Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Referring to fig. 1, the invention relates to a self-heating self-gas-generating proppant, which is spherical solid particles formed by sequentially wrapping an inner core 1, a medicament inner layer 2, a medicament outer layer 3 and a protective layer 4 from inside to outside, wherein the protective layer 4 is dissolved by oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 generate a chemical reaction to generate nitrogen and release heat;
the spherical solid particles comprise the following components in parts by weight:
170-75 parts of inner core;
212-18 parts of an inner medicament layer;
312-19 parts of an outer medicament layer;
and 41-2 parts of a protective layer.
Wherein, the inner core 1 is a ceramic proppant or a quartz sand proppant, and the grain diameter is 0.11 mm-0.85 mm.
Further, the medicament inner layer 2 consists of the following components in parts by weight:
8-12 parts of nitrite;
3-4 parts of a binder;
1-2 parts of curing agent.
Further, the nitrite is one or a mixture of two of sodium nitrite and potassium nitrite;
the binder is liquid polyethylene glycol, and the molecular weight of the binder is 200-600;
the curing agent is one or a mixture of more of propane diamine, hexane diamine, p-phenylene diamine and m-phenylene diamine.
Further, the outer layer 3 of the medicament consists of the following components in parts by weight:
7-11 parts of a nitrogen-containing compound;
1-2 parts of an acidic catalyst;
3-4 parts of a binder;
1-2 parts of curing agent.
Preferably, the nitrogen-containing compound is one or a mixture of ammonium chloride and urea;
the acid catalyst is one or a mixture of more of citric acid, tartaric acid and tartaric acid;
the binder is solid polyethylene glycol with molecular weight more than 1000;
the curing agent is one or a mixture of more of propane diamine, hexane diamine, p-phenylene diamine and m-phenylene diamine.
Preferably, the protective layer 4 is 1 to 2 parts by weight of oil-soluble phenolic resin.
The invention also provides a preparation method of the self-heating self-gas-generating proppant, which comprises the following steps:
s001, taking a ceramsite proppant or a quartz sand proppant according to the proportion, immersing the ceramsite proppant or the quartz sand proppant into a liquid binder, and taking out the ceramsite proppant or the quartz sand proppant after immersing for 0.5-1.5 min to obtain a product A;
s002, according to the proportion, putting nitrite and a curing agent into a stirring tank, stirring for 4-6 min, putting the product A into the stirring tank, continuously stirring for 9-11 min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified proppant;
s003, putting a nitrogen-containing compound, an acid catalyst, a solid binder, a curing agent and a modified propping agent into a stirring tank together according to the proportion, stirring for 9-11 min, taking out, uniformly dispersing, and airing to complete the coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 0.5-1.5 min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
In addition, the invention also protects an application method of the self-heating self-generating gas proppant, the self-heating self-generating gas proppant is carried to the stratum by the fracturing fluid, the self-heating self-generating gas proppant fills a fracturing crack, a protective layer 4 of the proppant is dissolved by oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 generate chemical reaction to generate nitrogen and release heat.
The mechanism is as follows: the fracturing fluid carries the self-heating self-gas-generating proppant to the stratum, a protective layer 4 of the proppant is dissolved when being contacted with oil, an outer layer of the medicament is exposed and is contacted with water in the fracture, and nitrite in the inner layer of the medicament reacts with a nitrogen-containing compound in the outer layer of the medicament under the action of an acid catalyst, for example, NaNO2And NH4Cl reacts to give off a large amount of heat and generate N2Due to N2、NaCl、H2O has no harm to the stratum, the temperature of a near-wellbore area can be greatly improved by heat generated by reaction, the pressure of the stratum can be increased by gas generated by reaction, and after the inner layer of the medicament reacts with the outer layer of the medicament, the propping agent of the inner core enters a crack to fill the crack.
In the proppant particles, the acid catalyst is solid, at the moment, the nitrite and the nitrogen-containing compound do not react, when the protective layer 4 is dissolved when meeting oil, the outer layer of the medicament is exposed, the acid catalyst meets water in cracks to become acid catalyst solution, such as citric acid solution, at the moment, the citric acid solution acts as the catalyst, so that the nitrite and the nitrogen-containing compound react, the citric acid solution improves the reaction rate, a large amount of heat is emitted, and N is generated2。
The purpose of the binder of the inner medicament layer is to carry out surface treatment on the proppant of the inner core so that nitrite powder in the next step is wrapped outside the inner core, and the curing agent can solidify the inner core and the outer covering film (inner medicament layer) to form primary particles.
The adhesive and the curing agent of the outer layer of the medicament have similar functions with the adhesive and the curing agent of the inner layer of the medicament, and the acid catalyst is used for improving the reaction rate of nitrite and nitrogen-containing compounds.
The oil-soluble phenolic resin is used as a protective layer to ensure that the proppant particles do not react before being put into the formation, and the proppant particles are dissolved only after being carried to the fracture and encountering oil.
Example 1:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 70 parts of ceramsite proppant, wherein the particle size is 0.212-0.425 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 8 parts of sodium nitrite (nitrite), 3 parts of liquid polyethylene glycol (binder), and 1.5 parts of propane diamine (curing agent), wherein the molecular weight of the liquid polyethylene glycol is 200-600;
outer layer of the medicament: 7 parts of ammonium chloride (nitrogen-containing compound), 1.2 parts of citric acid (acid catalyst), 3 parts of solid polyethylene glycol (binder) with the molecular weight of more than 1000 and 1 part of hexamethylene diamine (curing agent);
protective layer: 1 part of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, taking a ceramsite proppant according to the proportion, soaking the ceramsite proppant into liquid polyethylene glycol for 0.5min, and taking out the ceramsite proppant to obtain a product A;
s002, according to the proportion, putting sodium nitrite and propane diamine into a stirring tank, stirring for 4min, putting the product A into the stirring tank, continuously stirring for 9min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified propping agent;
s003, according to the proportion, putting ammonium chloride, citric acid, solid polyethylene glycol, hexamethylene diamine and a modified propping agent into a stirring tank together, stirring for 9min, taking out, uniformly dispersing, and airing to complete the coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 0.5-1.5 min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 2:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 71 parts of quartz sand propping agent, wherein the particle size is 0.15-0.35 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 9 parts of potassium nitrite (nitrite), 4 parts of liquid polyethylene glycol (binder), and 2 parts of hexamethylenediamine (curing agent), wherein the molecular weight of the hexamethylenediamine is 200-600;
outer layer of the medicament: 8 parts of a mixture of ammonium chloride and urea (nitrogen-containing compound), 1 part of fruit acid (acid catalyst), 3.5 parts of solid polyethylene glycol (binder), wherein the molecular weight is more than 1000, and 1.5 parts of hexamethylene diamine (curing agent);
protective layer: 2 parts of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, according to the proportion, soaking the quartz sand proppant into liquid polyethylene glycol for 0.6min, and taking out to obtain a product A;
s002, according to the proportion, putting potassium nitrite and hexamethylene diamine into a stirring tank, stirring for 5min, putting the product A into the stirring tank, continuously stirring for 10min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified proppant;
s003, according to the proportion, putting a mixture of ammonium chloride and urea, tartaric acid, solid polyethylene glycol, hexamethylenediamine and a modified propping agent into a stirring tank together, stirring for 10min, taking out, uniformly dispersing, and airing to complete coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 1min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 3:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 72 parts of quartz sand propping agent, wherein the particle size is 0.36-0.56 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 10 parts of potassium nitrite (nitrite), 3.2 parts of liquid polyethylene glycol (binder), and 1.2 parts of p-phenylenediamine (curing agent), wherein the molecular weight of the liquid polyethylene glycol is 200-600;
outer layer of the medicament: 9 parts of urea (nitrogen-containing compound), 1.5 parts of tartaric acid (acid catalyst), 4 parts of solid polyethylene glycol (binder) with the molecular weight of more than 1000, and 2 parts of hexamethylene diamine (curing agent);
protective layer: 1.5 parts of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, according to the proportion, soaking the quartz sand proppant into liquid polyethylene glycol for 1.3min, and taking out to obtain a product A;
s002, according to the proportion, putting the potassium nitrite and the p-phenylenediamine into a stirring tank, stirring for 6min, putting the product A into the stirring tank, continuously stirring for 11min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified propping agent;
s003, according to the proportion, putting urea, tartaric acid, solid polyethylene glycol, hexamethylene diamine and a modified propping agent into a stirring tank together, stirring for 11min, taking out, uniformly dispersing, and airing to complete the coating of the medicament outer layer 3 outside the medicament inner layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 1.4min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 4:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 73 parts of ceramsite proppant with the particle size of 0.23-0.43 mm and the mesh number of 40-70 meshes;
inner layer of medicament: 11 parts of sodium nitrite (nitrite), 3.5 parts of liquid polyethylene glycol (binder) and 1 part of m-phenylenediamine (curing agent), wherein the molecular weight of the liquid polyethylene glycol is 200-600;
outer layer of the medicament: 10 parts of ammonium chloride (nitrogen-containing compound), 2 parts of citric acid (acid catalyst), 3 parts of solid polyethylene glycol (binder), wherein the molecular weight is more than 1000, and 1.2 parts of propane diamine (curing agent);
protective layer: 1 part of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, taking a ceramsite proppant according to the proportion, soaking the ceramsite proppant into liquid polyethylene glycol for 0.7min, and taking out the ceramsite proppant to obtain a product A;
s002, according to the proportion, putting sodium nitrite and m-phenylenediamine into a stirring tank, stirring for 4min, putting the product A into the stirring tank, continuously stirring for 10min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified propping agent;
s003, according to the proportion, putting ammonium chloride, citric acid, solid polyethylene glycol, propylene diamine and a modified propping agent into a stirring tank together, stirring for 9min, taking out, uniformly dispersing, and airing to complete the coating of the medicament outer layer 3 outside the medicament inner layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 0.8min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 5:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 73.8 parts of ceramsite proppant, wherein the particle size is 0.46-0.76 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 12 parts of sodium nitrite (nitrite), 3 parts of liquid polyethylene glycol (binder) and 1.7 parts of mixture (curing agent) of p-phenylenediamine and hexamethylene diamine, wherein the molecular weight of the mixture is 200-600;
outer layer of the medicament: 11 parts of urea (nitrogen-containing compound), 1.7 parts of a mixture of tartaric acid and tartaric acid (acid catalyst), 3.2 parts of solid polyethylene glycol (binder) with the molecular weight of more than 1000 and 1 part of p-phenylenediamine (curing agent);
protective layer: 2 parts of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, taking a ceramsite proppant according to the proportion, soaking the ceramsite proppant into liquid polyethylene glycol for 0.9min, and taking out the ceramsite proppant to obtain a product A;
s002, according to the proportion, putting the mixture of sodium nitrite, p-phenylenediamine and hexamethylene diamine into a stirring tank, stirring for 5min, putting the product A into the stirring tank, continuously stirring for 10min, finishing coating of the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified proppant;
s003, according to the proportion, putting the mixture of urea, tartaric acid and tartaric acid, solid polyethylene glycol, p-phenylenediamine and modified propping agent into a stirring tank together, stirring for 10min, taking out, uniformly dispersing, and airing to complete the coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 1.4min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 6:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 74 parts of quartz sand propping agent, wherein the particle size is 0.56-0.84 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 10 parts of potassium nitrite (nitrite), 4 parts of liquid polyethylene glycol (binder) and 2 parts of p-phenylenediamine (curing agent), wherein the molecular weight of the liquid polyethylene glycol is 200-600;
outer layer of the medicament: 9 parts of ammonium chloride (nitrogen-containing compound), 2 parts of fruit acid (acid catalyst), 4 parts of solid polyethylene glycol (binder), wherein the molecular weight is more than 1000, and 1 part of p-phenylenediamine (curing agent);
protective layer: 2 parts of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, according to the proportion, soaking the quartz sand proppant into liquid polyethylene glycol for 1.5min, and taking out to obtain a product A;
s002, according to the proportion, putting the potassium nitrite and the p-phenylenediamine into a stirring tank, stirring for 6min, putting the product A into the stirring tank, continuously stirring for 11min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified propping agent;
s003, according to the proportion, putting ammonium chloride, tartaric acid, solid polyethylene glycol, p-phenylenediamine and a modified propping agent into a stirring tank together, stirring for 11min, taking out, uniformly dispersing, and airing to complete the coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 1.5min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 7:
the self-heating and self-generating proppant in the embodiment comprises the following components in parts by weight:
kernel: 75 parts of quartz sand propping agent, wherein the particle size is 0.56-0.84 mm, and the mesh number is 40-70 meshes;
inner layer of medicament: 11 parts of potassium nitrite (nitrite), 3 parts of liquid polyethylene glycol (binder), and 1 part of p-phenylenediamine (curing agent), wherein the molecular weight of the liquid polyethylene glycol is 200-600;
outer layer of the medicament: 7 parts of ammonium chloride (nitrogen-containing compound), 1 part of fruit acid (acid catalyst), 4 parts of solid polyethylene glycol (binder), and 2 parts of p-phenylenediamine (curing agent) with the molecular weight of more than 1000;
protective layer: 1 part of oil-soluble phenolic resin.
The preparation method of the self-heating and self-generating gas proppant comprises the following steps:
s001, according to the proportion, soaking the quartz sand proppant into liquid polyethylene glycol for 1.5min, and taking out to obtain a product A;
s002, according to the proportion, putting the potassium nitrite and the p-phenylenediamine into a stirring tank, stirring for 6min, putting the product A into the stirring tank, continuously stirring for 11min, finishing coating the inner layer 2 of the medicament outside the inner core 1 to form a product B, putting the product B into a vibrating screen, and screening powder which is not attached to the surface of the product B to obtain the modified propping agent;
s003, according to the proportion, putting ammonium chloride, tartaric acid, solid polyethylene glycol, p-phenylenediamine and a modified propping agent into a stirring tank together, stirring for 11min, taking out, uniformly dispersing, and airing to complete the coating of the outer medicament layer 3 outside the inner medicament layer 2 to obtain a product wool;
s004, rounding and polishing the rough material of the product, and then putting the rough material into a vibrating screen for screening to obtain a product C;
and S005, putting the product C into oil-soluble phenolic resin, soaking for 1.5min, taking out, airing, and finishing coating the protective layer 4 outside the medicament outer layer 3 to obtain the self-heating gas-generating proppant finished product.
The fracturing fluid is used for carrying the self-heating self-generating gas proppant prepared by the embodiment to a stratum, the self-heating self-generating gas proppant is used for filling fracturing cracks, a protective layer 4 of the proppant is dissolved when meeting oil, and the dissolved medicament inner layer 2 and the medicament outer layer 3 are subjected to chemical reaction to generate nitrogen and release heat.
Example 8:
this example prepares the self-heating self-gas-generating proppant in grams as follows:
taking 1000 g of 40/70-mesh quartz sand (with the particle size of 0.212-0.425 mm) for fracturing, putting liquid polyethylene glycol (with the molecular weight of 200-600) into the quartz sand, soaking the quartz sand for 1 minute, and taking out the quartz sand;
taking 120 g of sodium nitrite powder and 5 g of m-phenylenediamine, putting into a stirring tank, stirring for 5 minutes, adding the soaked quartz sand, stirring for 10 minutes, putting into a vibrating screen, and screening out the powder which is not attached to the quartz sand to obtain a modified proppant;
taking 110 g of ammonium chloride, 15 g of citric acid, 10 g of solid polyethylene glycol (molecular weight is more than 1000) and a modified propping agent, putting the materials into a stirring tank, stirring for 10 minutes, taking out the materials, uniformly dispersing and airing to obtain a product wool;
rounding and polishing the product wool, and then putting the product wool into a vibrating screen for screening;
and (3) putting the screened product into oil-soluble phenolic resin, soaking for 1 minute, taking out, and airing to obtain a finished product of the self-heating gas-generating multifunctional proppant.
In accordance with the data provided in example 8, a self-generated thermogenic proppant was prepared and filled into fractures in a field formation and found to last for more than 3 months for the effective period of the proppant and to increase the annual cumulative production by more than 30% over the conventional proppant control well.
The following are comparative tests of the performance of the proppants prepared in some of the above examples and conventional proppants, including acid solubility test, roundness test, sphericity test, and shatter resistance test.
See in particular the following table:
the acid solubility is the percentage of the mass of the proppant dissolved by the acid to the total proppant mass under a given acid solution and reaction conditions, and the lower the acid solubility of the proppant, the stronger the acid corrosion resistance.
The fracture resistance is characterized by the fracture resistance of a certain amount of proppant, wherein the fracture rate determined by a pressure bearing test under rated pressure represents the fracture resistance of the proppant, and for the proppant, the lower the fracture rate is, the better the fracture resistance is, and the higher the diversion of the formed support fracture is.
Roundness is a measure of the sharpness of the corners of the proppant particles or the curvature of the particles, sphericity is a measure of how spherical the proppant particles are, for proppants, the higher the sphericity the higher the fracture conductivity of the resulting propped fracture.
As can be seen from the above table, compared with the conventional proppant, the proppant prepared by the invention has the advantages that the acid solubility is obviously lower than 1.5%, the crushing resistance is lower than 7.5%, and the roundness and sphericity are 0.8, which are superior to those of the conventional proppant.
In conclusion, the self-heating autogenous gas generating proppant protected by the invention consists of an inner core, a medicament inner layer, a medicament outer layer and a protective layer from inside to outside, after entering a stratum, the protective layer is dissolved, and a nitrogen-containing compound in the medicament outer layer reacts with nitrite in the medicament inner layer under the action of an acid catalyst to generate nitrogen and release heat. The generated heat can improve the temperature of a near wellbore region, promote the rapid degradation of injected fluid, reduce the viscosity of crude oil and enhance the seepage capability of the crude oil; the generated large amount of gas is uniformly dispersed in the hydraulic fracture, thereby promoting flowback, reducing reservoir damage and replenishing formation energy in situ, and greatly improving the yield after pressing. The proppant has the functions of heating the stratum, promoting flowback and supplementing stratum energy besides supporting cracks, and has the advantages of quick response, long acting time, simple construction operation, small safety risk and easy popularization.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.