CN107474816B - High-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed and prepared and preparation method thereof - Google Patents
High-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed and prepared and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed and a preparation method thereof, and the high-temperature-resistant seawater-based polymer fracturing fluid comprises the following components in percentage by weight: 0.4-0.8 wt% of a thickening agent; 0.3-0.6 wt% of auxiliary synergist; 0.2-0.4 wt% of an activating agent; 0.2-0.4 wt% of metal ion stabilizer; 0.3-0.4 wt% of a temperature stabilizer; the other component is seawater. The invention has the following beneficial effects: the fracturing fluid system uses the water-soluble multipolymer as a thickening agent, can be quickly swelled in high salinity seawater, forms low-viscosity high-elasticity fluid with a strong space structure through the synergistic effect (non-crosslinking effect) between the thickening agent and an auxiliary synergist, has good sand carrying capacity when the apparent viscosity is more than 20mPa & s, is free from bacterial erosion, has the characteristics of good salt resistance, temperature resistance and shear resistance, low damage, cleanness without residues and the like, can be prepared by adopting seawater in batch and continuous mixing, can obviously reduce the offshore fracturing construction cost, and improves the fracturing construction efficiency and the reservoir yield increasing effect.
Description
Technical Field
The invention relates to the technical field of yield increase of oil and gas reservoirs, in particular to a high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed and a preparation method thereof.
Background
With the development of high-quality oil and gas reserves, the recoverable and easily recoverable reserves are continuously reduced, the key points of oil and gas development gradually change from high permeability to low permeability and from land to ocean, and the fracturing technology suitable for ocean oil and gas recovery becomes one of the hot spots researched by researchers at home and abroad. Na in seawater+、K+、Ca2+、Mg2+The plasma content is very high, and the fracturing fluid used in the fracturing construction at present is sensitive to ions, and the performance is reduced, so that the construction requirement cannot be met, therefore, the research on the seawater-based fracturing fluid is the key for solving the technical problem of the offshore fracturing and reducing the construction cost of the offshore fracturing. A great deal of foreign research shows that the temperature resistance of a boron crosslinked seawater-based fracturing fluid system can reach 120 ℃ but has high residue content, and seawater-based viscoelastic surfactant (VES) clean fracturing fluid has unique advantages in low damage but is not ideal in temperature resistance. The main domestic research focuses on the latter, the temperature resistance of the latter is not more than 90 ℃, and in recent years, a number of researches and attempts are made on synthetic polymer seawater-based fracturing fluid systems in China, but the remarkable advantages in temperature resistance and salt resistance of the fracturing fluid and residue damage are not reported.
The difficulty of the research of the low-damage seawater-based fracturing fluid is shown as follows: firstly, the seawater contains a large amount of inorganic salt, the mineralization degree can reach 40000ppm or even higher, the fracturing fluid system which can be prepared by adopting the seawater and has stable performance is few; secondly, a large amount of organic matters and saprophytic bacteria contained in the seawater easily cause the natural guanidine gum fracturing fluid to decay and deteriorate; thirdly, many synthetic low molecular polymer fracturing fluids solve the problem of salt tolerance, but the damage caused by residues and crosslinking is not fundamentally solved; fourthly, due to the influence of specific water quality environment, the improvement of the temperature resistance and the shearing resistance of the fracturing fluid is one of the key points.
At present, research on seawater-based fracturing fluids at home and abroad has also achieved some achievements, such as invention patent "seawater-based oil and gas well fracturing fluid" with application number CN201110357133, seawater-based fracturing fluid "with application number CN 10361941941 and a preparation method thereof," seawater-based fracturing fluid "with application number CN201310254620, low-damage seawater-based weighted fracturing fluid" with application number CN201410028371, and "seawater-based fracturing fluid and a preparation method of seawater-based fracturing fluid" with application number CN 201510651589. In the above results, most of the guar gum is used as a thickening agent, general guar gum fracturing fluid is very sensitive to seawater ions, and various problems exist as described above, and some synthetic polymers are used as thickening agents, but all the synthetic polymers need to be crosslinked by a metal crosslinking agent to form jelly glue to achieve good temperature resistance and sand carrying performance, but the crosslinking action can introduce and increase residue of the fracturing fluid, so that the cleaning and environmental protection effects are difficult to achieve.
Disclosure of Invention
The invention aims to solve the technical problems of the defects and limitations of the existing seawater-based fracturing fluid system and provides a high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed and a preparation method thereof. The fracturing fluid is not corroded by bacteria, has good salt resistance, temperature resistance and shear resistance, has little damage to the stratum, can obviously reduce the offshore fracturing construction cost, and improves the fracturing construction efficiency and the reservoir transformation effect.
In order to achieve the technical purpose, the invention provides a high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed, which mainly utilizes a salt-resistant and hypersalinity-resistant water-soluble polymer as a thickening agent, the formed solution is a fluid with a strong spatial structure and has excellent temperature resistance and shear resistance, the fluid is mixed with an auxiliary synergist, a metal ion stabilizer, a temperature stabilizer and seawater to form a seawater-based fracturing fluid system, seawater resources can be fully utilized, the dependence of offshore fracturing on fresh water resources is reduced, and the construction cost is greatly reduced.
The high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed comprises the following components in percentage by weight:
0.3-0.8 wt% of a thickening agent;
0.3-0.6 wt% of auxiliary synergist;
0.2-0.4 wt% of metal ion stabilizer;
0.3-0.4 wt% of a temperature stabilizer;
0.2-0.4 wt% of an activating agent;
the other component is seawater.
The thickening agent is a water-soluble multi-component copolymer, the product name is the thickening agent for clean fracturing fluid, the product code is BCG-1, and the thickening agent is an industrial product produced by Chengdoubai toon oil science and technology limited company. The BCG-1 is prepared by copolymerizing 2-5 wt% of acrylic acid, 10-15 wt% of acrylamide, 0.8-1.0 wt% of n-alkyl dimethyl allyl ammonium chloride (wherein n refers to 12, 14, 16 and 18), and 1-3 wt% of anionic unsaturated monomers (2-acrylamide-2-methyl propanesulfonic acid AMPS, methacrylic acid sodium salt and the like) under certain conditions, hydrophobic groups, temperature-resistant and salt-resistant groups are introduced into molecules, and molecular self-association is generated in an aqueous solution through the action of the hydrophobic groups to form a reversible spatial structure, so that the temperature-resistant and salt-resistant performances are improved. The molecular weight of the thickening agent is between 60 and 100 ten thousand, and the optimal using concentration is 0.4 to 0.6 weight percent.
The auxiliary synergist is a surfactant, is a thickening auxiliary agent for clean fracturing fluid, has a product code of B-55, and is an industrial product produced by Chengdoubai oil technology limited company. B-55 is obtained by reacting 16-18 wt% of hexadecyl dimethyl tertiary amine, 22-27 wt% of n-octadecyl alcohol and 15-20 wt% of dimethyl sulfate as main materials, dimethylbenzene as a solvent and azodiisobutyronitrile as a catalyst at a certain temperature to prepare a crude product, and then performing post-treatment, wherein the optimal use concentration is 0.4-0.5 wt%.
The conventional guanidine gum and low molecular polymer fracturing fluid used at present need to form high-viscosity jelly through the crosslinking action of a metal crosslinking agent (zirconium, titanium, boron and the like) to meet the performance requirements of temperature resistance and sand carrying of the fracturing fluid, but the problems of uncontrollable property (limited crosslinking condition and difficult control of delay time) of a crosslinking technology, high friction resistance, poor shearing resistance, additional damage and the like of the fracturing fluid caused by the crosslinking technology are not ignored and are difficult to solve. The action mechanisms of the auxiliary synergist B-55 and the metal cross-linking agent are completely different, after the B-55 is mixed with the thickening agent solution, the B-55 can be automatically associated into a hydrophobic micro-region of solution molecules and can generate a synergistic interaction with a thickening agent molecular chain (the thickening agent molecules, the thickening agent and the auxiliary synergist molecules are connected through hydrogen bonds, Van der Waals force, association and the like) to form weak gel (non-crosslinked gel) with a strong space structure, the apparent viscosity and the structural strength of the weak gel are remarkably improved, the viscoelastic sand carrying of the fracturing fluid is realized, no residue is generated basically, and the clean characteristic of the fracturing fluid is maintained.
The metal ion stabilizer is an organic carboxylate mixture, the product name is the metal ion stabilizer, the product code is BCG-5, and the product is produced and industrial products by Chengdoubai Toona oil science and technology limited company. BCG-5 is developed and produced for solving the influence of hypersalinity of seawater and complex ions on fracturing fluid, and is prepared by taking 10-15 wt% of sodium gluconate, 3-4 wt% of diethylenetriamine pentaacetic acid, 8-10 wt% of ammonium citrate and 15-20 wt% of methanol as main raw materials and 51-64 wt% of clear water as an auxiliary material, and dissolving, mixing and stirring the raw materials at a certain temperature. Because of the existence of high valence/variable valence metal ions in seawater, the addition of BCG-5 has strong chelation effect on the ions, effectively eliminates the influence on the performance of fracturing fluid, and simultaneously can reduce or reduce the precipitation (such as Ca (OH)) generated due to high temperature or pH value rise2，Mg(OH)2，Fe(OH)3Etc.) to reduce damage to the formation. Through optimization experiments, the effect tends to be stable when the addition amount of the BCG-5 is 0.4 wt%.
The temperature stabilizer is a mixed aqueous solution of 30 wt% of sodium thiosulfate and ammonium thiosulfate, wherein the mass ratio of the sodium thiosulfate to the ammonium thiosulfate is 1: 1. the temperature stabilizer can remove dissolved oxygen in the solution, effectively reduces the oxidative degradation and chain scission of the thickener molecules under the high temperature condition, and thus obviously improves the thermal stability of the fracturing fluid.
The activating agent is one of cocobetaine and n-alkyl glucoside, wherein n is an integer of 8-16; the addition of the activating agent can enhance the coordination effect among molecules of the thickening agent and between molecules of the thickening agent and the auxiliary synergist and improve the strength of the spatial network structure of the solution.
The invention also provides a preparation method of the low-damage seawater-based clean fracturing fluid, which comprises the following steps:
(1) the indoor preparation method comprises the following steps:
1) indoor preparation of base fluid of fracturing fluid:
adding seawater for preparing the fracturing fluid into a waring mixer (the waring mixer is an experimental instrument for preparing the fracturing fluid) or a similar instrument, starting a stirrer, adjusting the rotating speed of the stirrer until the vortex formed by the fluid can see the top end of a central shaft of a blade of the stirrer, adding a metal ion stabilizer and a temperature stabilizer into the solution according to the proportion of 0.4-0.8 wt% of the thickening agent, 0.2-0.4 wt% of the metal ion stabilizer and 0.3-0.4 wt% of the temperature stabilizer, uniformly stirring, slowly adding a thickening agent BCG-1, avoiding forming fish eyes during adding, constantly adjusting the rotating speed to ensure that the vortex state is reached, stopping stirring after the uniform solution is formed, and pouring the solution into a beaker for later use to obtain the fracturing fluid base fluid.
2) Indoor preparation of fracturing fluid:
weighing a certain volume of base fluid of the fracturing fluid, pouring the base fluid into a waring mixer, weighing 0.3-0.6 wt% of the auxiliary synergist and 0.2-0.4 wt% of the activating agent in the claim 1 under the stirring condition, adding the auxiliary synergist and the activating agent into the base fluid, and fully and uniformly mixing to obtain the high-viscoelasticity fracturing fluid;
(2) the field batch method comprises the following steps:
firstly, cleaning a large tank, ensuring that no sundries and no residual liquid exist in the tank, preparing liquid seawater, adding a metal ion stabilizer and a temperature stabilizer into the liquid seawater prepared by the large tank according to the proportion of 0.4-0.8 wt% of a thickening agent, 0.2-0.4 wt% of a metal ion stabilizer and 0.3-0.4 wt% of a temperature stabilizer, and uniformly stirring;
absorbing a thickening agent BCG-1 into seawater by using a jet technology under the stirring condition, wherein the absorption is slow, the blockage of a jet gun is prevented, and after the absorption is finished, continuously stirring until the viscosity is qualified, namely more than 50mPa & s, and standing for 2-4 h to obtain a fracturing fluid base fluid;
during fracturing construction, pumping the auxiliary synergist into a sand mixer by a liquid additive pump in a proportion of 0.3-0.6 wt%, pumping an activating agent in a proportion of 0.2-0.4 wt% and uniformly stirring and mixing the activating agent and a fracturing fluid base fluid in a sand mixing tank to form high-viscoelasticity fracturing fluid;
(3) the field continuous mixing method comprises the following steps:
the fracturing liquid system is suitable for continuous mixed fracturing construction, and comprises the following steps:
before construction, preparing additive materials of the prepared seawater and the fracturing fluid, and connecting a continuous mixing equipment pipeline, fracturing construction equipment and the like;
during construction, according to the components and the content of the fracturing fluid, a metal ion stabilizer and a temperature stabilizer are added into seawater at the inlet end of a continuous blending circulating tank, a thickening agent is sucked in through a jet gun, the additives and the liquid are mixed and then continuously circulated in the equipment, a fracturing fluid base fluid meeting conditions can be formed when the additives and the liquid flow out of the blending circulating tank, and the fracturing fluid base fluid immediately enters a sand mixer and is mixed with an activating agent and an auxiliary synergist pumped by a liquid additive pump to form a high-viscoelasticity fracturing fluid which is pressed into a stratum.
The seawater contains a large amount of inorganic salt, the mineralization degree reaches more than 30000ppm, and the existence of complex ionic elements in the seawater makes the conventional fracturing fluid high-molecular thickening agent difficult to stick or even precipitate in the hydration and dissolution process. Therefore, the seawater-based fracturing fluid systems with excellent performance reported in domestic research are few, and further, if seawater is adopted for continuous mixing, the fracturing fluid thickening agent must have excellent swelling performance (the swelling time is less than 10min) and temperature resistance and sand carrying performance to meet the requirements of online construction, and the seawater-based fracturing fluid is rarely reported.
The BCG-1 thickening agent adopted by the invention has high dissolution speed in seawater and stable performance, can meet the requirement of continuous mixing, has the temperature resistance of 140 ℃, and is mainly characterized in that a special rigid group and a hydrophobic functional group are introduced into a molecular chain segment of the thickening agent, so that the solubility and the salt resistance of the thickening agent in saline can be obviously improved. On one hand, when the mineralization degree of water is increased, the polarity of the solution is enhanced, the hydrophobic effect is also enhanced, and the macromolecular chain is spread in the solution, so that the hydrodynamic volume of the thickening agent is increased, and the dissolving speed of the thickening agent is increased; on the other hand, the inorganic salt shields the interaction of the ionic groups of the polymer molecules, so that the internal hydrogen bonds among the ions are destroyed, the molecular chain is expanded, and the solution viscosity is increased.
The invention has the beneficial effects that:
compared with the prior art, the invention has the following beneficial effects:
(1) the seawater resource is reasonably utilized during offshore fracturing, so that the demand of an offshore platform on the fresh water resource is relieved, and the construction cost of the fracturing fluid is greatly reduced;
(2) the fracturing fluid system uses a water-soluble multipolymer as a thickening agent, can be quickly dissolved and expanded to form a low-viscosity high-elasticity fluid in high-salinity seawater, is different from the action mechanism of the conventional guanidine gum fracturing fluid and low-molecular polymer fracturing fluid, does not adopt chemical crosslinking, but generates a synergistic interaction with an auxiliary synergistic agent through intermolecular self-association to form a strong spatial structure, and has good sand carrying capacity when the apparent viscosity is more than 20mPa & s;
(3) the activating agent is introduced into the system, so that the self-association effect among the molecules of the fracturing fluid can be further enhanced, and the spatial structure strength of the solution is improved, so that the temperature resistance and sand carrying performance of the fracturing fluid are improved;
(4) the thickening agent of the fracturing fluid system does not contain vegetable gum components, does not contain nutrient substances capable of enabling bacteria to survive, is not corroded by bacteria, has excellent salt resistance, good temperature resistance and shearing resistance, wide application temperature range, can well meet the requirements of fracturing construction, can be applied to continuous blending, and greatly improves the fracturing construction efficiency;
(5) the guanidine gum fracturing fluid system or the conventional low molecular polymer fracturing fluid system has the advantages that except the residue damage of the thickening agent, the damage introduced by adopting a crosslinking technology cannot be ignored, a large amount of residues cannot be discharged, the fracturing fluid thickening agent has no residue, the system does not adopt the crosslinking technology, the fracturing fluid thickening agent is clean and has no residue after gel breaking, the damage to the stratum is small, and the fracturing yield-increasing effect can be obviously improved.
Drawings
FIG. 1 is a test curve of the antibacterial stability of the seawater-based fracturing fluid provided by the present invention;
FIG. 2 is a temperature-resistant and shear-resistant performance test curve of the 90 ℃ seawater-based fracturing fluid provided by the invention;
FIG. 3 is a test curve of temperature resistance and shear resistance of the 140 ℃ seawater-based fracturing fluid provided by the invention;
FIG. 4 is a temperature-resistant and shear-resistant performance test curve of 140 ℃ seawater-based fracturing fluid for continuous blending construction provided by the invention;
fig. 5 shows the damage test result of the seawater-based fracturing fluid provided by the invention on the conductivity of the supporting filling layer.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
The present invention will be described in detail with reference to specific examples.
The percentages in the examples are given by mass unless otherwise indicated.
Example 1
The invention provides a continuously mixed high-temperature resistant seawater-based polymer fracturing fluid, which has the following antibacterial stability evaluation:
the formulations of the fracturing fluids used in the experiments are shown in table 1.
The experimental main ions and total mineralization in simulated seawater were as follows:
Ca2+1410mg/L、Mg2+1310mg/L、Na+13800mg/L、K+2390mg/L、SO4 2-1740mg/L、HCO3 -152mg/L、Cl-19700mg/L and the total mineralization is 45000 mg/L.
Respectively preparing fracturing fluid from tap water and seawater, standing at 30 deg.C for one week, and measuring with six-speed rotational viscometer for 170s-1The change of apparent viscosity was measured and recorded, and the test results are shown in FIG. 1. It can be seen that the apparent viscosity of the base fluid of the fracturing fluid is not changed and no precipitate is generated regardless of the preparation of tap water or seawater. Shows that the fracturing fluid is not thinnedBacteria erosion, excellent stability and being beneficial to industrial construction on an ocean platform.
Table 1 fracturing fluid formulation components and amounts for experiments
Example 2
The invention provides a formula optimization scheme of a high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed at 90 ℃ and 140 ℃, which comprises the following steps:
a large number of indoor experimental simulations are carried out to obtain a seawater-based fracturing fluid formula suitable for reservoir fracturing at 90 ℃ and 140 ℃, and the components and the using amount of the formula are shown in tables 2 and 3.
The temperature resistance and shear resistance of the seawater-based fracturing fluid formula at 90 ℃ and 140 ℃ are tested according to SY/T5107-2005 'evaluation method of performance of water-based fracturing fluid'.
An experimental instrument: haake RS6000 rheometer, rotating cylinder test system, using rotor PZ 38;
and (3) testing conditions are as follows: shear rate 170s-1The experimental temperature is 90 ℃, the experimental time is 120min at 140 ℃.
The experimental results of the temperature resistance and shear resistance test of the seawater-based fracturing fluid with the formula at 90 ℃ and 140 ℃ are respectively shown in fig. 2 and fig. 3. Fracturing fluid at two temperatures is treated for 170s-1After shearing for 120min, the apparent viscosity is finally kept in a relatively stable numerical range, which shows that the composite material has excellent temperature resistance and shearing resistance and can meet the requirements of fracturing construction.
Formula components and dosage of seawater-based fracturing fluid at 290 ℃ in table
Formula components and dosage of seawater-based fracturing fluid with temperature of 3140 ℃ in table
Example 3
The invention provides a formula optimization scheme for continuously mixed high-temperature-resistant seawater-based polymer fracturing fluid for continuously mixed fracturing construction, which comprises the following steps:
because continuous blending has high requirements on the swelling performance of the fracturing fluid (the swelling time is less than 10min, and the thickening agent can only swell about 80% in a short time), the construction formula must be optimized in an online simulation mode in an indoor test, and the specific method is as follows:
starting the rheometer, debugging a program, setting experiment conditions, preparing a fracturing fluid temperature-resistant and shear-resistant test preparation, preparing a seawater-based fracturing fluid base fluid according to a design formula, stirring for 10min, adding an auxiliary synergist, uniformly stirring, immediately transferring to a rheometer rotating cylinder test system, starting a temperature-resistant and shear-resistant test, and judging whether the temperature resistance of the fracturing fluid can meet the requirements of continuous mixed fracturing construction according to a test curve. The formula of the continuous mixed seawater-based fracturing fluid suitable for 140 ℃ reservoir fracturing is optimized in an experiment, and the components and the using amount of the continuous mixed seawater-based fracturing fluid are shown in table 4.
Table 4 seawater based fracturing fluid formula components at 140 ℃ and use amounts for continuous blended fracturing construction
The experimental results of the temperature resistance and shear resistance test of the 140 ℃ seawater-based fracturing fluid for continuous mixed fracturing construction are shown in figure 4. The initial viscosity of the fracturing fluid is low, the fracturing fluid has a swelling and self-associating process along with the rise of temperature, the viscosity slowly falls after rising, and the apparent viscosity of the fracturing fluid tends to be stable after the temperature is stable, so that the formula has excellent temperature resistance and shear resistance, and can meet the requirement of continuous mixed fracturing construction.
Example 4
The invention provides a continuously mixed high-temperature-resistant seawater-based polymer fracturing fluid sand-carrying performance evaluation:
and testing the falling time of the falling ball in the fracturing fluid by adopting a falling ball viscosity meter, calculating the viscosity of the falling ball, and intuitively reflecting the sand carrying performance of the fracturing fluid through the falling ball viscosity value (not apparent viscosity). The ball dropping time of the dropping balls in the fracturing fluids is tested in an experiment, the ball dropping viscosity of the fracturing fluids is calculated according to a formula, and the data records are shown in table 5. The experimental data show that the apparent viscosity of the guanidine gum base fluid is equivalent to that of the BCG seawater base fracturing fluid, but the falling ball viscosity values are far different, which shows that the seawater base fracturing fluid provided by the invention has good sand carrying performance under low viscosity, the settling speed of the proppant is low, and the sand carrying requirement of the fluid can be met.
Table 5 fracturing fluid ball drop test data (room temperature)
Example 5
The invention provides a high-temperature resistant seawater-based polymer fracturing fluid capable of being continuously mixed, which is used for breaking gel and testing the content of residues:
the fracturing fluid base fluid is prepared according to the formula of the seawater-based fracturing fluid at 90 ℃ in the example 2, the auxiliary synergist is added in proportion, the fluids are divided into two groups, 0.03 percent and 0.05 percent of the gel breaker ammonium persulfate are respectively added, the gel is broken at 90 ℃, and the experimental results are shown in the table 6. The data show that: the fracturing fluid can be completely broken within 4h, the viscosity of the gel breaking liquid is low, the surface tension is as low as 26mN/m, and the rapid flowback of the gel breaking liquid is facilitated; the content of the residue of the gel breaking liquid is measured to be below 5mg/L, so that the damage caused by the residue can be obviously reduced.
TABLE 6 gel breaking test results for seawater-based fracturing fluids
Example 6
The damage evaluation of the high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed on the flow conductivity of the proppant filling layer provided by the invention comprises the following steps:
installing an API diversion trench, selecting 0.35-0.90 mm ceramsite proppant and setting the sanding concentration to be 20kg/m2. First with a standard brine flowAnd (3) passing through a diversion trench, performing diversion capacity damage by using a prepared BCG seawater-based fracturing fluid gel breaking liquid, wherein the volume of the damage liquid is 600ml, finally performing repeated test once by using standard saline water, and recording the change data of the flow volume of the standard saline water in the diversion trench along with time before and after damage to generate the shape shown in the figure 5. Fitting the flow curve of the test medium in the diversion trench, wherein the ratio of the slope of the straight line after injury to the slope of the straight line before injury is the diversion capacity retention rate of the proppant filling layer, and the result shows that the diversion capacity retention rate of the proppant filling layer after injury of the BCG seawater-based fracturing fluid is 92.1%. The characteristic of clean and residue-free of the BCG seawater-based fracturing fluid is proved, and the method has obvious advantages in the aspect of reducing the damage of the fracturing fluid to the reservoir.
The formula provided by the invention can reasonably utilize seawater resources during offshore fracturing, so that the demand of an offshore platform on fresh water resources is relieved, and the construction cost of the fracturing fluid is greatly reduced; the system uses water-soluble multi-component copolymer as a thickening agent, can be quickly dissolved and expanded to form low-viscosity high-elasticity fluid in high-salinity seawater, is different from the action mechanism of the conventional guanidine gum fracturing fluid and low-molecular polymer fracturing fluid, does not adopt chemical crosslinking, but generates synergistic interaction with an auxiliary synergistic agent through intermolecular self-association to form a strong space structure, has apparent viscosity of more than 20mPa & s, and has good sand carrying capacity; the activating agent is introduced into the system, so that the self-association effect among the molecules of the fracturing fluid can be further enhanced, and the spatial structure strength of the solution is improved, so that the temperature resistance and sand carrying performance of the fracturing fluid are improved; the thickening agent of the fracturing fluid system does not contain vegetable gum components, does not contain nutrient substances capable of enabling bacteria to survive, and cannot propagate in the thickening agent, so that the fracturing fluid system cannot be damaged, the thickening agent is not corroded by the bacteria, the requirements of fracturing construction can be well met, the thickening agent can also be applied to continuous blending, and the fracturing construction efficiency is greatly improved;
meanwhile, except the residue damage of the thickening agent, the guanidine gum fracturing fluid system or the conventional low-molecular polymer fracturing fluid system cannot ignore the damage caused by adopting a crosslinking technology, and a large amount of residues cannot be discharged.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (3)
1. The high-temperature-resistant seawater-based polymer fracturing fluid capable of being continuously mixed is characterized by comprising the following components in percentage by weight:
0.4-0.8 wt% of a thickening agent;
0.3-0.6 wt% of auxiliary synergist;
0.2-0.4 wt% of an activating agent;
0.2-0.4 wt% of metal ion stabilizer;
0.3-0.4 wt% of a temperature stabilizer;
the other components are seawater;
the thickening agent is a water-soluble multi-component copolymer, the product name is the thickening agent for clean fracturing fluid, the product code is BCG-1, and the thickening agent is produced by Chengdou Toona oil science and technology limited company; the BCG-1 is prepared by copolymerizing 2-5 wt% of acrylic acid, 10-15 wt% of acrylamide, 0.8-1.0 wt% of n-alkyl dimethyl allyl ammonium chloride and 1-3 wt% of anionic unsaturated monomer under a certain condition, wherein n of the n-alkyl dimethyl allyl ammonium chloride is one of 12, 14, 16 and 18; the anionic unsaturated monomer is methacrylic acid sodium salt; hydrophobic groups, temperature-resistant and salt-resistant groups are introduced into molecules, and molecular self-association is generated in aqueous solution through the action of the hydrophobic groups to form a reversible spatial structure, so that the temperature-resistant and salt-resistant properties are improved; the molecular weight of the thickening agent is between 60 and 100 ten thousand;
the auxiliary synergist is a surfactant, the product name is thickening auxiliary agent, the product code is B-55, and the auxiliary synergist is produced by Chengdoubai oil science and technology limited company; b-55 is prepared by taking 16-18 wt% of hexadecyl dimethyl tertiary amine, 22-27 wt% of n-octadecyl alcohol and 15-20 wt% of dimethyl sulfate as main materials, taking xylene as a solvent and taking azobisisobutyronitrile as a catalyst;
the metal ion stabilizer is an organic carboxylate mixture, the product name is the metal ion stabilizer, the product code is BCG-5, and the product is produced by Chengdou Toona petroleum technology limited company; the BCG-5 is prepared by taking 10-15 wt% of sodium gluconate, 3-4 wt% of diethylene triamine pentaacetic acid sodium salt, 8-10 wt% of ammonium citrate and 15-20 wt% of methanol as main raw materials and taking 51-64 wt% of clear water as an auxiliary material;
the activating agent is one of cocobetaine and n-alkyl glucoside, wherein n is an integer of 8-16;
the temperature stabilizer is a mixed aqueous solution of 30 wt% of sodium thiosulfate and ammonium thiosulfate, wherein the mass ratio of the sodium thiosulfate to the ammonium thiosulfate is 1: 1.
2. the continuously-mixed high-temperature-resistant seawater-based polymer fracturing fluid as claimed in claim 1, wherein the use concentration of the auxiliary synergist is 0.4-0.5 wt%.
3. The continuously-compoundable high-temperature-resistant seawater-based polymer fracturing fluid of claim 1 or 2, which is prepared by the following method:
(1) the indoor preparation method comprises the following steps:
1) indoor preparation of base fluid of fracturing fluid:
adding seawater for liquid preparation into a waring mixer or similar instruments, starting a stirrer, regulating the rotating speed of the stirrer until the top end of a propeller blade center shaft of the stirrer can be seen by a vortex formed by liquid, adding a metal ion stabilizer and a temperature stabilizer into a solution according to the proportion of 0.4-0.8 wt% of a thickening agent, 0.2-0.4 wt% of a metal ion stabilizer and 0.3-0.4 wt% of a temperature stabilizer, uniformly stirring, slowly adding a thickening agent BCG-1, avoiding forming fish eyes during adding, constantly regulating the rotating speed to ensure that the vortex state is reached, stopping stirring after the uniform solution is formed, and pouring into a beaker for later use to obtain a fracturing fluid base fluid;
2) indoor preparation of fracturing fluid:
weighing a certain volume of fracturing fluid base fluid, pouring the fracturing fluid base fluid into a waring mixer, weighing 0.3-0.6 wt% of auxiliary synergist and 0.2-0.4 wt% of activating agent under the stirring condition, adding the auxiliary synergist and the activating agent into the base fluid, and fully and uniformly mixing to obtain the high-viscoelasticity fracturing fluid;
(2) the field batch method comprises the following steps:
firstly, cleaning a large tank, ensuring that no sundries and no residual liquid exist in the tank, preparing liquid seawater, adding a metal ion stabilizer and a temperature stabilizer into the liquid seawater prepared by the large tank according to the proportion of 0.4-0.8 wt% of a thickening agent, 0.2-0.4 wt% of a metal ion stabilizer and 0.3-0.4 wt% of a temperature stabilizer, and uniformly stirring;
absorbing a thickening agent BCG-1 into seawater by using a jet technology under the stirring condition, wherein the absorption is slow, the blockage of a jet gun is prevented, and after the absorption is finished, continuously stirring until the viscosity is qualified, namely more than 50mPa & s, and standing for 2-4 h to obtain a fracturing fluid base fluid;
during fracturing construction, pumping the auxiliary synergist into a sand mixer by a liquid additive pump in a proportion of 0.3-0.6 wt%, pumping an activating agent in a proportion of 0.2-0.4 wt% and uniformly stirring and mixing the activating agent and a fracturing fluid base fluid in a sand mixing tank to form high-viscoelasticity fracturing fluid;
(3) the field continuous mixing method comprises the following steps:
the fracturing liquid system is suitable for continuous mixed fracturing construction, and comprises the following steps:
before construction, preparing additive materials of the prepared seawater and the fracturing fluid, and connecting a continuous mixing equipment pipeline, fracturing construction equipment and the like;
during construction, at the inlet end of a continuous mixing and circulating tank, according to the components and content of the fracturing fluid disclosed by claim 1, a metal ion stabilizer and a temperature stabilizer are added into seawater, a thickening agent is sucked in through a jet gun, the additives are mixed with the liquid and then continuously circulated in equipment, a fracturing fluid base fluid meeting conditions can be formed when the additive flows out of the mixing and circulating tank, and the fracturing fluid base fluid immediately enters a sand mixer and is mixed with an auxiliary synergist and an activating agent pumped by a liquid additive pump to form a high-viscoelasticity fracturing fluid which is pressed into a stratum.
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| CN117384615A (en) * | 2023-09-21 | 2024-01-12 | 碳中能源科技(北京)有限公司 | Temperature-resistant sea water-based fracturing fluid and preparation method thereof |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103074049A (en) * | 2013-01-21 | 2013-05-01 | 西南石油大学 | Fracturing fluid prepared by recovery waste water of crude oil and preparation method of fracturing fluid |
| CN103305206A (en) * | 2012-11-01 | 2013-09-18 | 湖北菲特沃尔科技有限公司 | Method for continuously blending fracturing fluid by utilizing sea water |
| CN103820099A (en) * | 2014-03-05 | 2014-05-28 | 成都佰椿石油科技有限公司 | Acid liquor friction reducer and preparation method thereof |
| CN103965857A (en) * | 2013-01-30 | 2014-08-06 | 中国石油天然气集团公司 | Preparation method of High-temperature water base fracturing fluid |
| CN104178102A (en) * | 2014-05-16 | 2014-12-03 | 成都佰椿石油科技有限公司 | Cross-linkable high-temperature-resistant residue-free polybasic copolymerizable fracturing fluid and preparation method thereof |
| CN104650845A (en) * | 2013-11-22 | 2015-05-27 | 中国石油天然气股份有限公司 | High-temperature non-crosslinked clean fracturing fluid and preparation method thereof |
| CN105219370A (en) * | 2015-09-10 | 2016-01-06 | 成都佰椿石油科技有限公司 | A kind of multi-functional reservoir reconstruction liquid and preparation method thereof |
| CN105733547A (en) * | 2016-01-29 | 2016-07-06 | 成都佰椿石油科技有限公司 | High-temperature-resistance low-friction weighted clean fracturing fluid and preparation method thereof |
| CN105778884A (en) * | 2016-05-10 | 2016-07-20 | 西南石油大学 | Supramolecular polymer clean fracturing fluid resistant to high temperature of 170 DEG C |
| CN106190088A (en) * | 2016-07-08 | 2016-12-07 | 四川奥赛德材料科技有限公司 | Temperature-resistant anti-salt instant dissolving viscosifier for seawater-based fracturing fluid and preparation method thereof |
| CN106279523A (en) * | 2015-06-25 | 2017-01-04 | 中国石油天然气股份有限公司 | Thickening agent and preparation method and application thereof |
-
2017
- 2017-05-25 CN CN201710379182.1A patent/CN107474816B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103305206A (en) * | 2012-11-01 | 2013-09-18 | 湖北菲特沃尔科技有限公司 | Method for continuously blending fracturing fluid by utilizing sea water |
| CN103074049A (en) * | 2013-01-21 | 2013-05-01 | 西南石油大学 | Fracturing fluid prepared by recovery waste water of crude oil and preparation method of fracturing fluid |
| CN103965857A (en) * | 2013-01-30 | 2014-08-06 | 中国石油天然气集团公司 | Preparation method of High-temperature water base fracturing fluid |
| CN104650845A (en) * | 2013-11-22 | 2015-05-27 | 中国石油天然气股份有限公司 | High-temperature non-crosslinked clean fracturing fluid and preparation method thereof |
| CN103820099A (en) * | 2014-03-05 | 2014-05-28 | 成都佰椿石油科技有限公司 | Acid liquor friction reducer and preparation method thereof |
| CN104178102A (en) * | 2014-05-16 | 2014-12-03 | 成都佰椿石油科技有限公司 | Cross-linkable high-temperature-resistant residue-free polybasic copolymerizable fracturing fluid and preparation method thereof |
| CN106279523A (en) * | 2015-06-25 | 2017-01-04 | 中国石油天然气股份有限公司 | Thickening agent and preparation method and application thereof |
| CN105219370A (en) * | 2015-09-10 | 2016-01-06 | 成都佰椿石油科技有限公司 | A kind of multi-functional reservoir reconstruction liquid and preparation method thereof |
| CN105733547A (en) * | 2016-01-29 | 2016-07-06 | 成都佰椿石油科技有限公司 | High-temperature-resistance low-friction weighted clean fracturing fluid and preparation method thereof |
| CN105778884A (en) * | 2016-05-10 | 2016-07-20 | 西南石油大学 | Supramolecular polymer clean fracturing fluid resistant to high temperature of 170 DEG C |
| CN106190088A (en) * | 2016-07-08 | 2016-12-07 | 四川奥赛德材料科技有限公司 | Temperature-resistant anti-salt instant dissolving viscosifier for seawater-based fracturing fluid and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 一种海水基清洁压裂液体系研究;林波;《油田化学》;20150925;第32卷(第3期);337-340 * |
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