Loose sandstone heavy oil reservoir blocking remover and use method thereofTechnical Field
The invention relates to the technical field of oil and gas exploitation, in particular to a loose sandstone heavy oil reservoir blocking remover and a use method thereof.
Background
In the development process of loose sandstone heavy oil reservoirs, viscosity reduction and sand prevention processes are generally required to improve the development benefits of the oil wells, the viscosity reduction mode is mainly based on thermal viscosity reduction, and meanwhile, the sand prevention intensity is improved by matched extrusion filling sand prevention, so that the sand prevention effective period is prolonged. After the heavy components such as asphaltene, colloid and the like in the petroleum are doped with the muddy and fine sand to be accumulated on the near-wellbore zone and the periphery of the sand filtering pipe after the heavy oil well carries out the huff-puff operation for a plurality of times, the permeability of the areas is reduced, the yield of the oil well is reduced, and the effects of adopting cold production to reduce viscosity or acidizing and unblocking are not ideal. In the production, the operation can only be carried out because of low liquid production amount, and no stratum sand blocking is usually found in the sand filtering pipe during dissection. The problems are high measure cost, long construction period and influence on oil extraction time rate. It is necessary to invent a blocking remover for improving oil well production and reducing operating costs.
At present, the known oil layer blocking removal method adopts conventional acidification measures, but conventional acidification cannot solve the problems at one time, and has low blocking removal efficiency and poor blocking removal effect aiming at the problems. In addition, the patent of the application of the monomolecular quaternary ammonium salt compound as the clay stabilizing, anti-swelling and blocking-removing and injection-increasing agent is filed by the high mango, and the patent publication number is CN1556169A. It can stabilize clay and minerals in stratum, prevent clay expansion, and improve the permeability of stratum, so greatly raising the injection effect of water well and sand prevention and imbibition of oil well. The components, action mechanism (anti-swelling) and structure of the medicine are obviously different from the action mechanism (viscosity reduction and corrosion) of the medicine. The application range of the prior invention is narrow. The present invention can only solve the stratum blocking caused by clay expansion in inorganic blocking, and can solve inorganic stratum blocking and sand preventing screen blocking caused by clay (or particles) expansion, falling, migration, accumulation and scaling, and organic blocking caused by thick oil and reverse emulsion, such as asphalt colloid blocking.
The patent publication number CN105419760B discloses a multi-element synergistic blocking remover, which comprises, by mass, 80-120 parts of water, 5-10 parts of a cleaning and dissolving agent, 15-20 parts of an etching agent, 0.5-1 part of ammonium bifluoride, 0.4-0.6 part of Ninaer, 2.5-3 parts of dodecyl trimethyl ammonium chloride, 0.1-0.3 part of ammonium persulfate, 2.5-3 parts of an SA-3 corrosion inhibitor and 3-5 parts of an iron ion stabilizer for acidification, wherein the patent is obviously different from the patent application. The prior invention has wider application range but two defects. (1) The existing invention has weaker effect on blocking and viscosity reduction caused by deep oil thickening. (2) The prior invention has stronger corrosion effect on metal, and is not suitable for the blockage removal of the blockage type of the sand control screen. The formula of the invention is optimized by a plurality of experiments, has high viscosity reduction efficiency in the aspect of blocking and viscosity reduction caused by deep oil thickening, is specially treated in the aspect of removing the blocking of the sand control screen, and has high blocking removal efficiency and low injury.
Patent publication No. CN103224775B discloses a low-carbon mixed organic acid for oil well blocking removal, and a preparation method and application thereof. The low-carbon mixed organic acid is mainly prepared from the following raw materials, by mass, 4-6% of fatty alcohol, 2.4-2.5% of ethylene oxide, 4-6% of alkylbenzene sulfonic acid, 34-36% of sulfamic acid, 24-26% of oxalic acid, 4-6% of biuret, 8-12% of furazolidone, 8-12% of 3-benzofuranone and 2.4-2.6% of sodium nitrite, wherein the composition of the low-carbon mixed organic acid is obviously different from that of the patent application. The application range of the prior invention is narrow. The present invention can only remove the oil layer blockage (generally, the organic blockage such as asphalt colloid blockage, etc.) caused in the thick oil steam huff-puff process and improve the steam huff-puff exploitation effect, and the present invention can not only remove the inorganic stratum blockage and the sand screen blockage caused by the expansion, the falling, the migration, the accumulation and the scaling of clay (or particles), but also remove the organic blockage caused by the thick oil and the reverse emulsion reasons, including the asphalt colloid blockage.
Patent publication No. CN107325800A discloses a method for removing and inhibiting blockage in thickened oil exploitation and application of a nitrogenous organic compound as a blockage removing and inhibiting agent in thickened oil exploitation. The method comprises the steps of contacting a blocking remover with a blocking object, wherein the blocking remover contains a nitrogenous organic compound, mixing the blocking remover with thin oil, and then injecting the thin oil containing the blocking remover into an oil well to contact the thick oil, wherein the blocking remover contains the nitrogenous organic compound. The application range of the prior invention is narrow. The present invention can only remove the blockage of asphalt, colloid and paraffin in oil layer caused by the production process of thick oil well, and can not only remove the blockage of inorganic stratum and sand screen caused by the expansion, falling, migration, accumulation and scaling of clay (or particles), but also remove the blockage of organic blockage caused by the thick oil and reverse emulsion, including the blockage of asphalt colloid.
The patent publication No. CN111019621B discloses a blocking remover and a preparation method thereof, wherein the blocking remover comprises the following raw materials of bacillus boltzter biosurfactant fermentation liquor and hydrophobic nano silicon dioxide, and can also comprise an emulsifying agent, an antiscaling agent, an antiswelling agent and a cosolvent. The preparation method of the blocking remover comprises the following steps of firstly adding the biosurfactant fermentation liquor, the emulsifying agent and the cosolvent into a reaction vessel, heating, uniformly stirring, secondly adding the antiscaling agent and the antiswelling agent into the solution, stirring and dissolving, and finally continuously heating the prepared solution, adding the hydrophobic inorganic nano particles into the reaction vessel, and uniformly stirring. The blocking remover has lower oil-water interfacial tension, can effectively strip and emulsify the residual oil and colloid asphaltene sediment of a middle-low permeable layer to form low-viscosity emulsion, removes organic blockage, resists high mineralization, can be completely degraded by microorganisms, and is environment-friendly, and the patent is obviously different from the application patent in composition. The application range of the prior invention is narrow. The present invention can only remove the residual oil and deposited colloid asphaltene in the well near the bottom of the transfer well and the clay hydration expansion, and can remove the inorganic stratum blocking and sand screen blocking caused by clay (or particles) expansion, falling, migration, accumulation and scaling, and the organic blocking caused by thick oil and reverse emulsion.
The patent publication number CN102250602A discloses a composite acid blocking remover for an oil well, which comprises, by weight, 50-90 parts of hydrochloric acid, 20-50 parts of hydrofluoric acid, 15-35 parts of acetic acid, 15-35 parts of nitric acid, 4-10 parts of a corrosion inhibitor, 2-8 parts of a penetrating agent, 5-10 parts of inorganic salt, 12-25 parts of an oxidizing agent and 10-30 parts of a clay stabilizer, wherein the composition of the oil well is obviously different from that of the patent application. The application range of the prior invention is narrow. From the formula, the present invention can only remove inorganic blockage and clay hydration expansion in near-wellbore areas, and the present invention can not only remove inorganic stratum blockage and sand screen blockage caused by clay (or particles) expansion, falling, migration, accumulation and scaling, but also remove organic blockage caused by thick oil and reverse emulsion reasons, particularly has the unique high-efficiency thick oil macromolecule viscosity reduction effect, which is not provided by the present invention.
Patent publication No. CN115124989A discloses a thickened oil viscosity reduction cold recovery method and application thereof. The active high molecular viscosity reducer contains a series of active groups, and the surfactant is prepared by reacting at least one selected from polyvinyl alcohol, sulfonate and aromatic ring acid with a second alkali solution. The monomer for preparing the active high molecular viscosity reducer comprises acrylamide, acrylic acid, N-vinyl pyrrolidone and sodium styrenesulfonate, and the molar ratio of the acrylamide to the acrylic acid to the N-vinyl pyrrolidone to the sodium styrenesulfonate is 1:1:1:3. It is obvious that this patent differs significantly from the present invention in terms of composition, manufacture, formulation. The application range of the prior invention is narrow. The invention can only realize viscosity reduction of thick oil, and can solve inorganic stratum blockage and sand screen blockage caused by clay (or particles) expansion, falling, migration, accumulation and scaling, and can also solve organic blockage caused by thick oil and reverse emulsion reasons, including high-efficiency thick oil viscosity reduction function.
Disclosure of Invention
The invention provides a plugging remover for a loose sandstone heavy oil reservoir and a use method thereof, and aims to solve the problems that conventional acidification cannot solve the problems of high sand prevention cost and the like caused by organic and inorganic double plugging in the prior art. The plugging agent for the loose sandstone heavy oil reservoir consists of an organic plugging agent and an inorganic plugging agent, has good plugging performance, and can obviously reduce construction cost while improving the productivity of an oil well.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
The first aspect of the invention provides an organic blocking remover, which comprises the following raw materials of a macromolecular surfactant, an organic solvent, water and dodecylphenol polyoxyethylene ether;
the structural formula of the macromolecular surfactant is shown in the following formula I:
Further, the organic blocking remover comprises the following raw materials in parts by weight, per 100 parts by weight of organic solvent, 5-10 parts by weight of high-molecular surfactant, 3-8 parts by weight of dodecylphenol polyoxyethylene ether and 30-50 parts by weight of water.
Further, the organic solvent is one or more of toluene, xylene, methylnaphthalene and 200# solvent oil.
A second aspect of the present invention provides a method for preparing the organic blocking remover according to the first aspect, the method comprising the steps of:
the preparation of the macromolecular surfactant comprises the following steps:
Mixing and stirring 60-100 parts of dimethylbenzene, 30-60 parts of octadecyl acrylate and 50-100 parts of polymerizable surfactant NE-10, heating to 75-85 ℃ under the protection of nitrogen after reactants are completely dissolved, adding azobisisobutyronitrile for reflux polymerization, and removing a solvent after the reaction is finished to obtain the catalyst;
Adding a high molecular surfactant and dodecylphenol polyoxyethylene ether into an organic solvent according to a certain proportion, adding water while stirring, and stirring at a high speed to obtain the modified starch.
In a third aspect, the invention provides a loose sandstone heavy oil reservoir blocking remover, which consists of an inorganic blocking remover and the organic blocking remover in the first aspect.
Further, the organic blocking remover and the inorganic blocking remover are formed according to the volume ratio of 1-5:1-2.
Further, the inorganic blocking remover comprises, by weight, 20-25 parts of hydrochloric acid, 5-15 parts of hydrofluoric acid, 1-10 parts of fluoroboric acid, 1-5 parts of hydroxyethylidene diphosphate, 1-5 parts of diethylenetriamine penta-methylene phosphonic acid, 1-5 parts of polyaspartic acid, 3-5 parts of acidification corrosion inhibitor, 1-3 parts of anti-emulsifying agent and 30-70 parts of water.
Further, the acidification corrosion inhibitor is a quinoline quaternary ammonium salt acidification corrosion inhibitor.
Further, the emulsifier is polyoxyethylene polyoxypropylene stearyl alcohol ether.
According to the fourth aspect of the invention, the application method of the loose sandstone heavy oil reservoir blocking remover is provided, wherein after the stratum blocking condition is determined, the organic blocking remover is injected first, the inorganic blocking remover is injected after well stewing is finished, and the displacing fluid is injected to perform well shutting reaction.
Compared with the prior art, the invention has the following advantages:
the organic blocking remover has better dispersion and dissolution effects on colloid, asphaltene and wax, can quickly remove the organic blocking in near-wellbore zones, recover the permeability of the near-wellbore zones and improve the liquid production capacity of an oil well, can effectively prevent the wax, colloid and asphaltene from being aggregated again, has certain wax-preventing and blocking-preventing effects, and can be prepared into 5% -10% aqueous solution, and the dissolution and dispersion effects on colloid, asphaltene and wax are almost consistent with those of the oil-based blocking remover. Under the condition that the total dosage of the blocking remover is consistent, the blocking remover has wider blocking removing range and larger blocking removing radius, and can realize blocking removal of deep organic matters.
The inorganic blocking removal system contains multistage ionization weak acids such as fluoboric acid, hydroxyethylidene diphosphate, diethylenetriamine penta-methylene phosphonic acid and the like, has low acid-rock reaction speed, can realize deep acidification blocking removal of a reservoir, has large blocking removal radius, has better blocking removal effect than the existing acid liquor system, has stronger chelating ability on metal ions such as Ca2+、Mg2+、Fe2+、Fe3+ and the like existing in a stratum after acid-rock reaction, can effectively prevent the metal ions from forming secondary precipitation in the reservoir, and avoids secondary damage to the reservoir.
According to the invention, the inorganic blocking remover and the organic blocking remover are mixed according to different proportions, so that uniform emulsion is formed, no precipitate or floccule is generated, and the compatibility of the inorganic blocking remover and the organic blocking remover is good. The two can not cause secondary damage to the reservoir stratum and can not influence the performance of the two when being used simultaneously.
After the plugging removal agent for the loose sandstone heavy oil reservoir is used for removing plugs, the oil well productivity can be improved by more than 30%, and the construction cost is reduced by 70%.
Drawings
FIG. 1 is a graph of viscosity reduction of organic matter for organic plugging agents of different concentrations;
FIG. 2 is a graph showing the deblocking curves of inorganic blocking remover to inorganic substances at different concentrations;
FIG. 3 is a diagram showing the emulsion morphology after the compatibility of the organic blocking remover and the inorganic blocking remover.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present invention. As used herein, the singular forms also are intended to include the plural forms unless the context clearly indicates otherwise, and furthermore, it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, and/or combinations thereof.
In order to enable those skilled in the art to more clearly understand the technical scheme of the present invention, the technical scheme of the present invention will be described in detail with reference to specific embodiments.
Example 1 an organic blocking remover
Preparation method of polymer surfactant
Adding 60 parts of solvent dimethylbenzene into a three-neck flask with a condenser, a thermometer and a stirrer, adding 30 parts of octadecyl acrylate and 50 parts of NE-10, starting stirring, controlling the stirring speed to be 100rpm, heating to 60 ℃, heating to 80 ℃ under the protection of nitrogen after reactants are completely dissolved, weighing about 0.1 part of azodiisobutyronitrile, adding into the three-neck flask, carrying out reflux polymerization for 8 hours at 80 ℃, and evaporating the solvent by using a rotary evaporator to obtain the high-molecular surfactant.
The structural formula of the macromolecular surfactant is as follows:
preparation method of (II) organic blocking remover
Adding 5 parts of the synthesized high molecular surfactant and 8 parts of OP-10 into 100 parts of toluene, starting stirring, controlling the rotation speed to be 500rpm, adding 30 parts of water under the condition of stirring, and stirring at a high speed for 1h to obtain the organic blocking remover.
Example 2 an organic blocking remover
Preparation method of polymer surfactant
Adding 100 parts of solvent dimethylbenzene into a three-neck flask with a condenser, a thermometer and a stirrer, adding 60 parts of octadecyl acrylate and 100 parts of NE-10, starting stirring, controlling the stirring speed to be 100rpm, heating to 60 ℃, heating to 80 ℃ under the protection of nitrogen after reactants are completely dissolved, weighing about 0.1 part of azodiisobutyronitrile, adding into the three-neck flask, carrying out reflux polymerization for 8 hours at 80 ℃, and evaporating the solvent by using a rotary evaporator to obtain the high-molecular surfactant.
Preparation method of (II) organic blocking remover
10 Parts of the synthesized high-molecular surfactant and 3 parts of OP-10 are added into 100 parts of organic solvent (mixture of toluene, dimethylbenzene, methylnaphthalene and 200# solvent oil), stirring is started, the rotation speed is controlled to be 500rpm, 50 parts of tap water is added under the condition of stirring, and the organic blocking remover can be prepared by stirring at a high speed for 1 h.
Example 3 an organic blocking remover
Preparation method of polymer surfactant
Adding 80 parts of solvent dimethylbenzene into a three-neck flask with a condenser, a thermometer and a stirrer, adding 50 parts of octadecyl acrylate and 80 parts of NE-10, starting stirring, controlling the stirring speed to be 100rpm, heating to 60 ℃, heating to 80 ℃ under the protection of nitrogen after reactants are completely dissolved, weighing about 0.1 part of azodiisobutyronitrile, adding into the three-neck flask, carrying out reflux polymerization for 8 hours at 80 ℃, and evaporating the solvent by using a rotary evaporator to obtain the high-molecular surfactant.
Preparation method of (II) organic blocking remover
Adding 7 parts of the synthesized high-molecular surfactant and 5 parts of OP-10 into 100 parts of organic solvent dimethylbenzene, starting stirring, controlling the rotation speed to be 500rpm, adding 40 parts of water under the condition of stirring, and stirring at a high speed for 1h to obtain the organic blocking remover.
Example 4 blocking remover for loose sandstone heavy oil reservoir
The blocking remover consists of an inorganic blocking remover and the organic blocking remover in the volume ratio of 1:1.
The inorganic blocking remover comprises, by weight, 20 parts of hydrochloric acid, 5 parts of hydrofluoric acid, 1 part of fluoroboric acid, 1 part of hydroxyethylidene diphosphate, 1 part of diethylenetriamine penta-methylene phosphonic acid, 1 part of polyaspartic acid, 3 parts of an acidification corrosion inhibitor, 1 part of an anti-emulsifying agent and 67 parts of water.
The acidification corrosion inhibitor is a quinoline quaternary ammonium salt type acidification corrosion inhibitor.
The emulsifier is polyoxyethylene polyoxypropylene stearyl alcohol ether.
Example 5 blocking remover for loose sandstone heavy oil reservoir
The blocking remover consists of an inorganic blocking remover and the organic blocking remover in the embodiment 2 according to the volume ratio of 1:2.
The inorganic blocking remover comprises, by weight, 22.5 parts of hydrochloric acid, 9.6 parts of hydrofluoric acid, 5.2 parts of fluoroboric acid, 2.9 parts of hydroxyethylidene diphosphate, 2.5 parts of diethylenetriamine penta-methylene phosphonic acid, 2.3 parts of polyaspartic acid, 4.1 parts of an acidification corrosion inhibitor, 1.9 parts of an anti-emulsifying agent and 49 parts of water.
The acidification corrosion inhibitor is a quinoline quaternary ammonium salt type acidification corrosion inhibitor.
The emulsifier is polyoxyethylene polyoxypropylene stearyl alcohol ether.
Example 6A blocking remover for a Loose sandstone heavy oil reservoir
The blocking remover consists of an inorganic blocking remover and the organic blocking remover in the embodiment 3 according to the volume ratio of 2:1.
The inorganic blocking remover comprises, by weight, 25 parts of hydrochloric acid, 15 parts of hydrofluoric acid, 10 parts of fluoroboric acid, 5 parts of hydroxyethylidene diphosphate, 5 parts of diethylenetriamine penta-methylene phosphonic acid, 5 parts of polyaspartic acid, 5 parts of an acidification corrosion inhibitor, 3 parts of an anti-emulsifying agent and 30 parts of water.
The acidification corrosion inhibitor is a quinoline quaternary ammonium salt type acidification corrosion inhibitor.
The emulsifier is polyoxyethylene polyoxypropylene stearyl alcohol ether.
Test examples
The organic blocking remover in example 3 is prepared into aqueous solutions with different concentrations, and the viscosity reduction rate of the organic blocking remover on thick oil is evaluated according to the method specified by Q/SH CG 0065-2021.6.3, and the result is shown in figure 1. It can be seen that the viscosity reduction rate is gradually increased along with the increase of the concentration of the organic blocking remover, the viscosity reduction rate of 10% of the organic blocking remover can reach more than 95%, and the viscosity reduction efficiency is high.
The blocking remover for the sandstone heavy oil reservoir in the embodiment 6 is prepared into aqueous solutions with different concentrations, and the blocking removal rate of the aqueous solutions on the sandstone core is tested, and the result is shown in figure 2. As can be seen from FIG. 2, the blocking removal rate of the 40% organic blocking remover to the sandstone core can reach more than 80%, and the blocking removal effect is good.
Compatibility evaluation of inorganic blocking remover and organic blocking remover
The inorganic blocking remover and the organic blocking remover are mixed according to different proportions to form uniform emulsion, no sediment and no floccule are generated, and the compatibility of the inorganic blocking remover and the organic blocking remover is good, as shown in figure 3.
The indexes of wax dissolution rate, colloid asphaltene dissolution rate, sandstone corrosion rate, corrosion rate and the like of the organic blocking remover and the inorganic blocking remover which are mixed according to different proportions in the example 5 are examined later, and the results are shown in the following table 1.
TABLE 1 effects of organic and inorganic blocking remover after mixing in different proportions
The experimental data show that after the organic blocking remover and the inorganic blocking remover are mixed according to different proportions, the wax dissolution rate of the organic blocking remover and the colloid asphaltene dissolution rate are not obviously affected. The method has no influence on the corrosion rate and the corrosion rate of the inorganic blocking remover sandstone core. The two are used simultaneously, so that secondary damage to the reservoir is avoided, and the performance of the two is not influenced.
Site construction method
And the construction wellhead requires that the pressure resistance value meets the related technical standard.
The construction vehicles are required to be 1 700 pump truck, 112 m3 glass fiber reinforced plastic tank, 2 recovery residual liquid tank trucks and 2 water tank trucks.
The procedure was as follows.
(1) The pumping unit horsehead is stopped at the upper dead point by constructors, the pumping unit is stopped, and a wellhead jackscrew, a primary packing and a secondary packing are fastened.
(2) And after the pressure test of the ground pipeline is qualified, the back flushing pipeline is connected, and the back flushing pipeline is used for more than two weeks of oilfield produced water in the block.
(3) And stopping the well when the pressure rises to 3.0MPa, stabilizing the pressure for 5min, and stopping the blockage removing construction with the pump if the pressure drop is not more than 0.2 MPa.
(4) And (3) reversely buckling the polish rod, closing the wellhead main gate, tightening the wellhead jackscrew, and fixing the wellhead on the ground anchor by using four guy ropes.
(5) And closing a high-pressure gate of a flow outlet, performing sleeve test extrusion on oilfield produced water, continuing extrusion for 20m3 after the pressure is stable, measuring the water absorption capacity and the pressure drop condition, and determining the stratum blocking condition.
(6) The organic blocking remover described in example 4 was back extruded and the well was braised for 3 days.
(7) The inorganic blocking remover described in example 4 was back extruded.
(8) And (3) reversely squeezing displacement fluid (oilfield produced water).
(9) After the well is shut in for 1h, the polish rod and the blowout prevention box are respectively arranged after oil and sleeve pressure release, the liquid is discharged and produced by external pulling, and the PH value reaches 6-7 as a qualification after being tested by PH test paper, and the production is carried out by a production management unit.
The effect of each well is shown in table 2 below.
Table 2 statistical table of in-situ implementation effect of unblocking measure well
Construction cost accounting comparisons are shown in table 3 below.
Table 3 construction cost accounting table
* The treatment radius is designed to be 5.8m according to the oil layer thickness of 12.0m, the porosity of 39.0 percent and the permeability of 920 multiplied by 10-3um2.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.