Fracturing method for improving complexity of hydraulic fracture of horizontal well

Abstract

The invention discloses a fracturing method for improving the complexity of a hydraulic fracture of a horizontal well, which comprises the following steps: carrying out geological modeling and fracturing modeling on a target well according to data of the target well to obtain numerical simulation data of the target well; according to the characteristic parameter data of the target well, a physical model experiment is conducted, and a target temporary plugging agent is determined; and according to the numerical simulation data of the target well and the determined target temporary plugging agent, carrying out temporary plugging diversion fracturing treatment on the target well. Data such as geology, three-dimensional earthquakes and rock mechanics of shale oil reservoirs are utilized, temporary plugging bridges are arranged in fractured fractures in combination with a temporary plugging technology, monitoring and real-time adjustment are carried out through a microseism technology, and therefore the artificial fractures are turned, the problem that the complexity of horizontal well fractures is increased is solved, and the purposes of turning the artificial fractures and improving the horizontal well fractures are achieved. And full transformation of the shale oil reservoir is realized.

Description

Technical Field

[0001] The invention belongs to the field of oil production engineering and relates to a fracturing method for improving the complexity of hydraulic fractures in horizontal wells. Background Art

[0002] Unconventional oil and gas reservoirs, especially shale oil and tight oil, have made great progress in development in recent years, achieving rapid growth in oil and gas production. Shale oil reservoirs have poor physical properties, and volume fracturing technology is needed to form main fractures with high conductivity and open and communicate with natural fractures. The key to the effective development of shale reservoirs lies in creating a complex fracture network. Theory and practice show that the more fractures formed by hydraulic fracturing, the more complex the fracture network, and the higher the production capacity. Numerical simulations show that increasing the net pressure in the fracture is conducive to increasing the complexity of the fracture. Indoor simulations show that increasing the net pressure in the fracture is conducive to increasing the complexity of the fracture. At present, there are two conventional ways to increase the net pressure in the fracture: one is to increase the displacement, and the other is high-viscosity fracturing fluid. However, if the maximum and minimum horizontal principal stresses of an unconventional reservoir differ greatly, and the "hardness" of the reservoir itself and the weak layers and interlayers within the reservoir differ little, large-volume, high-pressure hydraulic fracturing will lead to uncontrolled fracture height and pressure channeling to adjacent wells; high-viscosity fracturing fluid is not conducive to creating complex fractures, and the existing slick water fracturing fluid system needs to add a large amount of chemical materials to achieve high viscosity, which is costly and inconvenient to construct. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the prior art and provide a fracturing method for increasing the complexity of hydraulic fractures in horizontal wells, thereby solving the problem of increasing the complexity of fractures in horizontal wells.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells, comprising:

[0006] According to the data of the target well, geological modeling and fracturing modeling are carried out for the target well to obtain numerical simulation data of the target well;

[0007] According to the characteristic parameter data of the target well, physical simulation experiments are carried out to determine the target temporary plugging agent;

[0008] According to the numerical simulation data of the target well and the determined target temporary plugging agent, the target well is subjected to temporary plugging and fracturing transformation.

[0009] Furthermore, the target well data includes reservoir geological data information, three-dimensional seismic data information, formation temperature and fluid data information, well network and well location deployment data information, wellbore structure data information, wellbore trajectory data information, logging data information, geostress data information, rock mechanics data information, adjacent well oil testing information and adjacent water injection well water injection information.

[0010] Furthermore, the geological modeling is to establish a three-dimensional geological model of the reservoir using reservoir modeling software according to the data of the target well, and the three-dimensional geological model includes a structural model, a lithofacies model and an attribute model.

[0011] Furthermore, the fracturing modeling is as follows: using fracturing simulation software according to the data of the target well, establishing a reservoir geostress model and a rock mechanics model, and performing geomechanical stratification to establish a fracturing model.

[0012] Furthermore, the characteristic parameter data of the target well includes formation temperature data, pressure data and fluid characteristic data.

[0013] Furthermore, the physical model experiment process is as follows:

[0014] According to the characteristic parameter data of the target well, indoor dissolution experiments are carried out on a variety of temporary plugging agents to determine at least one target temporary plugging agent;

[0015] The determined target temporary plugging agent is used to carry out a bridge-type crack plugging experiment to determine the particle size combination and plugging strength of the target temporary plugging agent.

[0016] Furthermore, the compressive strength of the target temporary plugging agent is greater than 60 MPa.

[0017] Furthermore, the temporary plugging and diverting fracturing treatment process is as follows:

[0018] Determine the fracturing plan based on the fracturing numerical simulation data corresponding to the target well;

[0019] According to the fracturing plan, the determined target temporary plugging agent is used to monitor the target well and the target adjacent wells with a microseismic monitoring instrument to obtain fracture extension data;

[0020] Adjust the fracturing plan data based on the fracture extension data.

[0021] Furthermore, the fracturing scheme data includes the number of temporary plugging times in the fracture, the timing of temporary plugging and the initial dosage of the target temporary plugging agent;

[0022] The initial dosage of the target temporary plugging agent is:

[0023] M=aρhLW

[0024] Wherein, M represents the initial dosage of the target temporary plugging agent, a represents the loss coefficient, ρ represents the density, h represents the height of the hydraulic fracture, L represents the thickness of the temporary plugging layer, and W represents the width of the hydraulic fracture.

[0025] Furthermore, the method for adjusting the fracturing scheme data is as follows:

[0026] When it is determined according to the fracture extension data that the fracture continues to extend longitudinally, the target temporary plugging agent is continuously added until the fracture no longer extends longitudinally;

[0027] When it is determined based on the crack extension data that the crack continues to extend, continue to add the target temporary plugging agent until the crack turns.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a fracturing method for increasing the complexity of hydraulic fractures in horizontal wells. According to the data of the target well, geological modeling and fracturing modeling are performed on the target well to obtain numerical simulation data corresponding to the target well; according to the characteristic parameter data of the target well, physical simulation experiments are performed on multiple temporary plugging agents to determine at least one target temporary plugging agent; according to the numerical simulation data corresponding to the target well and the determined target temporary plugging agent, temporary plugging and fracturing treatment is performed. The present invention utilizes the geological, three-dimensional seismic, rock mechanics and other data of the shale oil reservoir, and sets a temporary plugging bridge in the fracturing fracture in combination with the temporary plugging process, and uses microseismic technology for monitoring and real-time adjustment, so as to redirect the artificial fracture, thereby solving the problem of increasing the complexity of the horizontal well fracture, achieving the redirection of the artificial fracture, and achieving the full transformation of the shale oil reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 The present invention is a schematic flow chart of a fracturing method for increasing the complexity of hydraulic fractures in horizontal wells.

[0032] Figure 2 This is a schematic diagram of a microseismic event in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0037] See also Figure 1 The present invention provides a fracturing method for improving the complexity of hydraulic fractures in horizontal wells, comprising the following steps:

[0038] According to the data of the target well, geological modeling and fracturing modeling are carried out on the target well to obtain the numerical simulation data corresponding to the target well.

[0039] The data of the target wells include: reservoir geological data information, three-dimensional seismic data information, formation temperature and fluid data information, well network and well location deployment data information, wellbore structure data information, wellbore trajectory data information, logging data information, geostress data information, rock mechanics data information, adjacent well test oil information, and adjacent water injection well water injection information.

[0040] Among them, the target well data required for geological modeling and fracturing modeling include: reservoir geological data information, three-dimensional seismic data information, well network and well location deployment data information, wellbore structure data information, wellbore trajectory data information, logging data information, ground stress data information, rock mechanics data information, adjacent well oil testing information, and adjacent water injection well water injection information. Modeling through a variety of information can make the obtained numerical simulation data closer to the actual situation of the target well, that is, to obtain better modeling effect.

[0041] The oil testing conditions of neighboring wells refer to the vertical wells, highly deviated wells and horizontal wells within 1.5 km of the target well. The conditions of neighboring water injection wells refer to the water injection conditions of the target layer and the upper and lower layers within 1.5 km around the target well. Among them, selecting wells within 1.5 km around the target well as neighboring wells can make the data more accurately reflect the relevant conditions of the target well and make the modeling effect better.

[0042] Numerical simulation data is used to characterize the length of hydraulic fractures and the net pressure required for fracture diversion and new fracture opening. According to the data of the target well, geological modeling and fracturing modeling are carried out for the target well. According to the data of the target well, reservoir modeling software is used to establish a three-dimensional geological model of the reservoir. The three-dimensional geological model includes a structural model, a lithofacies model and an attribute model. On the basis of the three-dimensional geological model, the reservoir geostress model and rock mechanics model are established using fracturing simulation software according to the data of the target well, and the fracturing model is established by geomechanical stratification. According to the established model, numerical simulation of the initiation, extension and expansion of fractures in each perforation cluster under different temporary plugging conditions is carried out.

[0043] According to the characteristic parameter data of the target well, physical simulation experiments are carried out on a variety of temporary plugging agents to determine at least one target temporary plugging agent.

[0044] According to the characteristic parameter data of the target well, indoor dissolution experiments are conducted on multiple temporary plugging agents to determine the dissolution time of multiple temporary plugging agents, determine at least one target temporary plugging agent, and then use the target temporary plugging agent to conduct bridge plugging fracture plugging experiments to determine the particle size combination and plugging strength of the selected target temporary plugging agent. Through multiple physical modeling experiments, according to the characteristic parameter data of the target well, the most suitable target temporary plugging agent and the corresponding particle size combination and plugging strength can be selected.

[0045] Among them, the target temporary plugging agent with a compressive strength greater than 60MPa is selected, which can have a certain compressive strength during the temporary plugging process and a better temporary plugging effect. The temporary plugging agent needs to have good solubility, high temperature resistance, and no damage to the formation.

[0046] According to the numerical simulation data corresponding to the target well, the fracturing scheme data is determined, wherein the fracturing scheme data is used to characterize the number of temporary plugging in the fracture, the temporary plugging timing and the initial dosage of the target temporary plugging agent. According to the fracturing scheme data, the target well is subjected to temporary plugging and fracturing treatment using the determined target temporary plugging agent.

[0047] It is necessary to determine the number of temporary plugging times and the timing of temporary plugging in the fracture based on the numerical simulation data, and use the determined target temporary plugging agent to perform temporary plugging and fracturing treatment according to the calculated initial dosage; the appropriate amount of temporary plugging agent is added at the appropriate temporary plugging time to achieve a better temporary plugging effect while saving dosage.

[0048] The formula for determining the initial dosage of the target temporary plugging agent is:

[0049] M=aρhLW

[0050] Wherein, M represents the initial dosage of the target temporary plugging agent, kg; represents the loss coefficient, which is between 1.5 and 2.5 for Qingcheng shale oil horizontal wells, and is usually 2.2; ρ represents the density, g / cm 3 ; h represents the height of the hydraulic fracture, m; L represents the thickness of the temporary plugging layer, m; W represents the width of the hydraulic fracture, m.

[0051] Microseismic monitoring instruments are used in the target well's adjacent wells to obtain fracture extension data, where fracture extension data is used to characterize fracture extension in the target well during temporary plugging and fracturing treatment. Fracturing plan data is adjusted based on fracture extension data.

[0052] During fracturing construction, micro-seismic monitoring instruments are placed in adjacent wells to observe the crack extension process and adjust the temporary plugging plan in real time.

[0053] The target adjacent well of the target well where the microseismic monitoring instrument is installed is a horizontal well located in the same layer and direction as the target well, and the linear distance between the target adjacent well and the fracturing section of the target well is no more than 700m. Selecting such an adjacent well can make the data of the microseismic monitoring instrument more accurate, and the adjusted temporary plugging plan is more suitable for the target well.

[0054] Adjusting the fracturing scheme data according to the fracture extension data includes at least one of the following steps: when it is determined according to the fracture extension data that the fracture continues to extend longitudinally, continuing to add the target temporary plugging agent until the fracture no longer extends longitudinally; when it is determined according to the fracture extension data that the fracture continues to extend longitudinally, continuing to add the target temporary plugging agent until the fracture turns.

[0055] Whether to continue pumping plugging agent is determined based on the fracture extension data obtained by the microseismic monitoring instrument. If the fracture continues to extend longitudinally, the target temporary plugging agent is continuously injected until the fracture no longer extends longitudinally. If the fracture continues to extend along the old fracture, the temporary plugging agent is continuously injected until the fracture turns. By using microseismic technology for monitoring and real-time adjustment, artificial fracture turning can be achieved.

[0056] As can be seen from the above, according to the data of the target well, the target well is geologically modeled and fracturing modeled to obtain the numerical simulation data corresponding to the target well; according to the characteristic parameter data of the target well, a variety of temporary plugging agents are subjected to physical modeling experiments to determine at least one target temporary plugging agent; according to the numerical simulation data corresponding to the target well and the determined target temporary plugging agent, the target well is subjected to temporary plugging and fracturing treatment. The present invention utilizes the geological, three-dimensional seismic, rock mechanics and other data of the shale oil reservoir, and combines the temporary plugging process to set a temporary plugging bridge in the fracturing crack, and uses microseismic real-time monitoring technology to monitor and make real-time adjustments, thereby redirecting the artificial fractures and achieving full transformation of the shale oil reservoir.

[0057] Embodiment 1:

[0058] The fracturing method for increasing the complexity of hydraulic fractures in horizontal wells provided in this embodiment includes the following specific steps:

[0059] S1: The target well data are as follows: the vertical depth of the reservoir is 1694.1-1707.8m, the horizontal section length is 2947m, the oil layer drilling rate is 90.4%, the original formation pressure is 14.7MPa, the angle between the horizontal section and the maximum principal stress direction is 6°, the distance from the adjacent well is 180-670m, and the ground stress data and rock mechanics data can be interpreted based on the logging data. According to the reservoir data of the target well, the geological model and fracturing model are established for simulation analysis:

[0060] (1) Using reservoir modeling software based on the data of the target well, a three-dimensional geological model of the reservoir is established. The three-dimensional geological model includes a structural model, a lithofacies model, and an attribute model;

[0061] (2) Based on the three-dimensional geological model, the reservoir geostress model and rock mechanics model are established using fracturing simulation software according to the data of the target well, and the fracturing model is established by geomechanical stratification;

[0062] (3) Inputting the location of each cluster, type of fracturing fluid, type of proppant and pumping program into the established fracturing model, wherein the pumping program includes temporary plugging design (temporary plugging amount, temporary plugging timing and temporary plugging stage);

[0063] According to the crack expansion morphology, perforation scheme design and temporary plugging scheme preliminary design, determine the initial number of temporary plugging balls, the initial amount of temporary plugging agent, the priority of temporary plugging balls and temporary plugging agent placement, and the number of temporary plugging designs. According to the uniformity of crack expansion, continuously adjust the temporary plugging scheme.

[0064] S2: The horizontal section is divided into 23 sections and 75 clusters, with 2 to 4 clusters in a single section. According to the results of numerical simulation of cracks, the optimized crack half-length is 90 to 330 m, the crack spacing is 15 to 20 m, the section spacing is 60 to 80 m, and the construction displacement is 7 to 12 m 3 / min, sand ratio is 21%, single-stage sand volume is 116~318m 3 , single stage liquid volume is 807~2008m 3 In order to increase the fracture turning radius, each section is plugged twice. During the pre-liquid stage and when 1 / 3 of the sand is added, DA-2 temporary plugging is performed. 100 to 200 kg of DA-2 plugging agent is used for each temporary plugging.

[0065] S3: Fracturing construction was carried out on the target well. Temporary plugging was carried out in the fractures of the target well for a total of 10 sections. Temporary plugging agent was added twice in each section, and the temporary plugging agent was added 20 times in total. The injection speed was not less than 25kg / min. TA-1 (a dissolving agent for temporary plugging material) was quickly added within 1 minute before adding the temporary plugging agent. The amount of TA-1 was calculated based on 15L per bag of plugging agent, and the amount used for each stage of the target well was 60-120L.

[0066] While the target well is being fractured, downhole microseismic monitoring instruments are used to conduct real-time crack monitoring. Figure 2 The analysis of the microseismic distribution characteristics shown in the figure shows that the event point in the 14th section appeared more on the south side before temporary plugging. After the first-level temporary plugging, the cracks expanded to the north, and after the second-level temporary plugging, they expanded to the south again. The target well had an initial production of 22 tons, sufficient fluid supply, and a fast water reduction. Therefore, the temporary plugging effect of this embodiment is good, and temporary plugging can improve the asymmetric expansion of each section.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells, characterized in that: include: According to the data of the target well, geological modeling and fracturing modeling are carried out for the target well to obtain numerical simulation data of the target well; According to the characteristic parameter data of the target well, physical simulation experiments are carried out to determine the target temporary plugging agent; According to the numerical simulation data of the target well and the determined target temporary plugging agent, the target well is subjected to temporary plugging and fracturing transformation.

2. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The target well data include reservoir geological data information, three-dimensional seismic data information, formation temperature and fluid data information, well network and well location deployment data information, wellbore structure data information, wellbore trajectory data information, logging data information, geostress data information, rock mechanics data information, adjacent well oil testing information and adjacent water injection well water injection information.

3. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The geological modeling is to establish a three-dimensional geological model of the reservoir using reservoir modeling software based on the data of the target well, and the three-dimensional geological model includes a structural model, a lithofacies model and an attribute model.

4. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The fracturing modeling is as follows: using fracturing simulation software according to the data of the target well, establishing a reservoir geostress model and a rock mechanics model, and performing geomechanical stratification to establish a fracturing model.

5. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The characteristic parameter data of the target well includes formation temperature data, pressure data and fluid characteristic data.

6. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The physical model experiment process is as follows: According to the characteristic parameter data of the target well, indoor dissolution experiments are carried out on a variety of temporary plugging agents to determine at least one target temporary plugging agent; The determined target temporary plugging agent is used to carry out a bridge-type crack plugging experiment to determine the particle size combination and plugging strength of the target temporary plugging agent.

7. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The compressive strength of the target temporary plugging agent is greater than 60 MPa.

8. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 1, characterized in that: The temporary plugging and diverting fracturing treatment process is as follows: Determine the fracturing plan based on the fracturing numerical simulation data corresponding to the target well; According to the fracturing plan, the determined target temporary plugging agent is used to monitor the target well and the target adjacent wells with a microseismic monitoring instrument to obtain fracture extension data; Adjust the fracturing plan data based on the fracture extension data.

9. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 8, characterized in that: The fracturing scheme data includes the number of temporary plugging times in the fracture, the timing of temporary plugging and the initial dosage of the target temporary plugging agent; The initial dosage of the target temporary plugging agent is: M=aρhLW Wherein, M represents the initial dosage of the target temporary plugging agent, a represents the loss coefficient, ρ represents the density, h represents the height of the hydraulic fracture, L represents the thickness of the temporary plugging layer, and W represents the width of the hydraulic fracture.

10. A fracturing method for increasing the complexity of hydraulic fractures in horizontal wells according to claim 8, characterized in that: The adjustment method of the fracturing plan data is: When it is determined according to the fracture extension data that the fracture continues to extend longitudinally, the target temporary plugging agent is continuously added until the fracture no longer extends longitudinally; When it is determined based on the crack extension data that the crack continues to extend, continue to add the target temporary plugging agent until the crack turns.

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