CN111454709B - Seawater-based acid system - Google Patents
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- CN111454709B CN111454709B CN201910056328.8A CN201910056328A CN111454709B CN 111454709 B CN111454709 B CN 111454709B CN 201910056328 A CN201910056328 A CN 201910056328A CN 111454709 B CN111454709 B CN 111454709B
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Abstract
The invention discloses a seawater base acid liquid system, which consists of 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein the preposed acid consists of the following components: 10-15% of HCl, 2-10% of calcium sulfate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. The composition of the main acid is: 1.5-10% of fluoride, 5-15% of supporting acid, 2-4% of fluoride precipitation inhibitor, 2-8% of fluorosilicate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. The composition of the post acid is the same as that of the pre acid. The displacement fluid is selected from seawater. The seawater-based acid liquid system can be prepared by directly using filtered seawater, has the advantages of high dissolving speed, good compatibility, small secondary damage and the like, can greatly improve the offshore acidification construction efficiency, reduces the acidification construction cost, and provides technical support for realizing large-scale offshore acidification construction.
Description
Technical Field
The invention relates to a seawater-based acid liquid system which can be used for acidification operation of offshore oil fields.
Background
Acidification technology is one of the most common measures for increasing production and injection of offshore oil fields. During the acidification operation, clear water, acid liquor and other additives used for preparing the liquid come from the land. The amount of liquid used for acidifying a production well is about 30-100 square, and for a water injection well, the amount of liquid needed for acidifying is about 100-150 square. The transportation costs of such large volumes of water from land to offshore platforms in hundreds of seas are very significant. In addition, the water flooding recovery rate of offshore oil fields is usually only 18 to 25 percent, which is far lower than that of onshore oil fields. The method increases the acid liquor consumption, strengthens the acidification scale, and enables more acid liquor to enter deep stratum, is a feasible method for improving the water injection development effect, and is also one of the future development directions of acidification technologies. However, the increased acid usage will substantially increase material and transportation costs. Therefore, if local materials can be used, the use of seawater instead of fresh water for preparing the acid liquor system is very significant for most offshore oil fields with expensive or unavailable fresh water.
In recent years, with the large-scale development of offshore oil fields, the demand of fresh water resources for oil fields is increasing. Limited by the shortage and difficult acquisition of fresh water, researches and applications of various seawater-based systems are developed at home and abroad, and the method plays an important role in the fields of well drilling and completion, fracturing, oil displacement, profile control and water shutoff and the like. Because working fluids such as seawater-based drilling fluid, completion fluid, fracturing fluid and the like hardly react with the stratum, the seawater is relatively easy to prepare, and only some CaSO on the basis of the original seawater is added4、BaSO4A precipitated scale inhibitor. And the seawater base acid liquid is involved in the reaction with the formation minerals, so that various factors can cause system instability, particularly for sandstone oil reservoir seawater base acidification, the acid liquid system has various components, the acid rock reaction is more complex, and various potential damages caused by multi-step reactions can be amplified by seawater. Typical seawater compositions are shown in table 1. It can be seen that the seawater contains various metal ions, which are easy for acid liquor preparation and acid rock reactionSecondary precipitation during the process, e.g. F in acid liquors during the preparation of amino acids in seawater-Is easy to react with Ca in seawater2+、Mg2+Fluoride precipitates are generated through combination; sulfate precipitates, fluoride precipitates, fluorosilicate precipitates and the like generated in the reaction process of the seawater-based acid liquid and rocks are harmful to the stratum, and the prevention difficulty is high.
TABLE 1 typical seawater composition
The main types of injury in acid rock reactions include:
for oil reservoirs with high carbonate content, the main potential damage of the prepared seawater base acid solution is Ca generated by acid rock reaction2+、Mg2+Can react with a large amount of SO in seawater4 2-The reaction produces a sulfate precipitate.
For the conventional sandstone oil reservoir mainly comprising quartz and feldspar, the main potential damage of the prepared seawater base acid solution is F in acid liquor-With Ca in seawater2+、Mg2+The combination produces fluoride precipitate.
For sandstone oil reservoir with high clay content, the reaction speed and degree of HF and clay are far higher than those of quartz and feldspar, and a large amount of SiF is generated in the reaction process of acid liquor and clay6 2-Is very easy to react with Na in seawater+And K+Combine to form Na2SiF6And K2SiF6。
At present, no report is found about fluoride precipitation and a method for inhibiting fluorosilicate precipitation at home and abroad. Compared with fluoride precipitates, the acid dissolution effect of the fluosilicate precipitates is not obvious, so that the prevention and treatment difficulty is higher.
In conclusion, the research of the current seawater-based acidification system is still in the primary stage, and no great experience can be used for reference; as one of the development directions of offshore oilfield acidification technologies, the method has a wide application prospect.
Disclosure of Invention
Aiming at the prior art and aiming at the problems, the invention provides a seawater-based acid liquid system which can be prepared by directly using filtered seawater, has the advantages of high dissolving speed, good compatibility, small secondary damage and the like, can greatly improve the offshore acidification construction efficiency, reduce the acidification construction cost and provide technical support for realizing offshore large-scale acidification construction.
The invention is realized by the following technical scheme:
a seawater base acid liquid system comprises 4 slugs of pre-acid, main acid, post-acid and displacement liquid, wherein,
the pre-acid is composed of the following components in percentage by weight: 10-15% of HCl, 2-4% of calcium sulfate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. The primary function of the pad acid is to pretreat carbonate minerals in the formation and displace formation water, reducing the risk of fluoride precipitation from the reaction of the host acid with the rock or formation water.
The calcium sulfate precipitation inhibitor is selected from any one or the combination of more than two of diethylenetriamine pentamethylene phosphonic acid, amino trimethylene phosphonic acid, polyepoxysuccinic acid, polyaspartic acid, polyacrylic acid and hydrolyzed polymaleic anhydride; its main function is to prevent SO in seawater4 2-Ca produced by reaction with acid rocks2+Or high concentration of Ca contained in formation water2+Reaction to produce CaSO4Precipitation, causing secondary damage.
The corrosion inhibitor is selected from any one or a combination of more than two of mannich base, propiolic alcohol, imidazoline and phenformin.
The iron ion stabilizer is selected from one or the combination of more than two of citric acid, EDTA and acetic acid.
The demulsifier is selected from any one or the combination of more than two of polyoxyethylene polyoxypropylene octadecanol ether, polyoxyethylene polyoxypropylene polyether and alkyl phenyl polyoxyethylene ether.
The clay stabilizer is selected from one or more of diethylamine hydrochloride, tetramethylammonium chloride, hydroxypropyl trimethylammonium chloride and dimethyl diallyl ammonium chloride.
The main acid comprises the following components in percentage by weight: 1.5-10% of fluoride, 5-15% of supporting acid, 2-4% of fluoride precipitation inhibitor, 2-8% of fluorosilicate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. In order to maintain the compatibility among the slugs, the types of the corrosion inhibitor, the iron ion stabilizer, the demulsifier and the clay stabilizer selected from the main acid are the same as those selected from the pre-acid, and the use concentration can be adjusted according to the actual condition.
The fluoride is selected from HF and NH4HF2、NH4F、HBF4Any one or a combination of two or more of them; its main function is to slowly release F for reaction-And rock minerals such as quartz, feldspar and clay are corroded.
The supporting acid is HCl and has the main function of ionizing H in large quantity+And the lower pH environment of the system is maintained, and the generation of secondary precipitation is inhibited by utilizing the acid effect.
The fluoride precipitation inhibitor is selected from any one or the combination of more than two of hydroxyethylidene diphosphonic acid, ethylene diamine tetra methylene phosphonic acid, amino trimethylene phosphonic acid, 2-phosphonic butane-1, 2, 4-tricarboxylic acid and diethylenetriamine pentamethylene phosphonic acid; the main function of the acid liquor is to prevent F in the acid liquor-With Mg in seawater2-、Ca2+Or small amount of Mg produced by acid rock reaction2-、Ca2+Combined to form MgF2、CaF2And (4) precipitating.
The fluorosilicate precipitation inhibitor is selected from any one or the combination of more than two of 2-hydroxyphosphonoacetic acid, hexamethylenediamine tetramethylidene phosphonic acid, polyamino polyether methylene phosphonic acid and bis-1, 6 hexamethylene triamine pentamethylene phosphonic acid; its main function is to prevent H produced by acid rock reaction2SiF6With Na in seawater+And K+Combine to form Na2SiF6、K2SiF6And (4) precipitating.
The post acid is composed of the following components in percentage by weight: 10-15% of HCl, 2-10% of calcium sulfate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. The main function of the post-acid is to maintain a low pH environment during acidification, preventing pH rise causing controlled precipitate re-formation in the bulk acid. In order to maintain the compatibility among the slugs, the types of the components in the post acid are the same as those in the pre acid, and the use concentration can be adjusted according to the actual stratum conditions.
The displacement fluid is selected from seawater. The displacement fluid has the main function of enabling the acid liquor to fully enter the deep part of the stratum for reaction.
Further, the seawater is selected from seawater with turbidity less than or equal to 40FTU or filtered seawater, namely: seawater with turbidity less than or equal to 40FTU can be directly used as a displacement liquid, and seawater with turbidity more than 40FTU needs to be filtered through a filter tank filled with double-layer filter materials (the filling medium can be anthracite at the upper layer and quartz sand at the lower layer), so that the turbidity of the seawater is lower than 40 FTU.
The seawater-based acid liquid system is prepared by mixing the components uniformly and respectively preparing the pre-acid, the main acid and the post-acid.
The invention also discloses another seawater base acid liquid system (suitable for carbonate reservoirs or sandstone reservoirs with the carbonate content higher than 20%), which consists of preposed acid and displacement liquid, wherein,
the pre-acid is composed of the following components in percentage by weight: 10-15% of HCl, 4-10% of calcium sulfate precipitation inhibitor, 4-10% of ionic strength regulator, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater. The primary function of the pad acid is to pretreat carbonate minerals in the formation and displace formation water, reducing the risk of fluoride precipitation from the reaction of the host acid with the rock or formation water.
The calcium sulfate precipitation inhibitor is selected from diethylenetriamine pentamethyleneAny one or the combination of more than two of methylenephosphonic acid, amino trimethylene phosphonic acid, polyepoxysuccinic acid, polyaspartic acid, polyacrylic acid and hydrolyzed polymaleic anhydride; its main function is to prevent SO in seawater4 2-Ca produced by reaction with acid rocks2+Or high concentration of Ca contained in formation water2+Reaction to produce CaSO4Precipitation, causing secondary damage.
The ionic strength regulator is selected from ammonium chloride, is used for further increasing the solubility of calcium sulfate by improving the ionic strength under high carbonate content (more than 20 percent), and does not need to be added to a common sandstone reservoir with the carbonate content lower than 20 percent.
The corrosion inhibitor is selected from any one or a combination of more than two of mannich base, propiolic alcohol, imidazoline and chlordiazepoxide.
The iron ion stabilizer is selected from one or the combination of more than two of citric acid, EDTA and acetic acid.
The demulsifier is selected from one or the combination of more than two of polyoxyethylene polyoxypropylene octadecanol ether, polyoxyethylene polyoxypropylene polyether and alkyl phenyl polyoxyethylene ether.
The clay stabilizer is selected from one or more of diethylamine hydrochloride, tetramethylammonium chloride, hydroxypropyl trimethylammonium chloride and dimethyl diallyl ammonium chloride.
The displacement fluid is selected from seawater. The displacement fluid has the main function of enabling the acid liquor to fully enter the deep part of the stratum for reaction.
Further, the seawater is selected from seawater with turbidity less than or equal to 40FTU or filtered seawater, namely: the seawater with turbidity less than or equal to 40FTU can be directly used as a displacement liquid, and the seawater with turbidity more than 40FTU needs to be filtered through a filter tank filled with double-layer filter materials (the filling medium can select anthracite on the upper layer and quartz sand on the lower layer), so that the turbidity of the seawater is lower than 40 FTU.
The seawater-based acid liquid system is prepared by mixing and uniformly mixing the components to prepare the preposed acid.
The seawater-based acid liquid system can be used for acidizing operation of offshore oil fields and can be suitable for offshore oil reservoirs of different types. When the method is specifically applied, aiming at different types of oil reservoirs, the following selection principles can be adopted:
for carbonate reservoirs or sandstone reservoirs with the carbonate content higher than 20%, pre-acid and displacement fluid are directly used for acidizing, the selective concentration of the calcium sulfate precipitation inhibitor in the pre-acid is 4% -10%, and 4% -10% of ionic strength regulator needs to be added into the pre-acid.
For the conventional sandstone formation with clay content less than 15%, 4 slugs of pre-acid, main acid, post-acid and displacement fluid are used, and fluoride in the main acid is selected from HF and NH4HF2Or NH4F, the content is 1.5-3%.
For sandstone formations with clay content of more than or equal to 15%, 4 slugs of pre-acid, main acid, post-acid and displacement liquid are used, and HBF is selected as fluoride in the main acid4The content is 5 to 10 percent. HBF4Release H by 4-stage hydrolysis reaction+In contrast to HF and NH4HF2Etc. HBF4Release F-Slower speed of (2); considering that oil reservoirs with high clay content are easy to generate a large amount of fluosilicic acid due to excessive acid-rock reaction to generate fluosilicate which is difficult to dissolve in acid, HBF is required to pass4Controlling the reaction speed of acid rock and slowing down the generation of fluorosilicate precipitate.
The seawater base acid liquid system comprises 4 slugs of preposed acid, main acid, postpositive acid and displacement liquid. The preposed acid is mainly used for pretreating the stratum by using a hydrochloric acid system containing a calcium sulfate precipitation inhibitor, so that the Ca contained in a large amount of stratum water and generated by the reaction of the acid solution and carbonate minerals is prevented2+、Mg2+With SO in seawater4 2-Binding resulted in precipitation. The main acid adopts fluoride to slowly release F-The high-concentration HCl is used as the supporting acid, the precipitation solubility is increased by utilizing the acid effect, and meanwhile, a fluoride precipitation inhibitor and a fluosilicate precipitation inhibitor are added to prevent the generation of secondary precipitation in the preparation of seawater base acid solution and the acid rock reaction process. The post-acid system has the same components and content as the pre-acid system and mainly acts to maintain the acid liquidThe pH value is lower, and the controlled secondary precipitate is prevented from being separated out again after acidification. The displacement liquid adopts filtered seawater, so that acid liquor can enter a deep stratum.
The seawater-based acid liquid system disclosed by the invention takes seawater as a base liquid, so that the offshore acidification construction efficiency can be greatly improved, and the acidification construction cost is reduced; the system has high dissolving speed, easy mixing and good compatibility, can realize on-line continuous mixing construction, and can meet the requirement of large-scale offshore acidification construction; the system can inhibit secondary precipitation generated in the preparation and reaction processes of the seawater-based acid liquid system, and avoid secondary damage to the stratum.
The various terms and phrases used herein have the ordinary meaning as is well known to those skilled in the art.
Drawings
FIG. 1: schematic diagram of the change of the core permeability before and after acidizing evaluated by a core flow experimental device (example 1).
FIG. 2: schematic diagram of the change of the core permeability before and after acidizing evaluated by a core flow experimental device (example 2).
FIG. 3: schematic diagram of the change of the core permeability before and after acidizing evaluated by a core flow experimental device (example 3).
FIG. 4: cross-sectional view of the outlet of the core after acidizing (example 4).
FIG. 5: schematic diagram of the change of the core permeability before and after acidizing evaluated by a core flow experimental device (example 5).
FIG. 6: cross-sectional view of the outlet of the core after acidizing (example 5).
Detailed Description
The present invention will be further described with reference to the following examples. However, the scope of the present invention is not limited to the following examples. It will be understood by those skilled in the art that various changes and modifications may be made to the invention without departing from the spirit and scope of the invention.
The instruments, reagents, materials and the like used in the following examples are conventional instruments, reagents, materials and the like in the prior art and are commercially available in a normal manner unless otherwise specified. Unless otherwise specified, the experimental methods, detection methods, and the like described in the following examples are conventional experimental methods, detection methods, and the like in the prior art.
The filtered seawater referred to in the following examples refers to filtered seawater with turbidity less than or equal to 40FTU, namely: the seawater is filtered by a filter tank filled with double-layer filter materials (the filling medium selects anthracite on the upper layer and quartz sand on the lower layer) to ensure that the turbidity of the seawater is lower than 40 FTU.
Example 1 preparation of sandstone reservoir seawater-based acid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (the total weight is 100 g): 2g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of industrial hydrochloric acid with the mass concentration of 31% (containing 15g of HCl), 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 45.61g of filtered seawater.
The main acid is prepared from the following components (total weight 100 g): 3.75g of hydrofluoric acid with the mass concentration of 40% (including 1.5g of HF), 2g of hydroxyethylidene diphosphonic acid, 2g of 2-hydroxyphosphonoacetic acid, 32.26g of industrial hydrochloric acid with the mass concentration of 31% (including 10g of HCl), 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 55.99g of filtered seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding filtered seawater, diethylenetriamine pentamethylenephosphonic acid, hydrochloric acid, Mannich base, citric acid, polyoxyethylene polyoxypropylene octadecanol ether and diethylamine hydrochloride into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
Preparing a main acid: adding filtered seawater, hydroxyethylidene diphosphonic acid and 2-hydroxyphosphonoacetic acid into a container, starting a magnetic stirrer to stir continuously for 5min, adding hydrofluoric acid, hydrochloric acid, Mannich base, citric acid, polyoxyethylene polyoxypropylene octadecanol ether and diethylamine hydrochloride, and continuously stirring for 5min to obtain the main acid.
The preparation of the postposition acid is the same as that of the preposition acid.
The embodiment also provides an application effect of the prepared seawater base acid liquid system in the yield increase transformation of the sandstone oil reservoir at the temperature of 80 ℃, which comprises the following specific steps:
the change of the permeability of the core before and after acidification was evaluated by using a core flow experimental apparatus, and the result is shown in fig. 1. The core used in the experiment consisted of 60% quartz, 30% feldspar and 10% calcium carbonate. It can be seen that the pressure at the injection end of the core rises after acid injection because the interfacial tension of the acid liquid is high. While the inlet pressure after acidification was significantly lower than before acidification, indicating that acidification was effective. The change in core permeability before and after acidizing is shown in table 2. As can be seen from the table, for the reservoir with the quartz and feldspar contents higher than 90%, the permeability is improved by 45.45% after the acidification by using the seawater-based acid system, and the core permeability is obviously improved, which indicates that no serious secondary damage occurs.
Table 2 change in core permeability before and after acidification of seawater-based acid system in example 1
Example 2 preparation of sandstone reservoir seawater-based acid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 4g of polyepoxysuccinic acid, 38.71g of 31% industrial hydrochloric acid (containing HCl12g), 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 51.29g of filtered seawater.
The main acid is prepared from the following components (total weight 100 g): 2.5g of ammonium bifluoride, 3g of ethylenediamine tetramethylene phosphonic acid, 3g of hexamethylenediamine tetramethylene phosphonic acid, 38.71g (containing 12g of HCl) of 31% industrial hydrochloric acid, 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 46.79g of filtered seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding filtered seawater, polyepoxysuccinic acid, hydrochloric acid, propiolic alcohol, EDTA, polyoxyethylene polyoxypropylene polyether and tetramethylammonium chloride into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
Preparing a main acid: adding filtered seawater, ethylenediamine tetramethylene phosphonic acid and hexamethylenediamine tetramethylene phosphonic acid into a container, starting a magnetic stirrer to stir continuously for 5min, adding ammonium bifluoride, hydrochloric acid, propiolic alcohol, EDTA, polyoxyethylene polyoxypropylene polyether and tetramethylammonium chloride, and continuing to stir for 5min to obtain the main acid.
The method for preparing the postposition acid is the same as that of the preposition acid.
The embodiment also provides an application effect of the prepared seawater base acid liquid system in the yield-increasing transformation of the sandstone oil reservoir at 70 ℃, which comprises the following specific steps:
the change of the permeability of the rock core before and after acidification is evaluated by using a rock core flowing experimental device, and the experimental result is shown in figure 2. The cores used in the experiments consisted of 75% quartz, 10% feldspar and 15% clay minerals. It can be seen that the pressure at the injection end of the core rises after acid injection because the interfacial tension of the acid liquid is high. The inlet pressure after acidification was significantly lower than before acidification, indicating that acidification was effective. The change in core permeability before and after acidizing is shown in table 3. As can be seen from the table, for the reservoir with the quartz and feldspar contents higher than 90%, the permeability is improved by 20.93% after the acidification by using the seawater-based acid liquid system, and the core permeability is obviously improved, which indicates that no serious secondary damage occurs.
Table 3 change in core permeability before and after acidification of seawater-based acid system in example 2
Example 3 preparation of a seawater-based acid fluid system suitable for high clay content sandstone reservoirs
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacing liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 2g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of 31 percent industrial hydrochloric acid (containing 15g of HCl), 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 45.61g of filtered seawater.
The main acid is prepared from the following components (total weight 100 g): 20g of 40% aqueous fluoroboric acid solution (containing HBF)48g) 2g of hydroxyethylidene diphosphonic acid, 6g of 2-hydroxyphosphonoacetic acid, 32.26g of 31 percent industrial hydrochloric acid (containing 10g of HCl), 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 35.74g of filtered seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding filtered seawater, diethylenetriamine pentamethylenephosphonic acid, hydrochloric acid, Mannich base, citric acid, polyoxyethylene polyoxypropylene octadecanol ether and diethylamine hydrochloride into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
Preparing a main acid: adding filtered seawater, hydroxyethylidene diphosphonic acid and 2-hydroxyphosphonoacetic acid into a container, starting a magnetic stirrer to stir continuously for 5min, adding fluoboric acid, hydrochloric acid, Mannich base, citric acid, polyoxyethylene polyoxypropylene octadecanol ether and diethylamine hydrochloride, and continuously stirring for 5min to obtain the main acid.
The method for preparing the postposition acid is the same as that of the preposition acid.
The embodiment also provides an application effect of the prepared seawater base acid liquid system in the yield-increasing transformation of the 60 ℃ medium-low temperature sandstone oil reservoir, which comprises the following specific steps:
the change of the permeability of the core before and after acidizing is evaluated by using a core flow experimental device, and the result is shown in figure 3. The cores used in the experiments consisted of 75% quartz and 25% kaolin. It can be seen that the pressure at the injection end of the core rises after acid injection because the interfacial tension of the acid liquid is high. While the inlet pressure after acidification was significantly lower than before acidification, indicating that acidification was effective. The change in core permeability before and after acidizing is shown in table 4. As can be seen from the table, for the reservoir with the clay content higher than 20%, the permeability of the reservoir after being acidified by the seawater-based acid system is improved by 45.45%, the permeability of the core is obviously improved, and no serious secondary damage occurs.
Table 4 change in core permeability before and after acidification of seawater-based acid system in example 3
Example 4 preparation of a carbonate reservoir seawater-based acid System
Comprises a preposed acid and a displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 8g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of 31% industrial hydrochloric acid (containing 15g of HCl), 8g of ammonium chloride, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 31.61g of filtered seawater.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding filtered seawater, diethylenetriamine pentamethylenephosphonic acid, hydrochloric acid, ammonium chloride, Mannich base, citric acid, polyoxyethylene polyoxypropylene octadecanol ether and diethylamine hydrochloride into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
The embodiment also provides the application effect of the prepared seawater-based acid liquid system in the yield-increasing transformation of the carbonate reservoir at the temperature of 80 ℃, and the application effect is as follows:
and evaluating the change of the permeability of the rock core before and after acidification by using a rock core flowing experimental device. The core used in the experiment consisted of 50% calcite and 50% dolomite. And in the acid injection process, the pressure at the injection end of the rock core rises firstly and then falls. The cross section of the outlet of the acidified core is shown in figure 4, and for a carbonate reservoir, an acid-etched earthworm hole is formed after the reservoir is acidified by using a seawater-based acid liquid system, and the permeability of the core is approximately infinite in flow conductivity.
Example 5 preparation of seawater-based acid fluid system for acidification of sandstone reservoirs suitable for high carbonate content
Comprises a preposed acid and a displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 4g of polyepoxysuccinic acid, 38.71g of 31% industrial hydrochloric acid (containing HCl12g), 5g of ammonium chloride, 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 46.29g of filtered seawater.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding filtered seawater, polyepoxysuccinic acid, hydrochloric acid, ammonium chloride, propiolic alcohol, EDTA, polyoxyethylene polyoxypropylene polyether and tetramethylammonium chloride into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
The embodiment also provides the application effect of the prepared seawater-based acid liquid system in the yield-increasing transformation of the sandstone oil reservoir with high carbonate content (the carbonate content is more than or equal to 20%) at the temperature of 80 ℃, and the specific effect is as follows:
the change of the permeability of the rock core before and after acidification is evaluated by using a rock core flowing experimental device, and the experimental result is shown in figure 5. The cores used in the experiments consisted of 75% quartz and 25% calcium carbonate. It can be seen that the pressure in the inlet section rises first and then falls during the acid injection. The inlet pressure after acidification was significantly lower than before acidification, indicating that acidification was effective. The change in core permeability before and after acidizing is shown in table 5. As can be seen from the table, for the reservoir with the carbonate content higher than 20%, the permeability is improved by 72.69% after the acidification by the seawater-based acid system, and no serious secondary damage occurs. The picture of the end face of the outlet of the core after the experiment is shown in figure 6. The end face of the core is formed by fine pore passages.
Table 5 change in core permeability before and after acidification of seawater-based acid system in example 5
The above examples show that the seawater-based acid liquid system of the present invention can inhibit calcium sulfate precipitation generated during the acidification process, and avoid secondary damage to the formation. By adopting the system, the offshore acidification construction efficiency can be greatly improved, the acidification construction cost is reduced, the dissolution speed is high, the mixing is easy, the compatibility is good, the online continuous mixing construction can be realized, and the requirement of offshore large-scale acidification construction can be met.
EXAMPLE 6 preparation of amino acid liquid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (the total weight is 100 g): 2g of hydrolyzed polymaleic anhydride, 32.26g of 31% industrial hydrochloric acid (containing 10g of HCl), 2g of imidazoline, 2g of acetic acid, 2g of polyoxyethylene polyoxypropylene octadecanol ether, 2g of diethylamine hydrochloride and the balance of filtered seawater.
The main acid is prepared from the following components (total weight 100 g): 5g of hydrofluoric acid with the mass concentration of 40% (including 2g of HF), 3g of amino trimethylene phosphonic acid, 2g of 2-hydroxyphosphonoacetic acid, 16.13g of industrial hydrochloric acid with the mass concentration of 31% (including 5g of HCl), 2g of imidazoline, 2g of acetic acid, 2g of polyoxyethylene polyoxypropylene octadecanol ether, 2g of diethylamine hydrochloride and the balance of filtered seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is filtered seawater.
The preparation method comprises the following steps:
preparing a preposed acid: adding the components into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
Preparing a main acid: adding the components into a container, and stirring for 10min by using a magnetic stirrer to obtain the main acid.
The preparation of the postposition acid is the same as that of the preposition acid.
EXAMPLE 7 preparation of amino acid liquid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 3g of polyacrylic acid, 38.71g of 31% industrial hydrochloric acid (containing 12g of HCl), 1g of Mannich base, 1.5g of citric acid, 2g of alkylphenyl polyoxyethylene ether, 1g of hydroxypropyl trimethyl ammonium chloride and the balance of seawater.
The main acid is prepared from the following components (total weight 100 g): 3g of ammonium fluoride, 3g of 2-phosphonic butane-1, 2, 4-tricarboxylic acid, 4g of bis (1, 6) hexamethylene triamine pentamethylene phosphonic acid, 48.39g of 31% industrial hydrochloric acid (containing 15g of HCl), 1.5g of Mannich base, 2g of citric acid, 1g of alkylphenyl polyoxyethylene ether, 1.5g of hydroxypropyl trimethyl ammonium chloride and the balance of seawater.
The components for preparing the post acid are the same as those of the pre acid.
The displacement liquid is seawater.
The preparation method is the same as example 6.
EXAMPLE 8 preparation of amino acid liquid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 4g of polyaspartic acid, 32.26g of 31% industrial hydrochloric acid (containing 10g of HCl), 1.5g of Mannich base, 1.5g of acetic acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of dimethyl diallyl ammonium chloride and the balance of seawater.
The main acid is prepared from the following components (total weight 100 g): 25g of 40% aqueous fluoroboric acid solution (containing HBF)410g) 2g of diethylenetriamine pentamethylene phosphonic acid, 8g of 2-hydroxyphosphonoacetic acid, 16.13g of 31 percent industrial hydrochloric acid (containing 5g of HCl), 1g of Mannich base, 1g of acetic acid, 1.5g of polyoxyethylene polyoxypropylene octadecanol ether, 2g of dimethyl diallyl ammonium chloride and the balance of seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is seawater.
The preparation method is the same as example 6.
Example 9 preparation of an amino acid in seawater liquid System
Comprises 4 slugs of preposed acid, main acid, postposed acid and displacement liquid, wherein,
the components for preparing the front acid are as follows (total weight 100 g): 3g of amino trimethylene phosphonic acid, 38.71g of 31% industrial hydrochloric acid (containing 12g of HCl), 1.5g of Mannich base, 1.5g of acetic acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of dimethyl diallyl ammonium chloride and the balance of filtered seawater.
The main acid is prepared from the following components (total weight 100 g): 40% aqueous fluoroboric acid solution 12.5g (containing HBF)45g) 4g of hydroxyethylidene diphosphonic acid, 5g of polyamino polyether methylene phosphonic acid, 48.39g of 31 percent industrial hydrochloric acid (containing 15g of HCl), 1g of Mannich base, 1g of acetic acid, 1.5g of polyoxyethylene polyoxypropylene octadecanol ether, 2g of dimethyl diallyl ammonium chloride and the balance of filtered seawater.
The components for preparing the postposition acid are the same as those of the preposition acid.
The displacement liquid is filtered seawater.
The preparation method is the same as example 6.
EXAMPLE 10 preparation of amino acid liquid System
Comprises a preposed acid and a displacement liquid, wherein,
the components for preparing the front acid are as follows (the total weight is 100 g): 6g of polyacrylic acid, 38.71g of 31% industrial hydrochloric acid (containing 12g of HCl), 10g of ammonium chloride, 1g of imidazoline, 1.5g of citric acid, 1.5g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of hydroxypropyl trimethyl ammonium chloride and the balance of seawater.
The displacement liquid is seawater.
The preparation method comprises the following steps: preparing a preposed acid: adding the components into a container, and stirring for 5min by using a magnetic stirrer to obtain the preposed acid.
EXAMPLE 11 preparation of amino acid liquid System
Comprises a preposed acid and a displacement liquid, wherein,
the components for preparing the front acid are as follows (the total weight is 100 g): 10g of amino trimethylene phosphonic acid, 32.26g of 31% industrial hydrochloric acid (containing 10g of HCl), 4g of ammonium chloride, 2g of Mannich base, 2g of acetic acid, 2g of alkyl phenyl polyoxyethylene ether, 2g of dimethyl diallyl ammonium chloride and the balance of filtered seawater.
The displacement liquid is filtered seawater.
The preparation method is the same as that of example 10.
The above examples are provided to those of ordinary skill in the art to fully disclose and describe how to make and use the claimed embodiments, and are not intended to limit the scope of the disclosure herein. Modifications apparent to those skilled in the art are intended to be within the scope of the appended claims.
Claims (10)
1. The seawater-based acid liquid system is characterized in that: consists of preposed acid, main acid, postposition acid and displacement liquid, wherein,
the pre-acid is composed of the following components in percentage by weight: 10-15% of HCl, 2-4% of calcium sulfate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater;
the main acid comprises the following components in percentage by weight: 1.5-10% of fluoride, 5-15% of supporting acid, 2-4% of fluoride precipitation inhibitor, 2-8% of fluorosilicate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater;
the post acid is composed of the following components in percentage by weight: 10-15% of HCl, 2-10% of calcium sulfate precipitation inhibitor, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater;
the displacement fluid is selected from seawater;
the calcium sulfate precipitation inhibitor is selected from any one or the combination of more than two of diethylenetriamine pentamethylene phosphonic acid, amino trimethylene phosphonic acid, polyepoxysuccinic acid, polyaspartic acid, polyacrylic acid and hydrolyzed polymaleic anhydride;
the corrosion inhibitor is selected from any one or the combination of more than two of mannich base, propiolic alcohol, imidazoline and phenformin;
the iron ion stabilizer is selected from one or the combination of more than two of citric acid, EDTA and acetic acid;
the demulsifier is selected from any one or the combination of more than two of polyoxyethylene polyoxypropylene octadecanol ether, polyoxyethylene polyoxypropylene polyether and alkyl phenyl polyoxyethylene ether;
the clay stabilizer is selected from one or the combination of more than two of diethylamine hydrochloride, tetramethylammonium chloride, hydroxypropyl trimethylammonium chloride and dimethyl diallyl ammonium chloride;
said fluorinationThe substance is selected from HF and NH4HF2、NH4F、HBF4Any one or a combination of two or more of them;
the supporting acid is selected from HCl;
the fluoride precipitation inhibitor is selected from any one or the combination of more than two of hydroxyethylidene diphosphonic acid, ethylene diamine tetra methylene phosphonic acid, amino trimethylene phosphonic acid, 2-phosphonic butane-1, 2, 4-tricarboxylic acid and diethylenetriamine pentamethylene phosphonic acid;
the fluorosilicate precipitation inhibitor is selected from any one or the combination of more than two of 2-hydroxyphosphonoacetic acid, hexamethylenediamine tetramethylidene phosphonic acid, polyamino polyether methylene phosphonic acid and bis 1, 6 hexamethylene triamine pentamethylene phosphonic acid.
2. The amino acid fluid system of claim 1, wherein: the types of the corrosion inhibitor, the iron ion stabilizer, the demulsifier and the clay stabilizer selected from the main acid are the same as those selected from the front acid; the kinds of the components in the post-acid are the same as those in the pre-acid.
3. The amino acid fluid system of claim 1 or 2, wherein: the fluoride in the main acid is selected from HF and NH4HF2Or NH4F, the content is 1.5% -3%; or: the fluoride in the host acid is selected from HBF4The content is 5 to 10 percent.
4. The seawater-based acid system of claim 3, wherein: the components of the preposed acid are as follows: 2g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of industrial hydrochloric acid with the mass concentration of 31%, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 45.61g of seawater;
the main acid has the following components: 3.75g of hydrofluoric acid with the mass concentration of 40%, 2g of hydroxyethylidene diphosphonic acid, 2g of 2-hydroxyphosphonoacetic acid, 32.26g of industrial hydrochloric acid with the mass concentration of 31%, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 55.99g of seawater;
the components of the post acid are the same as those of the pre acid.
5. The seawater-based acid system of claim 3, wherein: the composition of the pre-acid is as follows: 4g of polyepoxysuccinic acid, 38.71g of 31% industrial hydrochloric acid, 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 51.29g of seawater;
the main acid has the following components: 2.5g of ammonium bifluoride, 3g of ethylenediamine tetramethylene phosphonic acid, 3g of hexamethylenediamine tetramethylene phosphonic acid, 38.71g of 31% industrial hydrochloric acid, 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 46.79g of seawater;
the components of the post acid are the same as those of the pre acid.
6. The seawater-based acid system of claim 3, wherein: the composition of the pre-acid is as follows: 2g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of 31% industrial hydrochloric acid, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 45.61g of seawater;
the main acid has the following components: 20g of 40% fluoroboric acid aqueous solution, 2g of hydroxyethylidene diphosphonic acid, 6g of 2-hydroxyphosphonoacetic acid, 32.26g of 31% industrial hydrochloric acid, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 35.74g of seawater;
the components of the post acid are the same as those of the pre acid.
7. The seawater-based acid liquid system is characterized in that: the displacement agent consists of a preposed acid and a displacement liquid, wherein the preposed acid consists of the following components in percentage by weight: 10-15% of HCl, 4-10% of calcium sulfate precipitation inhibitor, 4-10% of ionic strength regulator, 1-2% of corrosion inhibitor, 1-2% of iron ion stabilizer, 1-2% of demulsifier, 1-2% of clay stabilizer and the balance of seawater;
the calcium sulfate precipitation inhibitor is selected from any one or a combination of more than two of diethylenetriamine pentamethylene phosphonic acid, amino trimethylene phosphonic acid, polyepoxysuccinic acid, polyaspartic acid, polyacrylic acid and hydrolyzed polymaleic anhydride;
the ionic strength regulator is selected from ammonium chloride;
the corrosion inhibitor is selected from any one or the combination of more than two of mannich base, propiolic alcohol, imidazoline and phenformin;
the iron ion stabilizer is selected from one or the combination of more than two of citric acid, EDTA and acetic acid;
the demulsifier is selected from any one or the combination of more than two of polyoxyethylene polyoxypropylene octadecanol ether, polyoxyethylene polyoxypropylene polyether and alkyl phenyl polyoxyethylene ether;
the clay stabilizer is selected from one or the combination of more than two of diethylamine hydrochloride, tetramethylammonium chloride, hydroxypropyl trimethylammonium chloride and dimethyl diallyl ammonium chloride;
the displacement fluid is selected from seawater.
8. The seawater-based acid system of claim 7, wherein: the composition of the pre-acid is as follows: 8g of diethylenetriamine pentamethylene phosphonic acid, 48.39g of 31% industrial hydrochloric acid, 8g of ammonium chloride, 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene octadecanol ether, 1g of diethylamine hydrochloride and 31.61g of seawater.
9. The seawater-based acid system of claim 7, wherein: the components of the preposed acid are as follows: 4g of polyepoxysuccinic acid, 38.71g of 31% industrial hydrochloric acid, 5g of ammonium chloride, 1.5g of propiolic alcohol, 1.5g of EDTA, 1.5g of polyoxyethylene polyoxypropylene polyether, 1.5g of tetramethylammonium chloride and 46.29g of seawater.
10. The amino acid fluid system of any of claims 1, wherein: the seawater is selected from seawater with turbidity less than or equal to 40FTU or filtered seawater.
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