method.

Claims

Invention formula 1. A method of dilatancy influence on productive formations, including the placement of explosive charges (EC) - igdanite on the day surface or in pits located at a distance from each other, their detonation with a delay in relation to each other, while the number of explosive charges is equal to two or more, and the masses of each of the charges can be the same or different, but sufficient to carry out the dilatancy effect.

2. The method according to item 1, characterized in that, if the number of charges placed is more than two, the delay between their detonations may be the same or different.

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