阅读说明：本技术 一种钻井用复合堵漏剂及其应用 (Composite plugging agent for well drilling and application thereof ) 是由 赵正国 王中华 郭建华 乐明 田军 刘文堂 于 2018-09-04 设计创作，主要内容包括：本发明提供了一种钻井用复合堵漏剂及其应用,该复合堵漏剂包括如下质量份的组分：50～60份的颗粒架桥材料；30～40份的颗粒填充材料；2～5份的纤维材料；3～14份的柔性材料,所述柔性材料为聚合物薄膜碎片材料；各组分的质量份数之和为100。本发明通过柔性材料驻留成塞、颗粒架桥材料加固、颗粒填充材料和纤维材料充填拉筋作用,材料间相互协同在不同尺寸裂缝内形成稳固的封堵层。本发明中材料间的尺寸配比合理,颗粒架桥材料和颗粒填充材料的尺寸有明显的间隔,在保证形成致密封堵的同时,使得堵漏过程中有一定的滤失量,促使堵漏剂在裂缝内形成具有一定长度的封堵段,避免出现材料间瞬间形成致密堆积而导致的封堵段过短问题。(The invention provides a composite plugging agent for well drilling and an application thereof, wherein the composite plugging agent comprises the following components in parts by mass: 50-60 parts of a particle bridging material; 30-40 parts of a particle filling material; 2-5 parts of a fiber material; 3-14 parts of a flexible material, wherein the flexible material is a polymer film fragment material; the sum of the mass parts of the components is 100. According to the invention, the stable plugging layer is formed in cracks with different sizes by the mutual cooperation of the materials through the functions of a flexible material resident plug, particle bridging material reinforcement and particle filling material and fiber material filling tie bar. The size proportion of the materials is reasonable, the sizes of the particle bridging material and the particle filling material have obvious intervals, so that a certain filtration loss amount exists in the plugging process while the formation of compact plugging is ensured, the plugging agent is promoted to form a plugging section with a certain length in a crack, and the problem of short plugging section caused by the instant formation of compact accumulation among the materials is avoided.)

1. The composite plugging agent for drilling comprises the following components in parts by mass:

50-60 parts of a particle bridging material;

30-40 parts of a particle filling material;

2-5 parts of a fiber material;

3-14 parts of a flexible material, wherein the flexible material is a polymer film fragment material;

the sum of the mass parts of the components is 100.

2. The composite plugging agent for drilling well as recited in claim 1, wherein the flexible material is obtained by crushing a polymer film, and the polymer film is one or more selected from polyethylene film, polyvinyl chloride film, polypropylene film, polyester film and nylon film.

3. The composite plugging agent for drilling according to claim 2, wherein the thickness of the flexible material is 0.005-0.05 mm, and the side length is 2-15 mm.

4. The composite plugging agent for the drilling well as recited in any one of claims 1 to 3, wherein the particle bridging material is one or more selected from calcium carbonate, shell slag, quartz sand, walnut shell and PPS plastic, and the size of the particle bridging material is 20-60 meshes of a standard sample sieve.

5. The composite plugging agent for drilling according to any one of claims 1 to 3, wherein the particle filling material is one or more selected from calcium carbonate, quartz sand, limestone powder, walnut shells and expanded graphite, and the size of the particle filling material is 80-325 meshes of a standard sample sieve.

6. The composite plugging agent for drilling well as recited in any one of claims 1 to 3, wherein the fiber material is selected from one or more of paper fiber, hemp fiber, sepiolite fiber and polymer fiber.

7. The composite plugging agent for drilling as claimed in claim 6, wherein the length of the fiber material is 1-3 mm.

8. The application of the composite plugging agent for drilling well as defined in any one of claims 1-7 in drilling fluid plugging.

Technical Field

The invention belongs to the technical field of petroleum drilling engineering plugging, and particularly relates to a composite plugging agent for drilling and application thereof.

Background

In the process of oil and gas exploration and development, the problem that drilling fluid leaks into a stratum (short for lost circulation) exists for a long time and is not effectively solved so far is that the efficient operation of oil and gas drilling is seriously influenced, and if the lost circulation is improperly controlled, underground complicacies such as collapse, overflow, blowout and the like can be induced, so that safety accidents are caused. How to effectively plug an underground leaking layer and ensure the normal operation of drilling construction is always the key point of research of scientific research and engineering personnel.

Various types and different functions of plugging technologies are developed, the most widely applied current technology is bridging plug plugging technology, and the used bridging plug plugging agent is mainly formed by mixing various mineral particles with different sizes, shells, mica sheets, fibers and the like. The bridge plug plugging technology has the characteristics of wide material source, low cost and simple construction process, and is favored by field personnel.

However, the sizes of materials in the bridge plug plugging agent are different and the size distribution range is wide, so that the size matching difficulty of the conventional bridge plug plugging agent and a leak layer crack is large due to the fact that the size of the underground leak layer cannot be accurately obtained in field construction, and the following situations often occur: (1) the size of the opening of the crack is small, large particles in the bridge plug material are easy to rapidly form plugging at the crack opening, other materials are prevented from entering the crack to cause the false appearance of successful plugging, and the materials accumulated at the opening are easy to be damaged by the circulation scouring of a drilling tool or drilling fluid to cause repeated leakage; (2) the size of the opening of the crack is large, and bridge plug materials cannot stay and accumulate in the crack when entering the crack, so that an effective plugging layer is difficult to form; (3) even if the material enters the crack and forms plugging, the material size distribution is continuous, after the plugging is formed, the front end of the plugging layer is instantly filled with materials of all levels of sizes to form a compact layer, the plugging material in subsequent slurry cannot be continuously accumulated in the leaking layer, the formed plugging section is short, and the plugging layer is easily damaged by stratum pressure fluctuation. The problems lead the plugging success rate of the bridge plug plugging technology to be only about 50 percent or even lower.

Disclosure of Invention

In view of the above, the invention provides a composite plugging agent for well drilling and application thereof.

The invention provides a composite plugging agent for well drilling, which comprises the following components in parts by mass:

50-60 parts of a particle bridging material;

30-40 parts of a particle filling material;

2-5 parts of a fiber material;

3-14 parts of a flexible material, wherein the flexible material is a polymer film fragment material;

the sum of the mass parts of the components is 100.

Preferably, the flexible material is obtained by crushing a polymer film, and the polymer film is one or more selected from a polyethylene film, a polyvinyl chloride film, a polypropylene film, a polyester film and a nylon film.

Preferably, the thickness of the flexible material is 0.005-0.05 mm, and the side length is 2-15 mm.

Preferably, the particle bridging material is one or more selected from calcium carbonate, shell residues, quartz sand, walnut shells and PPS plastic, and the size of the particle bridging material is 20-60 meshes of a standard sample separation sieve.

Preferably, the particle filling material is one or more selected from calcium carbonate, quartz sand, limestone powder, walnut shells and expanded graphite, and the size of the particle filling material is 80-325 meshes of a standard sample sieve.

Preferably, the fiber material is selected from one or more of paper fiber, hemp fiber, sepiolite fiber and polymer fiber.

Preferably, the length of the fiber material is 1-3 mm.

The invention provides application of the composite plugging agent for drilling well as described above in drilling fluid plugging.

Compared with the prior art, the plugging agent provided by the invention mainly comprises a flexible material, a particle bridging material, a particle filling material and a fiber material in a certain proportion, wherein the flexible material is a polymer film fragment material. According to the invention, the stable plugging layer is formed in cracks with different sizes by the mutual cooperation of the materials through the functions of a flexible material resident plug, particle bridging material reinforcement and particle filling material and fiber material filling tie bar. The flexible material has strong deformability, can enter a crack with the width of more than 1mm, has large specific surface area and strong adhesion capability, can be effectively adhered to the crack surface, and meanwhile, the flexible materials are mutually adsorbed to promote the materials to form resident accumulation in the crack. Experimental results show that the flexible material and the like can smoothly enter a crack with the width of 1-10 mm and form a continuous plugging section. The size proportion of the materials is reasonable, the sizes of the particle bridging material and the particle filling material have obvious intervals, so that a certain filtration loss amount exists in the plugging process while the formation of compact plugging is ensured, the plugging agent is promoted to form a plugging section with a certain length in a crack, and the problem of short plugging section caused by the instant formation of compact accumulation among the materials is avoided.

In addition, the plugging agent can be suitable for plugging of the oil-based drilling fluid, and in an oil-based drilling fluid system, the plugging agent still shows excellent adaptability and good plugging capability to a leaking layer.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a composite plugging agent for well drilling, which comprises the following components in parts by mass:

50-60 parts of a particle bridging material;

30-40 parts of a particle filling material;

2-5 parts of a fiber material;

3-14 parts of a flexible material, wherein the flexible material is a polymer film fragment material;

the sum of the mass parts of the components is 100.

The application effect of the bridge plug plugging agent is insufficient, and the key problem is that the matching difficulty of the size of the plugging material and the size of a leak layer crack is high, so that the application effect of the bridge plug plugging technology is greatly limited in the face of the difficult problem that the size of the current leak layer cannot be accurately obtained, and the related reports of the bridge plug plugging agent capable of adapting to cracks with different widths at the same time are rarely found at present.

In order to solve the problems that the conventional bridging plugging agent is difficult to match with the size of a leaking layer and the retention effect of the plugging agent in the leaking layer is poor, the composite plugging agent provided by the invention has strong matching capability with the size of the leaking layer and strong adaptability to the size change of cracks, can enter cracks with different widths to form effective plugging, shows excellent retention capability in the cracks and has important significance for improving the success rate of bridging and plugging.

The composite plugging agent provided by the invention comprises the following raw materials in parts by weight based on 100 parts by weight of the composite plugging agent: 50-60 parts of a particle bridging material and 30-40 parts of a particle filling material. Wherein, the particle bridging material plays a role in reinforcement, and the particle filling material plays a role in filling and lacing; both are in particle form, but the particle size is different and the effect is different.

In the embodiment of the invention, the particle bridging material can be one or more selected from calcium carbonate, shell residues, quartz sand, walnut shells and PPS plastic; the size is 20-60 meshes of a standard sample separating sieve. The particle filling material can be one or more of calcium carbonate, quartz sand, limestone powder, walnut shells and expanded graphite, and the size of the particle filling material is 80-325 meshes of a standard sample sieve. The materials of the particle bridging material and the particle filling material can be the same or different, and preferably different materials are compounded for use. The sizes of the particle bridging material and the particle filling material are both less than 1mm, the particles can smoothly enter cracks with the width of more than 1mm, and the phenomenon of material blocking cannot occur.

Wherein the shell residues are obtained by processing shells, and the main components of the shells are 95 percent of calcium carbonate and a small amount of chitin. The quartz sand is quartz particles formed by crushing quartz stone; quartz is a nonmetallic mineral, is a hard, wear-resistant, chemically stable silicate mineral, and has SiO as main mineral component₂. The present invention may employ common quartz sand known in the art, i.e., SiO₂≥90-99％，Fe₂O₃≤0.06-0.02％。

The walnut shell is a granular walnut shell powder which is processed by degreasing, crushing, screening and the like of walnut peel. The walnut shell powder in some embodiments of the invention is preferably walnut shell powder with the moisture content of less than 2%, so that the storage time can be prolonged, and the influence of overhigh moisture on the use performance of the plugging agent can be prevented. PPS plastic (polyphenylene sulfide) is thermoplastic special engineering plastic with excellent comprehensive performance, and has the outstanding characteristics of high temperature resistance, corrosion resistance and excellent mechanical performance; the invention can adopt white PPS powder with the density of 1.5-1.7 g/cm³。

The Qingshi powder is formed by crushing bluestone; bluestone is also called limestone, and the main component of limestone is calcium carbonate (CaCO)₃) Density of 2.8g/cm³. Expanded Graphite (EG) is a loose and porous vermicular substance obtained by intercalation, water washing, drying and high-temperature expansion of natural Graphite flakes, belongs to a carbon material, and the expansion volume of the Expanded Graphite can reach more than 200 times of the original volume.

In addition to the granular material, the composite plugging agent comprises 3-14 parts by mass of a flexible material, wherein the flexible material is a polymer film fragment material and mainly plays a role in standing and plugging. In an embodiment of the invention, the flexible material is obtained by crushing a polymer film selected from the group consisting of polyethylene film, polyvinyl chloride film, polypropylene film, polyester film and nylonOne or more of films. The flexible material is formed by mixing and crushing films with different thicknesses within a set size range or by crushing and mixing films with a certain thickness within a set thickness range, and the side length of the crushed material is controlled within the range of 2-15 mm by a screen of a crusher in the crushing process. The thickness of the flexible material can be 0.005 mm-0.05 mm; the flexible material can be in a regular shape such as a square shape, and the side length is 2-15 mm; the density of the flexible material is 0.8-1.0 g/cm³. The thickness of the flexible material film is the most main influence factor of the film playing a role in staying and accumulating, and other mechanical parameters and the like have low relevance to the leaking stoppage effect.

The flexible material has strong deformability, can enter a crack with the width of more than 1mm, is flaky, has small thickness, low density, larger surface area under the same mass and strong adhesion capability, can be effectively adhered to the crack surface, and meanwhile, the flexible materials are mutually adsorbed to promote the material to form resident accumulation in the crack.

In the invention, the composite plugging agent for drilling comprises 2-5 parts of fiber materials; the particle filling material and the fiber material play a role of filling and lacing. In the embodiment of the invention, the fiber material can be selected from one or more of paper fiber, hemp fiber, sepiolite fiber and polymer fiber. The fiber material is a short fiber material, and the length of the fiber material can be 1 mm-3 mm.

Wherein, the paper fiber can be processed into a fibrous finished product by processing equipment from waste paper scraps (materials such as cartons, paper rolls, newspapers, book paper and the like); the fineness is 0.01-0.02 mm. The bast fiber refers to fiber obtained from various bast plants, and bast fiber crops mainly comprise ramie, jute, hemp, flax and the like; the embodiment of the invention can adopt fibrilia with the fineness of 0.011-0.045 mm, the breaking strength of 50-70 cN/tex and the breaking elongation of 2-4%. Sepiolite fibers are fibers containing sepiolite minerals as a main component, and are called sepiolite mineral fibers. The sepiolite fiber is a natural mineral fiber and is a fibrous variant of a sepiolite mineral, and the sepiolite is a layer-chain silicate mineral and has the characteristics of good heat resistance, good ion exchange, corrosion resistance and the like. The polymer fibers include, but are not limited to, polyester fibers, polyamide fibers; the fineness is 0.008-0.040 mm.

The sum of the mass parts of the components is 100; different raw material components can be weighed and mixed evenly to obtain the plugging agent. The plugging agent can be called as a self-adaptive plugging agent, and has the advantages of wide raw material source, simple manufacturing process and low cost.

According to the invention, the stable plugging layer is formed in cracks with different sizes by the mutual cooperation of the materials through the functions of a flexible material resident plug, particle bridging material reinforcement and particle filling material and fiber material filling tie bar. The composite plugging agent has strong matching capability with the size of a leaking layer and strong adaptability to the size change of a crack, can enter the crack with the width of 1-10 mm and form effective plugging, shows excellent staying capability in the crack, and has the highest pressure-bearing capacity of the plugging layer of more than 6 MPa.

The size proportion of the materials in the invention is reasonable, the sizes of the particle bridging material and the particle filling material have obvious intervals, and the plugging agent has certain filtration loss in the plugging process while ensuring the formation of compact plugging, so that the plugging agent forms a plugging section with certain length in a crack. In addition, the plugging agent is also suitable for plugging of the oil-based drilling fluid, and shows good plugging effect and excellent adaptability to a leaking layer in an oil-based drilling fluid system.

The invention relates to a composite plugging agent for drilling fluid for plugging a downhole leaking layer in an oil and gas drilling process, in particular to the composite plugging agent for drilling which can be applied to the plugging of the drilling fluid.

The invention can be applied to water-based drilling fluid and also oil-based drilling fluid; the composition of the base drilling fluid slurry is not particularly limited, and the drilling fluid can be prepared from the raw drilling fluid components commonly used in the field, such as xanthan gum or carboxymethyl cellulose as a tackifier.

According to the embodiments of the invention, the composite plugging agent is used for plugging under the condition of water-based drilling fluid, specifically, plugging base slurry is prepared by 4% of bentonite, 3.5% of anhydrous sodium carbonate and 0.2% of tackifier according to the formula, 6 parts of plugging base slurry and 400mL of plugging base slurry are measured, different amounts of the plugging agent product are respectively added, and plugging experiments are carried out on crack modules with different sizes. Wherein the dosage of the plugging agent is added according to the mass volume percentage, and the addition can be 8-20%.

The invention also discloses plugging of the composite plugging agent under the condition of the oil-based drilling fluid, and specifically comprises the following components in percentage by weight: 400mL of diesel oil, 100mL of (20% calcium chloride) solution, 2% of main milk, 2% of auxiliary milk, 4% of organic soil, 2% of calcium oxide and 350g of barite are mixed to prepare the oil-based plugging base slurry. The plugging agent products of the invention with different amounts are respectively added, and plugging experiments are carried out on the modules with different sizes of cracks. Wherein the dosage of the plugging agent is added according to the mass volume percentage, and the addition can be 12-20%.

Experimental results show that the flexible material and the like can smoothly enter a crack with the width of 1-10 mm and form a continuous plugging section. The plugging agent disclosed by the invention has excellent retention capacity in cracks, the highest pressure bearing capacity of a plugging layer exceeds 6MPa, and the success rate of bridging plug plugging is favorably improved.

For further understanding of the present application, the composite lost circulation additive for well drilling and the application thereof provided by the present application are specifically described below with reference to examples.

In the following examples, the flexible material used is from Yangzhou Hui packaging Limited company, the thickness of the material ranges from 0.005mm to 0.05mm, and no special requirements are made for other performance parameters, wherein the flexible material is formed by mixing and crushing films with different thicknesses within a set size range, or formed by mixing and crushing films with a certain thickness within a set thickness range, and the side length of the crushed material is controlled within a range of 2mm to 15mm by a crusher screen during the crushing process. The paper fiber and sepiolite fiber materials are from a processing plant of Huashuo mineral products in Lingshui county, the fineness range of the paper fiber is 0.01-0.02 mm, the length is 1-3 mm, and the length of the sepiolite fiber is 1-3 mm; the polypropylene fiber and the polyester fiber are both from Ningyang bang energy engineering materials Limited, the fineness range of the polypropylene fiber is 0.008-0.013 mm, the fineness range of the polyester fiber is 0.01-0.025 mm, and the length of the polyester fiber is 3 mm; the fibrilia is from Jiangxi Sichuang hemp industry Co., Ltd, and has fineness of 0.011-0.045 mm, breaking strength of 50-70 cN/tex and breaking elongation of 2-4%. The bridging particle material and the filling particle material are well known by technical personnel in the industry, wherein calcium carbonate, shell slag, quartz sand, walnut shells, Qing mountain flour and expanded graphite are from a Huashuo mineral processing plant in Lingshou county; the PPS plastic is obtained from Ningbo Tetrage plastics Co., Ltd after crushing and screening.