Device for simulating hydraulic fracture temporary plugging effect and experimental method

Abstract

The invention discloses a hydraulic fracture temporary plugging effect simulation device and an experiment method, belongs to the technical field of oil and gas field development, and provides a fracturing fluid filtration simulation method in a fracture permeability mode. Fracturing fluid filtration under the influence of the hydraulic fracture initial fracture width, the proppant particle size proportion coefficient and the fracture permeability mode is designed and considered, accurate simulation of the hydraulic fracture temporary plugging effect is achieved, and an experimental means and a design basis are provided for fracture temporary plugging parameter optimization. The hydraulic fracture single-wing fracture initiation is simulated at a shaft, the proportion coefficient alpha of the initial fracture width of the hydraulic fracture and the particle size of the propping agent is calculated, and the hydraulic fracture temporary plugging effect experiment is carried out according to the pump injection displacement Q experiment by simulating the fracture permeability mode fracturing fluid filtration. Finally, the hydraulic fracture temporary plugging effect is simulated, the hydraulic fracture temporary plugging effect is accurately simulated, and hydraulic fracture temporary plugging diversion fracturing design in unconventional oil and gas development is guided.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and relates to a method for temporary plugging effect of fracturing, in particular to a device for simulating temporary plugging effect of hydraulic fractures and an experimental method. Background Art

[0002] Unconventional tight oil and gas reservoirs have poor physical properties, generally low porosity and ultra-low permeability, strong planar heterogeneity, undeveloped natural fractures, many vertical layers, and a high proportion of thin interlayers. To achieve economic and effective development, effective transformation of the reservoir is required. Temporary plugging and diversion fracturing technology in hydraulic fractures is an important technical means for the efficient development of unconventional oil and gas reservoirs.

[0003] At present, under different hydraulic fracture conditions, the temporary plugging effect of temporary plugging materials on fractures is unclear, the selection of temporary plugging material particle size is relatively blind, and the method of multiple attempts is generally adopted, resulting in waste of temporary plugging materials and even wellbore blockage after the temporary materials are pumped in. Therefore, simulating the temporary plugging effect of hydraulic fractures and determining the parameters such as the dosage and particle size of temporary plugging agents are of great significance to the efficient development of unconventional oil and gas reservoirs. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a device and an experimental method for simulating the temporary plugging effect of hydraulic fractures, so as to solve the technical problem in the prior art that the temporary plugging effect of temporary plugging materials on fractures cannot be clearly determined under different hydraulic fracture conditions.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An experimental method for simulating the temporary plugging effect of hydraulic fractures comprises the following steps:

[0007] Simulate the initiation of a single wing hydraulic fracture at the wellbore, the dynamic change of the hydraulic fracture width, and the fracturing fluid loss in the experimental fracture permeability model;

[0008] Determine the experimental pumping displacement, and conduct a hydraulic fracture temporary plugging effect experiment under the experimental pumping displacement.

[0009] Preferably, the hydraulic fracture is simulated at the wellbore with a single wing fracture initiation, and the relationship between the fracture length and the wellbore diameter is:

[0010] D 井筒 =βL 水力裂缝

[0011] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, and β is the proportional coefficient between the wellbore diameter and the hydraulic fracture length.

[0012] Preferably, the ratio of the initial width of the hydraulic fracture to the particle size of the proppant is:

[0013] W 水力裂缝 =αD 支撑剂粒径

[0014] Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial fracture width and the proppant particle size.

[0015] Preferably, the dynamic change simulation method of the hydraulic fracture width is to control the thickness of the elastic filler.

[0016] Preferably, the elastic filler thickness calculation method is:

[0017] M 填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0018] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit of length, 1m; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

[0019] Preferably, the fracturing fluid loss in the simulated experimental fracture permeability mode is performed with an initial permeability of the experimental fracture:

[0020] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0021] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment.

[0022] Preferably, the experimental pumping displacement is determined by:

[0023] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0024] Among them, Q实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0025] Preferably, the temporary plugging effect experiment of hydraulic fractures under the experimental pumping displacement specifically includes:

[0026] S201: Experimental pumping displacement Q 实验 Injecting a mixture of temporary plugging particles and carrying fluid with a mass fraction of W;

[0027] S202: Record the initial pumping pressure Pinitial and the change of pumping pressure over time: P(t)~t;

[0028] S203: changing the temporary plugging particle mass concentration W, repeating the above steps, and recording the accumulated injection time corresponding to different temporary plugging particle mass concentrations.

[0029] Preferably, in S202, when the experimental pumping pressure P 暂堵 =P 初始 +P 转向 At this time, the pressure is the temporary blocking steering pressure P 暂堵 , stop the experiment and record the temporary blocking time.

[0030] The present invention also discloses a device for simulating the temporary plugging effect of hydraulic fractures, characterized in that it is applied to the experimental method for simulating the temporary plugging effect of hydraulic fractures as described in any one of claims 1 to 9, comprising a steel plate with cracks opened inside the steel plate, and elastic fillers for dynamically changing the width of the cracks are arranged at the cracks.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] At present, there are no literatures and patents related to experimental devices and methods for simulating the temporary plugging effect of hydraulic fractures, especially in the field of experimental devices for coupled simulation of the initiation of single-wing seam of hydraulic fractures in wellbore, dynamic changes in the width of hydraulic fractures, and loss of fracturing fluid. The present invention proposes a method for simulating fracturing fluid loss under the fracture permeability mode. Starting from the simulation of the initiation of single-wing seam of hydraulic fractures in wellbore, the design considers the ratio coefficient of the initial seam width of hydraulic fractures to the particle size of proppant, and the loss of fracturing fluid under the influence of fracture permeability mode, so as to achieve accurate simulation of the temporary plugging effect of hydraulic fractures, and provide experimental means and design basis for the optimization of fracture temporary plugging parameters. The initiation of single-wing seam of hydraulic fracture is simulated in the wellbore, and the ratio coefficient of the initial seam width of hydraulic fracture to the particle size of proppant is calculated as α. Through simulating the fracturing fluid loss in the experimental fracture permeability mode, according to the pumping displacement Q实验 Conduct hydraulic fracture temporary plugging effect experiments. Finally, simulate the hydraulic fracture temporary plugging effect accurately to guide the hydraulic fracture temporary plugging and fracturing design in unconventional oil and gas development. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the steps of the method of the present invention;

[0034] Figure 2 A simulation diagram of a device for simulating temporary plugging effect of hydraulic fractures according to the present invention;

[0035] Figure 3 This is a simulation diagram of the temporary plugging effect of hydraulic fractures in Example 1 provided in this specification;

[0036] Figure 4 This is a simulation diagram of the temporary plugging effect of hydraulic fractures in Example 2 provided in this specification;

[0037] Figure 5 This is a simulation diagram of the temporary plugging effect of hydraulic fractures in Example 3 provided in this specification. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0041] An experimental method for simulating the temporary plugging effect of hydraulic fractures, that is, simulating the initiation of a single wing fracture of a hydraulic fracture in the wellbore, calculating the ratio coefficient of the initial fracture width of the hydraulic fracture to the proppant particle size as α, and simulating the fracturing fluid loss in the experimental fracture permeability model according to the pumping displacement Q 实验 Conduct hydraulic fracture temporary plugging effect experiments. Finally, simulate the hydraulic fracture temporary plugging effect accurately to guide the hydraulic fracture temporary plugging and fracturing design in unconventional oil and gas development.

[0042] See also Figure 1 The present invention discloses an experimental method for simulating the temporary plugging effect of hydraulic fractures, comprising the following steps:

[0043] S1: Fracturing initiation of a single wing of a hydraulic fracture simulated at the wellbore, dynamic changes in the width of the hydraulic fracture, and fracturing fluid loss in the experimental fracture permeability model;

[0044] S2: Determine the experimental pumping displacement, and conduct a hydraulic fracture temporary plugging effect experiment under the experimental pumping displacement.

[0045] The present invention proposes a method for simulating fracturing fluid loss under the fracture permeability mode. Starting from simulating the initiation of a single-wing seam of a hydraulic fracture at a wellbore, the design considers the initial seam width of the hydraulic fracture and the proportional coefficient of the proppant particle size, and the fracturing fluid loss under the influence of the fracture permeability mode, so as to achieve an accurate simulation of the temporary plugging effect of the hydraulic fracture, and provide experimental means and design basis for the optimization of the temporary plugging parameters of the fracture. The initiation of a single-wing seam of a hydraulic fracture is simulated at the wellbore, and the proportional coefficient of the initial seam width of the hydraulic fracture and the proppant particle size is calculated as α. Through the simulation of the experimental fracture permeability mode fracturing fluid loss, according to the pumping displacement Q 实验 Conduct hydraulic fracture temporary plugging effect experiments. Finally, simulate the hydraulic fracture temporary plugging effect accurately to guide the hydraulic fracture temporary plugging and fracturing design in unconventional oil and gas development.

[0046] In some embodiments, a single-wing hydraulic fracture is simulated at the wellbore, and the relationship between the fracture length and the wellbore diameter is:

[0047] D 井筒 =βL 水力裂缝

[0048] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, and β is the proportional coefficient between the wellbore diameter and the hydraulic fracture length.

[0049] In some embodiments, the ratio of initial hydraulic fracture width to proppant particle size is:

[0050] W 水力裂缝 =αD 支撑剂粒径

[0051] Among them, W 水力裂缝is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial fracture width and the proppant particle size.

[0052] In some embodiments, the dynamic change simulation method of the hydraulic fracture width is to control the thickness of the elastic filler.

[0053] In some embodiments, the elastic filler thickness calculation method is:

[0054] M 填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0055] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit of length, 1m; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

[0056] In some embodiments, the experimental fracture permeability model is simulated to simulate the fracturing fluid loss, and the initial permeability of the experimental fracture is:

[0057] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0058] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment.

[0059] In some embodiments, the experimental pumping displacement is determined by:

[0060] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0061] Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0062] In some embodiments, the temporary plugging effect experiment of hydraulic fractures under the experimental pumping displacement specifically includes:

[0063] S201: Experimental pumping displacement Q 实验 Injecting a mixture of temporary plugging particles and carrying fluid with a mass fraction of W;

[0064] S202: Record the initial pumping pressure Pinitial and the change of pumping pressure over time: P(t)~t;

[0065] S203: changing the temporary plugging particle mass concentration W, repeating the above steps, and recording the accumulated injection time corresponding to different temporary plugging particle mass concentrations.

[0066] In some embodiments, in S202, when the experimental pumping pressure P=P 初始 +P 转向 At this time, the pressure is the temporary blocking steering pressure P 暂堵 , stop the experiment and record the temporary blocking time.

[0067] In some embodiments, an experimental method for simulating the temporary plugging effect of hydraulic fractures comprises the following steps:

[0068] Step 1: Simulate the initiation of a single-wing hydraulic fracture at the wellbore, and the ratio of the fracture length to the wellbore diameter is:

[0069] D 井筒 =βL 水力裂缝

[0070] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, and β is the proportional coefficient between the wellbore diameter and the hydraulic fracture length.

[0071] Step 2: The ratio of initial hydraulic fracture width to proppant particle size is:

[0072] W 水力裂缝 =αD 支撑剂粒径

[0073] Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial fracture width and the proppant particle size.

[0074] Step 3: The dynamic change simulation method of hydraulic fracture width is elastic filler thickness control, and the elastic filler thickness calculation method is:

[0075] M填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0076] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit of length, 1m; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

[0077] Step 4: Fracturing fluid loss through simulating experimental fracture permeability model, the initial permeability of the experimental fracture is:

[0078] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0079] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment.

[0080] Step 5: Determine the experimental pumping displacement. The specific method is:

[0081] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0082] Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0083] Step 6: Test pump displacement Q 实验 Inject a mixture of temporary plugging particles and carrying liquid with a mass fraction of W; record the initial pumping pressure Pinitial and the change of pumping pressure with time: P(t)~t.

[0084] Step 7: When the experimental pump pressure P 暂堵 =P 初始 +P 转向 At this time, the pressure is the temporary blocking steering pressure P 暂堵 , stop the experiment and record the temporary blocking time t 暂堵 .

[0085] Step 8: Change the temporary plugging particle mass concentration W, repeat steps 5 to 8, and record the corresponding cumulative injection time t under W1, W2, W3... 暂堵1 , t 暂堵2 , t 暂堵3 ….

[0086] See also Figure 2 , which is a simulation diagram of a device for simulating temporary plugging effect of hydraulic fractures in an embodiment of the present invention, a device for simulating temporary plugging effect of hydraulic fractures is designed, comprising a steel plate 1, a crack 2 is opened inside the steel plate 1, and an elastic filler 3 for dynamic change of the width of the crack 2 is arranged at the crack 2. The device simulates the initiation of a single hydraulic fracture at the wellbore, and the dynamic change of the width of the hydraulic fracture is simulated by the thickness control of the elastic filler. By simulating the fracturing fluid loss in the experimental fracture permeability mode, the temporary plugging effect experiment of the hydraulic fracture is carried out with the pumping displacement.

[0087] Embodiment 1:

[0088] The embodiment is based on the specific well parameter setting of a certain oil field, and the design of the wellbore simulates the single-wing fracture initiation of hydraulic fractures.

[0089] (1) Experimental design and preparation of wellbore diameter D 井筒 =2mm, 70 / 140 mesh quartz sand is used as proppant;

[0090] (2) Experimental simulation crack length L 水力裂缝 =2.56m,

[0091] D 井筒 =βL 水力裂缝

[0092] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, β is the ratio coefficient between the wellbore diameter and the hydraulic fracture length;

[0093] Calculate and determine β = 0.00078;

[0094] W 水力裂缝 =αD 支撑剂粒径

[0095] Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial crack width of the force fracture and the proppant particle size;

[0096] Crack width W 水力裂缝 =1.5mm, the proppant is quartz sand, and α is determined by calculation to be 10;

[0097] (3) Elastic filling

[0098] M 填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0099] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit dimension of length; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

[0100] ΔP net水力裂缝 =15MPa, E 储层岩石 =23GPa,M 充填物压实厚度 =1mm, ΔL=1m;

[0101] M 填充物厚度 =1.65mm;

[0102] (4) Based on the rock matrix permeability K of a certain oil field 岩石基质 =1mD, on-site crack height 75m, laboratory crack height 0.2m,

[0103] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0104] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment;

[0105] Laboratory simulated permeability K 实验 =26.4D;

[0106] (5) Determine the experimental pumping displacement. The specific method is as follows:

[0107] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0108] Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0109] Experimental displacement Q 实验 =50ml / min, experimental fracturing fluid viscosity μ 实验 =0.3mPa·s, on-site fracturing fluid viscosity μ 现场 =60mPa·s, experimental fracturing fluid density ρ 实验 =252g / cm 3 , density of on-site fracturing fluid ρ 现场 =1.68g / cm 3 . Corresponding on-site pumping displacement Q 现场 =4m 3 / min.

[0110] (6) A mixture of temporary plugging particles and a carrying liquid with a mass fraction W is injected at a pumping displacement Q, and the initial pumping pressure P initial and the change of the pumping pressure over time are recorded.

[0111] See also Figure 3 , which is a simulation diagram of the temporary plugging effect of the hydraulic fracture in this embodiment. It can be seen from the figure that the temporary plugging agent concentration is 0.07, the temporary plugging time is 0.3h, and the temporary plugging pressure is 12MPa; the temporary plugging agent concentration is 0.09, the temporary plugging time is 0.29h, and the temporary plugging pressure is 13MPa; the temporary plugging agent concentration is 0.11, the temporary plugging time is 0.27h, and the temporary plugging pressure is 14.5MPa; the temporary plugging agent concentration is 0.13, the temporary plugging time is 0.25h, and the temporary plugging pressure is 16MPa; the temporary plugging agent concentration is 0.15, the temporary plugging time is 0.25h, and the temporary plugging pressure is 16MPa.

[0112] Embodiment 2:

[0113] (1) Experimental design and preparation of wellbore diameter D 井筒 =2mm, 70 / 140 mesh quartz sand is used as proppant;

[0114] (2) Experimental simulation crack length L 水力裂缝 =2.56m,

[0115] D 井筒 =βL 水力裂缝

[0116] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, β is the ratio coefficient between the wellbore diameter and the hydraulic fracture length;

[0117] Calculate and determine β = 0.00078;

[0118] W 水力裂缝 =αD 支撑剂粒径

[0119] Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial crack width of the force fracture and the proppant particle size;

[0120] Crack width W 水力裂缝 =1.25mm, the proppant is quartz sand, and α is determined by calculation to be 8.3;

[0121] (3) Elastic filling

[0122] M 填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0123] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit dimension of length; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

[0124] ΔP net水力裂缝 =15MPa, E 储层岩石 =23GPa,M 充填物压实厚度 =1mm, ΔL=1m;

[0125] M 填充物厚度 =1.70mm;

[0126] (4) Based on the rock matrix permeability K of a certain oil field 岩石基质 =1mD, on-site crack height 75m, laboratory crack height 0.2m,

[0127] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0128] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment;

[0129] Laboratory simulated permeability K 实验 =26.4D;

[0130] (5) Determine the experimental pumping displacement. The specific method is as follows:

[0131] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0132] Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0133] Experimental displacement Q 实验 =62.5ml / min, experimental fracturing fluid viscosity μ 实验 =0.3mPa·s, on-site fracturing fluid viscosity μ 现场 =60mPa·s, experimental fracturing fluid density ρ 实验 =252g / cm 3 , density of on-site fracturing fluid ρ 现场 =1.68g / cm 3 . Corresponding on-site pumping displacement Q 现场 =5m 3 / min.

[0134] (6) A mixture of temporary plugging particles and a carrying liquid with a mass fraction W is injected at a pumping displacement Q, and the initial pumping pressure P initial and the change of the pumping pressure over time are recorded.

[0135] See also Figure 4, which is a simulation diagram of the temporary plugging effect of the hydraulic fracture in this embodiment. It can be seen from the figure that the temporary plugging agent concentration is 0.07, the temporary plugging time is 0.29h, and the temporary plugging pressure is 13MPa; the temporary plugging agent concentration is 0.09, the temporary plugging time is 0.27h, and the temporary plugging pressure is 14MPa; the temporary plugging agent concentration is 0.11, the temporary plugging time is 0.25h, and the temporary plugging pressure is 15MPa; the temporary plugging agent concentration is 0.13, the temporary plugging time is 0.22h, and the temporary plugging pressure is 16MPa; the temporary plugging agent concentration is 0.15, the temporary plugging time is 0.2h, and the temporary plugging pressure is 16.5MPa.

[0136] Embodiment 3:

[0137] (1) Experimental design and preparation of wellbore diameter D 井筒 =2mm, 70 / 140 mesh quartz sand is used as proppant;

[0138] (2) Experimental simulation crack length L 水力裂缝 =2.56m,

[0139] D 井筒 =βL 水力裂缝

[0140] Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, β is the ratio coefficient between the wellbore diameter and the hydraulic fracture length;

[0141] Calculate and determine β = 0.00078;

[0142] W 水力裂缝 =αD 支撑剂粒径

[0143] Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial crack width of the force fracture and the proppant particle size;

[0144] Crack width W 水力裂缝 =1.75mm, the proppant is quartz sand, and α is determined by calculation to be 11.67;

[0145] (3) Elastic filling

[0146] M 填充物厚度 =ΔLΔP net水力裂缝 / E 储层岩石 +M 充填物压实厚度

[0147] Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit dimension of length; ΔP net水力裂缝 is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度It is the thickness of the elastic filler after compaction.

[0148] ΔP net水力裂缝 =13MPa, E 储层岩石 =23GPa,M 充填物压实厚度 =1.2mm, ΔL=1m. M 填充物厚度 =1.76mm;

[0149] (4) Based on the rock matrix permeability K of a certain oil field 岩石基质 =1mD, on-site crack height 75m, laboratory crack height 0.2m,

[0150] K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 )

[0151] Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment;

[0152] Laboratory simulated permeability K 实验 =26.4D;

[0153] (5) Determine the experimental pumping displacement. The specific method is as follows:

[0154] Q 实验 =μ 实验 ρ 现场 Q 现场 / (μ 现场 ρ 实验 )

[0155] Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

[0156] Experimental displacement Q 实验 =43.75ml / min, experimental fracturing fluid viscosity μ 实验 =0.3mPa·s, on-site fracturing fluid viscosity μ 现场 =60mPa·s, experimental fracturing fluid density ρ实验 =252g / cm 3 , density of on-site fracturing fluid ρ 现场 =1.68g / cm 3 . Corresponding on-site pumping displacement Q 现场 =5m 3 / min.

[0157] (6) A mixture of temporary plugging particles and a carrying liquid with a mass fraction W is injected at a pumping displacement Q, and the initial pumping pressure P initial and the change of the pumping pressure over time are recorded.

[0158] See also Figure 5 , which is a simulation diagram of the temporary plugging effect of the hydraulic fracture in this embodiment. It can be seen from the figure that the temporary plugging agent concentration is 0.07, the temporary plugging time is 0.32h, and the temporary plugging pressure is 11.5MPa; the temporary plugging agent concentration is 0.09, the temporary plugging time is 0.29h, and the temporary plugging pressure is 12.5MPa; the temporary plugging agent concentration is 0.11, the temporary plugging time is 0.26h, and the temporary plugging pressure is 14MPa; the temporary plugging agent concentration is 0.13, the temporary plugging time is 0.24h, and the temporary plugging pressure is 15MPa; the temporary plugging agent concentration is 0.15, the temporary plugging time is 0.23h, and the temporary plugging pressure is 15.5MPa.

[0159] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An experimental method for simulating the temporary plugging effect of hydraulic fractures, characterized in that: The following steps are involved: Simulate the initiation of a single wing hydraulic fracture at the wellbore, the dynamic change of the hydraulic fracture width, and the fracturing fluid loss in the experimental fracture permeability model; Determine the experimental pumping displacement, and conduct a hydraulic fracture temporary plugging effect experiment under the experimental pumping displacement.

2. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: The relationship between the fracture length and the wellbore diameter of the simulated hydraulic fracture single wing crack initiation at the wellbore is: D 井筒 =βL 水力裂缝 Among them, D 井筒 is the wellbore diameter, L 水力裂缝 is the fracture length, and β is the proportional coefficient between the wellbore diameter and the hydraulic fracture length.

3. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: The ratio of initial hydraulic fracture width to proppant particle size is: W 水力裂缝 =αD 支撑剂粒径 Among them, W 水力裂缝 is the initial width of hydraulic fracture; D 支撑剂粒径 is the proppant particle size; α is the ratio coefficient between the initial fracture width and the proppant particle size.

4. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: The dynamic change simulation method of hydraulic fracture width is to control the thickness of elastic filler.

5. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 4, characterized in that: The elastic filler thickness calculation method is: Among them, M 填充物厚度 is the thickness of the elastic filler; ΔL is the unit dimension of length; is hydraulic fracture; E 储层岩石 is the Young's modulus of reservoir rock; M 充填物压实厚度 It is the thickness of the elastic filler after compaction.

6. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: Simulate the experimental fracture permeability model fracturing fluid loss, the initial permeability of the experimental fracture is: K 实验 =K 岩石基质 L 水力裂缝 H 水力裂缝 / (L 实验裂缝 H 实验裂缝 ) Among them, K 实验 is the experimental simulation permeability; K 岩石基质 is the rock matrix permeability; L 水力裂缝 H is the length of hydraulic fracture; 水力裂缝 is the hydraulic fracture height; L 实验裂缝 is the length of the crack simulated in the experiment; H 实验裂缝 Simulate the crack height for the experiment.

7. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: The specific method for determining the experimental pumping displacement is as follows: Q 实验 =μ 实验 r 现场 Q 现场 / (m 现场 r 实验 ) Among them, Q 实验 is the experimental pumping displacement; μ 实验 is the experimental fracturing fluid viscosity; ρ 现场 is the density of the on-site fracturing fluid; Q 现场 is the on-site pumping displacement; μ 现场 is the viscosity of the on-site fracturing fluid; ρ 实验 is the experimental fracturing fluid density.

8. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 1, characterized in that: The temporary plugging effect experiment of hydraulic fractures under the experimental pumping displacement specifically includes: S201: Experimental pumping displacement Q 实验 Injecting a mixture of temporary plugging particles and carrying fluid with a mass fraction of W; S202: Record the initial pumping pressure Pinitial and the change of pumping pressure over time: P(t)~t; S203: changing the temporary plugging particle mass concentration W, repeating the above steps, and recording the accumulated injection time corresponding to different temporary plugging particle mass concentrations.

9. The experimental method for simulating temporary plugging effect of hydraulic fractures according to claim 8, characterized in that: In S202, when the experimental pumping pressure P=P 初始 +P 转向 At this time, the pressure is the temporary blocking steering pressure P 暂堵 , stop the experiment and record the temporary blocking time.

10. A device for simulating temporary plugging effect of hydraulic fractures, characterized in that: The experimental method for simulating the temporary plugging effect of hydraulic fractures as described in any one of claims 1 to 9 comprises a steel plate (1), a crack (2) is provided inside the steel plate (1), and an elastic filler (3) is provided at the crack (2) for dynamically changing the width of the crack (2).

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