RU2191889C1 - Method of developing hydrocarbon deposits - Google Patents

Abstract

FIELD: oil, gas and coal industries for hydrocarbons recovery at various stages of deposits development. SUBSTANCE: method includes drilling of wells, withdrawal of hydrocarbons from wells, directed treatment of zone of oil-gas accumulation and/or deposit by elastic waves from vibration source. Prior to treatment, geodynamic model of zone of oil-gas accumulation and/or deposit is constructed using remote and geological and geophysical data. Singled-out on said model are ring and block structures paragenetically associated with traps of hydrocarbons. Present stressed-strained state of rocks and its effect on reservoir properties are determined. Zone of present abnormal stressed-strained state of rocks of ring and/or block structures and center of said zone are determined. Installed above said center on day surface or water area bottom is vibration source for treatment of said zone with elastic waves. EFFECT: higher efficiency of deposit development at various stages of deposit operation, increased withdrawal of hydrocarbons and higher safety. 12 cl, 7 dwg, 3 ex

Description

 The invention relates to the field of oil, gas and coal industry and can be used in hydrocarbon production at different stages of field development.

 A known method for the development of gas condensate, oil or oil and gas condensate deposits (RF patent 2061845, class E 21 B 43/00, 43/24, 1996), providing for directed exposure to the zone of gas-water or oil-water contacts, including using a surface vibration source. In this case, the released gas enters the overlying reservoir and displaces oil from it. The disadvantage of this method is the neglect of geological, tectonic, geodynamic features of the reservoir and its surrounding geomedium, which reduces the effectiveness of the method.

 A known method of production (collection) of coal gas in coal mines (Chinese patent CN 1053103 A, class E 21 F 7/00, 1991), providing for the pumping of gas by ventilation or vacuum pumps from the bottom of the mine using a piping system. The method also provides for explosions to open new gas-bearing coal seams and rock sections and work on pumping groundwater. The disadvantages of the method are: its low efficiency and small volumes of gas extraction. It is possible to pump gas from the drifts of the mine, but it is extremely problematic to degass directly the coal mass, in which industrial gas reserves are located. Blasting involves only a short-term action of elastic waves on coal seams, unable to seriously affect their degassing. Opening of new gas-bearing coal horizons and rock sections at the same time carries a great danger in contact with atmospheric air. The main disadvantage of this method, as well as methods involving the extraction of gas through pre-drilled wells (see, for example, RF patent 2133344, CL E 21 A 7/00, 1999, RF patent 2136890, CL E 21 F 7/00, 1999), is unstable gas production, which makes it not profitable for industrial purposes.

 A known method of degassing a coal seam (as USSR USSR 1657659, class E 21 F 7/00, 1991), including recording the acoustic "noise" of the array while drilling a degassing well, obtaining the amplitude-frequency characteristics and finding resonant frequencies of the array at each drilling interval, the acoustic effect at the resonant frequencies found on the coal seam using an emitter connected to the wellhead, gas extraction through a degassing well and a degassing gas pipeline. The disadvantage of this method is the limited radius of influence from the source of oscillations installed at the wellhead. The main disadvantage is the neglect of the tectonic features of the reservoir, the influence of the stress-strain state of the massif and its structure on the result of acoustic exposure, which significantly reduces its effectiveness.

 A known method of controlling rock pressure (RF patent 1760115, class E 21 C 41/20, 41/20, 41/18, 1992), including: determining the stress field and the main vectors in the rock mass using rock pressure sensors that establish in a control well, drilling wells in a mine and placing non-explosive pneumatic sources in them in such a way that they are in a plane passing through the line of action of the maximum principal stress, excitation of seismic vibrations, leading to improved hydro- and aerodynamic rock bonds in the massif and contributing to a more complete opening of pores and cracks in the massif and increasing the stability of the mine. The method has the following disadvantages: exposure can only be made on local sections of the massif; the difficulty of determining the stress field and the main vectors in the rock mass; the need to drill a large number of wells to accommodate sensors and pneumatic sources; difficulty synchronizing pneumatic sources.

 Closest to the invention is a method for the development of gas condensate and oil reservoirs (RF patent 1144448, class E 21 B 43/24, 1993), which includes the directed action of elastic vibrations of the infrasonic frequency range on the pressure zones previously identified in the developed reservoir in combination with thermal exposure . The method involves the construction of a field map with the allocation of high pressure zones on it, which are determined by the acoustic method, i.e. the construction of a certain geodynamic model, and the subsequent impact on these zones from a surface source of oscillations. At the same time, inter-grain bond breaks in the formation rock and cracking, a decrease in the viscosity of the fluid and an increase in its mobility in the reservoir are observed, which leads to an increase in production. The effectiveness of the method increases if, simultaneously with the action of elastic waves on the zone of high pressure, hot fluid is pumped into this zone mainly when half-waves of discharge pass through it. This leads not only to a decrease in oil viscosity, but also to an increase in porosity caused by both the opening of pores in the half-wave of the rarefaction wave and their wedging due to the forced entry of fluid into the pores in the half-period of the compression wave.

 The disadvantage of this method is that it provides for the impact only on individual zones of increased pressure of the reservoir, and not on the center of the zone of abnormal stress-strain state of rocks of the entire field and / or the entire oil and gas accumulation zone, which can have both high and low pressure at a relative tensile rocks and their reduced strength, and also involves additional thermal effect. This reduces the efficiency of the method, increases energy consumption and duration of exposure. Despite the possibility of an effect within a radius of 15 km or more from the source of oscillations, it is difficult to predict and control it.

 The problem to which the invention is directed is to increase the efficiency of developing gas, gas condensate, oil and oil and gas condensate fields at various stages of their operation and increase the recoverable hydrocarbon reserves; additionally, the problem of a more rational and effective impact of elastic waves on the field and / or a number of isolated deposits in the oil and gas accumulation zone is solved, as well as the task of gas production from coal seams and to increase the safety and efficiency of work in mines.

 The essence of the invention lies in the fact that wells are drilled into the productive horizon for the selection of hydrocarbons, or ready-made wells are used in the field containing oil, gas, gas condensate remaining in the formation, and the field is subjected to elastic waves from the vibration source. Before exposure begins by well-known methods (see, for example, A.I. Petrov, V.S.Shein. Geodynamic model of a reservoir with a siliceous-clay reservoir. Oil and gas geology, 9-10, 1999, pp. 7-13) by remote (hereinafter, by remote research is meant the analysis of data obtained by aerospace surveying methods) and geological and geophysical data, a geodynamic model of an object representing an oil and gas accumulation zone and / or a field containing heterogeneities such as formations, horizons, rock complexes p zlichnogo composition, folds, fractures and linear focal zones of abnormal fracture (tensile heterogeneity), and areas of anomalous field of compression stress - strain (density inhomogeneities); preliminary determine, taking into account the rock pressure and strength characteristics, the current stress-strain state of the rocks of the indicated heterogeneities in the occurrence conditions and its effect on the reservoir properties; distinguish modern active ring and / or block structures paragenetically connected on the model (hereinafter referred to as paragenetically connected, the joint finding of various folded and discontinuous tectonic forms (elements), geodynamically interconnected and simultaneously or sequentially formed) with hydrocarbon traps; determine the zone of the modern abnormal stress-strain state of the rocks of the ring and / or block structures and the position of its center; establish a source of oscillation on the day surface above the center of the specified zone and act on it with elastic waves; also, the oscillation source can be installed in a shaft or well both above the center of the zone and directly in it. They are also affected by a frequency providing a half-wave length equal to the distance between the oscillation source and this center. Similar actions are carried out in coal deposits to extract gas from them and increase the efficiency of mining.

 The essence of the geodynamic model allows us to determine the center of the zone of the modern anomalous stress-strain state of rocks of active ring and / or block structures, with which traps of the oil and gas accumulation zone or field are paragenetically connected. Zones of anomalous stress-strain state of rocks are formed as a result of concentration of compressive or tensile stresses by heterogeneities of the geomedium and primarily cover rocks with reduced initial or residual (after deformation) strength parameters for a particular type of stress state. Such zones are confined, as a rule, to active faults of ring and block structures with the position of their center at the intersection and complication of these faults and are heterogeneities of the geomedium with reduced (residual) rock strength due to anomalous fracture (discontinuity), actively reacts to the field stresses of various spatio-temporal scales by stress concentration and the formation of density inhomogeneities: with excess density during compression at the stage of elastic deformations cracking) and density inversion during dilatancy at the stages of plastic deformation, fracture, extreme deformation, as well as with a reduced density during relative tension and crack opening. In connection with the indicated features, the zones of the modern anomalous stress-strain state of rocks according to the corresponding response (useful signal) are recorded by various methods and observation systems, including: in the wave seismic field they are distinguished by dynamic (amplitude, phase-frequency, etc.) and kinematic (speed etc.) parametric anomalies, dissipative and nonlinear characteristics; on remote sensing materials are decoded according to the characteristic micro-macroelements of the landscape, grouped around the center of the zone and reflecting the anomalous deformations of the earth's surface; when monitoring the geological and geophysical environment, they are determined by abnormal changes in the parameters of geophysical fields, deformations of the earth's surface, the ratio of the amplitudes of the spectral components of the seismic field during passive seismic observations, fluctuations in the energy of exchange of seismic waves, etc.

 Achievable technical result when using the invention is to increase the volume of oil, gas, gas condensate and recoverable hydrocarbon reserves, the production of gas from coal seams and increase the safety of work in mines, as well as reducing costs and time for vibration exposure.

 The invention is based on the following premises.

 It is known that during the selection of fluids from a reservoir, the reservoir (pore) pressure decreases and the stress state of the rocks in the heterogeneities such as local structures, faults, fracture zones, formations, etc. changes. This leads to local, mostly slow deformations and associated processes (mass and fluid transfer etc.), which does not provide a stable state of the hydrodynamic system and fluid properties, as a result, well production rates and hydrocarbon production volumes decrease, a significant part of which remains in the reservoir.

 The essence of the action of elastic waves on the center of the zone of the abnormal stress-strain state of rocks of a ring and / or block structure consists in activating and accelerating the process of deformation and redistribution of stresses in the indicated center and excitation through it of the whole geodynamically unified system of heterogeneities of the tectonic structure, including hydrocarbon deposits. The physical essence of the process of activating deformations and changing the picture of the stress state of the geomedium consists of: 1) the pumping of additional energy by elastic waves to the center of the zone of the anomalous stress-strain state of the rocks and lowering the strength parameters of rocks; 2) a decrease under the action of elastic waves of friction forces at the boundaries of the indicated center and heterogeneities with host rocks, which leads to the unloading of anomalous stresses by the center and inhomogeneities and the release of the energy stored in them. Also, as a result of the effect, the petrostructure is repackaged, including the structure of the space. These processes lead to additional generation of elastic waves of a wide frequency range and to an increase in the intensity of seismic (acoustic) emission. The energy released by the geophysical medium can also amplify the main wave from the original source of oscillation. According to the quantum-mechanical model of the strength of solids (see: Zhurkov S.N.Dilatonic mechanism of the strength of solids. Physics of solids, vol. 25, issue 10, 1983, pp. 3119-3127). The processes of decreasing rock strength, activating deformations, and releasing energy are associated with the absorption of backgrounds and the accumulation of their energy by dilatons - short-lived microdynamic fluctuation defects. The absorption of the background energy by the dilaton leads to its expansion to a critical value, after which the dilaton decays. In an explosion, a pressure drop occurs at the boundary of the dilaton region; as a result, the dilaton is a hotbed of local destruction and, at the same time, a fluctuation source of dislocation. The avalanche increase in dislocations caused by the phonon pumped dilatons during prolonged exposure to elastic waves from a vibration source leads to the formation of a large number of microcracks. This process is especially active in the center of the anomalous stress-strain state of rocks. The greatest effect is achieved when the source of oscillations is located on the day surface above the center of the zone of the modern anomalous stress-strain state of the rocks of ring and / or block structures due to the minimum dispersion of the energy of elastic waves along the line of least resistance and when exposed to elastic waves with a frequency providing a half-wave length equal to the distance between the oscillation source and the given energy center.

 The release of accumulated energy during deformations and other listed and related processes in the activated energy center in the form of seismic emission of a wide spectrum of frequencies enhances the effect of elastic waves from an oscillation source, creates standing waves in stressed geological bodies, and generates its own stress waves. As a result, the energy center excites the associated geodynamic system of heterogeneities of the ring and / or block structure. In such an excited system, which has enormous potential energy, the restoration of the equilibrium stress-strain state of rocks, which is disrupted by the selection of fluids from the deposits associated with the activated tectonic structure, is primarily accelerated. At the same time, during deformation of the reservoir, existing rock formations are renewed and new disturbances are formed, which increase the drainage zone volume by connecting previously isolated fluid-containing reservoirs, which is recorded according to well research data in the form of deviations of indicator lines (in coordinates: bottomhole pressure - oil flow rates) in the direction flow rate axis. Reservoir deformations are also accompanied by seismic emission in combination with an external action of elastic waves, which, by the type of filter-pressing mechanism (a sharp pressure drop in mutually perpendicular directions), accelerates the phase differentiation of fluids, their displacement from the matrix into cracks, and drainage; as a result, the reservoir increases pressure in the reservoir, the filtration characteristics are improved, the flow rates of the wells increase, the coefficient of hydrocarbon reserves extraction increases.

 Elastic waves from a source of oscillations on the earth's surface have a similar effect on the zones of anomalous inhomogeneous stress-strain state of rocks in coal seams. The presence of such zones is indicated by mountain impacts. Activation of systems of cracks and cleavage in a coal seam contributes to the release and drainage of gas into the near-wellbore space with a lower reservoir pressure of the gas, its more uniform and stable flow into them, and the strength characteristics of the coal seam are also reduced, which facilitates coal mining and reduces energy costs. Unloading the abnormally stressed state due to elastic vibrations leads to relaxation and a more uniform distribution of stresses and deformations in the coal mass, which reduces and prevents the occurrence of rock shocks, increases the safety of work.

 The method is implemented as follows.

 Wells are drilled at a field into a productive horizon (s) for the extraction of hydrocarbons or finished wells are used at a depleted field with oil, gas, gas condensate remaining in the formation. A geodynamic model of the oil and gas accumulation zone and / or field is built from remote and geological and geophysical data, the current stress-strain state of the rocks is determined in the bedding conditions, ring and block structures of various ranks, local folds, faults, fracture zones and other heterogeneities are distinguished on the geodynamic model paragenetically associated hydrocarbon traps, analyze the stress field and determine the modern center of the zone of anomalous stress-strain state ence sawmills ring and / or block structures, mounted above it and / or directly to said central shaft in a well or the source of vibrations and impact at a certain frequency. Well production rates and oil, gas and condensate production increase, recoverable hydrocarbon reserves increase. In coal deposits, stable gas flows are obtained from wells drilled into drainage zones.

 Example 1. The implementation of the method is shown by the example of a group of large, medium and small fields by recoverable oil reserves of one of the oil and gas basins of Southeast Asia. In fields, productive horizons are opened by production wells and are at different stages of development, in some cases at the stage of depletion. Before exposure to the reservoir by elastic waves from a source of oscillations according to satellite imagery, geological and seismic 3D data using a known method (see: Kleschev K.A., Petrov A.I., Shein VS Geodynamics and new types of natural oil and gas reservoirs. - M .: Nedra, 1995, 286 pp.) A geodynamic model of the oil and gas accumulation zone was built, including this group of fields (Fig. 1 a, b), the current stress-strain state of the rocks was determined. As part of the geodynamic model, the main ring structure 1 with an external diameter ⌀ in the plan of about 42 km (Fig. 1a) and block structures of the foundation 2, limited by faults 3, 4, 5 penetrating into the sedimentary cover 6 (Fig. 1b), and other subvertical faults 7, 8, 9 (figa). In turn, in the structure of the ring structure 1, discontinuous violations 10, 11, 12, 13, 14, 15 of different radii of curvature are distinguished (Fig. 1a), which are associated with the formation in the sedimentary cover of 2 suspended anticline 16, 17, 18 and tectonically shielded 19 traps containing oil deposits (Fig. 1B). The modern center of the ring structure 20, defined by the focal zone of the anomalous stress-strain state of rocks of isometric shape with a diameter of about 3 km, has been determined. It is located on the axis of symmetry of the ring structure at the intersection of faults 3, 4, 5 of different spatial orientations at the boundary of the rocks of the foundation 6 and sedimentary cover 2 (Fig. 1b) in the depth interval 2.5-5.5 km. Directly above it is a field 17. The oscillation source 21 was installed on the day surface inside the annular structure above the center of the anomalous stress-strain state 20 and acted on the center by elastic waves. As a result of the action of elastic waves in the field 17, dynamic levels in production wells increased and stabilized, which made it possible to change the pumps to higher productivity, see, for example, FIG. 2. Well watering also decreased. As a result, a group of fields 17, 19, 22, 26 significantly increased oil production, see FIG. 3, which shows a graph of oil production before and after vibroseismic impact on a group of fields 17, 19, 22, 26, having one metering unit (flowmeter). The composition of oil has changed due to new components that indicate the involvement of previously unrecoverable reserves in the development. An increase in production with similar concomitant processes also manifested itself in fields 19, 22, 23, 24, 25, 26 within a radius of 25 km; no observations were made at other fields 27-46.

 An example implementation of the method in the water area is shown in FIG. 4a, b. At one of the oil fields 1 in the Black Sea, which has been exploited for a long time, active faults 2, 3 associated with the modern center of the anomalous stress-strain state of rocks 4, which is located in the site, are identified by elastic waves according to bathymetric, geological, and seismic data. the intersection of these faults near the contour of the field 1. The oscillation source 5 is installed at the bottom of the water area 6 above the specified center 4 (fig.4b) and acts on it by elastic waves, which leads to activation and the entire center of the anomalous stress-strain state of rocks 4 and related heterogeneities in the structure of reservoirs 1, as a result, oil production rates in wells increase by 20% or more. The source of elastic waves 7 (Fig. 4a) can also be installed above the indicated active fault 2 on land 8, if it can be traced there from the water area 9, and the distance to the center of the modern anomalous stress-strain state of rocks 4 with which it is associated does not exceed 50 km

 The implementation of the method for the degassing of coal seams and the selection of gas from them is shown on the example of a section of one of the coal deposits of the Turgai basin (figure 5). Prior to the impact of elastic waves by satellite images, geological and geophysical data, a modern center of anomalous stress-strain state of rocks 1, dedicated to the bending of fault of fault type 2, was identified on the site of the field. Oscillation source 3 is located on the earth's surface above this energy center and acts on it elastic waves. As a result, stress relaxation occurs in coal seams 4, gas drainage increases along fracture systems in the seams and along the fault in the direction of previously drilled exploratory wells 5-8, near which the gas reservoir pressure is lower due to its selection. As a result, the occurrence of mountain impacts is prevented, work productivity is increased, the gas production process is stabilized and its significant reserves are used in industry.

 The advantages of the method are that it allows you to optimize the effect of elastic waves on hydrocarbon deposits, significantly increases its efficiency, reduces energy consumption, duration of exposure, increases its radius and depth, while the effects of exposure can be predictable and controllable.

 Having determined the modern center of the anomalous stress-strain state of the rocks of the entire oil and gas zone and / or structure, including a group of fields, the impact on it allows to significantly increase production simultaneously at all geodynamically associated fields.

 These proposed geological and technological advantages of the method allow to obtain a significant economic effect due to a significant increase in the level of production and increase in recoverable hydrocarbon reserves in comparison with other methods.

Claims (12)

 1. A method of developing hydrocarbon deposits, including drilling wells, selecting fluids from them, constructing a geodynamic model of an oil and gas accumulation object, directed exposure of the object to elastic waves from a vibration source, characterized in that before the start of the action, ring and block structures are paragenetically associated with hydrocarbon traps, determine the zone of the modern anomalous stress-strain state of rocks and the center of this zone and affect it gimi waves.  2. The method according to claim 1, characterized in that they affect the center of the zone of the modern abnormal stress-strain state of rocks located on land.  3. The method according to claim 1, characterized in that they act on the center of the zone of the modern abnormal stress-strain state of the rocks located in the water area.  4. The method according to one of claims 1 to 3, characterized in that the geodynamic model is built from satellite images.  5. The method according to p. 1 or 3, characterized in that the geodynamic model of the field in the water is based on bathymetric data.  6. The method according to one of claims 1 to 5, characterized in that the geodynamic model is built according to seismic data.  7. The method according to one of claims 1 to 6, characterized in that the geodynamic model is built according to potential geophysical fields.  8. The method according to one of claims 1 to 7, characterized in that it is preliminarily determined, taking into account the rock pressure and strength characteristics, the current stress-strain state of the rocks in the occurrence conditions.  9. The method according to one of claims 1 to 9, characterized in that the elastic waves excite a surface source of oscillation.  10. The method according to one of claims 1 to 10, characterized in that the oscillation source is placed above the center of the zone of the modern abnormal stress-strain state of the rocks of the ring and / or block structures within the oil and gas accumulation zone or field.  11. The method according to one of claims 1 to 11, characterized in that the oscillation frequency is set to provide a half-wave length equal to the distance from the oscillation source to the center of the zone of the modern abnormal stress-strain state of the rocks.  12. The method according to one of claims 1, 3, 5, characterized in that at least one oscillation source is installed on the shore of the water area above the active tectonic element, on which the center of the zone of the anomalous stress-strain state located in the water area is located.

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