CN115324542B - Method and system for oil extraction by water injection between multiple well seams of horizontal well of low-permeability tight oil reservoir - Google Patents
Method and system for oil extraction by water injection between multiple well seams of horizontal well of low-permeability tight oil reservoir Download PDFInfo
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- CN115324542B CN115324542B CN202210833137.XA CN202210833137A CN115324542B CN 115324542 B CN115324542 B CN 115324542B CN 202210833137 A CN202210833137 A CN 202210833137A CN 115324542 B CN115324542 B CN 115324542B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/20—Displacing by water
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/40—Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
Abstract
The invention provides a method and a system for oil extraction by water injection between multiple well slots of a horizontal well of a low-permeability tight oil reservoir, comprising the following steps: injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network; judging whether a fracturing crack distribution mode in the target fracture network is a zipper type crack or not; if the fracture is a zip-type fracture, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining the fracture which is adjacent to two sides of the development fracture zone and surrounds the development fracture zone into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon. The invention realizes multi-well inter-seam quasi-anti-seven-point method area water injection, can eliminate the influence of inter-seam interference, fully plays roles of linear water injection and radial displacement, expands the water injection sweep range, increases the effective well, and improves the oil displacement efficiency and single well yield.
Description
Technical Field
The invention belongs to the technical field of geological resources and geological engineering, and particularly relates to a method and a system for water injection and oil extraction among multiple well seams of a horizontal well of a low-permeability tight oil reservoir.
Background
The area water injection method is widely applied to oil and gas reservoir development, and after the low permeability, ultra low permeability and dense oil reservoirs are injected with water, cracks are easy to be induced to expand and extend, so that a complex target crack network is formed. The dynamic cracks formed after the natural cracks are expanded are reasonably utilized, so that the injected water can achieve the effect of uniform displacement as much as possible, and the method is a difficult point for researching the development mode of the existing fractured tight oil reservoir. In order to solve the problems of low permeability, ultra-low permeability, high yield reduction after multiple times of water injection huff and puff of dense oil reservoirs and obvious ineffective water injection, each oil field adopts a new development mode. The long-day oil field adopts a rhombic reverse nine-point well pattern, so that the development effect is remarkable, but the injection and production mode is only suitable for a symmetrical seam distribution mode (namely, the symmetrical distribution of the fracturing cracks at two sides of the horizontal well), and is not suitable for a zip-type seam distribution mode (namely, the staggered distribution of the fracturing cracks at two sides of the horizontal well) oil reservoir.
The ultra-low permeability oil reservoir block of the Changqing oil field adopts a multi-stage fracturing horizontal well same-well asynchronous injection and production mode to convert the well-to-well displacement into the same-well fracture displacement, but neglects the fracture interference, and the fracture interference causes the non-uniform displacement phenomenon to be obvious, so that the injection efficiency is low, and the method is not suitable for the ultra-low permeability compact oil reservoir with physical anisotropy.
Disclosure of Invention
Aiming at the defects or shortcomings of the prior art, the invention provides a method and a system for oil extraction by water injection between multiple well slots of a horizontal well of a low-permeability tight oil reservoir, which are used for solving the technical problem of low water injection efficiency of the low-permeability tight oil reservoir in the prior art.
In order to achieve the above object, the present invention provides a method for water injection and oil recovery between multiple well joints of a low-permeability tight oil reservoir horizontal well, wherein the method for water injection and oil recovery between multiple well joints of a low-permeability tight oil reservoir horizontal well comprises:
injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
judging whether a fracturing crack distribution mode in the target fracture network is a zipper type crack or not;
if the fracture is a zip-type fracture, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining the fracture which is adjacent to two sides of the development fracture zone and surrounds the development fracture zone into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon.
In the embodiment of the invention, the expanding the natural fracture and communicating the fracturing fracture to form the target fracture network comprises the following steps:
establishing a well group geological model, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method according to the well group geological model and based on model size parameters, reservoir parameters, fluid parameters and well parameters and combining dynamic data and well test data of the target horizontal well, and fitting a production history to obtain a crack propagation permeability simulation map;
and obtaining the target fracture network with the natural fracture permeability and the fracture permeability tending to be stable according to the natural fracture permeability and the change trend of the fracture permeability along with the water injection time in the fracture expansion permeability simulation graph.
In the embodiment of the invention, the expanding the natural fracture and communicating the fracturing fracture to form the target fracture network comprises the following steps:
according to the well group geological model, combining dynamic monitoring data, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method, fitting a production history, and obtaining a pressure change curve of the target horizontal well;
and determining the target fracture network according to the change trend of the pressure change curve along with water injection time.
In an embodiment of the present invention, the pressure variation curve includes: matrix pressure profile, natural fracture pressure profile, and fracture pressure profile.
In an embodiment of the present invention, the determining the target fracture network according to the change trend of the pressure change curve along with the water injection time includes:
and comparing the natural fracture pressure change curve, the matrix pressure change curve and the fracturing fracture pressure change curve to obtain the target fracture network with large pressure difference and consistent pressure change trend.
In the embodiment of the present invention, the comparing the natural fracture pressure change curve, the matrix pressure change curve and the fracturing fracture pressure change curve to obtain the target fracture network with large pressure difference and consistent pressure change trend includes:
acquiring a first inflection point for slowing down the increase of matrix pressure in the matrix pressure change curve after water injection begins;
acquiring a second inflection point of the pressure drop of the matrix after the first inflection point;
acquiring a third inflection point of slow increase of matrix pressure after the second inflection point;
and determining the target fracture network according to the third inflection point.
In the embodiment of the invention, the expanding the natural fracture and communicating the fracturing fracture to form the target fracture network comprises the following steps:
and determining a target fracture network in which the permeability of the natural fracture and the permeability of the fracturing fracture tend to be stable by combining the third inflection point.
In an embodiment of the present invention, the determining a developing fracture zone on the target horizontal well includes:
and determining a high-conductivity dynamic fracture channel according to the fracture propagation permeability simulation diagram, and determining the development fracture zone according to the high-conductivity dynamic fracture channel.
In an embodiment of the present invention, the determining the development fracture zone according to the high-conductivity dynamic fracture channel includes:
and determining the development fracture zone by combining the high-conductivity dynamic fracture channel and the pressure change curve.
The invention also provides a multi-well inter-fracture water injection oil extraction system of the low-permeability tight oil reservoir horizontal well, which comprises the following components:
the data simulation module is used for injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
the data analysis module is used for judging whether a fracturing crack distribution mode in the target fracture network is a zip-type crack or not, if the fracturing crack distribution mode is the zip-type crack, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining the fracturing cracks which are adjacent to two sides of the development fracture zone and enclose into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon.
Through the technical scheme, the water injection oil extraction method between the multi-well seams of the low-permeability tight oil reservoir horizontal well provided by the embodiment of the invention has the following beneficial effects:
the injection huff and puff is converted into multi-well inter-seam pseudo-seven-point area injection, invalid injection can be avoided, the swept area is increased, the oil displacement efficiency is improved, the yield of an oil production section is increased, a target fracture network formed by natural fracture expansion is used as a seepage channel in the initial stage of injection, the displacement effect is fully exerted, along with the progress of injection water, the injection water uniformly flows to a matrix and replaces crude oil through the pseudo-seven-point well network under the dual effects of injection pressure and capillary pressure, and the radial displacement and imbibition effect simultaneously occur in the period. The target fracture network high diversion channel and the uniform displacement of the multi-well inter-fracture area water injection method are utilized to improve the multi-well inter-fracture quasi-anti-seven-point area water injection efficiency and the residual oil utilization degree, and technical support is provided for the establishment of subsequent inter-segment encryption and adjustment schemes and three-dimensional well pattern design schemes. The invention realizes multi-well inter-fracture quasi-anti-seven-point method area water injection, can eliminate the influence of inter-fracture interference, fully plays the roles of linear water injection and radial displacement, expands the water injection sweep range, increases the effective well, improves the oil displacement efficiency and the single well yield, and provides important technical guidance for the development scheme and measures of low permeability, ultra-low permeability and compact oil reservoir area water injection.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings are included to provide an understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the description serve to explain, without limitation, the invention. In the drawings:
FIG. 1 is a flow chart of a method for water injection and oil recovery between multiple well joints of a low permeability tight reservoir horizontal well according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an injection and production unit on a target horizontal well according to one embodiment of the invention;
FIG. 3 is a schematic diagram of a plurality of injection and production units on a target horizontal well according to one embodiment of the invention;
FIG. 4 is a simulated graph of crack propagation permeability at the initial stage of water flooding in accordance with one embodiment of the present invention;
FIG. 5 is a simulated graph of crack propagation permeability in mid-water flooding according to one embodiment of the present invention;
FIG. 6 is a simulated graph of fracture propagation permeability at the end of water injection according to one embodiment of the present invention;
FIG. 7 is a schematic diagram of a pressure variation curve in an embodiment according to the invention;
fig. 8 is a table of numerical simulation parameters in an embodiment in accordance with the invention.
Detailed Description
Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present invention.
The method for oil extraction by water injection between multiple well slots of a low-permeability tight oil reservoir horizontal well according to the invention is described below with reference to the accompanying drawings.
As shown in fig. 1, in an embodiment of the present invention, a method for water injection and oil recovery between multiple well seams of a low-permeability tight oil reservoir horizontal well is provided, and in a first embodiment of the present invention, the method for water injection and oil recovery between multiple well seams of a low-permeability tight oil reservoir horizontal well includes:
s10, injecting water into a target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
s20, judging whether a fracturing crack distribution mode in the target fracture network is a zipper type crack or not;
and S30, if the fracture is a zip-type fracture, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining the fracture fractures which are adjacent to two sides of the development fracture zone and enclose into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon.
It can be understood that, as shown in fig. 2, the horizontal line represents a target horizontal well, and six oil extraction sections in this embodiment cooperate with a central water injection section as one injection and production unit, as shown in fig. 3, a plurality of injection and production units can be arranged between the well joints of three target horizontal wells, and the same oil extraction section is shared between two adjacent injection and production units to utilize the beneficial displacement effect of inter-well and inter-joint interference, so that the number of effective well sections is increased, and the water injection utilization rate is improved. The fracturing cracks on two sides of the target horizontal well are symmetrically distributed in a symmetrical seam distribution mode, the fracturing cracks on two sides of the horizontal well are distributed in a staggered mode, and the fracturing cracks are distributed in a crossed mode like zipper teeth, so that the fracturing cracks on two sides of the target horizontal well are distributed in a zipper seam distribution mode.
In the embodiment, the water injection throughput is converted into multi-well inter-seam pseudo-seven-point method area water injection, invalid water injection can be avoided, the swept area is increased, the oil displacement efficiency is improved, the yield of an oil production section is increased, a target fracture network formed by natural fracture expansion is used as a seepage channel in the initial stage of water injection, the displacement effect is fully exerted, along with the progress of the injected water, under the dual effects of water injection pressure and capillary pressure, the injected water uniformly flows to a matrix through the pseudo-seven-point method well pattern and replaces crude oil, and the radial displacement and the imbibition effect simultaneously occur in the process. The target fracture network high diversion channel and the uniform displacement of the multi-well inter-fracture area water injection method are utilized to improve the multi-well inter-fracture quasi-anti-seven-point area water injection efficiency and the residual oil utilization degree, and technical support is provided for the establishment of subsequent inter-segment encryption and adjustment schemes and three-dimensional well pattern design schemes. The multi-well inter-fracture quasi-anti-seven-point method area water injection is realized, the influence of inter-fracture interference can be eliminated, linear water injection and radial displacement are fully exerted, the water injection sweep range is enlarged, the effective well is increased, the oil displacement efficiency and the single well yield are improved, and important technical guidance is provided for the low-permeability, ultra-low-permeability and compact oil reservoir area water injection development scheme and measure.
Further, according to a second embodiment of the method for water injection and oil recovery between multiple well fractures of a low permeability and tight reservoir horizontal well provided by the first embodiment of the invention, in the embodiment of the invention, the expanding natural fractures and communicating the fracturing fractures to form a target fracture network includes:
establishing a well group geological model, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method according to the well group geological model and based on model size parameters, reservoir parameters, fluid parameters and well parameters and combining dynamic data and well test data of the target horizontal well, and fitting a production history to obtain a crack propagation permeability simulation map;
and obtaining the target fracture network with the natural fracture permeability and the fracture permeability tending to be stable according to the natural fracture permeability and the change trend of the fracture permeability along with the water injection time in the fracture expansion permeability simulation graph.
The embodiment specifically discloses that a well group geological model is established, based on the dimension parameter, the reservoir parameter, the fluid parameter and the well parameter of the well group geological model, the dynamic data is combined as a basis, a numerical simulation method is adopted to fit the production history, the water injection is obtained to induce the natural cracks to expand so as to form a target crack network, the area water injection is utilized to expand the water injection sweep range, and the uniform displacement effect is fully exerted; the well group geologic model establishment and the oil reservoir method can both adopt the prior art, as shown in fig. 8, and specific parameters of numerical simulation are specifically shown in the drawing. Fitting the production history by numerical simulation means can obtain fracture propagation permeability simulation graphs as shown in fig. 4 to 6. After 30 days of injection, the stress field strength factor reaches fracture toughness, the pressure is increased to 41.7MPa, the originally closed natural fracture tip is excited and expanded, or the natural fracture with the filler is flushed, at the moment, a small amount of natural fracture is expanded, injected water enters the natural fracture, and the natural fracture permeability is gradually increased; as shown in fig. 5, after 50 days of water injection, the natural micro cracks are expanded to form a new seepage space, the flow conductivity of the natural cracks is increased, and the natural cracks are continuously expanded and extended along with the increase of the pressure in the cracks; as shown in fig. 6, the water injection is continued for 90 days, the natural cracks and the permeability in the fracturing cracks tend to be stable, the natural cracks communicated with each other continue to extend, the fracturing cracks are communicated, and a complex fracture network is formed. In the implementation, the most target fracture network can be precisely obtained by observing the change trend of the permeability along with the water injection time in the fracture propagation permeability simulation diagram in real time, and the multi-well inter-fracture-like anti-seven-point method area water injection is adopted based on the target fracture network.
According to a third embodiment of the method for water injection and oil recovery between multiple well fractures of a low-permeability tight oil reservoir horizontal well provided by the second embodiment of the method for water injection and oil recovery between multiple well fractures of a low-permeability tight oil reservoir horizontal well, in the embodiment of the invention, the expanding natural fractures and communicating fracturing fractures to form a target fracture network comprises:
according to the well group geological model, combining dynamic monitoring data, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method, fitting a production history, and obtaining a pressure change curve of the target horizontal well;
and determining the target fracture network according to the change trend of the pressure change curve along with water injection time.
In an embodiment, the target fracture network can be accurately determined according to the variation trend of the pressure along with the water injection time, three stages of the initial stage, the middle stage and the later stage of water injection can be accurately identified and distinguished according to the inflection point of the pressure variation curve, the crack expansion change is correspondingly performed, and the final target fracture network can be accurately identified according to the inflection point of the later stage of water injection.
According to a third embodiment of the low-permeability tight reservoir horizontal well multi-well inter-well fracture water injection oil extraction method provided by the present invention, a fourth embodiment of the low-permeability tight reservoir horizontal well multi-well inter-well fracture water injection oil extraction method is provided, and in an embodiment of the present invention, the pressure change curve includes: matrix pressure profile, natural fracture pressure profile, and fracture pressure profile. In the embodiment, the target fracture network is obtained by analyzing the change trend of the three pressure change curves together, so that the accuracy of the water injection oil extraction method is improved.
According to a fifth embodiment of the method for water injection and oil recovery between multiple well seams of a low-permeability tight oil reservoir horizontal well provided by the fourth embodiment of the method for water injection and oil recovery between multiple well seams of a low-permeability tight oil reservoir horizontal well, in the embodiment of the present invention, the determining a target fracture network according to a variation trend of the pressure variation curve along with water injection time includes:
and comparing the natural fracture pressure change curve, the matrix pressure change curve and the fracturing fracture pressure change curve to obtain the target fracture network with large pressure difference and consistent pressure change trend. In this embodiment, the change trend of the three pressure change curves along with the water injection time is specifically determined, and the inflection point with the consistent pressure change trend is used as the final water injection time of the target fracture network and water injection is stopped.
According to a fifth embodiment of the method for water injection and oil extraction between multiple well seams of a low-permeability and dense oil reservoir horizontal well provided by the present invention, in an embodiment of the present invention, the comparing the natural fracture pressure change curve, the matrix pressure change curve and the fracturing fracture pressure change curve to obtain the target fracture network with large pressure difference and consistent pressure change trend includes:
acquiring a first inflection point A for slowing down the increase of matrix pressure in the matrix pressure change curve after water injection begins;
acquiring a second inflection point B of the matrix pressure drop after the first inflection point;
acquiring a third inflection point C of which the matrix pressure slowly increases after the second inflection point B;
and determining the target fracture network according to the third inflection point C.
In this embodiment, the corresponding initial water injection period, middle water injection period and later water injection period are determined according to the first inflection point, the second inflection point and the third inflection point, and after the third inflection point is confirmed, the final inflection point F with large pressure difference and consistent pressure change trend of the three pressure change curves is obtained by scanning to determine the target fracture network. As shown in fig. 7, after the first inflection point a appears in the matrix pressure change curve after 30 days of water injection, the pressure increase is slowed down, the filler of the natural cracks is flushed in the initial stage of water injection, a small amount of natural cracks are expanded, and the matrix pressure is reduced; after 50 days of water injection, a second inflection point B appears on the matrix pressure curve, after that, the matrix pressure is not obviously increased any more, the natural cracks which are originally closed are also excited and expanded, the natural cracks with the filler are washed away, the water absorption space is increased, and the matrix pressure is reduced; after 70 days of water injection, the inflection point C appears on the matrix pressure curve again, the final inflection point F appears on the natural fracture pressure curve, and the natural fracture pressure is consistent with the change trend of the matrix pressure after that; after water injection is continued for 90 days, the difference among the natural fracture pressure, the matrix pressure and the fracturing fracture pressure is larger, but the change trend is consistent, so that the natural fracture extends and communicates with the fracturing fracture, and a high-diversion target fracture network is formed.
According to a seventh embodiment of the method for water injection and oil recovery between multiple well fractures of a low-permeability tight oil reservoir horizontal well provided by the present invention, in the embodiment of the present invention, expanding natural fractures and communicating fracturing fractures to form a target fracture network includes:
and determining a target fracture network in which the permeability of the natural fracture and the permeability of the fracturing fracture tend to be stable by combining the third inflection point. In the embodiment, the final target fracture network is determined by combining the permeability change trend with the third inflection point, so that the identification accuracy of the target fracture network can be further improved. Specifically, the target fracture network, in which the permeability of the natural fracture and the permeability of the fracturing fracture tend to be stable, can be determined after the water injection time corresponding to the third inflection point.
According to a third embodiment of the low-permeability tight reservoir horizontal well multi-well inter-well fracture water injection oil recovery method provided by the present invention, an eighth embodiment of the low-permeability tight reservoir horizontal well multi-well inter-well fracture water injection oil recovery method is provided, and in the embodiment of the present invention, the determining a development fracture zone on the target horizontal well includes:
and determining a high-conductivity dynamic fracture channel according to the fracture propagation permeability simulation diagram, and determining the development fracture zone according to the high-conductivity dynamic fracture channel. In the embodiment, the high-diversion dynamic fracture channel with larger permeability can be determined according to the water injection time, and the high-diversion dynamic fracture channel is used as a development fracture zone, so that the development fracture zone can be accurately identified.
According to a ninth embodiment of the method for water injection and oil recovery between multiple well seams of a low permeability and tight reservoir horizontal well provided by the present invention, in the embodiment of the present invention, the determining the development fracture zone according to the dynamic fracture channel with high diversion includes:
and determining the development fracture zone by combining the high-conductivity dynamic fracture channel and the pressure change curve. In the embodiment, the high-permeability cracks in the target fracture network are used as high-conductivity dynamic crack channels, and the development crack bands with large pressure difference are obtained according to the change trend of the pressure change curve along with the water injection time, so that the accuracy of identification of the development crack bands can be improved. In another embodiment, the natural fracture development zone is determined by performing a core electron microscopy scanning experiment; or the permeability and pressure parameters are obtained through on-site well test and engineering well logging methods, and the stratum with higher permeability and pressure is determined to be a crack development zone.
The invention also provides a multi-well inter-fracture water injection oil extraction system of the low-permeability tight oil reservoir horizontal well, which comprises the following components:
the data simulation module is used for injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
the data analysis module is used for judging whether a fracturing crack distribution mode in the target fracture network is a zip-type crack or not, if the fracturing crack distribution mode is the zip-type crack, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining the fracturing cracks which are adjacent to two sides of the development fracture zone and enclose into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon.
In the embodiment, the water injection throughput is converted into multi-well inter-seam pseudo-seven-point method area water injection, invalid water injection can be avoided, the swept area is increased, the oil displacement efficiency is improved, the yield of an oil production section is increased, a target fracture network formed by natural fracture expansion is used as a seepage channel in the initial stage of water injection, the displacement effect is fully exerted, along with the progress of the injected water, under the dual effects of water injection pressure and capillary pressure, the injected water uniformly flows to a matrix through the pseudo-seven-point method well pattern and replaces crude oil, and the radial displacement and the imbibition effect simultaneously occur in the process. The target fracture network high diversion channel and the uniform displacement of the multi-well inter-fracture area water injection method are utilized to improve the multi-well inter-fracture quasi-anti-seven-point area water injection efficiency and the residual oil utilization degree, and technical support is provided for the establishment of subsequent inter-segment encryption and adjustment schemes and three-dimensional well pattern design schemes. The multi-well fracture-like anti-seven-point method area water injection is realized, the influence of fracture interference can be eliminated, linear water injection and radial displacement are fully exerted, the water injection sweep range is enlarged, the effective well is increased, the oil displacement efficiency and the single well yield are improved, and important technical guidance is provided for the development scheme and measures of low permeability, ultra-low permeability and dense oil reservoir area water injection.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (7)
1. The method for oil extraction by water injection between multiple well seams of a low-permeability tight oil reservoir horizontal well is characterized by comprising the following steps:
injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
judging whether a fracturing crack distribution mode in the target fracture network is a zipper type crack or not;
if the fracture is a zip-type fracture, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining a fracturing fracture which is adjacent to two sides of the development fracture zone and surrounds the development fracture zone into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon;
the expanding the natural fracture and communicating the fracturing fracture to form a target fracture network comprises the following steps:
establishing a well group geological model, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method according to the well group geological model and based on model size parameters, reservoir parameters, fluid parameters and well parameters and combining dynamic data and well test data of the target horizontal well, and fitting a production history to obtain a crack propagation permeability simulation map;
according to the permeability of the natural cracks and the change trend of the permeability of the fracturing cracks along with the water injection time in the crack propagation permeability simulation graph, acquiring the target fracture network with the permeability of the natural cracks and the permeability of the fracturing cracks tending to be stable;
the expanding the natural fracture and communicating the fracturing fracture to form a target fracture network comprises the following steps:
according to the well group geological model, combining dynamic monitoring data, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method, fitting a production history, and obtaining a pressure change curve of the target horizontal well;
determining the target fracture network according to the change trend of the pressure change curve along with water injection time;
the determining a developing fracture zone on the target horizontal well comprises:
and determining a high-conductivity dynamic fracture channel according to the fracture propagation permeability simulation diagram, and determining the development fracture zone according to the high-conductivity dynamic fracture channel.
2. The method of low permeability, tight reservoir horizontal well multi-well inter-well water injection and oil recovery according to claim 1, wherein the pressure profile comprises: matrix pressure profile, natural fracture pressure profile, and fracture pressure profile.
3. The method for multi-well inter-fracture water injection and oil recovery of a low permeability tight reservoir horizontal well according to claim 2, wherein determining the target fracture network according to the trend of the pressure change curve with water injection time comprises:
and comparing the natural fracture pressure change curve, the matrix pressure change curve and the fracturing fracture pressure change curve to obtain the target fracture network with large pressure difference and consistent pressure change trend.
4. The method of producing multi-well inter-fracture water injection for horizontal wells of low permeability and tight reservoirs according to claim 3, wherein said comparing the natural fracture pressure profile, the matrix pressure profile and the fracture pressure profile to obtain the target fracture network with large pressure difference and consistent pressure variation trend comprises:
acquiring a first inflection point for slowing down the increase of matrix pressure in the matrix pressure change curve after water injection begins;
acquiring a second inflection point of the pressure drop of the matrix after the first inflection point;
acquiring a third inflection point of slow increase of matrix pressure after the second inflection point;
and determining the target fracture network according to the third inflection point.
5. The method of multi-well inter-fracture water injection and oil recovery for a low permeability tight reservoir horizontal well of claim 4, wherein expanding natural fractures and communicating fracturing fractures to form a target fracture network comprises:
and determining a target fracture network in which the permeability of the natural fracture and the permeability of the fracturing fracture tend to be stable by combining the third inflection point.
6. The method of multi-well inter-fracture water injection and oil recovery for a low permeability tight reservoir horizontal well of claim 1, wherein said determining the developing fracture zone from the high conductivity dynamic fracture channels comprises:
and determining the development fracture zone by combining the high-conductivity dynamic fracture channel and the pressure change curve.
7. A low permeability tight reservoir horizontal well multi-well inter-well joint water injection oil recovery system, comprising:
the data simulation module is used for injecting water into the target horizontal well, expanding natural cracks and communicating the fracturing cracks to form a target crack network;
the data analysis module is used for judging whether a fracturing crack distribution mode in the target fracture network is a zip-type crack, if so, determining a development fracture zone on the target horizontal well, determining the development fracture zone as a central water injection section, determining fracturing cracks which are adjacent to two sides of the development fracture zone and enclose into a regular oil extraction hexagon as an oil extraction section, and taking the central water injection section as a diagonal central line of the regular oil extraction hexagon;
wherein expanding the natural fracture and communicating the fracture to form a target fracture network comprises:
establishing a well group geological model, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method according to the well group geological model and based on model size parameters, reservoir parameters, fluid parameters and well parameters and combining dynamic data and well test data of the target horizontal well, and fitting a production history to obtain a crack propagation permeability simulation map;
according to the permeability of the natural cracks and the change trend of the permeability of the fracturing cracks along with the water injection time in the crack propagation permeability simulation graph, acquiring the target fracture network with the permeability of the natural cracks and the permeability of the fracturing cracks tending to be stable;
the expanding the natural fracture and communicating the fracturing fracture to form a target fracture network comprises the following steps:
according to the well group geological model, combining dynamic monitoring data, carrying out numerical simulation on a target horizontal well by utilizing an oil reservoir method, fitting a production history, and obtaining a pressure change curve of the target horizontal well;
determining the target fracture network according to the change trend of the pressure change curve along with water injection time;
the determining a developing fracture zone on the target horizontal well comprises:
and determining a high-conductivity dynamic fracture channel according to the fracture propagation permeability simulation diagram, and determining the development fracture zone according to the high-conductivity dynamic fracture channel.
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