CN114940892A - Solid paraffin inhibitor with controllable release rate and preparation method thereof - Google Patents

Abstract

The invention discloses a solid wax inhibitor with a controllable release rate. The anti-wax component, a foaming agent, an auxiliary foaming agent, a nucleating agent and a weighting agent are used as main raw materials. Prepared by foaming and other processes. The invention can effectively control the release rate of the solid wax inhibitor and ensure a higher wax inhibitor rate by regulating the size uniformity and average diameter of the cells in the solid wax inhibitor; Solid wax inhibitor with release rate to meet the differentiation of oil well production. The solid paraffin inhibitor of the present invention can effectively control the release rate of the paraffin component according to the application requirements during the extraction of the condensate, so as to achieve the effect of long-term effective paraffin prevention by one-time dosing, strengthen the protection of the pipeline, and ensure the It is suitable for the normal production of the oil field, reducing the maintenance cost and suitable for popularization.

Description

A kind of solid wax inhibitor with controllable release rate and preparation method thereof

technical field

The invention belongs to the technical field of condensate oil extraction from shale gas, and particularly relates to a solid paraffin inhibitor with a controllable release rate and a preparation method thereof.

Background technique

Clean, low-carbon and diversification are the main directions of global energy transformation. The demand for energy such as natural gas and renewable energy continues to rise. Natural gas has ushered in a golden development period. In 2020, my country's natural gas consumption will be about 300 billion cubic meters. The energy consumption structure accounts for 15% of the total. Conventional oil and gas development has entered the middle and late stage. Unconventional oil and gas resources are more than 4 times that of conventional oil and gas. The efficient development of unconventional oil and gas is a major demand for ensuring national energy security. Condensate is a special kind of crude oil mainly composed of low-carbon light hydrocarbons. It is widely distributed and has abundant reserves. Studies have shown that the global recoverable condensate resources exceed 50 billion tons, which is considered to be an alternative to traditional fossil fuels. High-quality oil and gas resources for fuel.

However, with the decrease of temperature and pressure during the production of condensate oil, the paraffin originally dissolved in the condensate oil will crystallize, grow and deposit on the surface of the pipeline, causing the problem of wax blockage, and the pipeline is blocked to the normal operation of the oil field. Exploitation has a great impact, which greatly reduces the oil production of the oil field. In order to solve the problem of wax blocking in the production process of condensate oil, two methods of physical and mechanical wax removal and chemical wax prevention are usually used. However, the traditional method of adding liquid wax inhibitor has a series of problems such as volatile, difficult dosing, short wax prevention period and high cost; The existing solid wax inhibitor also has problems such as uncontrollable release rate and unstable wax inhibitor effect. Therefore, the development of high-efficiency solid paraffin inhibitor with controllable release rate has become an urgent need for condensate production.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a solid wax inhibitor with a controllable release rate in view of the existing problems and deficiencies in the prior art, which has good slow-release effect, good wax-prevention effect, and a long effective wax-prevention period, and involves The preparation method has the advantages of simple operation, wide source of raw materials and low price, is suitable for solving the wax blocking problem in the fields of oil well pipelines, gathering pipelines and the like, and has very important practical application value.

To achieve the above object, the technical scheme adopted in the present invention is:

A preparation method of a solid paraffin inhibitor with a controllable release rate, comprising the following steps:

1) adding the anti-wax component, foaming agent, co-foaming agent, nucleating agent and weighting agent into the torque rheometer for mixing and cooling;

2) the product obtained in step 1) is crushed into granules with a crusher, and the obtained crushed granules are then dried;

3) Add the dried particles in step 2) into the mold, so that the particles evenly fill the mold, then put the mold into a hot press for molding and foaming, quickly release the pressure after molding, and cool and shape to obtain The solid wax inhibitor with controllable release rate.

In the above scheme, each component in step 1) and its mass percentage include: anti-wax component 95.4-98%, foaming agent 0.5-1.5%, co-foaming agent 0.2-0.6%, nucleating agent 0.2% ~ 1%, weight gainer 0.5 ~ 1.5%.

Preferably, the mass ratio between the foaming agent and the nucleating agent is 1:(0.7-1.2).

More preferably, the mass ratio between the foaming agent and the nucleating agent is 1:(0.9-1.1), which is conducive to the formation of a solid wax inhibitor with better cell size uniformity.

In the above scheme, the anti-wax component is an ethylene-vinyl acetate copolymer, which is in the form of transparent solid particles, its melting temperature is 65-80 ° C, the vinyl acetate content is 28-40 wt%, and the melt index is 43- 150g/10min.

In the above scheme, the foaming agent is azodicarbonamide, which is light yellow powder, non-toxic, and decomposes above 170°C to generate gases such as nitrogen, ammonia and carbon dioxide.

In the above scheme, the auxiliary foaming agent is zinc oxide, which is white powder and non-toxic. The addition of zinc oxide can widen the temperature range of foaming, so that azodicarbonamide can be decomposed in advance to generate gas at a lower temperature.

In the above scheme, the nucleating agent is nano-calcium carbonate, which is white powder and non-toxic; the addition of nano-calcium carbonate can improve the foaming conditions and adjust the uniformity of the obtained cell morphology and size.

In the above scheme, the weighting agent is barite powder, which is white powder. After the masterbatch is foamed, it will inevitably have its own density. The addition of barite powder can increase its density and ensure that the solid wax inhibitor is in the It is not easy to be washed away during the contact process of the oil flow.

In the above scheme, the temperature used in the kneading step is 85-95° C., the rotational speed is 30-60 rpm, and the time is 6-10 min.

In the above scheme, the size of the broken particles is required to pass through a 200-mesh sieve.

In the above scheme, the foaming temperature used in the molding foaming step is 165-180° C., the pressure is 8-10 MPa, and the time is 10-15 min.

The solid paraffin inhibitor with controllable release rate prepared according to the above scheme has a relatively uniform cell structure inside, the average cell diameter can be adjusted, and the cell size is relatively uniform (the range of pore size variation is less than 60 μm). The average diameter of the pores can be controlled to be 90-240 μm (preferably 120-230 μm), and the average release rate of the anti-wax component in the condensate can be controlled to be 140-170 mg/L/min; The foaming agent and nucleating agent are related to the adjustment of the foaming process, and the change of the cell diameter directly affects the release rate of the solid wax inhibitor.

The solid wax inhibitor with controllable release rate of the invention is suitable for solving the problem of wax blockage in oil and gas well pipelines and gathering and transportation pipelines, and has good slow release effect, easy use, and is compatible with existing liquid wax inhibitors and traditional solid wax inhibitors. Compared with the wax agent, it has the advantages of long effective wax prevention period, stable wax prevention effect and low price. During the production process, the condensate oil is constantly in contact with the solid wax inhibitor, and the wax inhibitor gradually dissolves in the condensate oil. The anti-waxing effect of the drug is long, which solves the problems of difficult dosing of liquid anti-waxing agent, short anti-waxing period and high cost, as well as problems such as slow release rate of traditional solid anti-waxing agent and unstable anti-waxing effect. During the maintenance period, the production stoppage caused by the paraffin blockage of oil well pipelines and gathering pipelines will improve the production efficiency of oil and gas fields, prolong the service life of oil field pipeline equipment, and greatly save manpower and material resources.

The invention selects the anti-wax component with wide source of raw materials, mixes it with components such as foaming agent, co-foaming agent, nucleating agent, etc., and then performs molding foaming, and adjusts the uniformity and average diameter of the cells to obtain Control the release rate and rate of the solid wax inhibitor, effectively take into account the good wax inhibitor effect and the effective wax inhibitor cycle (regulate the slow release rate of the wax inhibitor), so as to meet the requirements of adding the wax inhibitor at one time and maintaining the wax inhibitor effect for a long time. actual needs.

Compared with the prior art, the beneficial effects of the present invention are:

1) The present invention proposes for the first time to introduce a foaming modification system based on a foaming agent, an auxiliary foaming agent and a nucleating agent into the anti-wax system, and combine the molding foaming process to control the size uniformity and average of the obtained cells. Diameter, effectively control the release rate of the solid wax inhibitor and ensure a high wax inhibitor rate, which can provide a new idea for the optimization and regulation of the performance of the solid wax inhibitor;

2) The release rate of the solid paraffin inhibitor of the present invention is controllable, the paraffin preventive effect is stable, and it has an excellent inhibitory effect on paraffin, which can effectively alleviate the problem of wax blocking in wellbore and gathering pipelines, and can The solid wax inhibitor with different release rates can be put into the oil production to meet the difference of oil and gas well production;

3) The slow-release effect of the solid paraffin inhibitor of the present invention is good. During the exploitation process of the condensate oil, the condensate oil is continuously contacted with the solid paraffin inhibitor, and the solid paraffin inhibitor is evenly released into the condensate oil, which can reach one time. The purpose of adding, long-term wax prevention, the effective protection period of the pipeline is long, and it is beneficial to reduce the production and maintenance costs of the oil field.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the following examples, unless otherwise specified, the reagents used are commercially available chemical reagents.

In the following examples, the anti-wax component used is ethylene-vinyl acetate copolymer (EVA220, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.), which is a transparent solid particle, and the melting temperature is 72 ° C. The content of vinyl acetate is 28%, and the melt index is 150g/10min.

The foaming agent used is azodicarbonamide, which is light yellow powder, non-toxic, and decomposes above 170 ℃ to generate nitrogen, ammonia and carbon dioxide and other gases.

The auxiliary foaming agent used is zinc oxide, which is white powder and non-toxic. The addition of zinc oxide can widen the temperature range of foaming, so that azodicarbonamide can be decomposed in advance to generate gas at a lower temperature.

The nucleating agent used is nano-calcium carbonate, which is white powder and non-toxic.

The weighting agent used is barite powder, which is white powder, which can increase the density of foamed wood and ensure that the solid wax inhibitor is not easily washed away during the contact with the oil flow.

The used condensate was provided by Jianghan Oilfield Research Institute, and its wax precipitation temperature was 20°C.

Example 1

A kind of solid wax inhibitor with controllable release rate, its preparation method comprises the steps:

1) The copolymer of ethylene-vinyl acetate, azodicarbonamide, zinc oxide, nano-calcium carbonate and barite are added into the torque rheometer for mixing, and the mass percentage of each component is: Ethylene-vinyl acetate copolymer 97.5%, azodicarbonamide 0.7%, zinc oxide 0.6%, barite 0.7%, nano calcium carbonate 0.5%, the mixing temperature is 95 ℃, the rotation speed is 50 rpm, and the mixing time is After mixing, the product was taken out and cooled for use.

2) The product obtained in step 1) was crushed into granules (200 meshes), and then the obtained crushed granules were dried at room temperature for 24 h, and used after drying;

3) Add the dried broken particles into the mold, so that the particles evenly fill the mold, and then put the mold into a hot press for molding foaming, the molding foaming temperature used is 170 ° C, and the molding foaming pressure is The pressure is 10MPa, the molding time is 15min, the pressure is quickly released after the molding is completed, and the solid wax inhibitor with a controllable release rate can be obtained by cooling and shaping.

Through testing and calculation (obtain the cross-sectional topography of the obtained solid wax inhibitor, record the observed pore size and number, and take the average value of the cell diameter; the same below), it can be known that the foam in the wax inhibitor prepared in this example The average diameter of the pores is about 130 μm, and the uniformity of the cell size is good, and the pore size distribution range is mainly 95-146 μm.

The average release rate of the solid paraffin inhibitor with controllable release rate obtained in this example in the condensate at 70° C. is 155 mg/L/min, and the paraffin inhibitor rate is 59.8%.

Example 2

A kind of solid wax inhibitor with controllable release rate, its preparation method comprises the steps:

1) The copolymer of ethylene-vinyl acetate, azodicarbonamide, zinc oxide, nano-calcium carbonate and barite are added into the torque rheometer for mixing, and the mass percentage of each component is: Ethylene-vinyl acetate copolymer 97.1%, azodicarbonamide 0.9%, zinc oxide 0.6%, barite 0.7%, nano calcium carbonate 0.7%, the mixing temperature is 95 ℃, the rotating speed is 50 rpm, the mixing time is For 8min, take out the product after mixing, and cool it for use;

2) The product obtained in step 1) was crushed into granules (200 meshes), and then the obtained crushed granules were dried at room temperature for 24 h, and used after drying;

3) Add the dried broken particles into the mold, so that the particles evenly fill the mold, and then put the mold into a hot press for molding foaming, the molding foaming temperature used is 170 ° C, and the molding foaming pressure is The pressure is 10MPa, the molding time is 15min, the pressure is quickly released after the molding is completed, and the solid wax inhibitor with a controllable release rate can be obtained by cooling and shaping.

Through testing and calculation, it can be seen that the average diameter of the cells in the prepared paraffin inhibitor is about 220 μm, the uniformity of the cell size is good, and the distribution range of the pore size is mainly 182-235 μm.

The average release rate of the solid paraffin inhibitor with controllable release rate obtained in this example in condensate at 70° C. is 160 mg/L/min, and the paraffin inhibitor rate is 62.7%.

Example 3

A kind of solid wax inhibitor with controllable release rate, its preparation method comprises the steps:

1) The copolymer of ethylene-vinyl acetate, azodicarbonamide, zinc oxide, nano-calcium carbonate and barite are added into the torque rheometer for mixing, and the mass percentages of each component are: Ethylene-vinyl acetate copolymer 96.7%, azodicarbonamide 1%, zinc oxide 0.6%, barite 0.7%, nano calcium carbonate 1%, the mixing temperature is 95 ℃, the rotation speed is 50 rpm, the mixing time is For 8min, take out the product after mixing, and cool it for use;

2) The product obtained in step 1) was crushed into granules (200 meshes), and then the obtained crushed granules were dried at room temperature for 24 h, and used after drying;

3) Add the dried broken particles into the mold, so that the particles evenly fill the mold, and then put the mold into a hot press for molding foaming, the molding foaming temperature used is 170 ° C, and the molding foaming pressure is The pressure is 10MPa, the molding time is 15min, the pressure is quickly released after the molding is completed, and the solid wax inhibitor with a controllable release rate can be obtained by cooling and shaping.

Through testing and calculation, it can be seen that the average diameter of the cells in the wax inhibitor prepared in this example is about 220 μm, and the uniformity of the cell size is good, and the distribution range of the pore size is mainly 198-230 μm.

The average release rate of the solid paraffin inhibitor with controllable release rate obtained in this example in condensate at 70° C. is 166 mg/L/min, and the paraffin inhibitor rate is 65.9%.

Comparative Example 1

A kind of solid wax inhibitor with controllable release rate, its preparation method comprises the steps:

1) The copolymer of ethylene-vinyl acetate, azodicarbonamide, zinc oxide, nano-calcium carbonate and barite are added into the torque rheometer for mixing, and the mass percentages of each component are: Ethylene-vinyl acetate copolymer 98%, azodicarbonamide 0.7%, zinc oxide 0.6%, barite 0.7%, the mixing temperature is 95°C, the rotation speed is 50rpm, the mixing time is 8min, and the mixing is completed Then take out the product and cool it for use;

2) The product obtained in step 1) was crushed into granules (200 meshes), and then the obtained crushed granules were dried at room temperature for 24 h, and used after drying;

3) Add the dried broken particles into the mold, so that the particles evenly fill the mold, and then put the mold into a hot press for molding foaming, the molding foaming temperature used is 170 ° C, and the molding foaming pressure is The pressure is 10MPa, the molding time is 15min, the pressure is quickly released after the molding is completed, and the solid wax inhibitor with a controllable release rate can be obtained by cooling and shaping.

Through testing and calculation, it can be seen that the average diameter of the cells in the prepared paraffin inhibitor is about 135 μm, but the uniformity of the cell size is poor, and the distribution range of the pore size is mainly 72-148 μm (the variation of the pore size is up to 76 μm). .

The average release rate of the solid paraffin inhibitor with controllable release rate obtained in this example is 150 mg/L/min in condensate at 70°C, and its paraffin inhibitor rate is 58.6%; Under the condition of release rate, the anti-wax rate has a certain degree of decline.

The above-mentioned embodiments are only for the purpose of clearly illustrating the examples, and are not intended to limit the implementation. For those of ordinary skill in the art, other different forms of changes or changes can also be made on the basis of the above description, and it is not necessary and impossible to list all the implementations here. Therefore, the obvious changes or changes implied by It still falls within the protection scope of the present invention.

Claims (8)

1. A preparation method of a solid wax inhibitor with controllable release rate is characterized by comprising the following steps:

1) taking a wax-proof component, a foaming agent, a co-foaming agent, a nucleating agent and a weighting agent as main raw materials, adding the main raw materials into a torque rheometer for mixing, and cooling;

2) crushing the product obtained in the step 1), and then drying the obtained crushed particles;

3) adding the dried crushed particles obtained in the step 2) into a mold, carrying out mold pressing foaming, pressure relief, cooling and shaping to obtain the solid wax inhibitor with controllable release rate.

2. The preparation method according to claim 1, wherein the components in the step 1) and the mass percentages of the components comprise: 95.4-98% of an anti-wax component, 0.5-1.5% of a foaming agent, 0.2-0.6% of a co-foaming agent, 0.2-1% of a nucleating agent and 0.5-1.5% of a weighting agent.

3. The production method according to claim 1, wherein the blowing agent is azodicarbonamide; the assistant foaming agent is zinc oxide.

4. The method according to claim 1, wherein the wax-proofing component is an ethylene-vinyl acetate copolymer having a melting temperature of 65 to 80 ℃, a vinyl acetate content of 28 to 40 wt%, and a melt index of 43 to 150g/10 min.

5. The method of claim 1, wherein the nucleating agent is nano calcium carbonate.

6. The method according to claim 1, wherein the temperature used in the kneading step is 85 to 95 ℃, the rotation speed is 30 to 60rpm, and the time is 6 to 10 min.

7. The preparation method of claim 1, wherein the foaming temperature in the step of die pressing and foaming is 165-180 ℃, the pressure is 8-10 MPa, and the time is 10-15 min.

8. The solid paraffin inhibitor with controllable release rate prepared by the preparation method of any one of claims 1 to 7, characterized in that the inside of the solid paraffin inhibitor has a cell structure, the average diameter of cells is 90 to 240 μm, and the average release rate of the paraffin inhibitor in condensate oil is 140 to 160 mg/L/min.