CN115161004B - Catalytic viscosity-reducing proppant for fracturing and preparation method thereof - Google Patents

Abstract

The invention discloses a catalytic viscosity reduction propping agent for fracturing and a preparation method thereof, and belongs to the technical field of oil gas production. The catalytic viscosity reduction propping agent for fracturing comprises the following components in percentage by weight: 1.5-5% of viscosity reduction catalyst and 95-98.5% of propping agent; the viscosity reduction catalyst is metal salt; the viscosity reduction catalyst is spherical particles and is mixed with the propping agent, or the viscosity reduction catalyst is coated on the particle surfaces of the propping agent. The catalytic viscosity reduction propping agent for fracturing is characterized in that the viscosity reduction catalyst is made into particles and mixed with the propping agent, or the viscosity reduction catalyst is directly wrapped on the surface of the propping agent, in the fracturing process, the viscosity reduction catalyst and the propping agent are sent into a stratum together with fracturing fluid, an effective target horizon can be reached, in the flowback process, thick oil flows through the propping agent to undergo catalytic viscosity reduction reaction on site so as to reduce the viscosity of the thick oil, effectively improve the flowability of the thick oil, reduce the flow resistance of the thick oil, improve the diversion capacity of a reservoir and improve the flowability of the thick oil, and achieve the effect of prolonging the flowback and increasing the yield of fracturing.

Description

Catalytic viscosity-reducing proppant for fracturing and preparation method thereof

technical field

The invention belongs to the technical field of oil and gas production, and relates to a catalytic viscosity-reducing proppant for fracturing and a preparation method thereof.

Background technique

Heavy oil occupies a relatively large proportion of the world's oil and gas resources. In my country, heavy oil is mainly distributed in oil fields such as Shengli, Liaohe, Henan, Xinjiang and Bohai. Heavy oil recovery is not limited to thermal oil recovery, chemical flooding, gas flooding and other development methods. For heavy oil reservoirs with certain fluidity under oil layer conditions but low porosity, low permeability, and ultra-deep, it is necessary to implement single well wells through fracturing measures. Increase in production.

In the prior art, the materials involved in hydraulic fracturing mainly include fluids such as guar gum fluid and slick water, and solid-phase proppants such as quartz sand and ceramsite. The main function of proppants is to keep fractures open after fracturing and improve formation conductivity. ability. However, although proppant is used to maintain the oil flow channel in the fracture network after fracturing, the flow effect of heavy oil is still poor due to its high viscosity and poor flow ability.

Therefore, further solutions are needed for the above-mentioned technical problems.

Contents of the invention

In view of this, the purpose of the present invention is to provide a catalytic viscosity-reducing proppant for fracturing and its preparation method, so that it can enter the formation with the fracturing fluid during the fracturing process, and the heavy oil flows through the proppant during the flowback process. And the viscosity-reducing catalyst catalyzes the viscosity-reducing reaction in situ to reduce the viscosity, effectively improving the fluidity of heavy oil.

In order to solve the above technical problems, an embodiment of the present disclosure provides a catalytic viscosity-reducing proppant for fracturing, which comprises the following components in weight percentage:

1.5%-5% viscosity-reducing catalyst, 95%-98.5% proppant;

Wherein, the viscosity reducing catalyst is a metal salt;

The viscosity-reducing catalyst is spherical particles and mixed with the proppant, or the viscosity-reducing catalyst is wrapped on the particle surface of the proppant.

In some embodiments, wherein the weight percent of the viscosity reducing catalyst is 1.5%-2%;

The weight percentage of the proppant is 98%-98.5%.

In some embodiments, wherein the viscosity-reducing catalyst is wrapped on the particle skeleton to form spherical particles;

Wherein, the particle skeleton is a porous material, and the loading amount of the viscosity-reducing catalyst on the particle skeleton is 1.5%-10%.

In some embodiments, the material used for the particle skeleton is one or more of zeolite, carbon nanotubes, and porous ceramics.

In some embodiments, the particle size of the viscosity-reducing catalyst is 10-20 mesh larger than the particle size of the proppant particles.

In some embodiments, wherein the viscosity reducing catalyst is an inorganic acid salt, petroleum acid salt, benzoate or phthalate of at least one metal ion in iron, cobalt, nickel, manganese, copper, ruthenium and palladium salt.

In some embodiments, the proppant is quartz sand or ceramsite.

On the other hand, an embodiment of the present disclosure also provides a method for preparing a catalytic viscosity-reducing proppant for fracturing, including:

The viscosity-reducing catalyst is wrapped on the surface of the particle skeleton by an impregnation method to make spherical particles containing the viscosity-reducing catalyst, and the weight percentage of the viscosity-reducing proppant is 1.5%-5%, and the weight percentage of the proppant is 95%-98.5%, mixing the spherical particles and the proppant to prepare the catalytic viscosity-reducing proppant for fracturing;

Or, the viscosity-reducing catalyst is wrapped on the surface of the proppant by impregnation, and the weight percentage of the viscosity-reducing catalyst is 1.5%-5%, and the weight percentage of the proppant is 95%-98.5%, and the obtained Catalytic viscosity-reducing proppant for fracturing.

In some embodiments, the method wherein the impregnation method is used to prepare spherical particles containing the viscosity reducing catalyst is:

Prepare a solution of the viscosity-reducing catalyst at a concentration of 10%-20%;

Immerse the particle skeleton of the porous material into the solution of the viscosity-reducing catalyst, let it stand at 50°C-70°C for 12h-20h, then take out the particle skeleton and heat it at 120°C-150°C for 2h-3h for the first stage of drying treatment, and then dry at 300°C-350°C for 1.5h-2h for the second stage of drying treatment;

The impregnation and drying are repeated several times as above until the loading of the viscosity-reducing catalyst on the particle skeleton is 1.5%-10%.

In some embodiments, the method wherein the viscosity-reducing catalyst is wrapped on the surface of the proppant by impregnation is:

Prepare a solution of the viscosity-reducing catalyst at a concentration of 10%-20%;

Immerse the proppant in the solution of the viscosity-reducing catalyst, let it stand at 50°C-70°C for 12h-20h, then take out the particle skeleton and heat it at 120°C-150°C for 2h-3h to carry out the first-stage drying treatment, and then Dry at 300°C-350°C for 1.5h-2h for the second stage of drying treatment;

The impregnation and drying are repeated several times as above until the loading of the viscosity-reducing catalyst on the proppant is 1.5%-5%.

Compared with the prior art, the catalytic viscosity-reducing proppant for fracturing and the preparation method thereof of the present invention have the following beneficial effects:

In the catalytic viscosity-reducing proppant for fracturing disclosed in the embodiments of the present invention, the viscosity-reducing catalyst is made into particles and mixed with the proppant, or the viscosity-reducing catalyst is directly wrapped on the surface of the proppant. During the fracturing process, The viscosity-reducing catalyst and proppant are sent into the formation together with the fracturing fluid, and can reach the effective target layer. During the flowback process, the heavy oil flows through the proppant to catalyze the viscosity-reducing reaction on the spot to reduce the viscosity, effectively improving the viscosities. The fluidity of the oil can reduce the flow resistance of heavy oil, play a dual role of improving the reservoir conductivity and improving the fluidity of heavy oil, and achieve the effect of prolonging the fracturing return and increasing production; in addition, the fracturing disclosed in the embodiment of the present invention The components in the catalytic viscosity-reducing proppant are cheap and easy to obtain, easy to prepare, and can accurately reach the target layer with the fracturing fluid. Compared with other viscosity-reducing methods for heavy oil formations, the active components are more directional, Viscosity reduction is longer lasting.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention will be described in detail below.

Description of drawings

The above and other objects, features and advantages of the exemplary embodiments of the present application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present application are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

Fig. 1 is a schematic structural diagram of a one-dimensional sand filling model according to an embodiment of the present disclosure.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention.

The materials and reagents used in the following examples can all be obtained from commercial sources.

A catalytic viscosity-reducing proppant for fracturing disclosed in the embodiment of the present invention comprises the following components in weight percent:

1.5%-5% viscosity-reducing catalyst, 95%-98.5% proppant;

Wherein the viscosity-reducing catalyst is a metal salt;

The viscosity-reducing catalyst is spherical particles and mixed with the proppant, or the viscosity-reducing catalyst is wrapped on the particle surface of the proppant.

Specifically, since the selected viscosity-reducing catalyst is a metal salt, the catalytic viscosity-reducing proppant for fracturing can be made by the above two methods, but whether the viscosity-reducing catalyst is made into spherical particles in advance, or the viscosity-reducing catalyst is directly When the catalyst is wrapped on the surface of the proppant, it is necessary to ensure that the weight percentage of the viscosity-reducing catalyst accounts for 1.5%-5%, and the weight percentage of the proppant accounts for 95%-98.5%. For example, when the propping material is used to make spherical particles containing the viscosity-reducing catalyst in a surface-attached manner, the catalytic viscosity-reducing proppant for fracturing should still account for 1.5%-5% by weight of the viscosity-reducing catalyst.

Wherein, the proppant may be quartz sand or ceramsite which are commonly used in the current technology. As for the particle size of quartz sand or ceramsite, it can be selected according to the actual fracturing process standards.

In a specific implementation, the preferred weight percentage of the viscosity reducing catalyst is 1.5%-2%; the preferred weight percentage of the proppant is 98%-98.5%.

Further, the preferred weight percentage of the viscosity reducing catalyst can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%; the preferred weight percentage of the proppant can be 98%, 98.1%, 98.2%, 98.3% %, 98.4%, or 98.5%.

In a specific implementation, wherein the viscosity-reducing catalyst is wrapped on the particle skeleton to form spherical particles; wherein, the particle skeleton is a porous material, and the loading of the viscosity-reducing catalyst on the particle skeleton is 1.5%-10% .

Specifically, it should be noted that the particle skeleton is only used as a viscosity-reducing catalyst to form the skeleton of spherical particles, and the weight of the particle skeleton itself is not included in the component mass of the catalytic viscosity-reducing proppant for fracturing, that is, the viscosity-reducing catalyst is used in fracturing. The weight percentage in the catalytic viscosity-reducing proppant is calculated by its own mass.

Wherein, the material used for the particle skeleton of the porous material is one or more of zeolite, carbon nanotubes, and porous ceramics.

Further, the particle size of the viscosity-reducing catalyst of the spherical particles is 10-20 mesh larger than the particle size of the proppant, that is, the particle size of the proppant is larger than that of the viscosity-reducing catalyst of the spherical particles, so as to ensure the particle size of the spherical particles. The viscosity-reducing catalyst can be well mixed with the proppant, and it is guaranteed that the propping function of the proppant will not be affected after mixing.

In a specific implementation, the viscosity-reducing catalyst of the metal salt material can be an inorganic acid salt, petroleum acid salt, benzoate or o-phthalic acid salt of at least one metal ion in iron, cobalt, nickel, manganese, copper, ruthenium and palladium. diformate.

A method for preparing a catalytic viscosity-reducing proppant for fracturing disclosed in an embodiment of the present invention includes:

The viscosity-reducing catalyst is wrapped on the surface of the particle skeleton by an impregnation method to make spherical particles containing the viscosity-reducing catalyst, and the weight percentage of the viscosity-reducing proppant is 1.5%-5%, and the weight percentage of the proppant is 95%-98.5%, mixing the spherical particles and the proppant to prepare the catalytic viscosity-reducing proppant for fracturing;

Or, the viscosity-reducing catalyst is wrapped on the surface of the proppant by impregnation, and the weight percentage of the viscosity-reducing catalyst is 1.5%-5%, and the weight percentage of the proppant is 95%-98.5%, and the obtained Catalytic viscosity-reducing proppant for fracturing.

In specific implementation, the method for preparing spherical particles containing the viscosity-reducing catalyst by the impregnation method is: preparing a solution of the viscosity-reducing catalyst with a concentration of 10%-20%; immersing the particle skeleton of the porous material into the viscosity-reducing catalyst In the solution, let it stand at 50°C-70°C for 12h-20h, then take out the particle skeleton and heat it at 120°C-150°C for 2h-3h to carry out the first-stage drying treatment, and then dry it at 300°C-350°C for 1.5 Carry out the second stage of drying treatment for h-2h; repeat the dipping and drying several times as above, until the loading of the viscosity-reducing catalyst on the particle skeleton is 1.5%-10%.

Wherein, the concentration of the prepared viscosity-reducing catalyst solution can be specifically set according to the solubility of the selected metal salt, for example, the concentration can also be 10%, 11%, 12%, 13%, 14%, 15% during actual configuration , 16%, 17%, 18%, 19% or 20%, the way to configure the solution is mastered by the skilled person and will not be repeated here. The temperature of the dipping process can also be set according to the adhesion characteristics of the metal salt, and can be any integer temperature in the range of 50°C-70°C, but not limited to 50°C-70°C. The drying temperature of the impregnated particle skeleton adopts the above-mentioned stepped temperature, that is, it is first dried at a relatively low temperature, and then dried at a relatively high temperature, wherein the preferred value of the drying temperature in the first stage can be 120 °C, 130 °C, 140 °C, 150 °C, the preferred value of the second stage drying temperature can be 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, the drying time of the two stages, then It can be adjusted adaptively according to the weight of the material to be dried once.

In a specific implementation, the impregnation method is used to directly coat the viscosity-reducing catalyst on the proppant, and reference may be made to the above-mentioned method for preparing spherical particles containing the viscosity-reducing catalyst.

Wherein, the method for wrapping the viscosity-reducing catalyst on the surface of the proppant by the impregnation method is:

Prepare a solution of the viscosity-reducing catalyst with a concentration of 10%-20%; immerse the proppant in the solution of the viscosity-reducing catalyst, let it stand at 50°C-70°C for 12h-20h, and then take out the particle skeleton at 120°C Heating at -150°C for 2h-3h for the first-stage drying treatment, and then drying at 300°C-350°C for 1.5h-2h for the second-stage drying treatment; repeated dipping and drying several times as above until all the proppants on the proppant The loading amount of the viscosity reducing catalyst is 1.5%-5%.

Specifically, the actual concentration may also be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%. The temperature of the impregnation process can be any integer temperature in 50°C-70°C, but not limited to 50°C-70°C. The drying method after impregnation can be the same as the drying method after impregnation of the particle skeleton.

In order to better illustrate the preparation method and application effect of the catalytic viscosity-reducing proppant for fracturing provided by the embodiment of the present invention, the following specific examples are provided:

Example 1

Copper chloride is used as a viscosity-reducing catalyst, and quartz sand is used as a proppant;

Take 100g of quartz sand of 40-70 mesh, prepare 1000g of copper chloride aqueous solution with a concentration of 20%, mix the two, stir, and let stand at 60°C for 12h, then take out the quartz sand and heat and dry at 150°C for 3h, in the muffle furnace Drying at 300°C for 2 hours, repeated immersion and drying several times to prepare a catalytic viscosity-reducing proppant for fracturing with a loading capacity of 1.6% of the viscosity-reducing catalyst.

Embodiment 2, preparation of catalytic viscosity-reducing proppant for fracturing

Ferric chloride is used as a viscosity-reducing catalyst, and ceramsite is used as a proppant;

Take 100g of ceramsite of 30-50 mesh, prepare 1000g of ferric chloride aqueous solution with a concentration of 20%, mix the two, stir, and let stand at 60°C for 12h, then take out the ceramsite and heat and dry at 150°C for 3h, in the muffle furnace Drying at 300°C for 2 hours, repeated impregnation and drying several times to prepare a catalytic viscosity-reducing proppant for fracturing with a loading capacity of 1.5% of the viscosity-reducing catalyst.

Example 3

Copper chloride is used as a viscosity-reducing catalyst;

Take 100g of 40-80 mesh zeolite, prepare 1000g of copper chloride aqueous solution with a concentration of 20%, mix the two and stir, let stand at 60°C for 12h, then take out the zeolite and heat and dry it at 150°C for 3h, and heat it in a muffle furnace at 300°C Drying for 2 hours, repeated impregnation and drying several times to obtain a granular viscosity-reducing catalyst with a loading capacity of 10%.

At this time, the prepared granular viscosity-reducing catalyst can be mixed with ceramsite or quartz sand in proportion to prepare a catalytic viscosity-reducing proppant for fracturing.

Example 4

Using ferric chloride water as a viscosity-reducing catalyst;

Take 100g of 40-80mesh zeolite, prepare 1000g of ferric chloride aqueous solution with a concentration of 20%, mix the two and stir, let stand at 60°C for 12h, then take out the zeolite and heat and dry at 150°C for 3h, and heat it in a muffle furnace at 300°C Drying for 2 hours, repeated impregnation and drying several times to obtain a granular viscosity-reducing catalyst with a loading capacity of 10%.

At this time, the prepared granular viscosity-reducing catalyst can be mixed with ceramsite or quartz sand in proportion to prepare a catalytic viscosity-reducing proppant for fracturing.

Example 5

As shown in Figure 1, the one-dimensional sand-packing model was filled with the catalytic viscosity-reducing proppant prepared in Examples 1 and 2 (the outer part is the catalytic viscosity-reducing proppant inside the cylinder, the inner diameter of the model is 2.5 cm, and the length is 100 cm), and then the The one-dimensional sand-packing model is placed in a constant temperature box at 140°C, and heavy oil with a viscosity (140°C) of 328mPa.s is injected into the sand-packing model at a constant speed from the A-side of the model to the B-side to maintain the heavy oil in the sand-packing pipe. The flow time is 18 hours. After the heavy oil flows out of the B end, the sample is collected and its viscosity is measured.

After testing, the viscosity reduction rates of the heavy oil are 39% and 35%, respectively, which shows that the fluidity of the heavy oil is effectively improved.

Example 6

As shown in Figure 1, the particle-type catalytic viscosity reducer prepared in Examples 3 and 4 was mixed with quartz sand at a mass ratio of 1:5, and a one-dimensional sand filling model was filled (the outside is the cylinder filled with catalytic viscosity reducer proppant , the inner diameter of the model is 2.5cm, and the length is 100cm), and then the one-dimensional sand packing model is placed in a constant temperature box at 140°C, and heavy oil with a viscosity (140°C) of 328mPa. For the sand model, keep the heavy oil flowing in the sand pipe for 18 hours. After the heavy oil flows out of the B end, collect samples and measure their viscosity.

After testing, the viscosity reduction rates of the heavy oil are 32% and 33%, respectively, which shows that the fluidity of the heavy oil is effectively improved.

Example 7

As shown in Figure 1, the granular catalytic viscosity reducer prepared in Examples 3 and 4 were mixed with ceramsite at a mass ratio of 1:5, and a one-dimensional sand filling model was filled (the outside is the cylinder filled with catalytic viscosity reducer proppant , the inner diameter of the model is 2.5cm, and the length is 100cm), and then the one-dimensional sand packing model is placed in a constant temperature box at 140°C, and heavy oil with a viscosity (140°C) of 328mPa. For the sand model, keep the flow time of the heavy oil in the sand filling pipe for 18 hours. After the heavy oil flows out of the B end, collect samples and measure their viscosity;

After testing, the viscosity reduction rates of the heavy oil are 37% and 35%, respectively, which shows that the fluidity of the heavy oil is effectively improved.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (9)

1. The preparation method of the catalytic viscosity reduction propping agent for fracturing is characterized by comprising the following steps of:

coating a viscosity reduction catalyst on the surface of a propping agent by adopting an impregnation method, wherein the weight percentage of the viscosity reduction catalyst is 1.5-5%, and the weight percentage of the propping agent is 95-98.5%, so that the catalytic viscosity reduction propping agent for fracturing is obtained; the viscosity reduction catalyst is wrapped on a particle framework to form spherical particles;

the method for wrapping the viscosity reduction catalyst on the surface of the propping agent by adopting an impregnation method comprises the following steps:

preparing a solution of the viscosity reduction catalyst at a concentration of 10% -20%;

immersing a propping agent into the solution of the viscosity reduction catalyst, standing for 12-20 h at 50-70 ℃, then taking out the particle skeleton, heating for 2-3 h at 120-150 ℃ for first-stage drying treatment, and then drying for 1.5-2 h at 300-350 ℃ for second-stage drying treatment;

and repeatedly soaking and drying for a plurality of times until the loading amount of the viscosity reduction catalyst on the propping agent is 1.5-5%.

2. The method for preparing the catalytic viscosity reduction propping agent for fracturing according to claim 1, wherein the method for preparing spherical particles containing the viscosity reduction catalyst by adopting an impregnation method is as follows:

preparing a solution of the viscosity reduction catalyst at a concentration of 10% -20%;

immersing the particle skeleton of the porous material into the solution of the viscosity reduction catalyst, standing for 12-20 h at 50-70 ℃, then taking out the particle skeleton, heating for 2-3 h at 120-150 ℃ for first-stage drying treatment, and then drying for 1.5-2 h at 300-350 ℃ for second-stage drying treatment;

and repeatedly soaking and drying for a plurality of times until the loading capacity of the viscosity reduction catalyst on the particle skeleton is 1.5-10%, wherein the weight of the particle skeleton is not counted into the mass of the components of the catalytic viscosity reduction propping agent for fracturing, and the weight percentage of the viscosity reduction catalyst in the catalytic viscosity reduction propping agent for fracturing is calculated according to the mass of the catalyst.

3. The catalytic viscosity reduction propping agent for fracturing is prepared based on the preparation method of the catalytic viscosity reduction propping agent for fracturing of claim 1 or 2, and is characterized by comprising the following components in percentage by weight:

1.5-5% of viscosity reduction catalyst and 95-98.5% of propping agent;

wherein the viscosity reduction catalyst is a metal salt;

the viscosity reduction catalyst is coated on the particle surface of the propping agent.

4. The catalytic viscosity reducing proppant for fracturing according to claim 3,

the weight percentage of the viscosity reduction catalyst is 1.5% -2%;

the weight percentage of the propping agent is 98% -98.5%.

5. The catalytic viscosity reducing proppant for fracturing according to claim 3,

the particle skeleton is made of porous materials, and the loading capacity of the viscosity reduction catalyst on the particle skeleton is 1.5% -10%, wherein the weight of the particle skeleton is not counted by the mass of components of the catalytic viscosity reduction propping agent for fracturing, and the weight percentage of the viscosity reduction catalyst in the catalytic viscosity reduction propping agent for fracturing is calculated according to the mass of the catalyst.

6. The catalytic viscosity reducing proppant for fracturing according to claim 5,

the material used for the particle skeleton is one or more of zeolite, carbon nano tube and porous ceramic.

7. The catalytic viscosity reducing proppant for fracturing according to claim 5 or 6,

the particle size of the viscosity reduction catalyst is 10-20 meshes larger than the particle size of the propping agent.

8. The catalytic viscosity reducing proppant for fracturing according to claim 3,

the viscosity reduction catalyst is inorganic acid salt, petroleum acid salt, benzoate or phthalate of at least one metal ion of iron, cobalt, nickel, manganese, copper, ruthenium and palladium.

9. The catalytic viscosity reducing proppant for fracturing according to claim 3,

the propping agent is quartz sand or ceramsite.