Method and system for evaluating yield-increasing and injection-increasing aerodynamic force composite plug removal capacity of medium-low permeability reservoir

Abstract

The invention discloses a method and a system for evaluating yield-increasing and injection-increasing aerodynamic force composite plug removal capability of medium-low permeability reservoirs, and relates to the technical field of oil-gas field development. The method comprises the following steps: determining to-be-measured well types, including oil wells or water wells; based on the type of the well to be measured, whether measures are taken or not is judged according to well selection conditions; if measures are taken, well deviation data are collected, and the maximum well deviation position and the maximum well deviation size are found; determining a transmission type according to the well deviation; aerodynamic force operation is carried out according to the transmission type; acidizing operation is carried out after the aerodynamic force operation; and evaluating the effect of the oil well or the water well after the measures are taken. The method solves the problem that large-scale transformation of the fractured thin and poor layer of the medium-low permeability reservoir is difficult to realize, so that reserves are difficult to effectively use; the problems that traditional fracturing transformation measures are long in construction period, high in measure cost and poor in economic benefit are solved. The problem that there is no effective treatment means for a thin layer or a thin interlayer is solved; and the problem of difficulty in measure effect evaluation after traditional process measures is solved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method and system for evaluating the combined unblocking capacity of gas injection and production enhancement in medium- and low-permeability reservoirs. Background Technology

[0002] As water injection development deepens, the contradictions between injection layers in injection wells are becoming increasingly prominent, with severe single-layer fingering of the waterline, high injection pressure, and a rising proportion of under-injected wells year by year. In oil wells, production capacity is declining, production profiles are limited, and some oil layers suffer from severe complex blockage. Long-term water injection development has led to irreversible damage to reservoirs caused by particle migration clogging pore throats and deep formation scaling, resulting in a continuous and steady increase in injection pressure, posing a significant challenge to pressure reduction and injection enhancement. In recent years, extensive work has been done to improve complex blockage, injection water patterns, and reservoirs with poor fracture development. In water well acidizing, the core solutions are scaling, particle migration, water quality improvement, pore throat blockage caused by secondary precipitation during acidizing, and uneven water drive due to strong heterogeneity. In oil wells, the core solutions are complex scale, organic polymer colloids, waxes, asphaltene, pore throat blockage caused by secondary precipitation during acidizing, repeated fracturing filter cake, rust, and limited production profiles.

[0003] The thin interbedded water injection development reservoirs in Qinghai Oilfield are characterized by long well sections with generally thin layers (1-3 meters), strong planar heterogeneity, and large vertical permeability differences, which pose significant challenges to the efficient development of the reservoirs.

[0004] Regarding water injection wells: Water injection wells have long perforated sections, multiple stages (3-4 stages), and numerous injection layers per stage (3-4 layers), resulting in uneven water absorption and widespread single-layer surges. Existing depressurization and injection enhancement methods mainly rely on stratified acidizing and small-scale fracturing. Stratified acidizing has limited scope and a generally short effective period; small-scale fracturing makes it difficult to control fracture height within the effective reservoir thickness, making balanced stratified water injection a significant challenge for improving the utilization of reserves in thin interbedded reservoirs in the Qinghai Oilfield.

[0005] Regarding oil wells: Due to differences in reservoir properties, the effective utilization of thin, poorly shaped reservoirs has long been a challenge for the Qinghai Oilfield's thin interbedded reservoirs. As the production capacity of the main reservoirs declines, so does the production capacity of the wells, and the long-term production of the main reservoirs has led to severe complex blockage of the reservoir. In acidizing, conventional acidizing processes consume large quantities of acid rapidly upon contact with the formation, limiting their effective operating distance and causing a continuous decline in acidizing effectiveness. The difficulty in large-scale stimulation of thin, poorly shaped reservoirs hinders the effective utilization of reserves.

[0006] Pneumatic deep-penetration fracturing technology utilizes a primary agent (non-explosive) to react in the near-wellbore formation, generating controllable high-pressure gas to create multiple fractures uncontrolled by geostress. This indirectly triggers an exothermic reaction of auxiliary agents in the reservoir, generating a large amount of high-temperature, high-pressure gas (including HCl, N2, and CO2) as subsequent pressure replenishment, further expanding the created fractures. Finally, acid is injected and mixed with the hydrochloric acid produced earlier, causing the acid to etch the fracture walls, preventing complete closure after the fracturing process. This achieves a small-volume acid fracturing effect, relieving deep reservoir blockage. This technology produces lower peak pressures than explosive fracturing and high-energy gas fracturing, and the pressure is controllable. Furthermore, the nitrogen produced in the reaction aids in subsequent flowback. However, current pneumatic deep-penetration composite fracturing processes and devices suffer from drawbacks such as difficulty in well selection, poor process applicability, and difficulty in evaluating the effectiveness of the measures. Therefore, designing a pneumatic composite fracturing technology and evaluation method for enhancing production and injection in low-to-medium permeability reservoirs is essential. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for evaluating the combined production enhancement and gas injection unblocking capabilities of low-to-medium permeability reservoirs. This solves the problem of the difficulty in large-scale fracturing of thin, poor-permeability layers in low-to-medium permeability reservoirs, resulting in ineffective reserve utilization; it also addresses the issues of long construction cycles, high costs, and poor economic benefits associated with traditional fracturing techniques; it resolves the lack of effective treatment methods for thin layers or thin interlayers; and it overcomes the difficulty in evaluating the effectiveness of traditional fracturing techniques. To achieve the above objectives, this invention provides the following technical solution:

[0008] This invention provides a method for evaluating the combined unblocking capacity of gas injection and production enhancement in low-to-medium permeability reservoirs, the method comprising the following steps:

[0009] Determine the type of well to be addressed, which includes oil wells or water wells;

[0010] Based on the type of well to be addressed, determine whether to implement measures according to the well selection conditions;

[0011] If measures are implemented, well deviation data will be collected, and the location and magnitude of the maximum well deviation will be identified.

[0012] The transmission type is determined based on the shaft inclination.

[0013] Implement aerodynamic operations based on the transmission type;

[0014] Acidizing operations will be carried out after pneumatic operations;

[0015] Evaluate the effectiveness of the measures implemented on oil or water wells.

[0016] Furthermore, the well selection conditions include:

[0017] (1) The formation pressure level is maintained above 80%;

[0018] (2) The initial production capacity is greater than 2 tons / day, the cumulative oil production is less than 5,000 tons, and the remaining recoverable oil reserves are greater than 40%.

[0019] (3) The production of adjacent wells is greater than 2 tons / day;

[0020] (4) Daily oil production is less than 1 ton / day, water content is less than 40%, or liquid volume is less than 1 cubic meter / day, water content is greater than 80%;

[0021] (5)5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment, and acoustic amplitude < 40% well;

[0022] (6) The reservoir temperature is less than 90℃;

[0023] Measures can be implemented when the well selection conditions for oil wells meet (5) and (6), and at least one of (1)-(4) meets one of the conditions.

[0024] Furthermore, the well selection conditions include:

[0025] (1) The validity period of conventional acidification is less than 90 days, and the validity period of additional injection is less than 90 days;

[0026] (2) Wells with an effective period of less than 90 days after multiple measures;

[0027] (3) Wells where more than 4 years have passed since the last injection enhancement measure;

[0028] (4) Wells with a single-layer water absorption rate greater than 60%;

[0029] (5)5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment, and acoustic amplitude < 40% well;

[0030] (6) The reservoir temperature is less than 90℃;

[0031] Measures can be implemented when the well selection conditions meet (5) and (6), and at least one of (1)-(4) meets the conditions.

[0032] Furthermore, the determination of transmission type based on well inclination includes:

[0033] If the well inclination is less than 40°, use cable transmission; if the well inclination is greater than 40°, use tubing transmission.

[0034] Furthermore, the aforementioned implementation of aerodynamic operations based on transmission type includes:

[0035] 1) Pneumatic operation for oil pipeline transmission:

[0036] Use tubing to lower the pneumatic reagent to the designated target layer, activate the start-up device to initiate the reagent reaction; tubing transfer: refer to SY T 6412-1999 tubing delivery perforation process specification standard;

[0037] 2) Pneumatic operation of cable transmission:

[0038] Use a cable to lower the pneumatic reagent to the designated target layer, then activate the start-up device to initiate the reagent reaction; Cable transmission: Refer to SY / T 6821-2011 Technical Specification for Live Perforation Operations with Cable Transmission, SY / T 5600-2016 Technical Specification for Oil Cable Logging Operations, and SY / T 5299-2016 Technical Specification for Special Perforation Operations with Cable Transmission.

[0039] Furthermore, the oil wells are evaluated using the input-output ratio, and the calculation formula is as follows:

[0040]

[0041] In the formula: CB represents the incremental input-output ratio of the measure; Δq represents the cumulative increase in oil (gas) volume of the measure in the current year, in 10,000 tons (10,000 cubic meters); P represents the crude oil price, in yuan / ton (yuan / cubic meter); Tax represents the tax and fees per ton of oil, in yuan / ton; I represents the total input of the measure in the current year, in 10,000 yuan; ΔC represents the increase or decrease in costs incurred after the measure is implemented, in 10,000 yuan.

[0042] Furthermore, the formula for calculating Δq is as follows:

[0043]

[0044] In the formula: q mi After indicating the measures, verify the monthly oil production, q d Let d represent the average daily output before the measures, d represent the number of production days in the current month, and n≥1.

[0045] Furthermore, q d The calculation formula is as follows:

[0046]

[0047] In the formula: q di Let n represent the daily output for each of the n days prior to the implementation of the measure, where n ≥ 2.

[0048] Furthermore, the water well is evaluated using the rate of change in water absorption thickness, and the calculation formula is as follows:

[0049]

[0050] In the formula: λ represents the rate of change of water absorption thickness of the injection well, h0 represents the water absorption thickness of the injection well before the measures are taken, and h1 represents the water absorption thickness of the injection well after the measures are taken.

[0051] Furthermore, when λ≤0, the measure is ineffective; when 20≥λ>0, the measure is ineffective; when 60≥λ>20, the measure is good; and when λ>60, the measure is effective.

[0052] This invention also provides a system for evaluating the combined unblocking capacity of gas dynamics for increasing production and injection in low-to-medium permeability reservoirs, the system comprising:

[0053] A module for determining the type of well to be addressed, which includes oil wells or water wells;

[0054] The well selection condition judgment module is used to determine whether to implement measures based on the type of well to be treated and the well selection conditions.

[0055] The well deviation data collection module is used to collect well deviation data and find the location and magnitude of the maximum well deviation if measures are implemented.

[0056] The transmission type determination module is used to determine the transmission type based on the shaft inclination.

[0057] The pneumatic operation implementation module is used to perform pneumatic operations based on the transmission type.

[0058] Acidizing operation module, used to carry out acidizing operations after pneumatic operations;

[0059] The effect evaluation module is used to evaluate the effects of the measures implemented on oil wells or water wells.

[0060] The technical effects and advantages of this invention are as follows:

[0061] 1. Solve the problem of difficulty in large-scale fracturing of thin and poor-permeability reservoirs in low-to-medium permeability reservoirs, which makes it difficult to effectively utilize reserves:

[0062] Fracturing thin and poor-permeability reservoirs is characterized by thin reservoirs or interlayers. Traditional fracturing methods are prone to failure in thin layers due to the large scale of the fracturing operation; acidizing cannot accurately treat thin layers due to the physical sealing problem of packers. This invention can precisely deliver pneumatic agents to the layer to be treated via cable or tubing, and after activation, pneumatic fracturing can be used to create fractures layer by layer, allowing for layer-by-layer fracturing.

[0063] 2. Solves the problems of long construction cycle, high cost and poor economic benefits of traditional fracturing and modification measures:

[0064] Traditional fracturing costs mainly include labor, material (fracturing fluid, proppant), and machinery (fracturing truck and fuel). Fracturing also consumes a large amount of water (over 1000 cubic meters for vertical wells and over 10000 cubic meters for horizontal wells). The average well occupancy period is around 15 days, with treatment costs exceeding 1 million RMB. It has low tolerance for error and cannot be implemented in large-scale operations. This invention shortens the well occupancy period to approximately 5 days, with an overall treatment cost of around 300,000 RMB. It offers low treatment costs, wide applicability, and low oil production increase.

[0065] 3. Solve the problem of difficulty in evaluating the effectiveness of traditional process measures:

[0066] Traditional methods rely solely on increased oil production as the performance evaluation criterion, making it difficult to accurately describe the economic benefits of water injection wells. This invention quantifies the input-output ratio of oil wells, thus redefining the economic benefits of various indicators.

[0067] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0068] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0069] Figure 1 This is a flowchart of a method for evaluating the combined unblocking capacity of gas-injection-enhanced production in low-to-medium permeability reservoirs according to the present invention.

[0070] Figure 2 This is a schematic diagram of a combined gas injection and unblocking capability evaluation system for increasing production and injecting gas in medium-low permeability reservoirs according to the present invention. Detailed Implementation

[0071] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] The flowchart shown in the attached diagram is merely an illustrative example and does not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0073] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0074] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or sub-modules is not necessarily limited to those steps or sub-modules that are explicitly listed, but may include other steps or sub-modules that are not explicitly listed or that are inherent to such process, method, product, or device.

[0075] To address the shortcomings of existing technologies, this invention discloses a method for evaluating the combined unblocking capacity of gas injection and production enhancement in low-to-medium permeability reservoirs. Figure 1 This is a flowchart of a method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs, as described in this invention. Figure 1 As shown, the method includes the following steps:

[0076] Step S1: Determine the well to be addressed:

[0077] Oil wells showed a significant decline in production, resulting in low output and low efficiency; water wells showed high injection pressure, failing to meet geological requirements.

[0078] Step S2, Well Selection:

[0079] The technical measures and well selection criteria are determined, including the following:

[0080] 1) Well selection conditions (conditions (5) and (6) must be met, and at least one of (1)-(4) must be met).

[0081] (1) The formation pressure level remains high (the formation pressure level remains above 80%);

[0082] (2) High initial production capacity (greater than 2 tons / day), low cumulative production (cumulative oil production less than 5,000 tons), and abundant remaining oil (recoverable reserves of remaining oil greater than 40%).

[0083] (3) Wells with high production rates adjacent to the main well (greater than 2 tons / day);

[0084] (4) Low daily oil production (less than 1 ton / day), low water content (less than 40%) or low liquid volume (less than 1 cubic meter / day) high water content oil wells (more than 80%);

[0085] (5) Good well condition, intact casing (5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment), and good cementing quality (sound amplitude value < 40%).

[0086] (6) The reservoir temperature is less than 90℃.

[0087] 2) Well selection conditions (conditions (5) and (6) must be met, and at least one of (1)-(4) must be met).

[0088] (1) Conventional acidification has a short effective period (less than 90 days) and poor injection effect (injection effective period is less than 90 days);

[0089] (2) Wells where multiple measures have been taken but the measures have been ineffective or have poor results (validity period less than 90 days);

[0090] (3) Wells whose fractures have closed after a long period of water injection (more than 4 years since the last injection measure);

[0091] (4) Uneven water absorption in the perforated section, and single-layer water injection surge in wells (single-layer water absorption greater than 60%).

[0092] (5) Good well condition, intact casing (5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment), and good cementing quality (sound amplitude value < 40%).

[0093] (6) The reservoir temperature is less than 90℃.

[0094] Step S3: Collect well inclination data:

[0095] Collect wellbore inclination data and find the location and magnitude of the maximum inclination.

[0096] Step S4: Determine the transmission method:

[0097] If the well inclination is less than 40°, use cable transmission; if the well inclination is greater than 40°, use tubing transmission.

[0098] Step S5, Aerodynamic Operation:

[0099] Based on the geological design, the layers are reasonably stratified, the location and frequency of the measures are determined, and then, referring to the oil well perforation tubing and cable transmission methods, the pneumatic agent is placed into the target layer, equipped with a targeted start-up device, and pneumatic fracture creation is carried out after start-up.

[0100] Tubing transport: Refer to SY T 6412-1999 Tubing transport perforation process specification standard.

[0101] Cable transmission: Refer to SY / T 6821-2011 Technical Specification for Live Perforation Operations via Cable Transmission, SY / T5600-2016 Technical Specification for Oil Cable Logging Operations, and SY / T 5299-2016 Technical Specification for Special Perforation Operations via Cable Transmission.

[0102] 1) Pneumatic operation for oil pipeline transmission:

[0103] The pneumatic reagent is cascaded down to the designated target layer using an oil pipe, and the starting device is activated to induce a reaction in the reagent.

[0104] 2) Pneumatic operation of cable transmission:

[0105] Use a cable to lower the pneumatic reagent to the designated target layer, then turn on the starting device to initiate the reagent reaction.

[0106] Step S6: Acidization is performed after pneumatic operation.

[0107] To further enhance reservoir permeability at the distal end of the fracture, acidizing operations were conducted after pneumatic operations. The design, construction, and evaluation specifications for acidizing oil and water wells (SY / T6334-2013) were followed.

[0108] Pump in the designed amount of acid solution, which then enters the formation for acidification.

[0109] Step S7, Effect Evaluation:

[0110] 1) Evaluation of oil well performance:

[0111] Using the input-output ratio (CB) as the evaluation method, the specific calculation method is as follows:

[0112]

[0113] In the formula: CB represents the incremental input-output ratio of the measure; Δq represents the cumulative increase in oil (gas) volume of the measure in the current year, in 10,000 tons (10,000 cubic meters); P represents the crude oil price (excluding value-added tax, calculated based on the average sales price of the current year), in yuan / ton (yuan / cubic meter); Tax represents the taxes and fees per ton of oil (education surcharge, urban construction tax, resource tax, and mine resource compensation fee), in yuan / ton; I represents the total input of the measure in the current year (operating costs + external expenses), in 10,000 yuan; ΔC represents the increase or decrease in costs after the measure is implemented, with a positive or negative sign. When performing overall calculations for the current unit, for the sake of simplicity, 5% of the operating cost is taken, and a negative value is taken, in 10,000 yuan (generally speaking, the operating cost of oil and gas wells will generally decrease slightly after the measure is implemented).

[0114] 1) The method for determining the increase in oil (gas) volume Δq is as follows:

[0115] (1) In principle, the average daily oil production data verified several days before the measures shall be used as the standard; if the well to be measured is a long-term shut-in well, the calibration base shall be 0; if the production is abnormal several days before the measures (due to abnormal production conditions caused by non-geological factors), the average oil production of several days of normal production shall be used as the standard.

[0116]

[0117] In the formula: q d q represents the average daily output before the measures were implemented. di This represents the daily output over the n days prior to the measure, where n ≥ 2. To make the average daily output after the measure more accurate, the value of n can be adjusted, for example, by taking n = 30.

[0118] (2) Monthly oil production increase per well = verified monthly oil production after the measures – average daily production before the measures * number of production days in the current month (Note: ① A negative value for the monthly oil production increase of the measures well indicates that no oil production was increased in the current month, and the value is 0; ② Under normal production conditions, if the measures well does not produce oil for 3 consecutive months, it is considered that the measures are automatically terminated and the oil production increase will no longer be calculated), and the oil production increase per well = the sum of the monthly oil production increases of the single well.

[0119]

[0120] In the formula: q mi The measures are used to verify the monthly oil production, where d represents the number of production days in the current month, and n≥1.

[0121] (3) Daily oil production increase per well = Daily oil production verified after measures - Average daily production before measures.

[0122] 2) Evaluation of the effect of water wells:

[0123] The rate of change in the water absorption thickness of the injection well is used as a standard for the effectiveness of the water injection well measures.

[0124]

[0125] Where: λ represents the rate of change of water absorption thickness of the injection well, h0 represents the water absorption thickness of the injection well before the measures are taken, and h1 represents the water absorption thickness of the injection well after the measures are taken.

[0126] When λ≤0, the measure is ineffective; when 20≥λ>0, the measure is ineffective; when 60≥λ>20, the measure is good; when λ>60, the measure is effective.

[0127] Example 1: (Oil Well)

[0128] Example 1 of this invention discloses a method for evaluating the combined unblocking capacity of gas injection and production enhancement in low-to-medium permeability reservoirs, comprising the following steps:

[0129] Step S1: Determine the well to be addressed:

[0130] A well in the N1-N21 reservoir of the Gakule Oilfield in Qinghai Oilfield was put into production in March 2023, with an initial daily fluid production of 9.18 m³. 3 The daily oil production was 8.75 tons with a water content of 3.60%, maintained for 3 days, after which production gradually decreased to around 3.0 tons of oil per day. After two months of stable production, both liquid and oil production further declined, currently at 1.58 m³ per day. 3 The well produces 1.08 tons of oil per day with a water cut of 31.39%. The significant decrease in both fluid and oil production in this well meets the requirements for improvement measures.

[0131] Step S2, Well Selection:

[0132] This well is an oil well.

[0133] (1) The formation pressure level remains high, exceeding 100%;

[0134] (2) In the initial stage of production, the output was stable at 3 tons / day, with a cumulative output of 360 tons of oil and abundant remaining oil.

[0135] (3) The adjacent well is shut down and there are no producing wells;

[0136] (4) The current daily liquid production is 1.58m³. 3 Daily oil production is 1.08 tons, with a water content of 31.39%.

[0137] (5) The well condition is good, the casing is intact, and the cementing quality is good;

[0138] (6) Static temperature of the reservoir: 62.4℃.

[0139] Well selection conditions (1), (2), (5), and (6) can be implemented.

[0140] Step S3: Collect well inclination data:

[0141] The maximum inclination of the well is 5.73°, located at 1916m.

[0142] Step S4: Determine the transmission method:

[0143] For well inclination less than 40°, cable transmission is used.

[0144] Step S5, Aerodynamic Operation:

[0145] Use a cable to lower the pneumatic reagent to the designated target layer, then turn on the starting device to initiate the reagent reaction.

[0146] To achieve precise positioning and modification, the corresponding layers for the drug locations are shown in Table 1 below:

[0147] Table 1. Measure strata corresponding to the location of the drug agent.

[0148]

[0149] Step S6, Acidification:

[0150] Pump in acid (slow-speed acid), pump in the designed amount of acid (based on reservoir thickness, acidizing radius, and reservoir porosity), and the acid enters the formation for acidizing treatment;

[0151] Step S7, Effect Evaluation:

[0152] (1) Average daily output q before the measures d Sure.

[0153] The well began pumping on October 3, 2023, and as of December 19, 2023, it had been producing for 78 days, with a current daily fluid production of 4.48 m³. 3 It produces 4.2 tons of oil per day, with a water content of 9.6%.

[0154] When n = 30, q d =1.27t.

[0155] That is, the average daily output q before the measures. d It is 1.27t.

[0156] (2) Determination of the increase in oil volume Δq.

[0157] Δq=36.26-1.27*29+58.64-1.27*30+79.13-1.27*19=74.97t.

[0158] That is, the increase in oil production over 78 days is 74.97 tons.

[0159] (3) Daily oil increase determined.

[0160] Daily oil production increase per well = Verified daily oil production after measures - Average daily production before measures = 4.2 - 1.27 = 2.93t.

[0161] That is, the current daily oil production of this well is 2.93 tons.

[0162] (4) Calculate the input-output ratio (CB).

[0163] P—Crude oil price is calculated based on the average annual sales price in 2022, at 3800 yuan / ton (yuan / cubic meter);

[0164] Tax—tax and fees per ton of oil, 570 yuan / ton;

[0165] I—Total investment in measures for the year (operational costs + external expenses), 420,000 yuan. Of this, measures cost 225,000 yuan and technical service costs cost 195,000 yuan.

[0166] ΔC—Cost increase or decrease after the intervention operation, with a positive or negative sign. When performing overall calculations for this unit, for the sake of simplicity, it is taken as 5% of the operating cost, and a negative value of -25,250 yuan (generally speaking, the operating cost of oil and gas wells will usually decrease slightly after the intervention operation).

[0167]

[0168] If the input-output ratio reaches 1.0, the required Δq is: Δq=(42-2.525)×10000÷(3800-570)=122.2 tons. If the current output is maintained, it will take another 17 days to recover the input.

[0169] If the input-output ratio reaches 1.5, the required Δq is: Δq=(42-2.525)×10000÷(3800-570)=183.3 tons. If the current output is maintained, it will take another 37 days to obtain a 50% return.

[0170] Example 2: (Water Well)

[0171] Example 2 of this invention discloses a method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production in low-to-medium permeability reservoirs, comprising the following steps:

[0172] Step S1: Determine the well to be addressed:

[0173] A well in the N1-N21 reservoir of the Gakule Oilfield in Qinghai Oilfield was put into production in July 2018 and transferred to injection in November 2021. A single-layer surge occurred in a certain layer, and according to sealing data from March 2023, the packers were not airtight.

[0174] Step S2, Well Selection:

[0175] This well is a water well.

[0176] (1) Wells with uneven water absorption in the perforated section and single-layer water injection breakthrough;

[0177] (2) Wells with good well conditions, intact casing, and good cementing quality;

[0178] (3) Static temperature of the reservoir: 51.24℃, reservoir temperature less than 90℃;

[0179] Well selection conditions (4), (5), and (6) can be implemented.

[0180] Step S3: Collect well inclination data:

[0181] The maximum inclination of the well is 28.93°, located at 1470m.

[0182] Step S4: Determine the transmission method:

[0183] For well inclination less than 40°, cable transmission is used.

[0184] Step S5, Aerodynamic Operation:

[0185] Use a cable to lower the pneumatic reagent to the designated target layer, then turn on the starting device to initiate the reagent reaction.

[0186] To achieve precise positioning and modification, the corresponding measures at the drug locations are shown in Table 2 below:

[0187] Table 2. Measure strata corresponding to the location of the drug agent.

[0188]

[0189] Step S6, Acidification:

[0190] Pump in acid solution, pump in the designed amount of acid solution, and the acid solution enters the formation for acidification treatment;

[0191] Step S7, Effect Evaluation:

[0192] The water absorption profiles before and after the well treatment are shown in Table 3 below:

[0193] Table 3 Comparison of water absorption profiles before and after the measures.

[0194]

[0195]

[0196] (1) Determine the water absorption thickness h0 of the injection well before the measures are taken.

[0197] According to Table 3, h0 = 2.3 + 2.5 + 1.5 + 2.4 + 3.8 + 2.3 = 14.8 m;

[0198] (2) Determination of the water absorption thickness h1 of the injection well after the measures.

[0199] According to Table 3, h1 = 2.3 + 2.5 + 4.6 + 2.6 + 2.4 + 3.8 + 2.3 = 20.5m;

[0200] Where: λ represents the rate of change of water absorption thickness of the injection well after the measures, h0 represents the water absorption thickness of the injection well before the measures, and h1 represents the water absorption thickness of the injection well after the measures.

[0201] (3) Calculate the rate of change of water absorption thickness in the injection well.

[0202] λ=(20.5-14.8) / 14.8*100=38;

[0203] Since λ = 38, the effect of the measures is good.

[0204] Based on the above method, the present invention also provides an evaluation system for the combined unblocking capacity of gas injection and production enhancement in low-to-medium permeability reservoirs. Figure 2 This is a schematic diagram of a combined gas-dynamic unblocking capability evaluation system for increasing production and injection in low-to-medium permeability reservoirs according to the present invention. Figure 2 As shown, the system includes: a well type determination module 201, used to determine the type of well to be treated, which includes oil wells or water wells; a well selection condition judgment module 202, used to determine whether to implement measures based on the well type and well selection conditions; a well deviation data collection module 203, used to collect well deviation data and find the maximum well deviation location and well deviation size if measures are implemented; a transmission type determination module 204, used to determine the transmission type based on the well deviation size; a pneumatic operation implementation module 205, used to implement pneumatic operations based on the transmission type; an acidizing operation implementation module 206, used to carry out acidizing operations after pneumatic operations; and an effect evaluation module 207, used to evaluate the effect of the measures on the oil wells or water wells.

[0205] In summary, the beneficial effects achieved by this invention are as follows:

[0206] 1. This invention proposes targeted well selection criteria for oil and water wells using this technology.

[0207] 2. This invention clarifies that different transmission methods are used for different well inclination sizes (with 40° well inclination as the boundary), which can improve the construction period delay caused by cable transmission obstruction.

[0208] 3. This invention significantly improves economic efficiency: the well occupation time of the measure is one day longer than that of acidizing, the effective period is increased by 50%, the oil production is increased by 100%, and the cost of the measure is basically the same; the well occupation time of the measure is 3-4 days shorter than that of fracturing, the effective period of the measure is reduced by 10%, the oil production is reduced by 10%, and the cost of the measure is reduced by 50%.

[0209] 4. This invention improves the reservoir utilization rate of thin interlayers by 30%, thereby enhancing the development effect and recovery rate of oil wells.

[0210] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs, characterized in that, The method includes the following steps: Determine the type of well to be addressed, which includes oil wells or water wells; Based on the type of well to be addressed, determine whether to implement measures according to the well selection conditions; If measures are implemented, well deviation data will be collected, and the location and magnitude of the maximum well deviation will be identified. The transmission type is determined based on the shaft inclination. Implement aerodynamic operations based on the transmission type; Acidizing operations will be carried out after pneumatic operations; Evaluate the effectiveness of the measures implemented on oil or water wells.

2. The method for evaluating the combined unblocking capacity of gas-injection and production enhancement in low-to-medium permeability reservoirs according to claim 1, characterized in that, The well selection conditions include: (1) The formation pressure level is maintained above 80%; (2) The initial production capacity is greater than 2 tons / day, the cumulative oil production is less than 5,000 tons, and the remaining recoverable oil reserves are greater than 40%. (3) The production of adjacent wells is greater than 2 tons / day; (4) Daily oil production is less than 1 ton / day, water content is less than 40%, or liquid volume is less than 1 cubic meter / day, water content is greater than 80%; (5)5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment, and acoustic amplitude < 40% well; (6) The reservoir temperature is less than 90℃; Measures can be implemented when the well selection conditions for oil wells meet (5) and (6), and at least one of (1)-(4) meets one of the conditions.

3. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 1, characterized in that, The well selection conditions include: (1) The validity period of conventional acidification is less than 90 days, and the validity period of additional injection is less than 90 days; (2) Wells with an effective period of less than 90 days after multiple measures; (3) Wells where more than 4 years have passed since the last injection enhancement measure; (4) Wells with a single-layer water absorption rate greater than 60%; (5)5" 1 / 2 casing deformation less than 15%, 5" casing deformation less than 10%, no misalignment, and acoustic amplitude < 40% well; (6) The reservoir temperature is less than 90℃; Measures can be implemented when the well selection conditions meet (5) and (6), and at least one of (1)-(4) meets the conditions.

4. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 1, characterized in that, The method of determining the transmission type based on the well inclination includes: If the well inclination is less than 40°, use cable transmission; if the well inclination is greater than 40°, use tubing transmission.

5. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 1, characterized in that, The aforementioned implementation of aerodynamic operations based on transmission type includes: 1) Pneumatic operation for oil pipeline transmission: Use tubing to lower the pneumatic reagent to the designated target layer, activate the start-up device to initiate the reagent reaction; tubing transfer: refer to SY T 6412-1999 tubing delivery perforation process specification standard; 2) Pneumatic operation of cable transmission: Use a cable to lower the pneumatic reagent to the designated target layer, then activate the start-up device to initiate the reagent reaction; Cable transmission: Refer to SY / T 6821-2011 Technical Specification for Live Perforation Operations with Cable Transmission, SY / T 5600-2016 Technical Specification for Oil Cable Logging Operations, and SY / T 5299-2016 Technical Specification for Special Perforation Operations with Cable Transmission.

6. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 1, characterized in that, The oil wells are evaluated using the input-output ratio, and the calculation formula is as follows: In the formula: CB represents the incremental input-output ratio of the measures; Δq represents the cumulative increase in oil (gas) volume of the measures in the current year, in 10,000 tons (10,000 cubic meters); P represents the price of crude oil, in yuan / ton (yuan / cubic meter); Tax represents the tax and fees per ton of oil, in yuan / ton; I represents the total investment in the measures in the current year, in 10,000 yuan; ΔC represents the increase or decrease in costs incurred after the measures are implemented, in 10,000 yuan.

7. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 6, characterized in that, The formula for calculating Δq is as follows: In the formula: q mi After indicating the measures, verify the monthly oil production, q d Let d represent the average daily output before the measures, d represent the number of production days in the current month, and n≥1.

8. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 7, characterized in that, q d The calculation formula is as follows: In the formula: q di Let n represent the daily output for each of the n days prior to the implementation of the measure, where n ≥ 2.

9. The method for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 1, characterized in that, The water well is evaluated using the rate of change in water absorption thickness, and the calculation formula is as follows: In the formula: λ represents the rate of change of water absorption thickness of the injection well, h0 represents the water absorption thickness of the injection well before the measures are taken, and h1 represents the water absorption thickness of the injection well after the measures are taken.

10. The method for evaluating the combined unblocking capacity of gas dynamics for increasing production and injection in low-to-medium permeability reservoirs according to claim 9, characterized in that, When λ≤0, the measure is ineffective; when 20≥λ>0, the measure is ineffective; when 60≥λ>20, the measure is good; when λ>60, the measure is effective.

11. A system for evaluating the combined unblocking capacity of gas-injection dynamics for increasing production and injection in low-to-medium permeability reservoirs, characterized in that, The system includes: A module for determining the type of well to be addressed, which includes oil wells or water wells; The well selection condition judgment module is used to determine whether to implement measures based on the type of well to be treated and the well selection conditions. The well deviation data collection module is used to collect well deviation data and find the location and magnitude of the maximum well deviation if measures are implemented. The transmission type determination module is used to determine the transmission type based on the shaft inclination. The pneumatic operation implementation module is used to perform pneumatic operations based on the transmission type. Acidizing operation module, used to carry out acidizing operations after pneumatic operations; The effect evaluation module is used to evaluate the effects of the measures implemented on oil wells or water wells.

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