阅读说明：本技术 一种磁性纳米膜成像支撑剂及其制备方法和应用 (Magnetic nano-film imaging proppant and preparation method and application thereof ) 是由 张矿生 唐梅荣 王成旺 张翔 李川 杜现飞 马兵 王广涛 张同伍 李成政 于 2020-07-06 设计创作，主要内容包括：本发明提供了一种磁性纳米膜成像支撑剂及其制备方法和应用,包括支撑剂内核,支撑剂内核从内至外依次覆有磁性纳米膜、生气层和保护层,其中,各组分的质量配比为：支撑剂内核80-85份,磁性纳米膜2-4份,生气层10-15份,保护层1-2份。其中磁性纳米膜具有磁单畴尺寸、超顺磁性、磁性强的特性,可通过磁性纳米探针检测裂缝磁性扰动而成像；生气层遇水产水气泡,实现本体在水中悬浮；保护层起到抗结块、保护内部成分的作用。磁性纳米膜通过水、硝酸、异丙醇铝按比例制备得到有机酸性溶剂,可将磁性金属缩聚凝胶化,内部形成三维网络结构,磁畴分散性好、尺寸可控、均一性好。(The invention provides a magnetic nano-film imaging proppant as well as a preparation method and application thereof, and the magnetic nano-film imaging proppant comprises a proppant inner core, wherein the proppant inner core is sequentially covered with a magnetic nano-film, a gas generation layer and a protective layer from inside to outside, wherein the mass ratio of each component is as follows: 80-85 parts of a propping agent core, 2-4 parts of a magnetic nano film, 10-15 parts of a gas generating layer and 1-2 parts of a protective layer. The magnetic nano film has the characteristics of magnetic single domain size, superparamagnetism and strong magnetism, and can be used for detecting crack magnetic disturbance through a magnetic nano probe to form an image; the gas generating layer generates water bubbles when meeting water, so that the body is suspended in the water; the protective layer has the functions of anti-caking and protecting internal components. The magnetic nano-film is prepared from water, nitric acid and aluminum isopropoxide in proportion to obtain the organic acidic solvent, the magnetic metal can be condensed and gelatinized, a three-dimensional network structure is formed inside the organic acidic solvent, and the magnetic nano-film has the advantages of good magnetic domain dispersibility, controllable size and good uniformity.)

1. A magnetic nanomembrane imaging proppant, comprising: the composite proppant comprises a proppant inner core (1), wherein the proppant inner core (1) is sequentially coated with a magnetic nano film (2), a gas generating layer (3) and a protective layer (4) from inside to outside, and the weight ratio of each component is as follows: 80-85 parts of a proppant inner core (1), 2-4 parts of a magnetic nano film (2), 10-15 parts of a gas generating layer (3) and 1-2 parts of a protective layer (4).

2. The magnetic nanomembrane imaging proppant of claim 1, wherein: the magnetic nano film (2) is formed by attaching magnetic nano sol to a proppant inner core (1), wherein the magnetic nano sol consists of the following substances in percentage by mass: 20-25 parts of nitric acid, 1-2 parts of aluminum isopropoxide, 20-25 parts of nickel-iron-cobalt nitrate solution and the balance of water.

3. The magnetic nanomembrane imaging proppant of claim 1, wherein: the gas generation layer (3) comprises the following substances in parts by mass: 40-50 parts of binder, 30-35 parts of polyol resin, 18-24 parts of isocyanate, 2-4 parts of amine additive and 0.1-0.2 part of catalyst.

4. The magnetic nanomembrane imaging proppant of claim 1, wherein: the protective layer (4) comprises the following substances in parts by mass: 35-45 parts of degradable nano material and 55-65 parts of anti-caking agent.

5. The magnetic nanomembrane imaging proppant of claim 2, wherein: the molar ratio of nickel, iron and cobalt in the nickel-iron-cobalt nitrate solution is as follows: 65:31:4.

6. The magnetic nanomembrane imaging proppant of claim 3, wherein: the adhesive is a mixture of epoxy resin and phenolic resin, the weight ratio of the epoxy resin to the phenolic resin is 2-4:1, the hydroxyl equivalent of the polyalcohol resin is 60-300, the isocyanate resin is 2, 4-toluene diisocyanate, the amine additive is one or a mixture of more of diethylenetriamine, triethylamine, ethylamine, ethylenediamine and triethylenetetramine, and the catalyst is one or a mixture of two of alkyl tin compounds or alkyl lead compounds.

7. The magnetic nanomembrane imaging proppant of claim 4, wherein: the anti-caking agent is one or a mixture of more of calcium silicate, calcium carbonate, fumed silica, kaolin, corn starch, sodium stearate, bentonite, attapulgite, styrene maleic anhydride resin, a nike surfactant, triethanolamine titanium chelate and triethanolamine zirconium chelate.

8. The magnetic nanomembrane imaging proppant of claim 4, wherein: the degradable nano material comprises the following substances in parts by mass: 40-50 parts of starch, 30-40 parts of nano powder, 10-15 parts of plasticizer and 10-15 parts of polyvinyl alcohol, wherein the plasticizer is a mixture consisting of one or more of phthalate, adipate, azelate, sebacate, stearate, phosphate and glycerol.

9. The method for preparing the magnetic nanomembrane imaging proppant according to claim 3, comprising the following steps:

step 1) preparing a degradable nano material and a magnetic nano sol for later use;

step 2) mixing the magnetic nano sol and the proppant inner core (1) according to the mass ratio of 80-85:2-4, stirring in a marmite for 20-30 minutes, and then placing in an electromagnetic heating box to heat at the temperature of 350-;

step 3) heating the proppant intermediate to 250 ℃ of temperature of 200-;

step 4), when the temperature is reduced to 80-100 ℃, adding the degradable nano material and the anti-caking agent and stirring for 30-50 minutes; wherein the total mass ratio of the proppant to the degradable nano material to the anti-caking agent is 80-85:1-2, and the mass ratio of the degradable nano material to the anti-caking agent is 35-45: 55-65 parts;

and 5) uniformly dispersing, airing and screening to obtain the magnetic nano-film imaging proppant.

10. Use of a magnetic nanomembrane imaging proppant according to claims 1 to 8, comprising the steps of:

step 1) before fracturing, measuring a magnetic field of the depth of an underground reservoir stratum with the radius of 1 kilometer around an oil well by using an aeromagnetic magnetometer, a SQUID (superconducting quantum interference device) magnetometer or a magnetic magnetometer in the oil well;

step 2) reforming a target layer of the oil well, carrying the target layer by using clear water, and adding a magnetic nano-film imaging proppant or simultaneously injecting the magnetic nano-film imaging proppant and a conventional proppant;

and 3) carrying out secondary measurement on the magnetic field of the depth of the underground reservoir stratum with the radius of 1 kilometer around the oil well by using an aviation geomagnetic instrument, a SQUID geomagnetic instrument or a magnetic instrument in the oil well, and comparing the secondary measurement with the primary measurement data to obtain magnetic field data formed after the magnetic nano-film imaging proppant enters, thereby obtaining a fracture imaging result.

Technical Field

The invention belongs to the technical field of oilfield development, and particularly relates to a magnetic nano-film imaging proppant as well as a preparation method and application thereof.

Background

The resource reserves of low-permeability and compact oil gas and shale oil gas account for a quite high proportion in the world and at home, hydraulic fracturing becomes a conventional single-well production and injection increasing technology, generally, a hydraulic fracturing production increasing measure is required at the initial production stage of the oil gas well of the oil and gas reservoir, the diversion capability is expanded, the fracturing production increasing effect is improved, and the high-quality single-well yield is obtained by injecting a propping agent. The hydraulic fracture plays a crucial role in the field of stimulation measures, and monitoring of the trend, the shape and the size of the hydraulic fracture is particularly important. The approximate size of the crack, whether multiple cracks are generated, whether the crack extends in a target layer or not can be evaluated through crack monitoring imaging, the length and height growth of the crack can be obtained along with the increase of the construction scale, and the optimal construction scale and the transformation parameters are determined. But there is currently a lack of economical, direct, repeatable fracture monitoring methods to image fractures.

The existing fracture monitoring method mainly comprises tiltmeter fracture monitoring and microseism fracture monitoring, and has the defects that the general form of the fracture can only be obtained along with short observation distance and lower resolution, information on the aspects of proppant laying and flow conductivity cannot be obtained, and detailed information on fracture expansion cannot be obtained, and the two parameters play a key role in capacity prediction.

In order to obtain proppant placement information for hydraulic fracturing, radioisotope tracer monitoring methods have also been developed. In the method, radioactive components (sometimes adopting multiple isotopes) are added in the fracturing process, and spectral gamma ray logging is carried out after fracturing; the disadvantages are short detection distance and unsafe hidden danger of radioactivity. For this reason, symmington (2006) proposes a method for the use of a fracturing process for high temperature reservoirs, using conductive material (calcareous) proppants, to locate the proppant distribution. The method can image the expansion range, the crack development direction and the size of the propping agent, and has the defects of serious imaging interference, insufficient detection distance and accuracy due to the fact that background environments such as reservoir fluid and the like have conductive properties.

Disclosure of Invention

The invention aims to provide a magnetic nano-film imaging proppant as well as a preparation method and application thereof, and solves the problems of radioactive proppants and conductive material proppants in hydraulic fracture monitoring imaging.

The invention also aims to provide a preparation method of the magnetic nano-film imaging proppant, so as to obtain the superparamagnetic and strong-magnetism nano-film proppant.

Another objective of the present invention is to provide an application of the magnetic nanomembrane imaging proppant, which can accurately determine the shape of the hydraulic fracture and the laying condition of the proppant by monitoring the magnetic field change before and after fracturing.

Therefore, the technical scheme provided by the invention is as follows:

the magnetic nano-film imaging proppant comprises a proppant inner core, wherein the proppant inner core is sequentially coated with a magnetic nano-film, a gas generation layer and a protective layer from inside to outside, wherein the mass ratio of each component is as follows: 80-85 parts of a propping agent core, 2-4 parts of a magnetic nano film, 10-15 parts of a gas generating layer and 1-2 parts of a protective layer.

The magnetic nano film is formed by attaching magnetic nano sol to a propping agent, wherein the magnetic nano sol consists of the following substances in percentage by mass: 20-25 parts of nitric acid, 1-2 parts of aluminum isopropoxide, 20-25 parts of nickel-iron-cobalt nitrate solution and the balance of water.

The gas generation layer comprises the following substances in parts by mass: 40-50 parts of binder, 30-35 parts of polyol resin, 18-24 parts of isocyanate, 2-4 parts of amine additive and 0.1-0.2 part of catalyst.

The protective layer comprises the following substances in parts by mass: 35-45 parts of degradable nano material and 55-65 parts of anti-caking agent.

The molar ratio of nickel, iron and cobalt in the nickel-iron-cobalt nitrate solution is as follows: 65:31:4.

The adhesive is a mixture of epoxy resin and phenolic resin, the weight ratio of the epoxy resin to the phenolic resin is 2-4:1, the hydroxyl equivalent of the polyalcohol resin is 60-300, the isocyanate resin is 2, 4-toluene diisocyanate, the amine additive is one or a mixture of more of diethylenetriamine, triethylamine, ethylamine, ethylenediamine and triethylenetetramine, and the catalyst is one or a mixture of two of alkyl tin compounds or alkyl lead compounds.

The anti-caking agent is one or a mixture of more of calcium silicate, calcium carbonate, fumed silica, kaolin, corn starch, sodium stearate, bentonite, attapulgite, styrene maleic anhydride resin, a nike surfactant, triethanolamine titanium chelate and triethanolamine zirconium chelate.

The degradable nano material comprises the following substances in parts by mass: 40-50 parts of starch, 30-40 parts of nano powder, 10-15 parts of plasticizer and 10-15 parts of polyvinyl alcohol, wherein the plasticizer is a mixture consisting of one or more of phthalate, adipate, azelate, sebacate, stearate, phosphate and glycerol.

A preparation method of a magnetic nano-film imaging proppant comprises the following steps:

step 1) preparing a degradable nano material and a magnetic nano sol for later use;

step 2) mixing the magnetic nano sol and the propping agent according to the mass ratio of 80-85:2-4, stirring in a marmite for 20-30 minutes, and then placing in an electromagnetic heating box to heat at the temperature of 350-;

step 3) heating the proppant intermediate to 250 ℃ of temperature of 200-;

step 4), when the temperature is reduced to 80-100 ℃, adding the degradable nano material and the anti-caking agent and stirring for 30-50 minutes; wherein the total mass ratio of the proppant to the degradable nano material to the anti-caking agent is 80-85:1-2, and the mass ratio of the degradable nano material to the anti-caking agent is 35-45: 55-65 parts;

and 5) uniformly dispersing, airing and screening to obtain the magnetic nano-film imaging proppant.

Use of a magnetic nanomembrane imaging proppant comprising the steps of:

step 1) before fracturing, measuring a magnetic field of the depth of an underground reservoir stratum with the radius of 1 kilometer around an oil well by using an aeromagnetic magnetometer, a SQUID (superconducting quantum interference device) magnetometer or a magnetic magnetometer in the oil well;

step 2) reforming a target layer of the oil well, carrying the target layer by using clear water, and adding a magnetic nano-film imaging proppant or simultaneously injecting the magnetic nano-film imaging proppant and a conventional proppant;

and 3) carrying out secondary measurement on the magnetic field of the depth of the underground reservoir stratum with the radius of 1 kilometer around the oil well by using an aviation geomagnetic instrument, a SQUID geomagnetic instrument or a magnetic instrument in the oil well, and comparing the secondary measurement with the primary measurement data to obtain magnetic field data formed after the magnetic nano-film imaging proppant enters, thereby obtaining a fracture imaging result.

The invention has the beneficial effects that:

the magnetic nano-film imaging proppant provided by the invention comprises a proppant inner core, a magnetic nano-film, a gas generating layer and a protective layer from inside to outside in sequence, wherein the magnetic nano-film has the characteristics of magnetic single domain size, superparamagnetism and strong magnetism, and can be imaged by detecting crack magnetic disturbance through a magnetic nano probe; the gas generating layer generates water bubbles when meeting water, so that the body is suspended in the water; the protective layer has the functions of anti-caking and protecting internal components.

The magnetic nano-film is prepared by water, nitric acid and aluminum isopropoxide according to a proportion to obtain an organic acid solvent, so that the magnetic metal can be condensed and gelatinized, a three-dimensional network structure is formed inside, and the magnetic domain has good dispersibility, controllable size and good uniformity; the nickel-iron-cobalt nitrate solution and other components are adopted, and the formed magnetic nano film has the advantages of high density, high coercive force (up to 119.4 KA/m), high signal-to-noise ratio, good oxidation resistance and the like.

The protective layer is hydrophobic and oleophilic, can prevent a gas generation layer from reacting with water, can be dissolved in the oil layer, and then releases a gas generation material, so that partial isocyanate in the gas generation layer rapidly reacts with water under the action of the amine additive to release a large amount of nano-scale bubbles, and the suspension of the propping agent in water is realized, thereby additionally adding a thickening agent required by the preparation of the sand-carrying fluid in the conventional fracturing process is not needed.

The method realizes the tracing display and the fracture imaging of the propping agent by detecting the change of the stratum magnetic field before and after the magnetic nano-film imaging propping agent carried by clear water injected into hydraulic fracturing, and has the advantages of clear imaging, long monitoring distance, capability of mastering the laying condition of the propping agent and the like compared with other fracture imaging technologies. Meanwhile, the proppant is coated with functional materials which generate gas when meeting water, so that clear water injection is realized, and compared with the conventional proppant, the proppant has the advantages of cleanness, environmental protection, simplicity in operation, no harm to a reservoir and the like.

In order to make the aforementioned and other objects of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

FIG. 1 is a schematic diagram of a magnetic nanomembrane imaging proppant structure of the present invention;

FIG. 2 is a schematic structural diagram of the magnetic nanomembrane imaging proppant of the present invention after exposure to oil;

FIG. 3 is a histogram comparing the performance of magnetic nano-films formed from different alloy materials.

In the figure:

description of reference numerals:

1. an inner proppant core; 2. a magnetic nanomembrane; 3. a gas generation layer; 4. and a protective layer.

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.