阅读说明：本技术 一种携带自动解堵装置的防砂筛管 (Sand control screen pipe with automatic blockage removing device ) 是由 张国强 李海涛 蒋贝贝 于 2021-09-18 设计创作，主要内容包括：本发明公开了一种携带自动解堵装置的防砂筛管,属于天然气水合物开采技术领域,目的主要是解决天然气水合物开采过程中筛管堵塞问题,保证水合物开采作业的正常进行,防砂筛管在结构上具有以下特点：①由多层筛网的复合筛管+带有射流喷头的环形清洗装置构成；②对多层筛网的尺寸进行设计,保证能够最大限度的防砂；③在环形清洗器下方安装爪形的刮砂装置；④在射流喷头的端部连接自动控制阀；综上4个结构特点,结合其在水合物开采中的实际效果预测评价,此发明对于水合物的商业化开采具有重大的指导意义,也是水合物开采过程中一次新的探索和尝试,具有大范围推广的必要性。(The invention discloses a sand control screen pipe with an automatic blockage removing device, which belongs to the technical field of natural gas hydrate exploitation and mainly aims to solve the problem of screen pipe blockage in the natural gas hydrate exploitation process and ensure the normal operation of hydrate exploitation operation, and the sand control screen pipe structurally has the following characteristics: the device comprises a composite sieve tube with multiple layers of sieves and an annular cleaning device with a jet nozzle; secondly, the size of the multilayer screen is designed to ensure that sand can be prevented to the maximum extent; thirdly, a claw-shaped sand scraping device is arranged below the annular cleaner; fourthly, the end part of the jet flow nozzle is connected with an automatic control valve; in conclusion, the invention has great guiding significance for the commercial exploitation of the hydrate by combining the 4 structural characteristics and the prediction and evaluation of the actual effect of the hydrate in the exploitation of the hydrate, is a new exploration and attempt in the exploitation process of the hydrate, and has the necessity of large-scale popularization.)

1. A sand control screen pipe with automatic blockage removal function is characterized in that a sand control screen pipe which effectively solves the problem of sand blockage during the exploitation of natural gas hydrate is established; the method mainly comprises the following steps:

(A) determining the type of the sand control screen pipe by analyzing the characteristics of the hydrate reservoir;

(B) the sand control screen pipe with the automatic plugging removal function is structurally designed by analyzing the structure of the existing screen pipe;

(C) explaining the working principle of the automatic plugging removal sieve tube structure;

(D) based on the sand control effect evaluation of the common sieve tube, the effect and the application prospect of automatically plugging and unplugging the sand control sieve tube are contrastively analyzed.

2. The sand control screen pipe with the automatic blockage relieving function according to claim 1, wherein in the step A, taking the exploitation of natural gas hydrates in the sea area of the Shenhu in China as an example, a certain reservoir stratum is selected for particle size test evaluation and mud content analysis, and a reasonable type of the sand control screen pipe is determined by adopting a screen pipe selection method provided by Tiffin and King and combining the sizes of sand produced by different screen pipes and retained sand.

3. The sand control screen pipe with the automatic blockage removing function according to claim 1, wherein in the step B, the structure of the automatic blockage removing screen pipe is optimally designed on the basis of the structure of the existing screen pipe, so as to ensure the normal construction on the premise of effective sand control, and the specific structure design is as follows: the composite sieve tube with multiple layers of filter screens is selected as a sand control sieve tube (good sand blocking progress is guaranteed), an annular cleaning device is added into the annular space of the base tube and the filter screens (the main purpose is to solve the problem of sieve tube blockage), the sand control sieve tube is similar to a common sieve tube in appearance, and the main difference is that the sand control sieve tube is internally structured.

4. An annular cleaning device according to claim 3, characterized in that the cleaning device is equipped with claw-shaped steel bars against pressure and corrosion at the lower edge, and then 4-6 jet nozzles (designed according to actual requirements) are added in the circumferential direction of the ring, and the automatic control valves are connected at the end of the nozzles, so that effective sand scraping is realized in case of screen plugging, and simultaneously, when the propulsion is blocked, the plugging is automatically removed.

5. The sand control screen with the automatic plugging removal function as claimed in claim 1, wherein in the step C, as the production operation proceeds, the argillaceous silt is produced to plug the screen, and at the moment, the annular cleaning device starts to work, and the principle is as follows: the claw-shaped sand scraping plate at the lower edge of the ring starts to work, the propelling channel is blocked along with the accumulation of powder sand, the upper pressure of the ring cleaning device rises, when certain pressure (the opening pressure of a set automatic control valve) is reached, the automatic control valve is automatically opened, high-pressure water is ejected from a nozzle below the pipe cleaning device through a filter to form high-pressure water jet, accumulated silt in the front of the pipe cleaning device is dispersed, the advancing channel of the pipe cleaning device is opened, so that automatic blockage removal is realized, the problem of screen pipe blockage is effectively solved, and the smooth operation of mining operation is ensured.

6. The sand control screen pipe with the automatic plugging removal function according to claim 1, characterized in that in the step D, based on a common sand control screen pipe used for current hydrate production, adaptability evaluation analysis is performed, and by combining the sand control screen pipe structure in claim 3 and the working principle of the sand control screen pipe in claim 4, it is contrasted and found that the sand control screen pipe with the automatic plugging removal function provided by the invention can effectively solve the screen pipe plugging problem under the premise of ensuring high sand blocking precision, and by combining the actual reservoir characteristics and the challenges faced by production, the sand control screen pipe can be a brand new choice and attempt, and from theoretical analysis, a good effect can be obtained in actual operation, and therefore, popularizing the sand control screen pipe and testing the rationality thereof in practice can be a subsequent burdensome task.

Technical Field

The invention relates to a sand control screen pipe structure design with an automatic blockage removal function, in particular to a sand control screen pipe structure aiming at the problem of serious sand production in the existing natural gas hydrate exploitation, and belongs to the technical field of natural gas hydrate exploitation.

Background

The natural gas hydrate is a crystalline substance with a cage-shaped structure formed under the conditions of low temperature and high pressure, has the characteristics of large reserve and high combustion value, and is known as the most potential clean energy in the 21 st century. Because of the huge value, exploratory exploitation is carried out in individual countries (including Canada, America, Japan, China and the like) in the world, no country realizes commercial exploitation of natural gas hydrate at present, the most main reason is the reservoir specificity of the hydrate, more than 90% of the hydrate reservoir is found to be argillaceous powder sand mold according to research, and most of the hydrate found at present exists in deposited silt, so that the hydrate is decomposed and then moves with the silt while carrying out depressurization exploitation, thereby blocking a sand control screen and influencing production. Taking two trial productions in the sea area of the south China sea god fox as an example, the sand control completion technology used for the current hydrate exploitation is briefly analyzed: the sand prevention technology of Sidas easily energy technology company is adopted for the first test, the sand prevention effect is good, and no serious sand is produced; the secondary trial production adopts a composite three-stage sand prevention process of 'thick and thin' gravel filling and high-precision pre-filling sieve tubes, and along with the production of argillaceous silt, the sand production of a well completion section is serious, and a production zone section is blocked. From the final result of two trial productions, the effect of sand control is achieved by the current sand control means, but the screen pipe is blocked, so that the problem of sand production becomes a main factor restricting commercial exploitation of hydrates, and the current main task and challenge are to find a long-acting sand control completion method. Based on the current situation of sand control, the defects of the current sand control mode are discovered, and the sand control screen pipe with the automatic blockage removing function is designed by combining the characteristics of a hydrate reservoir and the characteristics of a common sand control screen pipe.

Disclosure of Invention

Aiming at the problem of serious sand blockage in the existing natural gas hydrate exploitation process, the invention provides a sand control screen pipe with an automatic blockage removing function, which mainly comprises the following design processes:

(A) determining the type of the sand control screen pipe by analyzing the characteristics of the hydrate reservoir;

(A1) analyzing the shale content of the hydrate reservoir and evaluating the granularity test;

(A2) the sand production of the reservoir is a necessary result, and a reasonable sand control screen pipe type is selected;

(B) carrying out structural design on the sand control screen pipe with the automatic blockage removing function;

(B1) the basic structure comprises: a composite sieve tube with multiple layers of sieves and an annular cleaning device;

(B2) the annular cleaning device is provided with a jet nozzle in the circumferential direction, and the end part of the nozzle is provided with an automatic control valve;

(B3) a claw-shaped sand scraping device is arranged at the edge below the annular device;

(C) explaining the working principle of the sieve tube structure according to the sieve tube structure;

(C1) the sand control screen pipe can be applied to vertical well and horizontal well types;

(C2) the working principle is as follows: the sand is produced from a reservoir, the sand control screen pipe effectively prevents sand, the multilayer screen is blocked along with the production of argillaceous silt, the yield is reduced sharply, at the moment, the annular cleaning device is used for scraping sand through a claw-shaped device below the annular cleaning device, the silt is accumulated along with the propulsion of the annular scraping device, the advance of the silt is blocked, when certain pressure is reached, the automatic control valve is opened, high-pressure water enters an annular space, high-pressure water jet is formed through a nozzle, the silt accumulated in the front is washed, an advancing channel of the annular cleaning device is opened, the automatic unblocking is realized, and the sand control effect is achieved during the process of the unblocking;

(D) performing effect prediction analysis on the sand control screen pipe subjected to automatic blockage removal;

(D1) compared with other sand control screen pipes, the invention has the advantages that the structure is improved, and the annular cleaner with the automatic blockage removing function is added on the composite screen pipe of the multi-layer screen;

(D2) the invention can effectively solve the problem of screen pipe blockage without influencing production from the viewpoint of the working principle.

The invention has the advantages that: based on the difficulty of sand control faced by the current hydrate exploitation, the invention designs a sand control screen pipe with an automatic plugging removal function from the characteristics of a hydrate reservoir (shale content and granularity analysis) and a current hydrate sand control completion mode (according to the investigation condition, most countries which carry out hydrate exploitation adopt various screen pipes for sand control, and the screen pipe sand control completion mode becomes the dominant mode of hydrate sand control), and the structural characteristics and the working principle of the screen pipe are highlighted. It has the following characteristics in structure: (1) the device consists of a composite sieve tube with multiple layers of screens and an annular cleaning device with a jet flow nozzle; (2) the size of the multilayer screen is designed to ensure that sand can be prevented to the maximum extent; (3) a claw-shaped sand scraping device is arranged below the annular cleaner; (4) the end of the jet flow spray head is connected with an automatic control valve; in conclusion, the method has great guiding significance for the commercial exploitation of the hydrate and has the necessity of large-scale popularization by combining the 4 structural characteristics and the prediction and evaluation of the actual effect of the method in the hydrate exploitation.

Drawings

FIG. 1 is a flow chart of a sand control screen design with an automatic plugging removal device according to the present invention;

FIG. 2 is a schematic plan view of a sand control screen with an automatic plugging removal device according to the present invention;

FIG. 3 is a schematic three-dimensional view of an automatic plugging removal sand control screen according to the present invention;

FIG. 4 is a schematic plan view of the annular cleaning apparatus provided in accordance with the present invention;

FIG. 5 is a three-dimensional schematic view of the annular cleaning apparatus provided in accordance with the present invention;

FIG. 6 is a schematic diagram of a double layer screen provided in accordance with an embodiment of the present invention;

FIG. 7 is a schematic illustration of a sand screen sand blocking process according to an embodiment of the present invention;

table 1 shows the shale content of a certain reservoir in the sea area of the fox tree provided in the embodiment of the present invention;

table 2 shows a comparison of the produced sand and the retained sand sizes for different screen configurations provided by examples of the present invention.

In the figure, 1-annular disc, 2-claw sand scraping steel bar, 3-jet nozzle pipeline, 4-pressure automatic control valve, 5-cylindrical water injection pipeline, 6-base pipe, 7-single layer screen, 8-double layer screen, 9-outer protecting pipe, 10-inner protecting pipe, 11-stratum sand body, 12-free sand body, 13-pipeline welding position, 1-1 annular disc upper end, 1-2 annular disc lower end, 2-1 claw sand scraper outer arm, 2-2 claw sand scraper inner wall, 3-1 jet nozzle, 3-2 jet nozzle and 3-3 jet nozzle end part.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention analyzes the design process of the sand control screen pipe with the automatic blockage relieving function, and in the analysis process, the invention focuses on the difficulty in the exploitation of the natural gas hydrate, combines the characteristics of a hydrate reservoir, determines the type of the sand screen pipe and the sand screen pipe structure, explains the working principle of the sand screen pipe, analyzes the sand blocking process, and predicts and evaluates the sand blocking and sand control effects of the sand screen pipe, thereby providing guidance for the subsequent commercial exploitation work of the natural gas hydrate.

The purpose, working principle and sand control effect of the design of the invention are further described by combining the current exploitation situation of natural gas hydrate in the sea area of Shenfox in North south China sea.

The natural gas hydrate is taken as an efficient clean energy source and favored by various countries, but no country realizes the commercial exploitation of the hydrate throughout the world, wherein the problems of sand production and sand blockage become key factors restricting the exploitation of the hydrate, and by taking two trial extractions of the natural gas hydrate in the sea area of the deity fox in China as an example, the following conclusion can be obtained: (1) the specificity of the natural gas hydrate reservoir determines the sand production necessity; (2) the key to solve the difficult problem of hydrate exploitation is the reasonable and effective sand prevention means. In view of the above problems, the present invention is applied to solve the challenges of current hydrate exploitation.

The design process of the sand control screen aiming at automatic blockage removal is shown in figure 1, and the specific operation is as follows:

s1: according to the test results of the particle size and the shale content of the hydrate reservoir in the sea area of the Homex procumbens, the median range of the particle size of the reservoir section can be found to be 16-25 mu m; the range of the inhomogeneous coefficient is 7-10, the homogeneous coefficient is more than 5, the heterogeneity is large, the range of the sorting coefficient is 20-38, the sorting coefficient is more than 20, and the sorting property is poor. The stratum sand is fine silt sand, and has strong heterogeneity and uneven distribution. Secondly, the shale content of the hydrate reservoir is in the range of 24-35%, the montmorillonite content of the illite mixed layer is 25%, the montmorillonite mineral content is about 36-40%, and the illite mineral content is about 29-34% (see table 1). The mud content is far higher than 15%, and the risk of screen pipe blockage is high.

S2: combining the analysis of the hydrate reservoir granularity and the shale content in S1, determining that the screen pipe sand-filtering type is deep-layer sand-filtering, blocking formation sand at the screen, allowing the formation sand to enter the screen pipe, and comparing and analyzing the sizes of sand produced and retained sand of different screen pipe structures, as shown in Table 2, determining that the sand-control screen pipe adopts a composite screen pipe with multiple layers of screen pipes, as shown in FIG. 6, thus ensuring normal production under the premise of sand control.

S3: according to the reservoir characteristic analysis in S1, we can find that the particularity of the hydrate reservoir inevitably leads to a result that sand is produced in the reservoir and then the sieve tube is blocked, and secondly, as can be seen from S2, the sieve tube with double-layer filter screens is adopted for sand control, although effective sand control can be achieved, the problem of sieve tube blockage still exists, therefore, an annular automatic blockage removing device with a nozzle is added, as shown in figures 4 and 5, the problem of sand blockage is timely solved in the hydrate exploitation process, and normal production is guaranteed.

S4: according to the descriptions of S1, S2 and S3, the sand control screen pipe with the automatic blockage removing device is shown in figures 2 and 3, the purpose of the sand control screen pipe is to solve the problem of screen pipe blockage in the hydrate production process, and the working principle of the sand control screen pipe is specifically described by combining the following figures: firstly, sand is produced from a reservoir during depressurization exploitation of natural gas hydrate, effective sand prevention is carried out on a multi-layer filter screen sand control screen pipe with an automatic blockage removal device, the schematic diagram of the sand control screen pipe is shown in figure 2, the multi-layer screen is blocked along with the production of argillaceous silty sand, so that the yield is sharply reduced, at the moment, sand scraping treatment is carried out through a claw-shaped device below an annular cleaner, the device is shown in figure 4, the forward power of the annular cleaner comes from water injection and pressurization of a shaft, the silty sand can be accumulated along with the propelling of the annular sand scraping device to prevent the silty sand from advancing, when certain pressure is reached, the automatic control valve is opened, high-pressure water in an annular space enters a connecting channel between the automatic control valve and a nozzle, then high-pressure water jet is formed through the nozzle, the silty sand accumulated in the front is washed, the advancing channel of the annular cleaner is opened, automatic blockage removal is realized, and the sand prevention effect is achieved during the opening.

S5: according to the working principle of the sand control screen pipe, the sand blocking process and the sand control prediction effect are briefly analyzed and explained, the sand blocking process is shown in figure 7, and the sand control screen pipe is composed of a composite screen pipe with a plurality of layers of screens, so that the effect of preventing coarse and fine sand can be achieved; secondly, because it carries an automatic unblock device, can be fine solve the screen pipe jam problem, guarantee normal exploitation operation. Therefore, the automatic blockage removing sand control screen pipe designed by the invention has better guiding significance and popularization necessity in the exploitation field of natural gas hydrates.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

TABLE 1 Mux Hovenia sea area certain reservoir mud content and relative mineral content table

TABLE 2 comparison of sizes of sand produced and retained in different screen pipe structures