阅读说明：本技术 一种钻井用新型复合堵漏剂及其应用 (Novel composite plugging agent for well drilling and application thereof ) 是由 乐明 赵正国 郭建华 田军 吕跃滨 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新型复合堵漏剂及其应用,该堵漏剂包括如下质量份的组分：20～40份的颗粒架桥材料；30～60份的颗粒填充材料；5～20份的柔性纤维；4～12份的软质泡沫材料,所述软质泡沫材料为聚乙烯发泡棉颗粒或发泡聚苯乙烯颗粒；各组分的质量份数之和为100。试验证明,本发明所述的复合堵漏剂可以封堵不同尺寸缝宽(2mm-8mm)的裂缝或者孔洞,且驻留效果好,封堵漏层后承压能力高。在裂缝、缝洞性复杂地质条件下,本发明堵漏施工安全、操作简单,封堵效果明显。(The invention provides a novel composite plugging agent for well drilling and application thereof, wherein the plugging agent comprises the following components in parts by mass: 20-40 parts of a particle bridging material; 30-60 parts of a particle filling material; 5-20 parts of flexible fibers; 4-12 parts of a soft foam material, wherein the soft foam material is polyethylene foam cotton particles or expanded polystyrene particles; the sum of the mass parts of the components is 100. Experiments prove that the composite plugging agent can be used for plugging cracks or holes with different sizes and seam widths (2mm-8mm), has a good retention effect, and has high pressure bearing capacity after plugging a leaking layer. Under the geological conditions of cracks and fissures, the invention has safe leaking stoppage construction, simple operation and obvious plugging effect.)

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

20-40 parts of a particle bridging material;

30-60 parts of a particle filling material;

5-20 parts of flexible fibers;

4-12 parts of a soft foam material, wherein the soft foam material is polyethylene foam cotton particles or expanded polystyrene particles;

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

2. The novel composite plugging agent for well drilling as claimed in claim 1, wherein the size range of the flexible foam material is 2-4 meshes of standard sample separation sieve.

3. The novel composite plugging agent for well drilling as claimed in claim 2, wherein the flexible fiber is selected from one or more of asbestos fiber, sepiolite fiber and polymer fiber.

4. The novel composite plugging agent for drilling as claimed in claim 3, wherein the length of the flexible fiber is 1-2mm, and the diameter is 0.001-0.1 mm.

5. The novel composite plugging agent for well drilling as claimed in any one of claims 1 to 4, wherein the particle bridging material is selected from one or more of polypropylene and PPS plastic, and the size of the particle bridging material is 20-40 meshes of a standard sample sieve.

6. The novel composite plugging agent for well drilling as claimed in any one of claims 1 to 4, wherein the particle filling material is selected from one or more of calcium carbonate and quartz sand, and the size of the particle filling material is 60-180 meshes of a standard sample sieve.

7. The novel composite plugging agent for well drilling as defined in any one of claims 1-6, for plugging a well in a drilling well.

8. The application of the novel composite plugging agent for well drilling as claimed in claim 7, wherein the novel composite plugging agent for well drilling is suitable for plugging cracks and/or holes with the width dimension of 2-8 mm.

Technical Field

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

Background

The leakage of drilling fluid into the stratum (called well leakage for short) is a common underground complex condition in the drilling process, and the well leakage problem is particularly prominent when the stratum develops in the case of drilling cracks and holes. Once lost circulation occurs, the well drilling time is affected, drilling fluid is lost, and oil and gas layers are damaged. In order to solve the above problems, it is a common practice to add a plugging agent (or called plugging agent) to the drilling fluid to improve the performance.

At present, commonly used plugging agents mainly comprise bridging agents, chemical gels, inorganic gelling plugging agents and the like. The chemical gel plugging is mainly characterized in that gel is formed by mutual reaction of materials to plug a stratum, but the chemical plugging material is high in price, complex in construction and poor in temperature resistance. The inorganic gelling system plugging is mainly the plugging of a cement slurry system, although the strength of a formed plugging layer is high, the cement slurry is not easy to stay in a leakage channel, and if the cement slurry is diluted after meeting formation water, the plugging effect is greatly weakened; and the time for waiting for setting is long, and the leakage is lost along with the fluctuation of formation fluid, thereby causing the failure of plugging.

Repeated or unsuccessful plugging severely restricts safe, rapid and efficient drilling and becomes a bottleneck of oil and gas exploration and development. The most widely applied bridge plug plugging technology is currently used, and the used bridge plug plugging material is mainly formed by mixing various mineral particles, shells, mica sheets, fibers and the like with different sizes. The bridge plug plugging technology has the characteristics of wide material source, low cost and simple construction process, and is favored by field personnel. Bridging leak stoppage is mainly based on the particle size grading principle, but on the premise of clearly mastering the leakage characteristics and fully knowing the properties of a leakage layer, a composite leak stoppage material with reasonable grading can be selected, otherwise, the leak stoppage material cannot stay in a bridging way in a leakage passage or form a door sealing phenomenon at a seam, so that the leak stoppage is failed. Therefore, the development of the plugging agent which can effectively reside in the leaking layer and form a high-pressure plugging layer after being compounded with the particles improves the adaptability of the plugging agent to the leaking layer, and is a problem which needs to be solved urgently in the drilling plugging work.

Disclosure of Invention

In view of the above, the invention provides a novel composite plugging agent for well drilling and application thereof, the plugging agent provided by the invention has low dependence on the size of a leaking layer, is suitable for cracks and holes with different width sizes, can form effective residence in a leakage passage, forms effective plugging after being compounded with particles, and has high pressure bearing capacity of the plugging layer.

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

20-40 parts of a particle bridging material;

30-60 parts of a particle filling material;

5-20 parts of flexible fibers;

4-12 parts of a soft foam material, wherein the soft foam material is polyethylene foam cotton particles or expanded polystyrene particles;

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

Preferably, the size range of the flexible foam material is 2-4 meshes of a standard sample separation sieve.

Preferably, the flexible fibers are selected from one or more of asbestos fibers, sepiolite fibers and polymer fibers.

Preferably, the length of the flexible fiber is 1-2mm, and the diameter of the flexible fiber is 0.001-0.1 mm.

Preferably, the particle bridging material is selected from one or more of polypropylene and PPS plastic, and the size of the particle bridging material is 20-40 meshes of a standard sample separation sieve.

Preferably, the particle filling material is one or more selected from calcium carbonate and quartz sand, and the size of the particle filling material is 60-180 meshes of a standard sample sieve.

The invention provides the application of the novel composite plugging agent for well drilling in well drilling plugging.

Preferably, the novel composite plugging agent for drilling is suitable for plugging cracks and/or holes with the width of 2-8 mm.

Compared with the prior art, the plugging agent provided by the invention mainly comprises a soft foam material, a particle bridging material, a particle filling material and flexible fibers in a certain ratio, wherein the soft foam material is polyethylene foam particles or expanded polystyrene particles and has a spatial net structure. In the invention, the plugging agent forms a long-section plugging layer in cracks or holes with different width sizes by the retention effect of the flexible foam material and the filling and stretching effects of the flexible fibers and the filling and reinforcing effects of the particles. Experiments prove that the composite plugging agent can be used for plugging cracks or holes with different sizes and seam widths (2mm-8mm), has a good retention effect, and has high pressure bearing capacity after plugging a leaking layer. Under the geological conditions of cracks and fissures, the invention has safe leaking stoppage construction, simple operation and obvious plugging effect.

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 novel composite plugging agent for well drilling, which comprises the following components in parts by mass:

20-40 parts of a particle bridging material;

30-60 parts of a particle filling material;

5-20 parts of flexible fibers;

4-12 parts of a soft foam material, wherein the soft foam material is polyethylene foam cotton particles or expanded polystyrene particles;

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

In order to overcome the defects of high dependency of the conventional plugging agent on the size of a leaking layer, difficulty in staying in the leaking layer, low pressure bearing capacity and the like, the invention provides the novel composite plugging agent for drilling, which can effectively stay in the leaking layer, can form a high pressure bearing plugging layer after being compounded with particles, has low dependency on the size of the leaking layer, and is suitable for cracks or holes with different seam width sizes.

The composite plugging agent mainly comprises the following raw materials in parts by weight: 20-40 parts of a particle bridging material and 30-60 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 is preferably one or more of polypropylene and PPS plastic; the size of the standard sample separating sieve is 20-40 meshes. The particle filling material is preferably one or two of calcium carbonate and quartz sand; the size of the standard sample separating sieve is 60-180 meshes.

The 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. In some embodiments of the invention, the polypropylene plastic particles and the PPS plastic particles are adopted as the particle bridging materials, the particle size is 20-40 meshes, the high temperature resistance is realized, the strength is high, and the density is low (such as 1.36 g/cm)³Left and right).

In the composite plugging agent provided by the embodiment of the invention, the large-particle bridging material is a standard sample separation sieve with 20-40 meshes, the small-particle filling material is a standard sample separation sieve with 60-180 meshes, the grading is reasonable, and the formed plugging layer is compact and pressure-bearing. The pressure bearing effect cannot be ensured when the grain size grading difference is too large; the density of the plugging slurry is greatly reduced on the premise of ensuring the granularity and the bearing strength of the polypropylene plastic particles and the PPS plastic particles, and the underground safety is ensured.

The embodiment of the invention mainly adopts calcium carbonate powder and quartz sand powder, the size of the calcium carbonate powder and the quartz sand powder is 60-180 meshes of a standard sample separating sieve, and the calcium carbonate powder and the quartz sand powder play a role in filling. 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 a common quartz sand powder known in the art, i.e., SiO₂≥90-99％，Fe₂O₃≤0.06-0.02％。

In addition to the granular materials, the composite plugging agent comprises 5-20 parts by mass of flexible fibers which mainly play a role in filling and stretching. The flexible fiber is soft and easy to deform, and can be selected from one or more of asbestos fiber, sepiolite fiber and polymer fiber. The flexible fiber is a short fiber-shaped material, the length of the flexible fiber can be 1 mm-2 mm, and the diameter of the flexible fiber is 0.001-0.1 mm.

The asbestos wool is a generic name of natural fibrous siliceous minerals, is silicate mineral fiber widely applied to building material fireproof plates, has good tensile strength and good heat insulation and corrosion resistance, and is not easy to burn; the embodiment of the invention can adopt chrysotile with the widest application. The sepiolite fiber is a natural mineral fiber and is a fibrous variant of a sepiolite mineral, and the sepiolite is a layer chain-shaped 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 product is commercially available.

In the composite plugging agent provided by the embodiment of the invention, the flexible fiber materials such as asbestos wool and sepiolite are soft in texture and easy to deform, and the structure is not influenced after stress. The flexibility means that the structure is not damaged and is deformed by an external force, and the structure can be restored to the original shape after the external force is removed. After the rigid fiber such as wood fiber is stressed, the rigid fiber can not restore the original shape after external force is removed, and the rigid fiber cannot play a role in suspending the lacing wire; and the later period of the formation of a blocking layer by paper fibers and the like is easy to corrode, so that the secondary leakage is caused.

In the invention, the composite plugging agent comprises 4-12 parts by mass of a soft foam material, and the soft foam material is polyethylene foam (EPE, pearl wool) particles or Expanded Polystyrene (EPS) particles. In the embodiment of the invention, the size range of the flexible foam material is 2-4 meshes of a standard sample separation sieve, and the flexible foam material can be obtained by crushing reticular fiber polyethylene foam cotton or expanded polystyrene through a high-speed crusher. The density of the flexible foam material described in the examples of the present invention ranges from 0.03 to 0.05g/cm³The tensile strength is 3.4-3.8kg/cm²The defects of easy breakage and poor recovery of common foaming glue are overcome.

The materials such as polyurethane used at ordinary times are hard in texture and strong in spatial structure, and are not easy to be compressed and deformed; the soft foam material has a spatial network structure, and has the characteristics of easiness in deformation under pressure, micro-expansion after soaking in a solution and the like. Aiming at the crack with smaller crack width, the crack enters the leakage layer through extrusion deformation to form a blocking layer; aiming at the cracks with larger seam widths, because the micropores in the foam are mutually communicated, the micro-expansion (similar to the water absorption theory of the sponge) is realized after the liquid is absorbed, and the micro-expansion is mutually accumulated and hung in the cracks or holes to form a blocking layer. According to the invention, the flexible fibers are adsorbed on the reticulated foam through the action of the suspension tie bars to reinforce the blocking layer, at the moment, the blocking layer cannot bear pressure, large particles are added to bridge, small particles are filled, and finally the blocking layer with high pressure is formed by stacking and compacting.

The plugging agent is a composite plugging agent, and comprises flexible foam with a space net structure, a particle bridging material, a filling material and a fiber material, wherein the sum of the mass parts of the components is 100. The composite plugging agent is obtained by uniformly mixing the components according to the content ratio at normal temperature and normal pressure. The production process flow of the plugging agent is simple, and the cost is low.

The materials of the invention interact with each other to form a long-section plugging layer in cracks or holes with different seam width sizes, and tests prove that the pressure-bearing capacity effect of the plugging layer is obvious.

The invention relates to a novel composite plugging agent for well drilling plugging, in particular to the novel composite plugging agent for well drilling which can be applied to the plugging of 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. The composite plugging agent disclosed by the invention has stable physical and chemical properties of various materials in the oil-based drilling fluid, can form effective residence and pressure bearing in oil reservoir fractures, and is also suitable for plugging of the oil-based drilling fluid.

According to the invention, some embodiments develop the leak stoppage of the composite leak stopping agent under the condition of water-based drilling fluid, specifically, leak stopping base slurry is prepared by 4% of bentonite, 3% -3.5% of anhydrous sodium carbonate and 0.2% of tackifier according to the formula, 8 parts of leak stopping base slurry and 300mL of leak stopping base slurry are measured, different amounts of the product are added respectively, and leak stopping experiments are developed on crack blocks or hole beds with different seam width sizes. Wherein, the dosage of the plugging agent is added according to the mass volume percentage, and the addition can be 5-15%.

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% of calcium chloride) solution, 2% of main emulsion, 2% of auxiliary emulsion, 4% of organic soil, 2% of calcium oxide and 350g of barite are prepared into oil-based plugging base slurry, the products of the invention with different concentrations are respectively added, and plugging experiments are carried out on crack blocks with different seam width sizes. Wherein the dosage of the plugging agent is added according to the mass volume percentage, and the addition can be 8-20%.

Experimental results show that the composite plugging agent can be used for plugging cracks or holes with different sizes and seam widths (2-8 mm), has a good retention effect, and is high in pressure bearing capacity after plugging a leaking layer. Under the geological conditions of cracks and fissures, the invention has safe leaking stoppage construction, simple operation and obvious plugging effect.

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

In the following examples, flexible foams having a spatial network structure were used, which are from Xinxiang City Xintian packaging materials Co., Ltd, and have a density in the range of 0.03 to 0.05g/cm³The tensile strength is 3.4-3.8kg/cm²The fiber is obtained by crushing reticular fibers, and the size range is 2-4 meshes of a standard sample separation sieve. The calcium carbonate and the quartz sand are commercially available, have no special requirements, and have the selected particle size of 60-180 meshes. The used flexible fiber comes from mineral product processing factories in Huachuan of Lingshou county, and the physical property requirements are as follows: the length of the fiber is 1-2mm, the diameter is 0.001-0.1mm, the key property is soft, and the residence length is not easily influenced by the crack blockage; the diameter of the flexible fiber is larger, the door is easy to seal, and the diameter of the flexible fiber is too small to play a role in suspending the lacing wire. The used particle bridging material polypropylene plastic particles and PPS plastic particles have the particle size of 20-40 meshes, high temperature resistance, high strength and the density of 1.36g/cm³。