Quantitative oil reservoir horizontal well fracturing propping agent substitution method

Abstract

The invention provides a quantitative oil reservoir horizontal well fracturing propping agent substitution method, which belongs to the technical field of petroleum development fracturing and comprises the following steps: establishing a flow conductivity matching model; obtaining a target stratum closed stress change rule; a corresponding relation curve of different cluster intervals, sand adding strength combinations and sand paving concentrations is obtained, and the lower limit of engineering parameter combinations is determined; the fracture long-term flow conductivity under different engineering parameters is obtained, and single well productivity simulation is conducted; the sand adding scale matching relation of the ceramsite reference well and the quartz sand replacement well is obtained; the effective profit ratio of single well quartz sand replacement is obtained; establishing a quartz sand replacement plate; and based on the quartz sand replacement chart, optimizing a pump injection program, recalculating an effective profit ratio, and determining engineering parameters and propping agent parameters. According to the method, the quartz sand replacement scale under the conditions of different vertical depths, cluster distances and sand adding strength can be determined, so that prediction of matching of the implementation well construction scale and the section cluster combination is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum development fracturing, and in particular relates to a quantitative oil reservoir horizontal well fracturing proppant replacement method. Background Art

[0002] The technical feasibility of developing unconventional reservoirs by combining horizontal wells with volume fracturing technology is high, but the scale of horizontal well volume fracturing is large, the cost is high, and the average fracturing cost per meter is high, making it difficult to achieve profitable development. Fracturing materials account for a high proportion of the total fracturing cost. The price difference between quartz sand and ceramsite is large, and there is a huge room for cost reduction. The technology of replacing ceramsite with quartz sand has broad application prospects.

[0003] However, there is currently a lack of systematic theoretical guidance on quartz sand replacement options, and it is impossible to design a reasonable replacement scale and cluster spacing. On the one hand, the replacement scale is designed to be small or the cluster spacing is too large, resulting in unclear transformation effects; on the other hand, the replacement scale is designed to be too large or the cluster spacing is too small, which will cause material waste and other negative effects.

[0004] Investigating the usage and proportion trends of foreign proppants, the proportion of quartz sand has increased rapidly in recent years, but the depth of quartz sand replacement is less than 3,200 meters. At present, we adhere to the concept of "quantity for quality", and the test of quartz sand replacing ceramsite is steadily advancing. In order to achieve efficient development, it is urgent to develop a set of proppant replacement scale charts with solid theory and sufficient practice to guide the construction plan of quartz sand replacing ceramsite at different burial depths. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs. The technical problem to be solved by the present invention is how to quickly predict the replacement scale of quartz sand replacing expanded clay under different conditions while considering the influence of engineering parameters and economic parameters.

[0006] In order to solve the above technical problems, the present invention provides a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs, comprising the following steps:

[0007] Step S1: using physical simulation experiments, establish a flow conductivity matching model for quartz sand with different particle sizes, ceramsite and combined paving;

[0008] Step S2: combining the closure stress corresponding to different depths of the reservoir with the on-site fracturing construction and production curves to obtain the closure stress variation law of the target formation at different production stages; based on the simulated fracture morphology under different cluster spacing and sand addition intensity combinations, obtain the corresponding relationship curves of different cluster spacing, sand addition intensity combinations and sand filling concentrations, and determine the lower limit of the engineering parameter combination;

[0009] Step S3: Substituting the closure stress and the sand concentration obtained in step S2 into the conductivity matching model, obtaining the long-term conductivity of the fracture under different engineering parameters, performing single well production capacity simulation based on the ceramsite benchmark well, obtaining the matching relationship curve between the engineering parameters and the cumulative production of the ceramsite benchmark well, and determining the upper limit of the engineering parameter combination based on production feasibility;

[0010] Step S4: Based on the conductivity matching model, the required sanding concentration of single-size and combined-size quartz sands at different reservoir depths for the quartz sand replacement wells is obtained; based on the corresponding relationship curves of different cluster spacings, sanding intensity combinations and sanding concentrations, the sanding scale matching relationship between the ceramsite benchmark well and the quartz sand replacement well is obtained;

[0011] Step S5: using the effective profit ratio calculation method, calculating the net profit value of the quartz sand replacement well and the net profit value of the ceramsite base well, and comparing the net profit value of the quartz sand replacement well with the net profit value of the ceramsite base well to obtain the effective profit ratio of quartz sand replacement in a single well;

[0012] Step S6: Determine the cluster spacing and sand adding strength combination corresponding to the effective development under different vertical depths according to the effective profit ratio, clarify the optimal solution of parameter combination based on economic feasibility, and establish a quartz sand replacement chart; the optimal solution of parameter combination includes the proppant type cluster spacing and sand adding strength;

[0013] Step S7: Based on the quartz sand replacement chart, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

[0014] Furthermore, in step S2, logging parameters are obtained, and the closure stress corresponding to different depths of the reservoir is obtained using a rock mechanics calculation method.

[0015] Furthermore, in step S2, formation parameters are obtained, and the fracture morphology and proppant placement status in the fractures under different cluster spacing and sand addition strength combinations are simulated based on FrSmart software to obtain corresponding relationship curves between different cluster spacing, sand addition strength combinations and sand placement concentrations.

[0016] Furthermore, in step S2, the minimum cluster spacing under different sand adding intensities is determined based on crack interference.

[0017] Furthermore, in step S3, the engineering parameters include cluster spacing, sand addition intensity and vertical depth.

[0018] Furthermore, in step S3, based on the matching relationship curve between the engineering parameters of the ceramsite benchmark well and the cumulative production and the production feasibility, the optimal sand addition intensity corresponding to different cluster spacings and different vertical depths is determined.

[0019] Furthermore, in step S4, the matching relationship between the sand adding scale of the expanded clay base well and the quartz sand replacement well includes the corresponding relationship between the sand adding scale of the quartz sand replacement well with a single particle size and the expanded clay base well and the corresponding relationship between the sand adding scale of the quartz sand replacement well with different combination ratios and the expanded clay base well.

[0020] Furthermore, in step S5, the upper limit of the combination of engineering parameters and the matching relationship between the sand adding scale of the expanded clay base well and the quartz sand replacement well are determined based on the production feasibility, and an effective profit ratio calculation method is established. The effective profit ratio calculation method includes evaluating the economic benefits of the selected cluster spacing and sand adding intensity combination at a fixed oil price, and determining the net profit value under each working condition based on the production capacity and the input of proppant fracturing materials.

[0021] Furthermore, in step S7, the proppant parameters include proppant type and particle size.

[0022] Furthermore, in step S7, the cluster spacing and sand addition strength combinations under different proppant particle sizes corresponding to the efficient development of the target reservoir under vertical depth are obtained according to the effective profit ratio, the proppant type and combination ratio range when the effective profit ratio is the highest are selected, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

[0023] The present invention has the following beneficial effects:

[0024] (1) The proppant replacement chart was drawn based on a large amount of theoretical research, numerical simulation research and field application, and has been verified by regional wells. The results are reliable.

[0025] (2) Good economic efficiency. The chart of the present invention can accurately predict the proppant replacement amount (sand addition strength) of the implementation well, provide clear quantitative guidance for on-site construction, and introduce economic evaluation means to achieve efficient development of the target area.

[0026] (3) Convenient and fast. The proppant substitution chart can be used to quickly determine the scale of quartz sand replacement under different vertical depths, cluster spacing and sand addition intensity conditions, and can conveniently and quickly predict the matching between the well construction scale and the segment cluster combination; the proppant substitution chart can be used to solve the optimal combination of quartz sand addition intensity and cluster spacing under different vertical depths, that is, the quartz sand replacement scale.

[0027] The quantitative oil reservoir horizontal well fracturing proppant replacement method of the present invention comprehensively considers the influence of engineering parameters and economic parameters, can quickly predict the replacement scale of quartz sand replacing ceramsite under different conditions, and can quantitatively guide on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a flow chart of a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs.

[0029] Figure 2 It is a schematic diagram of quartz sand replacement at different vertical depths in a shale oil reservoir in a quantitative method for replacing proppant for horizontal well fracturing in an oil reservoir according to the present invention.

[0030] Figure 3 The present invention is a schematic diagram of a quartz sand combination conductivity chart for a quantitative method of replacing a proppant for fracturing a horizontal well in an oil reservoir.

[0031] Figure 4 (a) is a schematic diagram of fracture morphology when the cluster spacing is 5 m in a quantitative method for replacing proppant for fracturing horizontal wells in oil reservoirs according to the present invention; Figure 4 (b) is a schematic diagram of fracture morphology when the cluster spacing is 10 m in a quantitative method for replacing proppant for fracturing horizontal wells in oil reservoirs according to the present invention; Figure 4 (c) is a schematic diagram of fracture morphology when the cluster spacing is 15 m in a quantitative method for replacing proppant for fracturing horizontal wells in oil reservoirs according to the present invention; Figure 4 (d) is a schematic diagram of fracture morphology when the cluster spacing is 20m in a quantitative method of replacing proppant for fracturing horizontal wells in oil reservoirs according to the present invention.

[0032] Figure 5 It is a schematic diagram of single-slit sand concentration corresponding to sand addition strength under different cluster spacings in a quantitative method for replacing fracturing proppants for horizontal wells in oil reservoirs of the present invention.

[0033] Figure 6 It is a schematic diagram of the three-year cumulative oil production of a ceramsite benchmark well at different vertical depths according to a quantitative method for replacing fracturing proppants in horizontal wells of oil reservoirs of the present invention.

[0034] Figure 7 It is a diagrammatic representation of the relationship between sand addition intensity, cluster spacing and cumulative oil production at a vertical depth of 3400m for a quantitative method of replacing proppant for fracturing horizontal wells in oil reservoirs according to the present invention.

[0035] Figure 8 This is a production well verification diagram of a quantitative oil reservoir horizontal well fracturing proppant replacement method of the present invention. DETAILED DESCRIPTION

[0036] 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. 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.

[0037] 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.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In order to better understand the purpose, structure and function of the present invention, a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0041] Embodiment 1:

[0042] Figure 1 The present invention shows a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs, comprising the following steps:

[0043] Step S1: using physical simulation experiments, establish a flow conductivity matching model for quartz sand with different particle sizes, ceramsite and combined paving;

[0044] Step S2: combining the closure stress corresponding to different depths of the reservoir with the on-site fracturing production curve to obtain the closure stress variation law of the target formation at different production stages; based on the simulated fracture morphology under different cluster spacing and sand addition intensity combinations, obtain the corresponding relationship curves of different cluster spacing, sand addition intensity combinations and sand filling concentrations, and determine the lower limit of the engineering parameter combination;

[0045] Step S3: Bring the closure stress and sand concentration obtained in step S2 into the conductivity matching model to obtain the long-term conductivity of the fracture under different engineering parameters, and perform single well production simulation based on the target block proppant being ceramsite to obtain the matching relationship curve between the engineering parameters of the ceramsite benchmark well and the cumulative production, and determine the upper limit of the engineering parameter combination based on production feasibility;

[0046] Step S4: Based on the conductivity matching model, the required sanding concentration of single-size and combined-size quartz sands at different reservoir depths for the quartz sand replacement wells is obtained; based on the corresponding relationship curves of different cluster spacings, sanding intensity combinations and sanding concentrations, the sanding scale matching relationship between the ceramsite benchmark well and the quartz sand replacement well is obtained;

[0047] Step S5: using the effective profit ratio calculation method, calculating the net profit value of the quartz sand replacement well and the net profit value of the ceramsite base well, and comparing the two to obtain the effective profit ratio of quartz sand replacement in a single well;

[0048] Step S6: Determine the cluster spacing and sand addition intensity combination corresponding to the benefit development under different vertical depths according to the effective profit ratio, clarify the optimal solution of parameter combination based on economic feasibility, and establish a quartz sand substitution chart;

[0049] Step S7: Based on the quartz sand replacement chart, the cluster spacing and sand addition strength combination under different proppant particle sizes corresponding to the efficient development of the target reservoir under vertical depth are obtained according to the effective profit ratio, the proppant type and combination ratio range when the effective profit ratio is the highest are selected, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

[0050] Embodiment 2:

[0051] Figure 1 The present invention shows a quantitative method for replacing proppant for horizontal well fracturing in oil reservoirs, comprising the following steps:

[0052] Step S1: using physical simulation experiments, establish a flow conductivity matching model for quartz sand with different particle sizes, ceramsite and combined paving;

[0053] Step S2: combining the closure stress corresponding to different depths of the reservoir with the on-site fracturing production curve to obtain the closure stress variation law of the target formation at different production stages; based on the simulated fracture morphology under different cluster spacing and sand addition intensity combinations, obtain the corresponding relationship curves of different cluster spacing, sand addition intensity combinations and sand filling concentrations, and determine the lower limit of the engineering parameter combination;

[0054] Step S3: Substitute the closure stress and the sand concentration obtained in step S2 into the conductivity matching model to obtain the long-term conductivity of the fracture under different engineering parameters, and perform single well production simulation when the proppant of the target block is ceramsite to obtain the matching relationship curve between the engineering parameters and the cumulative production of the ceramsite benchmark well, and determine the upper limit of the engineering parameter combination based on production feasibility;

[0055] Step S4: Based on the conductivity matching model, the required sanding concentration of single-size and combined-size quartz sands at different reservoir depths for the quartz sand replacement wells is obtained; based on the corresponding relationship curves of different cluster spacings, sanding intensity combinations and sanding concentrations, the sanding scale matching relationship between the ceramsite benchmark well and the quartz sand replacement well is obtained;

[0056] Step S5: using the effective profit ratio calculation method, calculating the net profit value of the quartz sand replacement well and the net profit value of the ceramsite base well, and comparing the two to obtain the effective profit ratio of quartz sand replacement in a single well;

[0057] Step S6: Determine the cluster spacing and sand addition intensity combination corresponding to the benefit development under different vertical depths according to the effective profit ratio, clarify the optimal solution of parameter combination based on economic feasibility, and establish a quartz sand substitution chart;

[0058] Step S7: Based on the quartz sand replacement chart, the cluster spacing and sand addition strength combination under different proppant particle sizes corresponding to the efficient development of the target reservoir under vertical depth are obtained according to the effective profit ratio, the proppant type and combination ratio range when the effective profit ratio is the highest are selected, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

[0059] In step S1, the conductivity matching model includes a long-term conductivity matching model of ceramsite, a long-term conductivity matching model of quartz sand, and a conductivity matching model of quartz sand with different particle sizes;

[0060] In the step S1, a physical simulation experiment of long-term flow conductivity under different particle sizes of quartz sand and ceramsite is constructed to obtain the long-term flow conductivity of proppants (quartz sand, ceramsite) with a single particle size (20 / 40 mesh, 30 / 50 mesh, 40 / 70 mesh, 70 / 140 mesh) under different closure stresses;

[0061] The long-term conductivity under different closure stresses when quartz sand particle size combinations and proportions are laid is obtained. Based on the experimental results, a conductivity matching model for quartz sand and expanded clay with different particle sizes and combinations is established, and the matching relationship between sand concentration, proppant type, particle size, combination ratio and long-term conductivity is obtained.

[0062] In step S2, logging parameters are obtained, and the closure stress corresponding to different depths of the reservoir is obtained using a rock mechanics calculation method;

[0063] In step S2, formation parameters are obtained, and the fracture morphology and proppant placement state in the fracture under different cluster spacing and sand adding strength combinations are simulated based on FrSmart software to obtain corresponding relationship curves between different cluster spacing, sand adding strength combinations and sand spreading concentrations.

[0064] In the step S2, the minimum cluster spacing under different sand adding intensities is determined based on the crack interference.

[0065] In step S3, the engineering parameters include cluster spacing, sand addition intensity and vertical depth.

[0066] In step S3, based on the matching relationship curve between the engineering parameters of the ceramsite benchmark well and the cumulative production and the production feasibility, the optimal sand addition intensity corresponding to different cluster spacings and different vertical depths is determined.

[0067] In step S4, the matching relationship between the sand adding scale of the ceramsite base well and the quartz sand replacement well includes the corresponding relationship between the sand adding scale of the quartz sand replacement well with a single particle size and the ceramsite base well and the corresponding relationship between the sand adding scale of the quartz sand replacement well with different combination ratios and the ceramsite base well.

[0068] In step S5, the upper limit of the combination of engineering parameters and the matching relationship between the sand adding scale of the ceramsite base well and the quartz sand replacement well are determined based on the production feasibility, and an effective profit ratio calculation method is established. The effective profit ratio calculation method includes evaluating the economic benefits of the selected cluster spacing and sand adding intensity combination at a fixed oil price, and determining the net profit value under each working condition according to the production capacity and the input of proppant fracturing materials.

[0069] In step S7, the proppant parameters include proppant type and particle size.

[0070] Embodiment 3:

[0071] Figure 1 The invention shows a quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs, comprising the following steps: Step S1: using numerical simulation software, establishing a horizontal well fracturing model, and conducting single well productivity simulation, simulating a buried depth of 2500-4200m, the oil layer is divided into two layers, the upper layer has an average thickness of 3.1m, a porosity of 8.24%, and a permeability of 0.0289; the lower layer has an average thickness of 3.8m, a porosity of 9.87%, and a permeability of 0.0148. Taking the horizontal fracturing section length of 1200m and the fracture half length of 150m, simulating the daily production demand, a good production can be achieved when the conductivity is 10-20D·cm.

[0072] Based on this, and according to the current status of wells that have been implemented on site, physical simulation experiments on long-term conductivity under different particle sizes of quartz sand and ceramsite were constructed to determine the proppant particle size (20 / 40 mesh, 30 / 50 mesh, 40 / 70 mesh, 70 / 140 mesh), proppant, closure stress (10-60MPa) and combination mode (two combinations or three combinations);

[0073] Based on the requirements of conductivity and combined with the formation closure pressure, proppant types and combinations with different mesh sizes and sand concentrations are selected. The proppant and proppant combination are used as variables to construct a conductivity matching model, such as Figure 3 shown.

[0074] Step S2: Obtain logging parameters, use rock mechanics calculation methods to obtain the closure stress corresponding to different depths of the reservoir, and determine the closure stress (20-60MPa), as shown in Table 1;

[0075] Table 1 Effective closure stress of cracks at different vertical depths

[0076]

[0077] Acquire formation parameters and simulate the fracture morphology and proppant placement status in fractures under different cluster spacing and sand addition strength combinations based on FrSmart software. 3 The crack morphology under different cluster spacing under the sand addition strength is as follows: Figure 4 As shown;

[0078] Based on the simulated artificial crack morphology under different cluster spacing and sand adding intensity combinations, the corresponding relationship curves of different cluster spacing, sand adding intensity combinations and sand concentration are obtained, such as Figure 5 As shown in the figure, the lower limit of the engineering parameter combination is determined based on crack interference, that is, the minimum cluster spacing under different sand addition intensities. The lower limit of cluster spacing is determined to be 5m, and the lower limit of sand addition intensity is 2.0m. 3 / m.

[0079] Step S3: When the proppant of the target block is ceramsite, the single well productivity simulation is performed using CMG software, such as Figure 6 As shown;

[0080] Based on the closing stress and sand concentration parameters obtained in step S2, the ceramsite long-term conductivity matching model in step S1 is introduced to obtain the long-term conductivity of the cracks under different cluster spacing, sand addition intensity and vertical depth;

[0081] Based on the above simulation parameters, the matching relationship between the cluster spacing, sand addition intensity, vertical depth and three-year cumulative production of expanded clay benchmark wells was obtained. Through the inflection point of the curve, the upper limit of the engineering parameter combination was determined based on production feasibility, that is, the optimal sand addition intensity corresponding to the "production inflection point" under different cluster spacing and different vertical depths.

[0082] Step S4: In order to make the quartz sand replacement well achieve the artificial fracture long-term conductivity similar to that of the ceramsite benchmark well, based on the ceramsite long-term conductivity matching model, the quartz sand long-term conductivity matching model and the quartz sand different particle size combination conductivity matching model in step S1, the required sand concentration of single particle size and combined particle size quartz sand in the quartz sand replacement well at a certain reservoir depth is obtained;

[0083] The above-mentioned sand concentration is brought into step S2 to obtain the corresponding relationship between the sand adding scale of a single particle size of the quartz sand replacement well and the ceramsite reference well. At the same time, if a combination of multiple quartz sand particle sizes is used, the corresponding relationship between the sand adding scale and the ceramsite reference well under different combination ratios is obtained;

[0084] At a vertical depth of 3400m, the “production inflection point” of 5-20m cluster spacing corresponds to a sand addition intensity of 2.8-3.5m 3 / m, such as Figure 7 shown.

[0085] The sand addition intensity corresponding to the “production inflection point” at different vertical depths is obtained, as shown in Table 2.

[0086] Table 2 Sand addition intensity corresponding to the “production inflection point” at different vertical depths

[0087]

[0088] Step S5: Based on the optimal sand adding strength combination under different cluster spacings selected in step S3 and the sand adding scale matching relationship between ceramsite wells and quartz sand wells in step 4, an effective profit ratio calculation method is established, that is, the economic benefit of the optimal cluster spacing and sand adding strength combination is evaluated at a fixed oil price of US$45 / barrel, and the net profit value under each working condition is determined according to the production capacity and the input of proppant fracturing materials, where the oil price is US$45 / barrel and the quartz sand is RMB750 / m 3 , ceramsite 3570 yuan / m 3 , low viscosity fracturing fluid 24 yuan / m 3 , high viscosity fracturing fluid 92 yuan / m 3 , liquid-sand ratio 12%;

[0089] The net profit value calculated from the quartz sand replacement wells was compared with the expanded clay benchmark wells to obtain the effective profit ratio of quartz sand replacement for a single well, as shown in Table 3.

[0090] Table 3 Effective profit ratio under different working conditions

[0091]

[0092]

[0093] Step S6: Determine the cluster spacing and sand addition intensity combination corresponding to the benefit development under different vertical depths according to the effective profit ratio, clarify the optimal solution of parameter combination based on economic feasibility, and establish a quartz sand substitution chart, such as Figure 2 shown.

[0094] Step S7: Based on the actual working conditions and the quartz sand replacement chart, according to the effective profit ratio, the vertical depth of the three wells in the upper sweet spot of the target reservoir is 2608-2636m, the cluster spacing is 15m, and the sand addition intensity is 1.7-3.1m 3 / m, the particle size combination is 20 / 40+40 / 70 mesh quartz sand, and the combination ratio is 8:2; the vertical depth of the three wells in the lower sweet spot is 3872-4062m, the cluster spacing is 6.8-14.6m, and the sand addition strength is 2.0-4.0m 3 / m, with an average daily oil production of 16.2 to 36.4t. The particle size combination is 20 / 40 + 40 / 70 mesh quartz sand, and the combination ratio is 7:3.

[0095] By designing and optimizing the implementation parameters, the plate was verified according to the production of the implementation well (see Table 4) and the construction parameters. The vertical depth of JHW034 well is 2625m, the cluster spacing is 15m, and the sand addition intensity is 2.6m 3 / m, with 978 days of production and an average daily oil production of 23.7t / d. By comparing the wells JHW032 and JHW035 in the same layer, it is found that the equal amount of replacement obviously cannot meet the production demand. By comparing the two wells JHW07121 and J10044-H in the lower sweet spot, the production time, vertical depth and cluster spacing of the two wells are basically the same. The sand addition intensity of JHW07121 well is significantly higher than that of J10044-H well, but its production increase is not obvious. The analysis shows that both of them have achieved the most economical development because of the addition of J10044-H well. The sand intensity is too small and has not reached the sand intensity required for the actual "production inflection point". On the contrary, the sand intensity of JHW07121 well exceeds the optimal sand intensity, so the production improvement is not obvious. Compared with the sweet spot well J10057-H well, it uses the equal amount replacement method. It can be seen that it is in the green range on the chart, which means that its sand intensity is far from the sand intensity corresponding to the "production inflection point" and has not achieved efficient development. Its replacement scale needs to be further increased; the distribution positions of each well are basically consistent with the established chart, and it is determined that the chart is valid (see Figure 8 ).

[0096] Table 4 Statistics of production of quartz sand wells put into production

[0097]

[0098] The above description is only a preferred embodiment of the present invention and is 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 are included in the protection scope of the present invention.

Claims

1. A quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs, characterized in that: The following steps are involved: Step S1: using physical simulation experiments, establish a flow conductivity matching model for quartz sand with different particle sizes, ceramsite and combined paving; Step S2: combining the closure stress corresponding to different depths of the reservoir with the on-site fracturing production curve to obtain the closure stress variation law of the target formation at different production stages; based on the simulated fracture morphology under different cluster spacing and sand addition intensity combinations, obtain the corresponding relationship curves of different cluster spacing, sand addition intensity combinations and sand filling concentrations, and determine the lower limit of the engineering parameter combination; Step S3: Substituting the closure stress and the sand concentration obtained in step S2 into the conductivity matching model, obtaining the long-term conductivity of the fracture under different engineering parameters, performing single well production capacity simulation based on the ceramsite benchmark well, obtaining the matching relationship curve between the engineering parameters and the cumulative production of the ceramsite benchmark well, and determining the upper limit of the engineering parameter combination based on production feasibility; Step S4: Based on the conductivity matching model, the required sanding concentration of single-size and combined-size quartz sands at different reservoir depths for the quartz sand replacement wells is obtained; based on the corresponding relationship curves of different cluster spacings, sanding intensity combinations and sanding concentrations, the sanding scale matching relationship between the ceramsite benchmark well and the quartz sand replacement well is obtained; Step S5: using the effective profit ratio calculation method, calculating the net profit value of the quartz sand replacement well and the net profit value of the ceramsite base well, and comparing the net profit value of the quartz sand replacement well with the net profit value of the ceramsite base well to obtain the effective profit ratio of quartz sand replacement in a single well; Step S6: Determine the cluster spacing and sand addition intensity combination corresponding to the benefit development under different vertical depths according to the effective profit ratio, clarify the optimal solution of parameter combination based on economic feasibility, and establish a quartz sand substitution chart; Step S7: Based on the quartz sand replacement chart, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

2. The quantitative reservoir horizontal well fracturing proppant replacement method according to claim 1, characterized in that: In step S2, logging parameters are obtained, and the closure stress corresponding to different depths of the reservoir is obtained using a rock mechanics calculation method.

3. The quantitative reservoir horizontal well fracturing proppant replacement method according to claim 1, characterized in that: In step S2, formation parameters are obtained, and the fracture morphology and proppant placement state in the fracture under different cluster spacing and sand adding strength combinations are simulated based on FrSmart software to obtain corresponding relationship curves between different cluster spacing, sand adding strength combinations and sand spreading concentrations.

4. The quantitative reservoir horizontal well fracturing proppant replacement method according to claim 1, characterized in that: In the step S2, the minimum cluster spacing under different sand adding intensities is determined based on the crack interference.

5. The quantitative reservoir horizontal well fracturing proppant replacement method according to claim 1, characterized in that: In step S3, the engineering parameters include cluster spacing, sand addition intensity and vertical depth.

6. The quantitative reservoir horizontal well fracturing proppant replacement method according to claim 1, characterized in that: In step S3, based on the matching relationship curve between the engineering parameters of the ceramsite benchmark well and the cumulative production and the production feasibility, the optimal sand addition intensity corresponding to different cluster spacings and different vertical depths is determined.

7. The quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs according to claim 1, characterized in that: In step S4, the matching relationship between the sand adding scale of the ceramsite base well and the quartz sand replacement well includes the corresponding relationship between the sand adding scale of the quartz sand replacement well with a single particle size and the ceramsite base well and the corresponding relationship between the sand adding scale of the quartz sand replacement well with different combination ratios and the ceramsite base well.

8. The quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs according to claim 1, characterized in that: In step S5, the upper limit of the combination of engineering parameters and the matching relationship between the sand adding scale of the ceramsite base well and the quartz sand replacement well are determined based on the production feasibility, and an effective profit ratio calculation method is established. The effective profit ratio calculation method includes evaluating the economic benefits of the selected cluster spacing and sand adding intensity combination at a fixed oil price, and determining the net profit value under each working condition according to the production capacity and the input of proppant fracturing materials.

9. The quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs according to claim 1, characterized in that: In step S7, the proppant parameters include proppant type and particle size.

10. The quantitative method for replacing proppant in horizontal well fracturing of oil reservoirs according to claim 1, characterized in that: In step S7, the cluster spacing and sand addition strength combinations under different proppant particle sizes corresponding to the efficient development of the target reservoir under vertical depth are obtained according to the effective profit ratio, the proppant type and combination ratio range when the effective profit ratio is the highest are selected, the pumping program is optimized, the effective profit ratio is recalculated, and the engineering parameters and proppant parameters are determined.

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