CN112360424B - Cross-layer fracturing method, device, equipment and readable storage medium - Google Patents
Cross-layer fracturing method, device, equipment and readable storage medium Download PDFInfo
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- CN112360424B CN112360424B CN202011056587.XA CN202011056587A CN112360424B CN 112360424 B CN112360424 B CN 112360424B CN 202011056587 A CN202011056587 A CN 202011056587A CN 112360424 B CN112360424 B CN 112360424B
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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
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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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
Abstract
The embodiment of the application provides a cross-layer fracturing method, a cross-layer fracturing device, equipment and a readable storage medium, and relates to the technical field of oil exploitation. The specific implementation scheme is as follows: after the stratum and the horizontal well section for implementing the cross-layer fracturing are selected, firstly pumping fracturing fluid into a shaft at constant discharge capacity, when the pressure of the shaft is increased to a low value, closing a valve at the well mouth, gradually reducing the pressure in the shaft due to the filtration loss of the fracturing fluid, after the pumping pressure at the valve at the well mouth is sharply increased to a peak value far beyond the conventional fracture pressure, opening the valve at the well mouth, rapidly reducing the pumping pressure, rapidly increasing the pressure of the shaft to form pressure impact, namely a 'water hammer impact effect', and breaking the limitation of a interlayer of a layered stratum to the extension of a hydraulic fracture through the pressure impact far beyond the conventional fracture pressure of rock, so that the hydraulic fracture penetrates through the bedding and the interlayer, the purpose of hydraulic fracture cross-layer extension is achieved, and the modification volume of the reservoir is increased.
Description
Technical Field
The application relates to the technical field of oil exploitation, in particular to a through-stratum fracturing method, a through-stratum fracturing device, a through-stratum fracturing equipment and a readable storage medium.
Background
With the continuous development of drilling technology and downhole tools, the technology of through-the-formation fracturing has become the main technology for developing oil and gas fields.
At present, a common cross-layer fracturing technology is a hydraulic fracturing method. The method injects high-discharge and high-viscosity fracturing fluid into a stratum through a shaft to generate high pressure at the bottom of the shaft, so that the original ground stress and the fracture toughness of the rock are overcome, and the rock is cracked to generate cracks and gradually extends to a stratum area far away from the shaft.
However, the interlayer stratum is usually mudstone and has the characteristics of high stress, strong plasticity, high fracture pressure, large characteristic difference between sand and mudstone layers and the like. If the conventional hydraulic fracturing method is adopted, when the interlayer is encountered in the fracturing process, the fracturing fluid is easy to be filtered along the bedding surface, hydraulic cracks expand along the bedding surface, the interlayer cannot be pressed open or cracks with effective width cannot be formed, the condition that the fluid passes through the interlayer and sand does not pass through the interlayer is caused, sand blockage is easy to cause at the seam opening, and the construction failure is caused.
Disclosure of Invention
The embodiment of the application provides a cross-layer fracturing method, a device, equipment and a readable storage medium, which can carry out cross-layer fracturing through a water hammer impact effect and ensure effectiveness and success rate of cross-layer fracturing construction.
In a first aspect, a through-layer fracturing design method provided in an embodiment of the present application includes:
determining a well site and a target oil interval of the cross-layer fracturing;
performing directional perforation of the wellbore and the target oil interval at the well site;
injecting a pre-fracturing fluid into the shaft pump after the directional perforation;
closing a wellhead valve when the pressure of the wellbore rises to a first threshold value, the first threshold value being less than a reservoir fracture pressure of a reservoir, the wellbore having the wellhead valve disposed therein;
opening the wellhead valve to increase the pressure of the wellbore when the pumping pressure at the wellhead valve rises to a second threshold value, the second threshold value being greater than a conventional fracturing pressure, the pumping pressure being indicative of the pressure generated by the pre-fracturing fluid, the conventional fracturing pressure being the pressure generated by the hydraulic fracturing method and also being indicative of the barrier fracturing pressure;
the increased pressure is used to fracture the barrier, which is the barrier between the well site and the oil interval of interest that needs to be fractured, to form the hydraulic fracture.
In one possible implementation, the performing directional perforations on the wellbore and the target oil interval includes:
determining a first number and a second number according to the position relation of the interlayer between the well position and the target oil interval, wherein the first number is the number of the perforations for the directional perforation above the shaft, and the second number is the number of the perforations for the directional perforation below the shaft;
and orienting perforations above the shaft according to the first number and orienting perforations below the shaft according to the second number.
In one possible implementation, the first number is greater than the second number when the barrier is above the wellbore; alternatively, the first number is less than the second number when the barrier is below the wellbore; alternatively, when there are two of the compartments, the first number is equal to the second number when the wellbore is between the compartments.
In one possible implementation, before closing a wellhead valve when the pressure of the wellbore rises to a first threshold, the method further includes:
determining reservoir fracture pressure from petromechanical properties including at least one of the following petromechanical properties: rock tensile strength, rock friction coefficient, rock shear strength, and reservoir pressure;
the reservoir includes an oil interval of interest.
In one possible implementation, before closing a wellhead valve when the pressure of the wellbore rises to a first threshold, the method further includes: determining the rock mechanical property from well log data, the well log data comprising at least one of: time difference of longitudinal and transverse waves, rock density and natural gamma well logging information.
One possible implementation manner, after fracturing the target oil interval and the isolation layer after the directional perforation by using the increased pressure to form the hydraulic fracture, the method further comprises the following steps:
injecting the pad fracturing fluid into the wellbore such that the pad fracturing fluid extends the hydraulic fracture;
injecting a sand-carrying fluid and a displacement fluid into the extended hydraulic fracture, wherein the sand-carrying fluid is used for conveying a proppant to the hydraulic fracture.
In one possible implementation manner, the pre-fracturing fluid comprises any one of slickwater and jelly; the proppant comprises at least one of ceramsite and quartz sand.
In one possible implementation, the determining the fractured wellbore and the target oil interval comprises:
and determining the wellbore and the target oil interval according to the development characteristics and the physical characteristics of the interlayer and the development characteristics and the physical characteristics of the target oil interval.
In a second aspect, an embodiment of the present application provides a through-layer fracturing device, including:
the first determination module is used for determining the well position of the through-layer fracturing and the target oil interval;
the perforation module is used for carrying out directional perforation on a shaft of the well site and the target oil interval;
the pump injection module is used for pumping and injecting the pre-fracturing fluid into the shaft after the directional perforation;
a closing module, configured to close a wellhead valve when a pressure of the wellbore rises to a first threshold value, where the first threshold value is less than a reservoir fracture pressure of a reservoir, the wellbore being provided with the wellhead valve, and the reservoir including the oil interval of interest;
an opening module for opening the wellhead valve to increase the pressure of the wellbore when the pumping pressure at the wellhead valve rises to a second threshold, the second threshold being greater than the barrier rupture pressure;
and the fracturing module is used for fracturing the interlayer by utilizing the increased pressure to form the hydraulic fracture, and the interlayer is the interlayer which needs to be broken between the well site and the target oil interval.
In a possible implementation manner, the perforation module is configured to determine a first number and a second number according to a position relationship of a barrier between the well location and a target oil interval, orient and perforate an upper portion of the wellbore according to the first number, orient and perforate a lower portion of the wellbore according to the second number, the first number is a number of perforations for orienting and perforating the upper portion of the wellbore, and the second number is a number of perforations for orienting and perforating the lower portion of the wellbore.
In one possible implementation, the first number is greater than the second number when the barrier is above the wellbore; alternatively, the first number is less than the second number when the barrier is below the wellbore; alternatively, when there are two of the compartments, the first number is equal to the second number when the wellbore is between the compartments.
In a possible implementation manner, the apparatus further includes: a second determination module to determine a reservoir fracture pressure from rock mechanics properties before the closing module closes a wellhead valve when the pressure of the wellbore rises to a first threshold.
In a possible implementation manner, the apparatus further includes:
a third determination module to determine the rock-mechanical property from the well log data prior to the second determination module determining the reservoir fracture pressure from the rock-mechanical property.
In a possible implementation manner, the apparatus further includes:
the expansion module is used for injecting the pre-fracturing fluid into the shaft after the fracturing module utilizes the increased pressure to fracture the target oil interval and the interlayer after the directional perforation so as to form a hydraulic fracture, so that the pre-fracturing fluid expands the hydraulic fracture;
and the propping module is used for injecting a sand-carrying fluid and a displacing fluid into the extended hydraulic fracture, the sand-carrying fluid is used for conveying a propping agent to the hydraulic fracture, the displacing fluid is used for conveying the sand-carrying fluid in the well bore to the hydraulic fracture, and the propping agent is a substance for propping the hydraulic fracture.
In one possible implementation manner, the pre-fracturing fluid comprises any one of slickwater and jelly; the proppant comprises at least one of ceramsite and quartz sand.
In a third aspect, an embodiment of the present application provides an electronic device, including: a processor, memory, and executable instructions; wherein the executable instructions are stored in the memory and configured to be executed by the processor, the executable instructions comprising instructions for performing the method as described above in the first aspect or in various possible implementations of the first aspect.
In a fourth aspect, embodiments of the present application provide a computer-readable storage medium having stored therein computer-executable instructions for implementing the method according to the first aspect or in various possible implementations of the first aspect when executed by a processor.
According to the cross-layer fracturing method, the device, the equipment and the readable storage medium, after the well position and the target oil interval of cross-layer fracturing are determined, directional perforation is conducted on the well position and the target oil interval, and pre-fracturing fluid is injected into a shaft pump after the directional perforation. During pumping, a wellhead valve disposed within the wellbore is closed when the pressure of the wellbore rises to a first threshold value, such that the continued injection of the pre-fracturing fluid creates a percussion pressure at the wellhead valve. When the impact pressure rises to a second threshold value, a wellhead valve is opened, so that the impact pressure is released instantly to form a water hammer impact effect, the interlayer between the well position and the target oil layer end is fractured by using the water hammer impact effect, the hydraulic fracture penetrates through the bedding and the interlayer, the purpose of hydraulic fracture crossing and expanding is achieved, the reservoir transformation volume is increased, and the effectiveness and the success rate of crossing fracturing construction are guaranteed.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
Fig. 1 is a schematic flow chart of a through-layer fracturing method provided in an embodiment of the present application;
fig. 2 is a scene schematic diagram of the application of the cross-fracture method provided by the embodiment of the present application to a horizontal well;
fig. 3 is a schematic view of a scenario in which the cross-zonal fracturing method provided in the embodiment of the present application is applied to a vertical well;
fig. 4 is a schematic structural diagram of a through-layer fracturing device according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of another through-layer fracturing device provided in an embodiment of the present application;
fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
A continental shale oil reservoir is typically a source-reservoir integrated, multi-source commingled oil reservoir. The continental facies shale oil reservoir has all the typical characteristics of thin interbed and shale stratum, such as thin interbed, various lithological variation in the longitudinal direction, strong heterogeneity and the like. The 'composite layer effect' of the continental facies shale oil reservoir on the high inhibition of the hydraulic fracture is more obvious. The existence of the bedding structure leads the shale to have different mechanical properties in all directions, and the change of the lithology in the longitudinal direction leads the hydraulic fracture expansion situation to be complicated.
And aiming at the thin and mutual multilayer stratum, exploiting by adopting a hydraulic fracturing exploitation mode. In traditional hydraulic fracturing exploitation, high-discharge and high-viscosity fracturing fluid is injected into a stratum through a shaft, so that high pressure is generated at the bottom of the shaft, original ground stress and rock fracture toughness are overcome, and the rock is fractured to generate cracks and gradually extend to the stratum area far away from the shaft.
However, the shale bedding has low cementing strength, and the interlayer stratum is usually mudstone, so the interlayer fracture pressure is high due to the characteristics of high stress, strong plasticity, high fracture pressure, large characteristic difference between sand and mudstone layers and the like. If adopt conventional hydraulic fracturing mode, because the cracking pressure of interlayer is higher, can lead to the crack to open the bedding face very easily and extend along the bedding face extension, fracturing fluid leaks along the bedding face easily, hydraulic fracture expands along the bedding, lead to can not press open the interlayer or can not form the crack of effective width, artifical crack height and vertical transformation volume are restricted, difficult formation complicated seam net, and then lead to the fact the condition of too little sand of liquid, cause sand blocking easily at the seam crossing, lead to the construction failure. Therefore, in the prior art, an effective method for solving the cross-layer fracturing does not exist.
Therefore, the application provides a cross-layer fracturing method, a device, equipment and a readable storage medium, cross-layer fracturing is carried out through a water hammer impact effect, and effectiveness and success rate of cross-layer fracturing construction are guaranteed.
Fig. 1 is a schematic flow chart of a through-layer fracturing method provided in an embodiment of the present application, where an execution main body of the method is a through-layer fracturing device, and the through-layer fracturing device is disposed on an electronic device. The method comprises the following steps:
101. and determining the well site of the through-layer fracturing and the target oil interval.
Wherein the well site includes, but is not limited to, horizontal well, vertical well, etc., and the reservoir includes the oil interval of interest.
The cross-layer fracturing device analyzes the development characteristics and physical properties of the storage layer and the interlayer, and selects a well position and a target oil interval for cross-layer fracturing according to the well selection and layer selection standard.
For example, when the difference of the earth stress between the storage layer and the interlayer is less than or equal to 5MPa, the gamma value of the interlayer is less than or equal to 135API, the difference of the gamma value of the storage layer and the interlayer is less than or equal to 60API, the thickness of a single interlayer is less than or equal to 3.5m, the overall thickness of the storage layer and the interlayer is less than or equal to 15m, and the difference of the lateral resistivity in depth is less than 100 omega.m, the cross-layer fracturing device can select a well location and a target oil interval.
102. And performing directional perforation on the wellbore of the well site and the target oil interval.
Illustratively, the through-hole fracturing device orients the perforations in real time according to the position relationship of the barriers between the wellbore and the target oil interval.
103. And pumping the pre-fracturing fluid into the well shaft after the directional perforation.
The wellbore refers to a cylindrical wall or space from a wellhead to a bottom of a horizontal well or a vertical well. The purpose of pumping the pre-fracturing fluid into the well bore after directional perforation is to generate sufficient pressure in the well bore.
Illustratively, the through-layer fracturing device determines an appropriate pumping displacement according to the equipment condition of a pumping vehicle group on an actual construction site, and pumps and injects the pre-fracturing fluid into the well bore after the directional perforation according to the pumping displacement. During pumping of the pre-fracturing fluid, the pumping capacity is constant, for example, 10m at all times3And the pre-fracturing fluid is pumped into the shaft by the aid of the pump injection displacement of/min.
104. Closing a wellhead valve when the pressure of the wellbore rises to a first threshold value, the first threshold value being less than a reservoir fracture pressure of a reservoir, the wellbore having the wellhead valve disposed therein.
In the process of injecting the front fracturing fluid into the shaft pump, the through-stratum fracturing device detects the pressure of the shaft and compares the pressure of the shaft with a first threshold value stored in advance. And when the pressure of the well bore is less than a first threshold value, continuing to pump the pre-fracturing fluid into the well bore. The zonal fracturing apparatus closes a wellhead valve disposed within the wellbore when the pressure of the wellbore rises to a first threshold. Wherein the first threshold value is a value less than the reservoir fracture pressure, and the through-bed fracturing device prestores the first threshold value.
In this step, the closing of the wellhead valve when the pressure in the wellbore rises to the first threshold is to establish the wellbore pressure, fill the wellbore with the pre-fracturing fluid, and control the wellbore pressure below the reservoir fracture pressure to prevent the hydraulic fracture from opening the bedding, which is between the faces of the reservoir and the barrier. The first threshold value is, for example, 10 MPa.
105. Opening the wellhead valve to cause the pressure of the wellbore to increase when the pumping pressure at the wellhead valve rises to a second threshold value, the second threshold value being greater than the barrier rupture pressure.
After the wellhead valve is closed in the step 104, the through-stratum fracturing device controls the pre-fracturing fluid pumping equipment to continue pumping the pre-fracturing fluid into the well shaft after the directional perforation, and the pre-fracturing fluid flows through the pumping pipeline and is accumulated at the wellhead valve, so that the pumping pressure at the wellhead valve is continuously increased.
And the cross-layer fracturing device detects the pumping pressure at the wellhead valve and compares the pumping pressure at the wellhead valve with a second threshold value stored in advance. And when the pumping pressure at the wellhead valve is smaller than a second threshold value, continuously pumping the front fracturing fluid into the shaft after the directional perforation. When the pumping pressure at the wellhead valve rises to a second threshold, the cross-zonal fracturing apparatus opens a wellhead valve disposed within the wellbore. Wherein the second threshold is a value greater than the barrier burst pressure, and the through-bed fracturing device prestores the second threshold.
106. The increased pressure is used to fracture the barrier, which is the barrier between the well site and the oil interval of interest that needs to be fractured, to form the hydraulic fracture.
Illustratively, when the pumping pressure at the wellhead valve rises to a second threshold, a surge pressure is created at the wellhead valve that is much higher than the pressure of a conventional hydraulic fracturing pressure. At the moment, after the cross-layer fracturing device opens a well mouth valve arranged in a shaft, the impact pressure is released instantly to form a water hammer impact effect, so that an interlayer between a well position and a target oil interval is penetrated, and cross-layer fracturing is realized.
According to the cross-layer fracturing method provided by the embodiment of the application, after the well position and the target oil interval of cross-layer fracturing are determined, directional perforation is carried out on the well position and the target oil interval, and pre-fracturing fluid is injected into a shaft pump after the directional perforation. During pumping, a wellhead valve disposed within the wellbore is closed when the pressure of the wellbore rises to a first threshold value, such that the continued injection of the pre-fracturing fluid creates a percussion pressure at the wellhead valve. When the impact pressure rises to a second threshold value, a wellhead valve is opened, so that the impact pressure is released instantly to form a water hammer impact effect, the interlayer between the well position and the target oil layer end is fractured by using the water hammer impact effect, the hydraulic fracture penetrates through the bedding and the interlayer, the purpose of hydraulic fracture crossing and expanding is achieved, the reservoir transformation volume is increased, and the effectiveness and the success rate of crossing fracturing construction are guaranteed.
In the above embodiments, the cross-zonal fracturing method provided by the embodiment of the present application may be applied to any oil reservoir to be exploited. In addition, when the rupture pressure of the interlayer is small, the mining requirement can be met by adopting a conventional hydraulic fracturing method or a cross-layer fracturing method. Therefore, the embodiment of the application can be used in a scene without limitation on the rupture pressure of the interlayer. At this time, before the through-stratum fracturing device executes the embodiment of the application, the distribution of the reservoir and the interlayer, the rock mechanical property difference and the like are determined according to the logging data. And then, judging whether the conventional hydraulic fracturing method can penetrate the interlayer according to the distribution of the reservoir and the interlayer, the mechanical property difference of rocks and the like. If the conventional hydraulic fracturing method can penetrate through the interlayer, the conventional hydraulic fracturing method can be adopted, and a cross-layer fracturing method can also be adopted; if the conventional hydraulic fracturing method cannot penetrate the barrier, the cross-fracture method described in the examples of the present application is used.
In the above embodiment, when the through-layer fracturing device performs directional perforation on the wellbore and the target oil interval, first, a first number and a second number are determined according to the position relationship of the separation layer between the well location and the target oil interval, where the first number is the number of perforations for the directional perforation above the wellbore, and the second number is the number of perforations for the directional perforation below the wellbore. Then, perforating the upper portion of the wellbore directionally according to the first number, and perforating the lower portion of the wellbore directionally according to the second number.
For example, directional perforation refers to perforation at the place where hydraulic fractures need to be generated, so that the probability of generating hydraulic fractures is higher by utilizing the front fracturing hydraulic fracture isolation layer. And the perforating fracturing device conducts directional perforation on the upper part and the lower part of the shaft according to the position relation of the interlayer between the well position and the target oil interval.
By adopting the scheme, the well bore and the target oil interval are subjected to directional perforation, so that ideal hydraulic fractures are generated conveniently.
In the above embodiment, the first number is greater than the second number when the barrier is above the wellbore; alternatively, the first number is less than the second number when the barrier is below the wellbore; alternatively, when there are two of the compartments, the first number is equal to the second number when the wellbore is between the compartments.
The directional perforation is used for generating hydraulic fractures in places where the hydraulic fractures need to be generated, so that the interlayer can be conveniently fractured by the aid of the front fracturing hydraulic pressure later, the hydraulic fractures can be generated with higher probability, when the interlayer is located above the shaft, the number of the directional perforations above the shaft is increased, the interlayer above the shaft can be fractured when the front fracturing fluid is used for performing through-layer fracturing, the reservoir is communicated, and the probability of generating the hydraulic fractures is higher; when the interlayer is positioned below the shaft, the number of directional perforations below the shaft is selected to be increased, and the probability of generating hydraulic fractures is improved, so that the interlayer below the shaft is fractured; similarly, when the number of the interlayers is two, and the shaft is arranged between the interlayers, the directional perforation holes are uniformly distributed up and down, so that the probability of generating hydraulic fractures is improved, and the interlayers above and below the shaft are fractured conveniently.
Therefore, when the through-stratum fracturing device conducts directional perforation on the well site and the target oil interval, the directional perforation is conducted according to the position relation of the isolation layer between the well site and the target oil interval. For example, when the barrier is above the well site, the first number is greater than a preset value, and the second number is, for example, 0, then directional upward perforation is performed; when the barrier is below the well location, the second number is greater than a preset value, the first number is, for example, 0, and then directional downward perforation is performed; when the wellbore has barriers both above and below, the first number equals the second number, at which time directed up and directed down perforations are performed.
By adopting the scheme, the number of the directional perforation is determined according to the position relation of the interlayer between the well position and the target oil interval, and the aim of accurately implementing the directional perforation is fulfilled.
In the above embodiment, the first threshold is a value less than the reservoir fracture pressure. Therefore, to determine the first threshold, the reservoir fracture pressure needs to be determined first. In one approach, the through-layer fracturing device determines reservoir fracture pressure from rock mechanical properties, wherein the rock mechanical properties include at least one of the following rock mechanical properties: rock tensile strength, rock coefficient of friction, rock shear strength, and reservoir pressure. Rock tensile strength is used to indicate the average tensile stress on a cross section perpendicular to the tensile force when a rock specimen fails under tensile stress.
By adopting the scheme, the reservoir fracture pressure is determined according to the rock mechanical properties, and then the first threshold value is determined by utilizing the reservoir fracture pressure, so that the aim of accurately controlling the wellhead valve is fulfilled.
In the above embodiment, the rock mechanical property is determined from log data, and the log data includes at least one of the following log data: time difference of longitudinal and transverse waves, rock density and natural gamma well logging information.
By adopting the scheme, the mechanical property of the rock is determined according to the logging data, and then the aim of accurately controlling the wellhead valve is fulfilled.
In the above embodiment, the second threshold is a pressure value greater than the burst pressure of the barrier. Therefore, to determine the second threshold, the barrier rupture pressure needs to be determined first. In one mode, the through-layer fracturing device determines the barrier fracture pressure according to the rock mechanical property, wherein the relevant description about the rock mechanical property can be referred to the above process for determining the reservoir fracture pressure, and the details are not repeated here. The burst pressure of the interlayer is, for example, 60MPa, the second threshold is, for example, 70MPa, etc., and the embodiments of the present application are not limited thereto.
By adopting the scheme, the interlayer fracture pressure is determined according to the mechanical properties of the rock, and then the first threshold value is determined by utilizing the reservoir fracture pressure, so that the aim of accurately controlling the wellhead valve is fulfilled.
In the above embodiments, the barriers are located between the well site and the interval of interest, the reservoir includes the interval of interest, and this topography comprising the barriers and the reservoir is referred to as a stratigraphic layer.
The layered formation includes the compartments and a reservoir.
In the above embodiment, the through-layer fracturing device fractures the target oil interval and the isolation layer after the directional perforation by using the increased pressure, so as to form a hydraulic fracture, and then injects the pre-fracturing fluid into the wellbore, so that the pre-fracturing fluid extends the hydraulic fracture. And then injecting a sand-carrying fluid and a displacing fluid into the extended hydraulic fracture, wherein the sand-carrying fluid is used for conveying the propping agent to the hydraulic fracture.
Illustratively, after a hydraulic fracture is formed by water hammer impact, the through-stratum fracturing device injects the pre-fracturing fluid into the wellbore, so that the pre-fracturing fluid expands the hydraulic fracture, thereby increasing the reservoir reconstruction volume, and meanwhile, preparing for the entering of a sand-carrying fluid and a displacement fluid. The displacement fluid is a fluid used for conveying the sand-carrying fluid in the well bore to the hydraulic fracture.
By adopting the scheme, the purpose of expanding the hydraulic fracture is realized by continuously injecting the pre-fracturing fluid into the hydraulic fracture, and the purpose of supporting the hydraulic fracture is realized by inputting the sand-carrying fluid and the displacing fluid into the expanded hydraulic fracture. In the above embodiments, the pre-fracturing fluid includes any one of slickwater and jelly.
Illustratively, the fracturing fluid comprises the pre-fracturing fluid, the sand-carrying fluid and the displacing fluid, and the dosage of the fracturing fluid is optimized by design through fracture propagation simulation software.
In the above embodiment, the total pad fluid amount may be 1000m in single-stage fracturing3The total amount of the sand-carrying liquid can be 450m3The total amount of the displacing liquid may be 50m3. The proppant can be ceramsite, quartz sand and the like, and the fracturing fluid can be slick water, jelly and the like, which is not limited by the application.
In the above embodiments, the well location is, for example, a horizontal well or a vertical well, and the embodiments of the present application are not limited. Fig. 2 is a scene schematic diagram of the application of the cross-zonal fracturing method provided by the embodiment of the present application to a horizontal well. Fig. 3 is a schematic view of a scenario in which the cross-zonal fracturing method provided in the embodiment of the present application is applied to a vertical well.
Referring to fig. 2, in a scenario to which the embodiment of the present application is applicable, the positions of the horizontal well and the target oil interval that need to be fractured by crossing the layer may be determined according to the well selection and layer selection criteria according to the analysis of the development characteristics and physical characteristics of the storage layer and the interlayer.
Referring to fig. 3, in a scenario where the embodiments of the present application are applicable, the standards for the vertical well and the target oil interval of the through-layer fracturing are referred to in the standards for the vertical well and the target oil interval.
The following are embodiments of the apparatus of the present application that may be used to perform embodiments of the method of the present application. For details which are not disclosed in the embodiments of the apparatus of the present application, reference is made to the embodiments of the method of the present application.
Fig. 4 is a schematic structural diagram of a through-layer fracturing device according to an embodiment of the present application. The through-bed fracturing apparatus 100 may be implemented in software and/or hardware. As shown in fig. 4, the through-layer fracturing apparatus 100 includes:
the first determination module 11 is used for determining a well site of the cross-layer fracturing and a target oil interval;
a perforation module 12 for performing directional perforation of the wellbore and the interval of interest at the well site;
the pumping module 13 is used for pumping the pre-fracturing fluid into the shaft after the directional perforation;
a closing module 14, configured to close a wellhead valve when the pressure in the wellbore rises to a first threshold value, where the first threshold value is smaller than a reservoir fracture pressure of a reservoir, the wellbore being provided with the wellhead valve, and the reservoir including the oil interval of interest;
an opening module 15 for opening the wellhead valve to increase the pressure of the wellbore when the pumping pressure at the wellhead valve rises to a second threshold, the second threshold being greater than the barrier rupture pressure;
a fracturing module 16 for fracturing the barrier with the increased pressure to form the hydraulic fracture, the barrier being the barrier between the well site and the oil interval of interest that needs to be fractured.
In a possible implementation manner, the perforation module 12 is configured to determine a first number and a second number according to a position relationship of the separation layer between the well location and the target oil interval, orient and perforate the upper part of the wellbore according to the first number, orient and perforate the lower part of the wellbore according to the second number, the first number is the number of perforations for orienting and perforating the upper part of the wellbore, and the second number is the number of perforations for orienting and perforating the lower part of the wellbore.
In one possible implementation, the first number is greater than the second number when the barrier is above the wellbore; alternatively, the first number is less than the second number when the barrier is below the wellbore; alternatively, when there are two of the compartments, the first number is equal to the second number when the wellbore is between the compartments.
Fig. 5 is a schematic structural diagram of another through-layer fracturing device provided in an embodiment of the present application. Referring to fig. 5, the through-layer fracturing device 100 provided in this embodiment further includes, on the basis of fig. 4:
a second determination module 17 for determining a reservoir fracture pressure from rock mechanics properties before the closing module 14 closes the wellhead valve when the pressure of the wellbore rises to a first threshold.
Referring to fig. 5 again, in a possible implementation manner, the above-mentioned through-layer fracturing device 100 further includes:
a third determination module 18 for determining the rock-mechanical property from the well log data before the second determination module 17 determines the reservoir fracture pressure from the rock-mechanical property.
Referring to fig. 5 again, in a possible implementation manner, the above-mentioned through-layer fracturing device 100 further includes:
an expanding module 19, configured to inject the pre-fracturing fluid into the wellbore after the fracturing module 16 fractures the targeted oil interval and the isolation layer after the directional perforation by using the increased pressure to form a hydraulic fracture, so that the pre-fracturing fluid expands the hydraulic fracture;
and the propping module 20 is used for injecting a sand-carrying fluid and a displacing fluid into the extended hydraulic fracture, wherein the sand-carrying fluid is used for conveying a propping agent to the hydraulic fracture, the displacing fluid is used for conveying the sand-carrying fluid in the well bore to the hydraulic fracture, and the propping agent is a substance for propping the hydraulic fracture.
In one possible implementation manner, the pre-fracturing fluid comprises any one of slickwater and jelly; the proppant comprises at least one of ceramsite and quartz sand.
The speech recognition device provided in the embodiment of the present application can execute the actions of the server in the above method embodiments, and the implementation principle and technical effect are similar, which are not described herein again.
Fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application. As shown in fig. 6, the electronic apparatus 200 includes:
a processor 21 and a memory 22;
the memory 22 stores executable instructions;
the at least one processor 21 executes the executable instructions stored by the memory 22 to cause the at least one processor 21 to perform the cross-zone fracturing method as described above.
For a specific implementation process of the processor 21, reference may be made to the above method embodiments, which implement similar principles and technical effects, and this embodiment is not described herein again.
Optionally, the electronic device 200 further comprises a communication component 23. The processor 21, the memory 22, and the communication unit 23 may be connected by a bus 24.
Embodiments of the present application further provide a computer-readable storage medium, in which executable instructions are stored, and when executed by a processor, the executable instructions are used to implement the cross-layer fracturing method as described above.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.
Claims (10)
1. A method of through-layer fracturing, comprising:
determining a well site and a target oil interval of the cross-layer fracturing;
performing directional perforation of the wellbore and the target oil interval at the well site;
injecting a pre-fracturing fluid into the shaft pump after the directional perforation;
closing a wellhead valve when the pressure of the wellbore rises to a first threshold value, the first threshold value being less than a reservoir fracture pressure of the reservoir to prevent hydraulic fractures from opening a bedding, the bedding being at the face of the reservoir and the barrier; the well mouth valve is arranged in the well bore, and the reservoir stratum comprises the target oil interval;
continuing pumping the pre-fracturing fluid into the well bore after the directional perforation, and opening the well head valve when the pumping pressure at the well head valve is increased to a second threshold value so as to increase the pressure of the well bore, wherein the second threshold value is greater than the interlayer rupture pressure;
the increased pressure is used to fracture the barrier, which is the barrier between the well site and the oil interval of interest that needs to be fractured, to form the hydraulic fracture.
2. The method of claim 1, wherein the performing directional perforations of the wellbore and the interval of interest comprises:
determining a first number and a second number according to the position relation of the separation layers between the well position and the target oil interval, wherein the first number is the number of the perforations for the directional perforation above the shaft, and the second number is the number of the perforations for the directional perforation below the shaft;
and orienting perforations above the shaft according to the first number and orienting perforations below the shaft according to the second number.
3. The method of claim 2,
the first number is greater than the second number when the barrier is above the wellbore;
alternatively, the first and second electrodes may be,
the first number is less than the second number when the barrier is below the wellbore;
alternatively, the first and second electrodes may be,
when there are two of the compartments, the first number is equal to the second number when the wellbore is between the compartments.
4. The method of any of claims 1-3, further comprising, prior to closing a wellhead valve when the pressure of the wellbore rises to a first threshold value:
determining reservoir fracture pressure from petromechanical properties including at least one of the following petromechanical properties: rock tensile strength, rock coefficient of friction, rock shear strength, and reservoir pressure.
5. The method of claim 4, wherein prior to determining the reservoir fracture pressure from the petromechanical properties, further comprising:
determining the rock mechanical property from well log data, the well log data comprising at least one of: time difference of longitudinal and transverse waves, rock density and natural gamma well logging information.
6. The method of any of claims 1-3, wherein after fracturing the oil interval and barrier of interest after the directional perforation with the increased pressure to form a hydraulic fracture, further comprising:
injecting the pad fracturing fluid into the wellbore such that the pad fracturing fluid extends the hydraulic fracture;
and injecting a sand-carrying fluid and a displacement fluid into the extended hydraulic fracture, wherein the sand-carrying fluid is used for conveying a propping agent to the hydraulic fracture, the displacement fluid is used for conveying the sand-carrying fluid in the well bore to the hydraulic fracture, and the propping agent is a substance for propping the hydraulic fracture.
7. The method of claim 6,
the pre-fracturing fluid comprises any one of slickwater and jelly;
the proppant comprises at least one of ceramsite and quartz sand.
8. A through-layer fracturing apparatus, comprising:
the first determination module is used for determining the well position of the through-layer fracturing and the target oil interval;
the perforation module is used for carrying out directional perforation on a shaft of the well site and the target oil interval;
the pump injection module is used for pumping and injecting the pre-fracturing fluid into the shaft after the directional perforation;
a shut-off module for closing the wellhead valve when the pressure of the wellbore rises to a first threshold, the first threshold being less than a reservoir fracture pressure of the reservoir to prevent hydraulic fractures from opening a bedding, the bedding being at the face of the reservoir and the barrier; the well mouth valve is arranged in the well bore, and the reservoir stratum comprises the target oil interval;
the opening module is used for opening the wellhead valve when the pumping pressure at the wellhead valve is increased to a second threshold value when the pumping module continues to pump the front fracturing fluid into the well shaft after the directional perforation, so that the pressure of the well shaft is increased, and the second threshold value is larger than the interlayer fracture pressure;
and the fracturing module is used for fracturing the interlayer by utilizing the increased pressure to form the hydraulic fracture, and the interlayer is the interlayer which needs to be broken between the well site and the target oil interval.
9. An electronic device comprising a processor, a memory and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method according to any of the claims 1-7 when executing the program.
10. A readable storage medium having stored therein instructions that, when executed on an electronic device, cause the electronic device to perform the method of any one of claims 1-7.
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