阅读说明：本技术 一种固井用高界面粘结力纤维颗粒及其制备方法 (High-interface-binding-force fiber particles for well cementation and preparation method thereof ) 是由 刘学鹏 刘伟 周仕明 于 2018-06-20 设计创作，主要内容包括：本发明涉及固井领域,特别涉及一种用于固井用高界面粘结力纤维颗粒及其制备方法。该颗粒以刚性纤维或树脂作为芯料,以温敏树脂为中间层,以韧性纤维长丝缠绕为表皮层,同时提供一种制备高界面粘结力纤维颗粒的方法。该纤维颗粒在水泥浆中的添加比例随需要任意调整；颗粒随水泥浆到达井下,当温度达到温敏软化温度后,颗粒“释放”出纤维长丝,在水泥浆的带动下,纤维打开,产生体积位阻效应,完成封堵过程,同时提高水泥石的和强度和韧性。(The invention relates to the field of well cementation, in particular to high-interface-binding-force fiber particles for well cementation and a preparation method thereof. The particle takes rigid fiber or resin as a core material, takes temperature-sensitive resin as an intermediate layer, and takes flexible fiber filament wound as a skin layer, and simultaneously provides a method for preparing the fiber particle with high interfacial adhesion. The adding proportion of the fiber particles in the cement paste is randomly adjusted according to the requirement; the particles reach the underground along with cement paste, when the temperature reaches the temperature-sensitive softening temperature, the particles release fiber filaments, the fibers are opened under the drive of the cement paste, the volume steric effect is generated, the plugging process is completed, and the strength and the toughness of the set cement are improved.)

1. The high-interface-binding-force fiber particle for well cementation is characterized in that the fiber particle takes rigid fibers or resin as a core material, takes temperature-sensitive resin as an intermediate layer and takes a tough fiber filament wound as a surface layer, wherein the particle size of the fiber particle is 0.5-3.0 mm.

2. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the particle size of the fiber particles is 0.7-1.5 mm, preferably 0.8-1.2 mm.

3. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the rigid fiber or resin is selected from one or more of polyester fiber, polypropylene fiber, carbon fiber, glass fiber, asbestos fiber, polyethylene fiber, polyvinyl chloride fiber, polyamide fiber and polyester.

4. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the fineness of the rigid fibers or the resin is 30-150 deniers, and preferably 50-120 deniers.

5. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the softening temperature of the temperature-sensitive resin is 60-105 ℃, and the preferred temperature is 75-95 ℃.

6. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the temperature-sensitive resin is selected from one or more of paraffin, rosin, polyurethane, polyvinyl alcohol, copolyolefin and polyester.

7. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the fineness of the tough fiber filament is 1-2 dtex, the cross section of the tough fiber filament is circular, and the effective length of the tough fiber filament is 8-20 cm.

8. The high interfacial adhesion fiber particle for well cementation according to claim 7, wherein:

the fineness of the tough fiber filament is 1.2-1.8 dtex, and the effective length of the tough fiber filament is 12-15 cm.

9. The high interfacial adhesion fiber particle for well cementation according to claim 1, wherein:

the tough fiber filament is selected from at least one of polypropylene filament, nylon filament or polyester filament.

10. A method for preparing the high interfacial adhesion fiber particle for well cementation according to any one of claims 1 to 9, characterized by comprising the steps of:

(1) heating and melting the temperature-sensitive resin;

(2) coating the surface of the rigid fiber or resin with the molten temperature-sensitive resin;

(3) winding the tough fiber filament onto the surface of the temperature-sensitive resin;

(4) and (4) cooling, drawing and cutting the product obtained in the step (3) to obtain the fiber particles.

Technical Field

The invention relates to the field of well cementation, in particular to high-interfacial-binding-force fiber particles for well cementation and a preparation method thereof.

Background

Well cementation is an important link in the process of petroleum drilling, and the well cementation quality and efficiency directly relate to the operation stability and the exploitation cost of an oil well.

The problem that the leakage occurs in the well cementation process is difficult to overcome, if the problem is not solved well, the leakage of cement slurry is directly caused, the cement slurry is lost, the well cementation quality is poor, and the like. Meanwhile, the cement stone has large brittleness and is easy to be brittle by external force, so that the sealing integrity of the cement sheath is influenced.

In order to solve the above two problems, fibers are often added in well cementation (for example, patent CN201310066429, "an elastic well cementation cement slurry and a preparation method thereof"), that is, the fibers mainly have two functions: firstly, plugging; secondly, the toughness of the set cement is enhanced.

Solving the problem of leakage of oil and gas wells has been the subject of concern in various large oil and gas fields. The conventional well cementation cement paste has no leakage blocking function, but after the inert fiber material is added, a net-shaped structure is easily formed in a leakage passage due to the accumulation and bridging action of the fibers, and the conventional performance of the cement paste is not changed greatly, so that the leakage in the well drilling and well cementation processes can be blocked to a certain degree. And moreover, the addition of the fibers can also improve the toughness of the set cement and ensure that the later perforating operation is better carried out.

The fiber is used as an inert material and is commonly used for preparing fiber cement slurry for well cementation operation. The fiber cement paste is prepared by mixing fiber materials with a certain proportion and length in a cement paste basic formula, the performance of the mixed cement paste is not greatly changed compared with that of primary pulp, and fibers are easy to form a net-shaped structure in a leakage channel through accumulation and bridging. Therefore, the fiber cement slurry can also be used for the lost circulation plugging operation. At present, a fiber plugging cement paste system is mainly formed by changing the addition amount (<5 per thousand, the amount of cement) and the length (1-6 mm) of fibers. Such systems typically rely on the operator to add the fibers to the cement truck. It should be noted here that the fibers cannot be dry blended in the cement because of their mass entanglement. Meanwhile, the speed of manually scattering fibers on a cement truck is slow, and the rheological property of cement paste is influenced by excessive addition of the fibers, so that the addition amount is less than 5 per thousand (accounting for the amount of the cement). In addition, the length of the fiber cannot be too long, so that the leakage stoppage effect of the fiber leakage stoppage slurry is limited, and the traditional fiber has poor surface hydrophobicity or hydrophilicity and poor cement cementation.

At present, in the well cementation process, the traditional leakage prevention and leakage stoppage methods are methods of adding chopped fibers into cement slurry, but one fatal defect of the methods is that the addition amount cannot be increased, so that the well cementation quality cannot be ensured under the condition of serious well leakage; and the chopped fibers are easy to agglomerate and wind and are not uniformly mixed, and only can be manually thrown.

Disclosure of Invention

In order to effectively solve the defects in the prior art, the invention provides the high-interface bonding force fiber particles which are used for leakage prevention and leakage stoppage, in particular for forming a leakage prevention and leakage stoppage oil well cement slurry system and drilling fluid leakage stoppage, the fiber particles can be directly dry-mixed with cement ash or wet-mixed with cement slurry on a well cementation site, and in the well cementation process, the fiber particles enter the underground along with the cement slurry, and after the temperature-sensitive temperature is reached, the fiber particles generate orientation deformation under the shearing action of the cement slurry, so that the flow resistance of the system is increased, and rock gaps are effectively blocked.

The invention aims to provide high-interfacial-binding-force fiber particles for well cementation, which take rigid fibers or resin as a core material, take temperature-sensitive resin as an intermediate layer and take tough fiber filaments as a skin layer by winding.

The particle size of the fiber particles is 0.5-3.0 mm, preferably 0.7-1.5 mm, and particularly preferably 0.8-1.2 mm.

The rigid fiber or resin is preferably one or more of polyester fiber, polypropylene fiber (polypropylene), carbon fiber, glass fiber, asbestos fiber, polyethylene fiber (polyethylene), polyvinyl chloride fiber (polyvinyl chloride), polyamide fiber (nylon) and polyester, more preferably one or more of polyester fiber, polyvinyl chloride fiber, polyamide fiber and polyester, and particularly preferably one or more of polyester fiber, polyamide fiber and polyester.

The rigid fiber or resin plays a role of supporting and bearing the temperature-sensitive resin, and the fiber or resin with the winding characteristic can be used as the core layer material of the invention, and is not limited to the fiber or resin varieties listed above.

The fineness of the rigid fiber or the resin is preferably 30-150 denier, more preferably 50-120 denier, and particularly preferably 80-100 denier.

The diameter of the core rigid fiber or resin is preferably 0.3 to 0.8mm, and more preferably 0.5 to 0.7 mm.

The softening temperature of the temperature-sensitive resin is preferably 60-105 ℃, and the more preferably temperature is 75-95 ℃.

The temperature-sensitive resin is preferably one or more of paraffin, rosin, polyurethane, polyvinyl alcohol, copolymerized olefin and polyester, and particularly preferably polyurethane or copolymerized olefin.

The cross section of the tough fiber filament is circular or non-circular, and the preferred cross section is circular.

The fineness of the tough fiber filament is preferably 1 to 2dtex, more preferably 1.2 to 1.8 dtex.

The effective length of the tough fiber filament is preferably 8-20 cm, and more preferably 12-15 cm.

The tough filament is selected from at least one of polypropylene filament, nylon filament or polyester filament, and is preferably polypropylene filament.

In the invention, the fiber particles are added into the leakage-proof and leakage-stopping slurry, the added particles have smaller particle size, so that the particles are convenient to be uniformly mixed in a cement slurry system, and the phenomenon of agglomeration in the leakage-stopping slurry is avoided. Meanwhile, the temperature is low and does not reach the softening temperature of the temperature-sensitive resin at the initial stage of injecting into the shaft, so that the blocking fiber filaments cannot be dispersed and released. When the temperature of the stratum is gradually increased along with the entering of the plugging slurry into the well, the bonding effect is weakened when the temperature-sensitive resin softening temperature is reached, the original granular matters are deformed, and the tough fiber filaments are released under the driving of cement slurry and are uniformly dispersed into the plugging slurry under the action of flowing shear. Therefore, the invention not only solves the defect that the adding amount of the traditional chopped fibers is limited, but also can not agglomerate among the particles, avoids the risk of winding accessories in the well, adopts the direct mixing adding mode, has the addition amount which can be randomly adjusted according to the needs, is simple to operate, avoids the operation procedure that the fibers need to be added while being injected in the process of using the chopped fibers, and simultaneously avoids the problem that the leakage prevention and/or leakage stoppage effects can not be fully exerted because the adding amount is too small, and the fiber particles are more uniformly distributed in the leakage stoppage liquid, thereby effectively preventing and/or stopping the leakage.

The invention also aims to provide a preparation method of the high-interfacial-binding-force fiber particles for well cementation, which comprises the following steps:

(1) heating and melting the temperature-sensitive resin;

(2) coating the surface of the rigid fiber or resin with the molten temperature-sensitive resin;

(3) winding the tough fiber filament onto the surface of the temperature-sensitive resin;

(4) and (4) cooling, drawing and cutting the product obtained in the step (3) to obtain the fiber particles.

Preferably, the preparation method of the fiber particles specifically comprises the following steps:

(1) adding the temperature-sensitive resin into an extruder, heating, melting and extruding;

(2) feeding the rigid fiber or resin into the head of an extruder by using a wire feeder, and coating the surface of the rigid fiber or resin with the molten temperature-sensitive resin;

(3) feeding the rigid fiber or resin coated with the temperature-sensitive resin into a winding machine filled with a tough fiber filament to wind on the surface of the temperature-sensitive resin;

(4) and (3) sequentially and continuously passing the wound and compounded intermediate product through a cooler, a tractor and a cutting machine to finish the preparation of the high-interface-binding-force fiber particles.

In the preparation process, the adopted processes are all common processing processes in the prior art, and the used equipment is also the combination of common equipment in the prior art.

The fiber particles and the preparation method thereof provided by the invention have the following characteristics:

firstly, forming composite fiber particles by taking a temperature-sensitive shape memory polymer as a binder;

the fiber particles can be added into cement in a dry mixing way or into drilling mud;

the addition amount of the fiber particles can be adjusted randomly according to needs, and the mixing and injection of cement paste are not influenced;

when the fiber particles enter the oil well and reach the deformation temperature of the temperature-sensitive shape memory polymer, the surface layer tough fiber filaments are oriented and deformed, and the effects of leakage prevention and leakage stoppage are exerted;

the fiber particles also have the function of obviously improving the toughness of the set cement.

The fiber particles for well cementation of the present invention are solid particles with high interfacial adhesion. Aiming at solving the following problems: the problems of poor hydrophobicity or hydrophilicity of the fiber surface and poor cement cementation property in the traditional well cementation are solved; secondly, the traditional fibers for well cementation have the agglomeration winding property and cannot be dry-mixed in cement. The new material can replace the traditional fiber for application and has better popularization and application values.

The volume size of the fiber particles is 1mm³The addition proportion in the cement paste is randomly adjusted according to the needs, so that the viscosity of a cement paste system is not obviously increased; when cement slurry reaches the underground, fiber particles are released to form flexible fiber filaments after the temperature reaches the temperature-sensitive softening temperature, and the fibers are opened under the drive of the cement slurry to generate a volume steric effect, so that the plugging process is completed, and the strength and the toughness of the set cement are improved. Earlier stage scientific research verifies that the principle is feasible and has good effect.

Drawings

FIG. 1 is a flow diagram of a fiber particle preparation process.

Fig. 2 is a schematic view of the structure of the fiber particles.

Description of reference numerals: 1-rigid fibers or resins; 2-a wire feeder; 3-a feed inlet; 4-an extruder; 5-a winding machine; 6-a cooler; 7-a tractor; 8-a cutting machine; 9-product; 10-a temperature sensitive resin; 11-tough filament.

Detailed Description