A heterogeneous reservoir biological composite plug removal process

Abstract

The present application relates to the technical field of oilfield stimulation and reconstruction, and particularly relates to a biological composite plugging removal process for heterogeneous reservoirs, which comprises the following steps: (1) injecting a biological plugging removal fluid into an oil well; (2) injecting a diverting acid system into the oil well; (3) injecting the biological plugging removal fluid into the oil well; and (4) injecting a displacement fluid into the oil well. The biological plugging removal fluid first enters a high-permeability reservoir, effectively removes organic plugging caused by wax and asphaltene precipitation, and exposes inorganic impurities wrapped therein, which is beneficial to the subsequent dissolution of inorganic plugging by the diverting acid system. After the injection of the diverting acid system, the acid enters the high-permeability reservoir, effectively removes inorganic scale, and meets the needs of plugging removal in complex scale reservoirs of the oil well. With the acid-rock reaction, the viscosity of the acid system increases, temporarily plugs the high-permeability reservoir, forces the subsequent acid and biological plugging removal fluid to enter a low-permeability reservoir, so that the low-permeability oil layer is treated, and the needs of the heterogeneous oil well stimulation are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field stimulation and reconstruction, and particularly relates to a biological composite plugging removal process for heterogeneous reservoirs. BACKGROUND

[0002] With the oil field development entering the middle and high water cut later stage, the oil well scaling problem becomes more and more serious, and the oil well scaling problem seriously restricts the normal production development of the oil field and brings major economic losses. The scaling is mainly formed by inorganic scales such as calcium carbonate, calcium sulfate, iron rust and organic scales such as colloid, asphaltene and wax. The current scaling removal using organic solvents is difficult to remove the mixed scale type, and has problems such as high toxicity and low flash point. The simple hot well washing process is also difficult to achieve the purpose.

[0003] The biological enzyme plugging removal technology is a new oil reservoir plugging removal technology developed in recent years under the background of rapid development of biological technology. It has good safety and stability, does not harm the operating personnel and does not pollute the environment. It does not corrode the oil and gas field pipelines and pipe columns, only biochemical reactions occur between it and the crude oil, the characteristics of the crude oil are not changed, no emulsification occurs, and no new derivatives are produced. Therefore, after being injected into the formation, it will not plug the oil reservoir due to scaling, and will not pollute the oil reservoir. Therefore, it has been widely used in the development of oil and gas fields. However, the biological enzyme plugging removal product has poor effect in solving the plugging of heterogeneous formations. After the biological enzyme plugging removal agent is squeezed into the formation, it mostly enters the high water cut layer with good permeability. The biological enzyme plugging removal agent only has the effect of removing organic plugging such as wax and asphaltene, and cannot remove inorganic scales such as calcium carbonate, calcium sulfate and iron rust. This greatly limits its application in the oil field plugging removal process. Therefore, a composite plugging removal system is needed to enter the formation, which can effectively remove the organic and inorganic plugging in the near wellbore zone of the heavy oil reservoir, and can also reform the low permeability reservoir in the heterogeneous oil reservoir to meet the needs of increasing the production of the heterogeneous oil well. SUMMARY

[0004] The present application aims at the deficiencies in the prior art, and provides a biological composite plugging removal process for heterogeneous reservoirs to solve the problems in the prior art acidizing plugging removal technology. The biological composite plugging removal process for heterogeneous reservoirs can remove organic and inorganic plugging, temporarily plug the high permeability reservoir, force the biological plugging removal liquid and the acid liquid to enter the low permeability reservoir, treat the low permeability reservoir, and meet the needs of increasing the production of the heterogeneous oil well.

[0005] To solve the above technical problems, the technical scheme provided by the present application is as follows:

[0006] The present application provides a biological composite plugging removal process for heterogeneous reservoirs, which comprises the following steps: (1) injecting a biological plugging removal liquid into an oil well; (2) injecting a diverting acid system into the oil well; (3) injecting a biological plugging removal liquid into the oil well; and (4) injecting a displacement liquid into the oil well.

[0007] The biological plugging solution comprises the following raw materials in parts by weight: 2-5 parts of biological enzyme, 1-3 parts of biological enzyme stabilizer, 0.5-1 part of surfactant, and the rest is water.

[0008] Further,

[0009] The biological enzyme is a new glycoprotein produced by thermophilic bacillus DM-2, and the composition includes glucose, lysine, alanine, valine, methionine and glycine.

[0010] The biological enzyme stabilizer is one or both of dodecyl alcohol polyoxyethylene ether sodium sulfate and disodium ethylenediaminetetraacetate.

[0011] The surfactant is one or both of fluorinated heavy alkyl benzene sulfonate, lignin sulfonate and petroleum sulfonate.

[0012] Further,

[0013] The preparation steps of the biological plugging solution include: adding 2-5 parts of biological enzyme in a stirring tank, then adding 91-96.5 parts of water, 1-3 parts of biological enzyme stabilizer, and 0.5-1 part of surfactant, and stirring uniformly to obtain the biological plugging solution.

[0014] Further,

[0015] The diverting acid system comprises the following raw materials in parts by weight: 15-20 parts of industrial hydrochloric acid, 5-8 parts of diverting agent, 1-2 parts of corrosion inhibitor, 1-2 parts of multi-effect additive, and the rest is water.

[0016] Further,

[0017] The diverting agent is any one of oleic acid amide propyl betaine, erucic acid amide propyl betaine, cocamide propyl hydroxyl sulfobetaine, and lauryl amide propyl betaine.

[0018] The corrosion inhibitor is any one or mixture of any ratio of the following: aldehyde ketone amine polycondensate corrosion inhibitor, pyridine quaternary ammonium salt corrosion inhibitor, and imidazoline corrosion inhibitor.

[0019] The multi-effect additive comprises the following composition: citric acid, octadecyl trimethyl ammonium chloride, and lauryl amide propyl betaine.

[0020] Further,

[0021] The weight parts of each raw material in the multi-effect additive are as follows: 20-40 parts of citric acid, 10-15 parts of octadecyl trimethyl ammonium chloride, and 5-10 parts of lauryl amide propyl betaine, and the rest is water.

[0022] Further,

[0023] The preparation steps of the multi-effect additive include: adding water in a kettle equipped with stirring device, then adding 20-40 parts of citric acid, 10-15 parts of octadecyl trimethyl ammonium chloride, stirring for 1h until completely dissolved, then adding 5-10 parts of lauryl amide propyl betaine, and stirring uniformly, thereby obtaining the multi-effect additive.

[0024] Further,

[0025] The preparation steps of the diverting acid system include: adding 15-20 parts of industrial hydrochloric acid in a stirring tank, then adding 5-8 parts of diverting agent, 1-2 parts of corrosion inhibitor, 1-2 parts of multi-effect additive, and 68-88 parts of water, and stirring uniformly, thereby obtaining the diverting acid system.

[0026] Further,

[0027] The displacement fluid includes the following raw materials in parts by weight: 2-4 parts of KCl and 96-98 parts of water.

[0028] Further,

[0029] The on-site usage of the biological plugging removal fluid is 40-60 cubic meters;

[0030] The on-site usage of the diverting acid system is 40-60 cubic meters;

[0031] The on-site usage of the displacement fluid is 10-20 cubic meters.

[0032] The technical effects that can be achieved by the above technical solutions are as follows:

[0033] The biological plugging removal fluid provided by the application firstly enters the high-permeability reservoir, effectively removes the organic plugging caused by the precipitation of wax and asphaltene, fully exposes the inorganic impurities wrapped therein, and is beneficial to the dissolution of inorganic plugging materials by the subsequent diverting acid system. After the diverting acid system is injected, the acid liquid enters the high-permeability reservoir, effectively removes inorganic scale, and meets the needs of removing plugging in complex scale reservoirs of oil wells. With the acid-rock reaction, the viscosity of the acid liquid system gradually increases, temporarily plugs the high-permeability reservoir, forces the subsequent acid liquid and biological plugging removal fluid to enter the low-permeability reservoir, so that the low-permeability oil layer is treated, and the needs of increasing production of heterogeneous oil wells are met.

[0034] The non-homogeneous reservoir biological composite plugging removal process provided by the application is applicable to plugging removal of oil wells in non-homogeneous reservoirs, can effectively remove organic plugging in the near-wellbore zone of the oil well reservoir, can remove plugging formed by mineral particles and inorganic scale in the formation, and has good temporary plugging and steering effect by using a diverting acid system, temporarily plugs high-permeability reservoirs, forces subsequent acid and biological plugging removal liquid into low-permeability reservoirs, so that the low-permeability oil layer is treated. In addition, the biological plugging removal liquid system does not change the properties of crude oil, does not produce emulsification, does not produce new derivatives, and does not pollute the oil layer. The diverting acid system automatically breaks gel after encountering oil, has small viscosity, no residue, and is easy to flow back, and has small damage to the formation, and has important significance for increasing production of oil wells in non-homogeneous reservoirs. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples.

[0036] Therefore, the following detailed description of the examples of the present application provided herein is not intended to limit the scope of the claimed application, but only represents selected examples of the application. Based on the examples of the present application, all other examples obtained by those skilled in the art without creative work fall within the scope of the present application.

[0037] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples can be obtained from commercial channels unless otherwise specified.

[0038] Example 1

[0039] A non-homogeneous reservoir biological composite plugging removal process, comprising the following steps: (1) injecting biological plugging removal liquid into the oil well; (2) injecting a diverting acid system into the oil well; (3) injecting biological plugging removal liquid into the oil well; (4) injecting a displacement fluid into the oil well.

[0040] In this example, the biological plugging removal liquid is mainly composed of the following raw materials in parts by weight: 5 parts of biological enzyme, 3 parts of biological enzyme stabilizer, 1 part of surfactant and 91 parts of water. The biological enzyme stabilizer is composed of dodecyl alcohol polyoxyethylene ether sodium sulfate and disodium ethylenediaminetetraacetate in a weight ratio of 1:1; the surfactant is composed of fluorinated heavy alkyl benzene sulfonate and lignin sulfonate in a weight ratio of 2:1; the preparation steps of the biological plugging removal liquid include: adding 5 parts of biological enzyme in a stirring tank, then adding 91 parts of water, 3 parts of biological enzyme stabilizer and 1 part of surfactant and stirring uniformly.

[0041] In this embodiment, the diverting acid system is mainly composed of the following raw materials in parts by weight: 15 parts of industrial hydrochloric acid, 6 parts of diverting agent, 1.5 parts of corrosion inhibitor, 1 part of multi-effect additive, 76.5 parts of water; the diverting agent is oleic acid amide propyl betaine; the corrosion inhibitor is composed of aldehyde ketone amine polycondensate corrosion inhibitor, pyridine quaternary ammonium salt corrosion inhibitor, imidazoline corrosion inhibitor in a weight ratio of 5:3:2; the multi-effect additive is mainly composed of the following raw materials in parts by weight: 20 parts of citric acid, 15 parts of octadecyl trimethyl ammonium chloride, 10 parts of lauryl amide propyl betaine; the preparation steps of the multi-effect additive include: adding 55 parts of water into a kettle equipped with a stirring device, then adding 20 parts of citric acid, 15 parts of octadecyl trimethyl ammonium chloride, stirring for 1 h until completely dissolved, then adding 10 parts of lauryl amide propyl betaine, and stirring uniformly to obtain the multi-effect additive.

[0042] In this embodiment, the preparation steps of the diverting acid system include: adding 15 parts of industrial hydrochloric acid into a stirring tank, then adding 6 parts of diverting agent, 1 part of corrosion inhibitor, 1 part of multi-effect additive, and 77 parts of water, and stirring uniformly to obtain the diverting acid system.

[0043] In this embodiment, the displacement fluid is mainly composed of the following raw materials in parts by weight: 2 parts of KCl and 98 parts of water. The preparation steps of the displacement fluid include: adding 98 parts of water into a stirring tank, then adding 2 parts of KCl, and stirring uniformly to obtain the displacement fluid.

[0044] This embodiment is applied in Qinghai Oilfield Yue 4750 well, and the specific process is as follows:

[0045] The production layer depth of Qinghai Oilfield Yue 4750 well is 1685.3m-1706.4m, the permeability is different from 16.8mD to 240.3mD, the permeability range J k =14.3. The oil layer thickness is 19.2m / 2 layers, the effective porosity is 22%, and the average daily liquid production of the well is 1.29m 3 before the process is implemented, and the daily oil production is 0.96t. The non-homogeneous reservoir biological composite plugging removal process of Example 1 is used for plugging removal construction of the well, and the specific implementation steps are as follows:

[0046] S1, plugging component analysis

[0047] Before construction, the oil well plugging sample is analyzed, and the organic plugging material is mainly gum, wax and asphaltene, and the inorganic plugging material is mainly iron tetrasulfide, ferrous sulfide and calcium carbonate.

[0048] S2, determination of the injection amount of biological plugging removal fluid and diverting acid system

[0049] According to the formula Q=π·(R 2 -r w 2)·h·φ Calculation of the amount of biological plugging solution, diversion acid system: design processing radius R = 3 m, effective thickness of 19.2 m, the average reservoir porosity of 22%, the amount of liquid required 120 m 3 (Q: liquid volume, m 3 , R: processing radius, m; h: processing layer thickness, m; φ: processing layer porosity, %; r w : wellbore radius, m).

[0050] S3, injection mode

[0051] First, inject 30 m 3 of biological enzyme plugging agent into the oil well at an injection rate of 0.4 m 3 / min, then inject 60 m 3 of the diversion acid system into the oil well at an injection rate of 0.4-0.6 m 3 / min, then inject 30 m 3 of biological enzyme plugging agent into the oil well at an injection rate of 0.3-0.5 m 3 / min, and finally inject 15 m 3 of displacement fluid into the oil well, and shut in for 4 h.

[0052] S4, effect evaluation

[0053] The average daily liquid production of the well before construction was 1.29 m 3 , the daily oil production was 0.96 t, and the daily water production was 0.33 m 3 . After six months of production, the average daily oil production was 2.79 t / d, and the cumulative oil production was 574.32 t in 454 days, with obvious oil production increase effect.

[0054] The adjacent same layer of well Y6-43 used conventional biological enzyme products for plugging treatment, and injected 100 m 3 of 2% biological enzyme plugging solution at an injection rate of 0.3-0.4 m 3 / min, and shut in for 4 h. The average daily liquid production of the well before construction was 1.45 m 3 , the daily oil production was 0.90 t, and the daily water production was 0.55 m 3 . After 27 days of production, the average daily liquid production was 3.24 m 3 , the average daily oil production was 0.52 t, and the average daily water production was 2.72 m 3 , and the measure was ineffective.

[0055] Example 2:

[0056] A biological composite plugging removal process for heterogeneous reservoirs, comprising the following steps: (1) injecting biological plugging removal fluid into the oil well; (2) injecting diversion acid system into the oil well; (3) injecting biological plugging removal fluid into the oil well; (4) injecting displacement fluid into the oil well.

[0057] In this embodiment, the biological plugging removal fluid is mainly composed of the following raw materials in parts by weight: 2 parts of biological enzyme, 1 part of biological enzyme stabilizer, 0.5 part of surfactant and 96.5 parts of water. The biological enzyme stabilizer is sodium dodecyl alcohol polyoxyethylene ether sulfate; the surfactant is fluorinated heavy alkyl benzene sulfonate and petroleum sulfonate in a weight ratio of 1:2; the preparation steps of the biological plugging removal fluid include: adding 2 parts of biological enzyme in a stirring tank, then adding 96.5 parts of water, 1 part of biological enzyme stabilizer and 0.5 part of surfactant, and stirring uniformly to obtain the biological plugging removal fluid.

[0058] In this embodiment, the diverting acid system is mainly composed of the following raw materials in parts by weight: 20 parts of industrial hydrochloric acid, 8 parts of diverting agent, 2 parts of corrosion inhibitor, 1 part of multi-effect additive, and 69 parts of water; the diverting agent is lauryl amide propyl betaine; the corrosion inhibitor is composed of aldehyde ketone amine polycondensate corrosion inhibitor, pyridine quaternary ammonium salt corrosion inhibitor and imidazoline corrosion inhibitor in a weight ratio of 3:5:2; the multi-effect additive is mainly composed of the following raw materials in parts by weight: 30 parts of citric acid, 10 parts of octadecyl trimethyl ammonium chloride, 8 parts of lauryl amide propyl betaine, and 52 parts of water; the preparation steps of the multi-effect additive include: adding 52 parts of water in a kettle with stirring device, then adding 30 parts of citric acid and 10 parts of octadecyl trimethyl ammonium chloride, stirring for 1 h until completely dissolved, then adding 8 parts of lauryl amide propyl betaine, and stirring uniformly to obtain the multi-effect additive.

[0059] In this embodiment, the preparation steps of the diverting acid system include: adding 20 parts of industrial hydrochloric acid in a stirring tank, then adding 8 parts of diverting agent, 2 parts of corrosion inhibitor, 1 part of multi-effect additive surfactant and 69 parts of water, and stirring uniformly to obtain the diverting acid system.

[0060] In this embodiment, the displacement fluid is mainly composed of the following raw materials in parts by weight: 4 parts of KCl and 96 parts of water. The preparation steps of the displacement fluid include: adding 96 parts of water in a stirring tank, then adding 4 parts of KCl, and stirring uniformly to obtain the displacement fluid.

[0061] This embodiment is applied in Qinghai Oilfield Yueshi 515 inclined well, and the specific process is as follows:

[0062] The Qinghai Oilfield Yueshi 515 inclined well has a production layer depth of 1708m-2122.3m, a permeability of 8mD-63mD, and a permeability range J k =7.88. The oil layer has a thickness of 13.4m / 5 layers, an effective porosity of 17.7%, and a daily liquid production of 2.3m 3 , a daily oil production of 1.31t, and a daily water production of 0.99m 3 . The non-homogeneous reservoir biological composite plugging removal process of Example 2 is used for plugging removal construction of the well, and the specific implementation steps are as follows:

[0063] S1, analysis of the composition of the blockage

[0064] The blockage of the oil well was sampled and analyzed before construction. The results showed that the organic blockage was mainly composed of colloid, wax and asphaltene, and the inorganic blockage was mainly composed of iron sulfide, ferrous sulfide and calcium carbonate.

[0065] S2, determination of the injection amount of the biological blockage removal fluid and the diverting acid system

[0066] The amount of the biological blockage removal fluid and the diverting acid system was calculated according to the formula Q=π·(R 2 -r w 2 )·h·φ, wherein R is the treatment radius (3.2 m), h is the effective thickness (13.4 m), φ is the average porosity of the reservoir (17.7%), and r is the wellbore radius (0.5 m). 3 (Q: liquid amount, m 3 , R: treatment radius, m; h: treatment layer thickness, m; φ: treatment layer porosity, %; r w : wellbore radius, m).

[0067] S3, injection mode

[0068] First, 20 m 3 of the biological enzyme blockage removal agent was injected into the oil well at a speed of 0.4 m 3 / min, then 46 m 3 of the diverting acid system was injected into the oil well at a speed of 0.4-0.6 m 3 / min, then 20 m 3 of the biological enzyme blockage removal agent was injected into the oil well at a speed of 0.3-0.5 m 3 / min, and finally 18 m 3 of the displacement fluid was injected into the oil well, and the well was shut in for 4 h.

[0069] S4, evaluation of the implementation effect

[0070] One month before the construction of the well, the daily liquid production of the well was 2.3 m 3 , the daily oil production was 1.31 t, and the daily water production was 0.99 m 3 . After the pumping was started, the average daily oil production was 2.04 t / d for six months, and the cumulative oil production was 195.82 t for 356 days, which showed a significant increase in oil production.

[0071] The well Yue 343, which is adjacent to the same layer, was treated by using the conventional biological enzyme product for blockage removal. 80 m 3 of the 2% biological enzyme blockage removal fluid was injected at a speed of 0.3-0.4 m 3 / min, the well was shut in for 4 h, one month before the construction of the well, the average daily liquid production of the well was 0.3 m 3 , the daily oil production was 0.26 t, and the daily water production was 0.04 m 3, the average daily liquid production is 2.65m 3 , the average daily oil production is 0.89t, and the average daily water production is 1.76m 3 . The effective period of the measures is 120 days, and the cumulative oil increment of the well is 75.57t, with an average oil increment effect.

[0072] Example 3:

[0073] A heterogeneous reservoir biological composite plugging removal process, comprising the following steps: (1) injecting a biological plugging removal fluid into the oil well; (2) injecting a diverting acid system into the oil well; (3) injecting a biological plugging removal fluid into the oil well; (4) injecting a displacement fluid into the oil well.

[0074] In this embodiment, the biological plugging removal fluid is mainly composed of the following raw materials in parts by weight: 3 parts of biological enzyme, 2 parts of biological enzyme stabilizer, 0.8 parts of surfactant and 94.2 parts of water. The biological enzyme stabilizer is disodium ethylenediaminetetraacetate; the surfactant is composed of lignin sulfonate and petroleum sulfonate in a weight ratio of 3:2; the preparation steps of the biological plugging removal fluid include: adding 3 parts of biological enzyme in a stirring tank, then adding 94.2 parts of water, 2 parts of biological enzyme stabilizer and 0.8 parts of surfactant, and stirring uniformly to obtain the biological plugging removal fluid.

[0075] In this embodiment, the diverting acid system is mainly composed of the following raw materials in parts by weight: 18 parts of industrial hydrochloric acid, 7 parts of diverting agent, 1.5 parts of corrosion inhibitor, 2 parts of multi-effect additive, and 71.5 parts of water; the diverting agent is cocamide propyl hydroxyl sulfobetaine; the corrosion inhibitor is composed of aldehyde ketone amine polycondensate corrosion inhibitor and pyridine quaternary ammonium salt corrosion inhibitor in a weight ratio of 1:1; the multi-effect additive is mainly composed of the following raw materials in parts by weight: 40 parts of citric acid, 10 parts of octadecyl trimethyl ammonium chloride, 5 parts of lauryl amide propyl betaine, and 45 parts of water; the preparation steps of the multi-effect additive include: adding 45 parts of water in a kettle equipped with a stirring device, then adding 40 parts of citric acid, 10 parts of octadecyl trimethyl ammonium chloride, stirring for 1h until completely dissolved, then adding 5 parts of lauryl amide propyl betaine, and stirring uniformly to obtain the multi-effect additive.

[0076] In this embodiment, the preparation steps of the diverting acid system include: adding 18 parts of industrial hydrochloric acid in a stirring tank, then adding 7 parts of diverting agent, 1.5 parts of corrosion inhibitor, 2 parts of multi-effect additive surfactant, and 71.5 parts of water, and stirring uniformly to obtain the diverting acid system.

[0077] In this embodiment, the displacement fluid is mainly composed of the following raw materials in parts by weight: 3 parts of KCl and 97 parts of water. The preparation steps of the displacement fluid include: adding 97 parts of water in a stirring tank, then adding 3 parts of KCl, and stirring uniformly to obtain the displacement fluid.

[0078] This embodiment is applied in Well Ying 5-2-B2 in Qinghai Oilfield, and the specific process is as follows:

[0079] Ying 5-2-B2 well in Qinghai oilfield, production layer depth 1115.2m-1144.9m, permeability from 60.06mD-160.48mD, permeability difference J k =2.67. Oil layer thickness 15.7m / 7 layers, effective porosity 21.35%, one month before the process implementation, the daily liquid production of the well was 2.96m 3 , the average daily oil production was 2.38t, and the daily water production was 0.38m 3 . The non-homogeneous reservoir biological composite plugging removal process of Example 3 was used for plugging removal construction of the well, and the specific implementation steps were as follows:

[0080] S1, plugging component analysis

[0081] Before construction, the plugging of the oil well was sampled and analyzed, and the analysis showed that the organic plugging material was mainly gum, wax and asphaltene, and the inorganic plugging material was mainly iron tetrasulfide, ferrous sulfide and calcium carbonate.

[0082] S2, determination of biological plugging removal fluid and diverting acid system injection amount

[0083] According to the formula Q=π·(R 2 -r w 2 )·h·φ, the amount of biological plugging removal fluid and diverting acid system was calculated: the design treatment radius R was 2.8m, the effective thickness was 15.7m, the average porosity of the reservoir was 21.3%, and the liquid amount required was 80m 3 (Q: liquid amount, m 3 , R: treatment radius, m; h: treatment layer thickness, m; φ: treatment layer porosity, %; r w : wellbore radius, m).

[0084] S3, injection mode

[0085] First, 20m 3 of biological enzyme plugging removal agent was injected into the oil well at a speed of 0.4m 3 / min, then 40m 3 of diverting acid system was injected into the oil well at a speed of 0.4-0.6m 3 / min, then 20m 3 of biological enzyme plugging removal agent was injected at a speed of 0.3-0.5m 3 / min, and finally 10m 3 of displacement fluid was injected into the oil well, and the well was shut in for 4h.

[0086] S4, implementation effect evaluation

[0087] The daily liquid production of the well before construction was 2.96m 3 , the average daily oil production was 2.38t, and the daily water production was 0.38m3 The average daily oil production is 4.0t / d in six months after the production is started, the cumulative oil production is 382.75t in 234 days, and the oil production effect is obvious.

[0088] The well Ying 5-2-B5 is treated by using the conventional biological enzyme product to remove the blockage, 100m 3 of 2% biological enzyme blockage removing liquid is injected at the injection speed of 0.3-0.4m 3 / min, the well is closed for 4h, the average daily liquid production of the well is 0.57m 3 before the construction, the daily oil production is 0.55t, and the daily water production is 0.02m 3 , the cumulative oil production of the well is 109.47t in 194 days after the production is started, the average daily oil production is 0.56t, and the oil production is increased by 2.77t, and the oil production effect is general.

[0089] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A non-homogeneous reservoir biocomposite plugging removal process, characterized in that, It comprises the following steps: (1) injecting a biological plugging removal fluid into the oil well; (2) injecting a diverting acid system into the oil well; (3) injecting a biological plugging removal fluid into the oil well; (4) injecting a displacement fluid into the oil well; The biological plugging removal fluid comprises the following raw materials in parts by weight: 2-5 parts of biological enzyme, 1-3 parts of biological enzyme stabilizer, 0.5-1 part of surfactant, and the rest is water; The biological plugging removal fluid first enters the high-permeability reservoir, effectively removing the organic plugging caused by wax and asphaltene precipitation, and exposing the inorganic impurities wrapped therein, which is beneficial to the subsequent dissolution of inorganic plugging by the diverting acid system; After the diverting acid system is injected, the acid enters the high-permeability reservoir, effectively removing inorganic scale, and meeting the requirements of oil well complex scale formation plugging removal; With the progress of acid-rock reaction, the viscosity of the acid system gradually increases, temporarily plugging the high-permeability reservoir, forcing the subsequent acid and the biological plugging removal fluid to enter the low-permeability reservoir, so that the low-permeability oil layer is treated.

2. The biological composite plugging removal process for heterogeneous reservoirs according to claim 1, characterized in that The biological enzyme is a new type of glycoprotein produced by thermophilic bacillus DM-2, and the composition includes: glucose, lysine, alanine, valine, methionine and glycine; The biological enzyme stabilizer is one or both of dodecyl alcohol polyoxyethylene ether sodium sulfate and disodium ethylenediaminetetraacetate; The surfactant is one or both of fluorinated heavy alkyl benzene sulfonate and lignin sulfonate.

3. The biological composite plugging removal process for heterogeneous reservoirs according to claim 1, characterized in that The preparation steps of the biological plugging removal fluid include: adding 2-5 parts of biological enzyme in a stirring tank, then adding 91-96.5 parts of water, 1-3 parts of biological enzyme stabilizer, and 0.5-1 part of surfactant, and stirring uniformly to obtain the biological plugging removal fluid.

4. The biological composite plugging removal process for heterogeneous reservoirs according to claim 1, characterized in that The diverting acid system comprises the following raw materials in parts by weight: 15-20 parts of industrial hydrochloric acid, 5-8 parts of diverting agent, 1-2 parts of corrosion inhibitor, 1-2 parts of multi-effect additive, and the rest is water.

5. The biological composite plugging removal process for heterogeneous reservoirs according to claim 4, characterized in that The diverting agent is any one of oleic acid amide propyl betaine, erucic acid amide propyl betaine, cocamide propyl hydroxyl sulfobetaine, and lauryl amide propyl betaine; The corrosion inhibitor is any one or a mixture of any ratio of aldehyde ketone amine polycondensate corrosion inhibitor, pyridine quaternary ammonium salt corrosion inhibitor, and imidazoline corrosion inhibitor; The multi-effect additive comprises citric acid, octadecyl trimethyl ammonium chloride, and lauryl amide propyl betaine.

6. The biological composite plugging removal process for heterogeneous reservoirs according to claim 5, characterized in that The weight parts of each raw material in the multi-effect additive are: 20-40 parts of citric acid, 10-15 parts of octadecyl trimethyl ammonium chloride, 5-10 parts of lauryl amide propyl betaine, and the rest is water.

7. The biological composite plugging removal process for heterogeneous reservoirs according to claim 5, characterized in that The preparation steps of the multi-effect additive include: adding water in a kettle with stirring device, then adding 20-40 parts of citric acid, 10-15 parts of octadecyl trimethyl ammonium chloride, stirring for 1 h until completely dissolved, then adding 5-10 parts of lauryl amide propyl betaine, and stirring uniformly, thus obtaining the multi-effect additive.

8. The non-homogeneous reservoir biological composite plugging removal process according to claim 4, characterized in that, The preparation steps of the diverting acid system include: adding 15-20 parts of industrial hydrochloric acid in a stirring tank, then adding 5-8 parts of diverting agent, 1-2 parts of corrosion inhibitor, 1-2 parts of multi-effect additive, and 68-88 parts of water, and stirring uniformly, thus obtaining the diverting acid system.

9. The non-homogeneous reservoir biological composite plugging removal process according to claim 1, characterized in that, The displacement fluid comprises the following raw materials in parts by weight: 2-4 parts of KCl and 96-98 parts of water.

10. The non-homogeneous reservoir biological composite plugging removal process according to claim 1, characterized in that, The on-site usage of the biological plugging removal fluid is 40-60 cubic meters; The on-site usage of the diverting acid system is 40-60 cubic meters; The on-site usage of the displacement fluid is 10-20 cubic meters.