1. The corrosion and scale inhibiting slow releasing oil well granule features that its material composition includes adsorbent, composite scale inhibitor and curing agent; the raw material components comprise, by mass, 45-55% of an adsorbent, 25-35% of a composite scale inhibitor and 5-15% of a curing agent.

2. The oil well corrosion and scale inhibition slow-release particle as claimed in claim 1, wherein the adsorbent is a combination of two compounds selected from semi-calcined silica, alumina, iron oxide, calcium oxide and magnesium oxide, and the mass ratio of the compound combination is 1: 2-2: 1.

3. The oil well corrosion and scale inhibition slow release particle according to claim 1, wherein the components of the composite scale inhibitor comprise aminotrimethylene phosphonic acid, 2-phosphonobutane-1, 2, 4-tricarboxylic acid, hydroxyethylidene diphosphonic acid, and phosphonocarboxylate.

4. The oil well corrosion and scale inhibition slow-release particle as claimed in claim 3, wherein the ratio of aminotrimethylene phosphonic acid to 2-phosphonobutane-1, 2, 4-tricarboxylic acid to hydroxyethylidene diphosphonic acid to phosphonocarboxylate in the component of the composite scale inhibitor is 10-15: 10-20: 20-30: 35-60 by mass.

5. The oil well corrosion and scale inhibiting slow release particle of claim 3 wherein the salt of phosphorus carboxylic acid comprises potassium or sodium salt of phosphorus carboxylic acid.

6. The oil well corrosion and scale inhibition slow release particle of claim 1, wherein the curing agent is an aqueous solution of polyvinyl alcohol.

7. The oil well corrosion and scale inhibition slow-release particle according to claim 6, wherein the aqueous solution of polyvinyl alcohol is a polyvinyl alcohol solution with a volume fraction of 10%; the polymerization degree of the polyvinyl alcohol is 1700, and the alcoholysis degree of the polyvinyl alcohol is 88%.

8. The method for preparing the corrosion and scale inhibiting slow release particles for the oil well as defined in any one of claims 1 to 7 is characterized in that the adsorbent is soaked by using the composite scale inhibitor and then dried, a polyvinyl alcohol solution is added to be uniformly mixed, and the corrosion and scale inhibiting slow release particles for the oil well are obtained after drying.

9. The preparation method of claim 8, wherein the oil well corrosion and scale inhibition slow release particles have a loading rate of not less than 35%, a release time of not less than 60 days at 50 ℃ and a compressive strength of more than 5 MPa.

10. Use of the oil well corrosion and scale inhibiting slow release particles of any one of claims 1 to 7 in oil and gas production.

Background

In each production link of drilling, oil extraction, gathering and transportation and the like in the petroleum industry, from an oil-water well to pipelines, storage tanks and various process equipment, the phenomena of serious corrosion, scaling and the like are suffered, the damage to the equipment and the pipelines is aggravated, serious malignant accidents are caused, the personal health is seriously threatened, and the environment is polluted; the corrosion and scaling phenomena of pipelines and equipment cause the loss of products, increase the production cost of the petroleum industry and even influence the normal production. In particular, in recent years, the problems of water content increase, equipment aging, corrosion and scaling of crude oil become more and more serious when a plurality of oil field production developments enter the later production stage.

At present, the corrosion prevention, scale removal and paraffin removal are generally finished independently in three links, most of the chemicals such as scale inhibition and paraffin removal of liquid are directly injected into a well, the chemicals often flow away or adhere to the pipe wall along with produced liquid quickly and need to be continuously and frequently injected, and a lot of troubles are brought to production and management. Solid scale inhibitors are relatively researched more, and are mostly single scale inhibitors or corrosion inhibitors, a special dosing tool is generally needed, and meanwhile, the currently researched and developed solid scale inhibitors have the technical problems of quick release, short effective period, incompatibility with fracturing fluid and the like, and cannot effectively solve the problems in the current oil well development process.

The fracturing fluid is surface fresh water, and the fluid is possibly incompatible with formation water and has a scaling tendency, the fracturing fluid remained in the formation is at the far end of a crack, and the reconstruction volume is reduced once scaling occurs.

Disclosure of Invention

The invention aims to solve the technical problems of incompatibility of the scale inhibitor and fracturing fluid, low scale inhibition rate, short effective period and complex process, and provides the corrosion and scale inhibition slow-release particles for the oil well, the effective release period of the slow-release particles is more than 60 days, the compressive strength of the slow-release particles is more than 5MPa, and the phenomena of scaling and corrosion in oil field exploitation can be effectively solved.

Specifically, the invention adopts the following technical scheme:

the oil well corrosion-preventing scale-inhibiting slow releasing granule has material components including adsorbent, composite scale inhibitor and curing agent; specifically, the raw material components comprise, by mass, 45% -55% of an adsorbent, 25% -35% of a composite scale inhibitor and 5% -15% of a curing agent.

As a preferred embodiment of the present invention, the adsorbent of the present invention is selected from two combinations of silica, alumina, iron oxide, calcium oxide, and magnesium oxide. The research of the inventor finds that the oil well corrosion and scale inhibition slow-release particles prepared by mixing the adsorbent material with other materials can be quickly dissolved in water if the adsorbent material is not calcined; the oil well corrosion-prevention scale-inhibition slow-release particles prepared by mixing the adsorbent material with other materials after being completely calcined are extremely difficult to dissolve in water. Therefore, the adsorbent of the invention is preferably a combination of two compounds selected from semi-calcined silica, alumina, iron oxide, calcium oxide and magnesium oxide, and the mass ratio of the compound combination is 1: 2-2: 1.

The research of the inventor finds that the adsorbent can fully adsorb the composite scale inhibitor, and the semi-calcination process operation method ensures that the adsorption balls (silicon dioxide, aluminum oxide, iron oxide, calcium oxide and magnesium oxide particles after semi-calcination) have enough compressive strength, and can be dissolved after being soaked for a long time (more than 60 days), so that the adsorbent has little damage to the stratum.

As a preferred embodiment of the present invention, the components of the complex scale inhibitor include aminotrimethylene phosphonic Acid (ATMP), 2-phosphonobutane-1, 2, 4-tricarboxylic acid (PBTCA), hydroxyethylidene diphosphonic acid (HEDP), phosphonocarboxylates; the curing agent is a polyvinyl alcohol aqueous solution.

Furthermore, the composite scale inhibitor comprises, by mass, 10-15: 10-20: 20-30: 35-60 parts of aminotrimethylene phosphonic acid, 2-phosphonobutane-1, 2, 4-tricarboxylic acid, hydroxyethylidene diphosphonic acid and phosphonocarboxylate.

Further, the phosphorus carboxylate comprises potassium phosphorus carboxylate, sodium phosphorus carboxylate; the polyvinyl alcohol aqueous solution is a polyvinyl alcohol solution with the volume fraction of 10%.

Further, the polymerization degree of the polyvinyl alcohol is 1700, and the alcoholysis degree is 88%.

The invention provides a preparation method of the oil well corrosion and scale inhibition slow release particles, which comprises the steps of soaking an adsorbent in a composite scale inhibitor for 24 hours, drying, adding a polyvinyl alcohol solution, uniformly mixing, and drying to obtain the oil well corrosion and scale inhibition slow release particles.

Furthermore, the volume fraction of the polyvinyl alcohol solution is 10%, and the polyvinyl alcohol solution is uniformly adhered to the surface of the oil well corrosion and scale inhibition slow-release particles in various modes such as spraying, stirring and the like.

The oil well corrosion-resistant scale-inhibiting slow-release particles prepared by the method have the loading rate of not less than 35 percent, the release time at 50 ℃ of not less than 60 days and the compressive strength of more than 5MPa according to performance verification.

The invention also provides application of the oil well corrosion and scale inhibition slow-release particles in oil and gas exploitation.

Compared with the prior art, the invention has the following beneficial effects or advantages:

(1) the corrosion-resistant scale-inhibiting slow-release particles provided by the invention take silicon dioxide, aluminum oxide and the like after semi-calcination as adsorption carriers (namely adsorbents), and the adsorbents have high compressive strength after semi-calcination, can be dissolved after being soaked for a long time (more than 60 days), and have little damage to the stratum.

(2) The high-purity scale and corrosion inhibition liquid is adsorbed and then wrapped by the curing agent polyvinyl alcohol, and can be mixed with the fracturing sand and then added into an oil well without adding a medicine adding process. The scale and corrosion inhibitor is fully absorbed by utilizing the adsorption principle of the molecular sieve, and after being wrapped, the wrapped scale and corrosion inhibitor enters the stratum along with the fracturing sand belt, so that the oil well, the oil pipeline and the equipment are protected in an all-around way from the source.

(3) The preparation method of the corrosion-resistant scale-inhibiting slow-release particles is simple and easy to operate, and the prepared corrosion-resistant scale-inhibiting slow-release particles can protect the whole crack section, protect an oil well from the source and comprehensively and long-term inhibit scaling and corrosion phenomena of the oil well, a pipeline and equipment thereof.

(4) The corrosion-resistant scale-inhibiting slow-release particles provided by the invention do not need an additional medicine adding process, and the medicament exists independently, so that the problem of compatibility with a fracturing material and a stratum is not required to be considered, and the corrosion-resistant scale-inhibiting slow-release particles are economic, environment-friendly and practical.

Detailed Description

The present invention will be further explained with reference to specific embodiments, but the present invention is not limited to the embodiments described below.

Example 1

A preparation method of corrosion-resistant scale-inhibition slow-release particles.

The anticorrosive scale-inhibiting slow-releasing granule is prepared with the material including: adsorbent, composite scale inhibitor and curing agent. Wherein the adsorbent is selected from two compounds of semi-calcined silicon dioxide, aluminum oxide, ferric oxide, calcium oxide and magnesium oxide; the components of the composite scale inhibitor comprise aminotrimethylene phosphonic Acid (ATMP), 2-phosphonic butane-1, 2, 4-tricarboxylic acid (PBTCA), hydroxyethylidene diphosphonic acid (HEDP) and phosphorus carboxylate; the curing agent is a polyvinyl alcohol solution with the volume fraction of 10%.

The composite scale inhibitor comprises, by mass, 10-15: 10-20: 20-30: 35-60 parts of ATMP, PBTCA, HEDP and phosphorus carboxylate.

The phosphorus carboxylate comprises sodium phosphorus carboxylate and potassium phosphorus carboxylate.

The polymerization degree of the polyvinyl alcohol is 1700, and the alcoholysis degree of the polyvinyl alcohol is 88%.

The mass ratio of the raw material components of the adsorbent is 1: 2-2: 1.

The preparation materials of the corrosion-resistant scale-inhibiting slow-release particles comprise the following components in percentage by mass: 45-55% of adsorbent, 25-35% of composite scale inhibitor and 5-15% of curing agent. Soaking the adsorbent in the composite scale inhibitor for 24 hours, drying, adding the curing agent, mixing uniformly, and drying to obtain the oil well corrosion and scale inhibition slow-release particles.

Three kinds of corrosion-resistant and scale-inhibiting slow-release particles are respectively prepared by the method of the embodiment, and the numbers of the particles are FDZH-01, FDZH-02 and FDZH-03 respectively.

The formula and the content of FDZH-01 are as follows: 45% of adsorbent (semi-calcined silicon dioxide and calcium oxide in a mass ratio of 2:1), 40% of composite scale inhibitor (ATMP: PBTCA: HEDP: sodium phosphonocarboxylate in a mass ratio of 10:10:20:60) and 15% of curing agent (10% polyvinyl alcohol solution).

The formula and the content of FDZH-02 are as follows: 55% of adsorbent (half-calcined alumina and magnesia in a mass ratio of 1:1), 40% of composite scale inhibitor (ATMP: PBTCA: HEDP: sodium phosphonocarboxylate in a mass ratio of 15:15:25:45) and 5% of curing agent (10% polyvinyl alcohol solution).

The formula and the content of FDZH-03 are as follows: 50% of adsorbent (half-calcined iron oxide and magnesium oxide in a mass ratio of 1:2), 35% of composite scale inhibitor (ATMP: PBTCA: HEDP: sodium phosphonocarboxylate in a mass ratio of 15:20:30:35), and 15% of curing agent (10% polyvinyl alcohol solution).

Example 2

In order to further investigate the application performance of the oil well corrosion and scale inhibition slow release particles, the present example evaluates the dispersion performance, scale inhibition performance and corrosion prevention performance of the oil well corrosion and scale inhibition slow release particles prepared in example 1.

1. Reagents and materials

The reagents required for the test are FDZH-01, FDZH-02 and FDZH-03 prepared by the method described in the examples; the test control treatment agents were DZ-01 and DZ-02.

Wherein, the formula and the content of DZ-01 are as follows: 45% of adsorbent (uncalcined silica), 40% of scale inhibitor (PBTCA) and 15% of curing agent (10% polyvinyl alcohol solution);

the formula and the content of DZ-02 are as follows: 45% of adsorbent (fully calcined silica), 40% of scale inhibitor (PBTCA) and 15% of curing agent (10% polyvinyl alcohol solution).

The materials required by the test are carbon steel hanging pieces, stainless steel hanging pieces and brass hanging pieces, and the pretreatment is carried out by the following steps:

wiping the anti-rust grease on the hanging piece to be tested by using filter paper, respectively scrubbing the hanging piece to be tested by using absorbent cotton in acetone and absolute ethyl alcohol (no less than 50mL of the reagent is used for each 10 test pieces), placing the hanging piece on clean filter paper, sucking the hanging piece by using the filter paper, placing the hanging piece on a dryer for more than 4h, weighing the hanging piece (the weight is accurate to 0.0002g), and storing the hanging piece in the dryer for later use.

2. Test procedure

The calcium carbonate scale inhibition rate is determined according to a calcium carbonate deposition method for determining scale inhibition performance of a water treatment agent (GB/T16632-2008), and the rotating hanging sheet experiment is performed according to a rotating hanging sheet method for determining corrosion inhibition performance of water treatment (GB/T18175-2000).

1.1 evaluation of Dispersion Performance

The test reagents FDZH-01, FDZH-02, FDZH-03, DZ-01 and DZ-02 are weighed in batches, about 50g (to the accuracy of 0.0002g) of each reagent is taken and placed in a 500mL beaker, tap water is added, and the mixture is slowly stirred at normal temperature.

3 treatments were set per experimental group and each treatment was repeated 3 times. The first treatment group in each test group filters out and dries the medicament treated in the 30 th treatment group after the test is started, the second treatment group in the 60 th treatment group and the third treatment group in the 90 th treatment group, weighs (to the precision of 0.0002g), calculates the average value of each treatment, and records the data.

1.2 evaluation of Scale inhibition Performance

The calcium carbonate scale inhibition rate test is carried out according to the test conditions shown in the national standard GB/T16632-2008, the test temperature is 60 ℃, the time is 10h, the test treatment group setting is the same as 1.1, and the test is carried out by taking no medicament as a blank control. After completion of the test, calcium (Ca) in the test solution was measured²⁺) And (4) calculating the scale inhibition rate according to the ion concentration, and recording test data.

1.3 evaluation of anticorrosive Properties

The rotary hanging piece experiment is carried out according to the rotary hanging piece method (GB/T18175-2000) for measuring the corrosion inhibition performance of water treatment.

The test water is circulating water of an oil well water injection system, and the water quality monitoring results are shown in a table 1:

TABLE 1 test Water quality

The test treatment group was set up as 1.1 and tested with no added agent as a blank control. The data of the relevant parameters of the test hanging strip are as follows:

TABLE 2 test coupon-related parameters

The test time is 30d, the mass of the hanging piece before and after the test is recorded, and the corrosion rate is calculated.

1.4, analysis of results

TABLE 3 results of evaluation of dispersibility

The corrosion-resistant scale inhibitor slow-release agent provided by the invention is firstly slowly dissolved by the slow-release scale inhibitor adsorbed on the surface in water, and then the adsorption carrier is dispersed in the water. In Table 3, the adsorbent used in DZ-01 was uncalcined silica, and the results showed that it was completely dispersed after 30 days of dissolution, indicating that the uncalcined silica was very readily dispersible in water; the adsorbent used in DZ-02 was fully calcined silica, and the result showed 38.9125g of mass remaining after 60d dissolution and 37.6241g of mass remaining after 90d dissolution, indicating that the fully calcined silica was difficult to disperse and dissolve in water. Compared with the prior art, the adsorbent of FDZH-01, FDZH-02 and FDZH-03 adopts semi-calcined silicon dioxide, aluminum oxide, iron oxide, calcium oxide and magnesium oxide, and the results show that the change of the mass of the adsorbent is uniform in the time periods of 0-30 d and 30-60 d, and the change of the mass of the adsorbent is small in the time period of 60 d-90 d, which indicates that the anti-corrosion and anti-scale particles provided by the invention can uniformly and slowly release anti-corrosion and anti-scale components, and the anti-corrosion and anti-scale particles are basically and completely released in the 60 d.

TABLE 4 evaluation results of Scale inhibition Properties

In Table 4, the scale inhibitor used in DZ-01 and DZ-02 was PBTCA, and the scale inhibition rates were tested to be 63.7% and 68.2%, respectively. The scale inhibitors used in the FDZH-01, FDZH-02 and FDZH-03 provided by the invention are compounds of ATMP, PBTCA, HEDP and phosphorus carboxylate, and the scale inhibition rates are respectively 87.5%, 88.9% and 85.3%. The results show that the scale inhibition rate of the compound scale inhibitor compounded in a certain proportion is remarkably improved.

TABLE 5 evaluation results of anticorrosive property

According to the requirements of GB50050-2007 design code for industrial circulating cooling water treatment, the corrosion rate of the water side of the heat transfer surface of the carbon steel equipment is less than 0.075mm/a, the corrosion rate of the water side of the heat transfer surface of the copper and stainless steel equipment is less than 0.005mm/a, and no obvious pitting corrosion or pitting corrosion phenomena occur. The results in Table 5 show that after the corrosion-resistant scale-inhibiting slow-release particles provided by the invention, corrosion rates of carbon steel hanging pieces, stainless steel hanging pieces and brass hanging pieces meet the design specification of GB50050-2007 industrial circulating cooling water treatment.

The detection results show that the corrosion and scale inhibition slow-release particles for the oil well, provided by the invention, can meet the index requirements of the oil field industry in the aspects of scale inhibition and corrosion alleviation.

As described above, the present invention can be preferably implemented, and the above-mentioned embodiments only describe the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various changes and modifications of the technical solution of the present invention made by those skilled in the art without departing from the design spirit of the present invention shall fall within the protection scope defined by the present invention.