阅读说明：本技术 钻井液防漏堵漏效果评价实验系统 (Drilling fluid leak protection leaking stoppage effect evaluation experiment system ) 是由 颜帮川 吴旭东 蒋官澄 黄熠 欧阳铁兵 陈浩东 向雄 徐超 刁欢 李占东 张健 于 2020-05-08 设计创作，主要内容包括：本发明涉及钻井液防漏堵漏技术领域,公开了一种钻井液防漏堵漏效果评价实验系统,包括：加压装置,其适于向外输出压缩气体,以形成预定的实验压力；液杯,其包括具有内腔的杯体,杯体上端与加压装置相连接,杯体下端设有放液口；漏失模型,其包括选择性安装至杯体内的渗透型漏失模型和裂缝型漏失模型,以适于在安装位置将杯体分割为与加压装置相连通的加压腔和与放液口相连通的漏液腔,其中,渗透型漏失模型为柱状砂盘；裂缝型漏失模型包括柱状模型本体,柱状模型本体具有适于将加压腔和漏液腔相连通的裂缝,裂缝的内壁上形成有多道缝纹。本发明能够较真实的模拟地层裂缝型漏失和渗透型漏失。(The invention relates to the technical field of drilling fluid leakage prevention and stoppage, and discloses an experimental system for evaluating the leakage prevention and stoppage effect of drilling fluid, which comprises: a pressurizing device adapted to output the compressed gas to the outside to form a predetermined experimental pressure; the liquid cup comprises a cup body with an inner cavity, the upper end of the cup body is connected with a pressurizing device, and the lower end of the cup body is provided with a liquid discharging port; a leakage model comprising a permeation type leakage model and a crack type leakage model selectively installed into the cup body to be suitable for dividing the cup body into a pressurizing chamber communicated with the pressurizing device and a leakage chamber communicated with the liquid discharge port at an installation position, wherein the permeation type leakage model is a columnar sand tray; the crack-type leakage model comprises a columnar model body, the columnar model body is provided with a crack suitable for communicating the pressurizing cavity with the leakage cavity, and a plurality of cracks are formed on the inner wall of the crack. The invention can simulate the stratum fracture loss and the seepage loss more truly.)

1. The utility model provides a drilling fluid leak protection leaking stoppage effect evaluation experimental system which characterized in that includes:

a pressurizing device adapted to output compressed gas outwardly to form a predetermined test pressure;

the liquid cup comprises a cup body (502) with an inner cavity, the upper end of the cup body (502) is connected with the pressurizing device, and the lower end of the cup body (502) is provided with a liquid discharging port (510);

a loss-through pattern (504), said loss-through pattern (504) comprising a seepage-type loss-through pattern and a crevice-type loss-through pattern selectively mounted within said cup (502) so as to be adapted to divide said cup (502) in a mounted position into a pressurized chamber (508) in communication with said pressurizing means and a weep chamber in communication with said weep hole (510), wherein,

the seepage type leakage model is a columnar sand tray;

the crack type leakage model comprises a cylindrical model body, the cylindrical model body is provided with a crack (5043) suitable for communicating the pressurization cavity (508) with the liquid leakage cavity, and a plurality of cracks (5040) are formed on the inner wall of the crack (5043).

2. The drilling fluid leakage prevention and plugging effect evaluation experiment system as claimed in claim 1, wherein the columnar model body comprises two semi-columnar modules (5042) and a detachable connector (5041) for connecting the two semi-columnar modules (5042) together, and the crack (5043) is formed between the two semi-columnar modules (5042).

3. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in claim 2, wherein the detachable connecting piece (5041) is an annular connecting piece surrounding the outer peripheral surfaces of the two semi-cylindrical modules (5042); along the axis direction of the columnar model body, two detachable connecting pieces (5041) are arranged on the outer peripheral surface of the two semi-cylindrical modules (5042) at intervals.

4. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in claim 3, wherein the two detachable connectors (5041) are connected to the outer peripheral surfaces of the two semi-cylindrical modules (5042) through threads.

5. The drilling fluid leakage prevention and plugging effect evaluation experiment system as claimed in claim 1, wherein the slits (5040) are radial slits arranged at equal intervals in the axial direction of the columnar model body, or axial slits arranged at equal intervals in the radial direction of the columnar model body.

6. The drilling fluid leakage-proof and leakage-stopping effect evaluation experiment system according to claim 1, wherein the cup body (502) is of a cylindrical structure, an upper cup cover (500) and a lower cup cover (501) are respectively arranged at two ends of the cup body (502), an air inlet (509) communicated with the pressurization cavity (508) is arranged on the upper cup cover (500), the air inlet (509) is connected to the pressurization device through an air inlet pipeline, and the lower cup cover (501) is provided with the liquid outlet (510); a positioning step (511) used for limiting the axial position of the loss model (504) is arranged in the cup body (502), and the lower cup cover (501) is at least partially embedded in the cup body (502) so as to press the loss model (504) against the positioning step (511).

7. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in claim 6, wherein a first sealing ring (506) is arranged on the positioning step (511), and a second sealing ring (507) is arranged between the outer side wall of the lower cup cover (501) and the inner side wall of the cup body (502).

8. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in any one of claims 1 to 7, wherein the cup body (502) is externally coated with a heating jacket (503).

9. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in any one of claims 1 to 7, wherein a liquid discharge control valve (6) is arranged on the liquid discharge port (510), and a measuring cylinder (7) for containing and measuring the volume of leakage is arranged below the liquid discharge port (510).

10. The drilling fluid leakage prevention and stoppage effect evaluation experiment system as claimed in any one of claims 1 to 7, wherein the pressurizing device comprises a high-pressure gas cylinder (1) connected to the pressurizing cavity (508) through an air inlet pipeline, and a pressurizing valve (2), a pressure relief valve (3) and an air inlet valve (4) which are respectively arranged on the air inlet pipeline.

Technical Field

The invention relates to the technical field of drilling fluid leakage prevention and leakage stoppage, in particular to an experimental system for evaluating the leakage prevention and leakage prevention effect of drilling fluid.

Background

The deep water oil gas resources in south China sea are rich, and the deep water oil gas resources are the main take-over areas for the petroleum yield in China. In deep water and ultra-deep water drilling operation, with the increase of water depth, the stratum fracture pressure is lower and lower, and the safe density window of drilling fluid becomes narrow, so that the well leakage is frequent in the drilling operation. The deep water well leakage brings serious harm to the drilling operation, and mainly comprises the following aspects: a large amount of drilling fluid is lost, resulting in expensive production cost; drilling fluid of the riser is lost, so that the riser is damaged by extrusion; a large amount of plugging materials are consumed, and the drilling cost is increased; the working condition is delayed, and the offshore operation cost is increased; normal operation of geological work is influenced, and analysis of oil and gas reservoir data is interfered; the reservoir is damaged, and the later oil and gas resource production is influenced; causing downhole complications such as well collapse, blowout, stuck drill, etc. Meanwhile, the treatment of deepwater lost circulation is very complicated, and the deepwater drilling operation cost is very expensive. Therefore, the successful prevention and control of lost circulation during deepwater operation is especially important.

The success rate of the deepwater drilling plugging effect is generally low, and the main reasons are as follows: firstly, the uncertainty of the leakage stratum causes poor matching between the plugging material and the leakage stratum; secondly, a proper leakage stoppage effect evaluation method is lacked before leakage stoppage, and experience plugging is still taken as the main point on site. The indoor evaluation of the plugging effect of the plugging material for the deepwater drilling is a key technology for solving deepwater leakage and is also a guiding foundation for field construction.

Currently, there are two main types of devices used for indoor simulation of plugging effects: the QD type leak stoppage instrument developed in the 20 th century is mainly based on the principle that a crack type leak stoppage stratum and a cave type leak stoppage stratum are simulated through a single seam width gap plate and steel balls with different grain diameters; the other method is to simulate a leaking layer by using a high-temperature high-pressure dehydration instrument through a sand bed made of natural cores or artificial cores with different seam widths and sand grains with different grain diameters.

However, the two experimental devices have certain limitations in the aspect of leakage authenticity, and parameters of a leakage stratum cannot be quantitatively given.

Disclosure of Invention

The invention aims to solve the technical problem of providing an experimental system for evaluating the leakage-proof and plugging effect of drilling fluid, which can truly simulate stratum fracture loss and seepage loss.

In order to solve the technical problems, the invention provides an experimental system for evaluating the leakage-proof and plugging effects of drilling fluid, which comprises: a pressurizing device adapted to output compressed gas outwardly to form a predetermined test pressure; the liquid cup comprises a cup body with an inner cavity, the upper end of the cup body is connected with the pressurizing device, and the lower end of the cup body is provided with a liquid discharging port; a leakage model comprising a seepage type leakage model and a crack type leakage model selectively installed into the cup body so as to be suitable for dividing the cup body into a pressurizing cavity communicated with the pressurizing device and a leakage cavity communicated with the liquid discharge port at an installation position, wherein the seepage type leakage model is a columnar sand tray; the crack type leakage model comprises a columnar model body, the columnar model body is provided with a crack suitable for communicating the pressurization cavity with the leakage cavity, and a plurality of cracks are formed on the inner wall of the crack.

Specifically, the columnar model body includes two semi-columnar modules and a detachable connecting member for connecting the two semi-columnar modules together, and the slit is formed between the two semi-columnar modules.

More specifically, the detachable connecting piece is an annular connecting piece surrounding the outer peripheral surfaces of the two semi-cylindrical modules; along the axis direction of the columnar model body, two detachable connecting pieces are arranged on the outer peripheral surfaces of the two semi-columnar modules at intervals.

Preferably, the two detachable connectors are each connected to the outer peripheral surfaces of the two semi-cylindrical modules by a screw.

Specifically, the seam lines are radial seam lines arranged at equal intervals along the axial direction of the columnar model body, or axial seam lines arranged at equal intervals along the radial direction of the columnar model body.

The cup body is of a cylindrical structure, an upper cup cover and a lower cup cover are respectively arranged at two ends of the cup body, an air inlet communicated with the pressurizing cavity is formed in the upper cup cover, the air inlet is connected to the pressurizing device through an air inlet pipeline, and a liquid discharging opening is formed in the lower cup cover; the cup body is internally provided with a positioning step for limiting the axial position of the leakage model, and the lower cup cover is at least partially embedded into the cup body so as to press the leakage model against the positioning step.

Preferably, a first sealing ring is arranged on the positioning step, and a second sealing ring is arranged between the outer side wall of the lower cup cover and the inner side wall of the cup body.

Preferably, the cup body is externally covered with a heating sleeve.

Preferably, a liquid discharge control valve is arranged on the liquid discharge port, and a measuring cylinder for containing and measuring the volume of leaked liquid is arranged below the liquid discharge port.

Specifically, the pressurizing device comprises a high-pressure gas cylinder connected to the pressurizing cavity through an air inlet pipeline, and a pressurizing valve, a pressure relief valve and an air inlet valve which are respectively arranged on the air inlet pipeline.

The existing leakage model usually adopts a natural rock core or an artificial rock core as a fractured leakage model and a sand bed as a permeable leakage model, but the natural rock core or the artificial rock core is easy to deform in the experimental process, so that the gap width is changed; although the leakage model constructed by the sand bed can be close to the real stratum condition through the selection of the particle size of sand grains, the thickness of the sand bed is difficult to reach uniformity, and the evaluation authenticity of the leakage blocking effect is influenced. The columnar quartz sand disc is used as a seepage type leakage model, so that the problem of inconsistent thickness caused by the application of the sand bed is avoided; utilize the column model body as crack type leakage model, can lead to reliable fixed form and suitable material selection, avoid the deformation problem of natural rock core or artificial rock core, especially, form the seam line at the cracked inner wall, simulation stratum crack that can be more true makes the experimental result press close to true condition more, improves the authenticity of experimental result. Meanwhile, the plugging slurry is injected into the pressurizing cavity and pressurized by the pressurizing device, and all experimental data can be completely measured by measuring the outflow condition of the plugging slurry flowing out from the liquid discharge port and the relation between the pressure of the flowing plugging slurry and the pressure of the pressurizing device; and the leakage model can be taken out from the liquid cup for observation and cleaning, and the repeatability of the experiment is good.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

FIG. 1 is a schematic block diagram of one embodiment of the present invention;

FIG. 2 is a cross-sectional view of an assembled structure of a liquid cup and a fractured fluid loss model in an embodiment of the invention;

FIG. 3 is a schematic illustration of an explosive structure of a fractured leak-off model in an embodiment of the invention;

FIG. 4 is a schematic illustration of an assembly configuration of a fractured leak-off model in an embodiment of the invention.

Description of the reference numerals

1 high-pressure gas cylinder 2 pressure valve

3 relief valve 4 admission valve

500 upper cup cover 501 lower cup cover

502 cup 503 heating jacket

504 missing model 5040 seam

5041 Detachable connecting piece 5042 semi-cylindrical module

5043 crack 505 third seal ring

506 first seal ring 507 second seal ring

508 pressurizing chamber 509 inlet

510 tap 511 positioning step

6 liquid discharge control valve 7 graduated cylinder

Detailed Description

In the description of the present invention, it is to be understood that the terms "upper", "lower", "inner", "outer", and the like, indicate orientations or positional relationships and are used merely to facilitate description of the present invention and to simplify description, but do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present invention.

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1 to 4, an embodiment of the drilling fluid leakage prevention and stoppage effect evaluation experiment system of the present invention includes: a pressurizing device, a liquid cup, and a loss-through model 504, wherein the loss-through model 504 includes a selectively installable permeability loss-through model and a fracture loss-through model depending on the type of formation being simulated by the experimental system.

Specifically, as shown in fig. 1, the pressurizing device includes a high-pressure gas cylinder 1 connected to the liquid cup through an intake line, and a pressurizing valve 2, a pressure relief valve 3, and an intake valve 4 respectively provided on the intake line. The pressure of the gas output from the high-pressure gas bottle 1 is controlled by the opening degree of the valve port of the pressurizing valve 2 so as to adjust the output gas pressure of the pressurizing device, and the pressure relief valve 3 and the gas inlet valve 4 are respectively used for releasing the pressure in the liquid cup and controlling the pressure of the gas entering the liquid cup after the experiment is finished. It should be understood that the pressurizing device of the present invention is for outputting the compressed gas to the outside to form the predetermined experimental pressure, and therefore, the compressed gas may be any compressed gas capable of satisfying the experimental conditions.

Specifically, as shown in fig. 1 and fig. 2, the liquid cup includes a cup body 502 having an inner cavity, the cup body 502 is preferably a cylindrical structure, an upper cup cover 500 and a lower cup cover 501 are respectively disposed at two ends of the cup body 502, a leakage model 504 is installed in the cup body 502 and divides the cup body 502 into a pressurization cavity 508 and a leakage cavity, an air inlet 509 communicated with the pressurization cavity 508 is disposed on the upper cup cover 500, the air inlet 509 is connected to a pressurization device through an air inlet pipeline, so that gas with a predetermined pressure output from the high-pressure gas cylinder 1 can enter the pressurization cavity 508 through the air inlet 509, a liquid discharge port 510 communicated with the leakage cavity is disposed on the lower cup cover 501, a measuring cylinder 7 for receiving and measuring a volume of leakage liquid is disposed below the liquid discharge port 510, and a liquid discharge control valve 6 is further preferably disposed on the liquid discharge port 510 for opening the liquid discharge port 510 when the volume of the leakage blocking slurry needs to be discharged and measured. In order to prevent the leakage stopping slurry flowing out of the tapping port 510 from blocking the tapping port 510 and the tapping control valve 6 thereon, the pipe diameter of the pipeline where the tapping port 510 and the tapping control valve 6 are located should be larger than that of the air inlet pipeline.

In some embodiments of the present invention, the loss models 504 are divided into a permeability loss model and a fracture loss model, which are used to simulate permeability loss and fracture loss, respectively, of the formation. In order to enable the leakage-proof and leakage-stopping effect evaluation experiment to have good repeatable operability, the permeation type leakage-stopping model selects quartz sand with specific particle size, a columnar quartz sand tray with accurate permeability capable of being calculated is formed through high-pressure compression, and is cut into shapes and sizes capable of being installed in the cup body 502. The crack type leakage model comprises a columnar model body, the columnar model body is provided with a crack 5043 which can communicate the pressurizing cavity 508 and the leakage cavity, and a plurality of cracks 5040 similar to the simulated formation core are formed on the inner wall of the crack 5043, so that the crack model is closer to the condition of a real leakage layer and the experimental result is more accurate.

Specifically, as shown in fig. 3 and 4, the cylindrical model body includes two semi-cylindrical modules 5042 and a detachable connector 5041 for connecting the two semi-cylindrical modules 5042 together, and a slit 5043 is formed between the two semi-cylindrical modules 5042, i.e., a slit 5043 is formed at a position of being spliced after the two semi-cylindrical modules 5042 are connected.

More specifically, the detachable connector 5041 is an annular connector surrounding the outer peripheral surfaces of the two semi-cylindrical modules 5042; along the axial direction of the columnar model body, two detachable connecting pieces 5041 are arranged on the outer peripheral surfaces of the two semi-cylindrical modules 5042 at intervals. Preferably, the two detachable connections 5041 are each screwed to the outer peripheral surfaces of the two semi-cylindrical modules 5042. Wherein, the external diameter of two detachable connecting pieces 5041 is not more than the external diameter of the columnar model body, preferably equal to the external diameter of the columnar model body, thereby facilitating the placement of the columnar model body in the cup body 502. It should be noted that the detachable connection 5041 may also be a connection of other structures, such as a snap ring or a resilient clip, and still fall within the scope of the present invention.

Because half cylindrical module 5042 and detachable connecting piece 5041 are for dismantling the setting, after the simulation experiment, can take apart the actual conditions that the column model body observed the leaking stoppage to guide the evaluation of leaking stoppage effect. And, because the detachable connection 5041 surrounds the peripheral face of two semi-cylindrical modules 5042 and is in threaded connection with it, when the liquid cup is pressurized, the relative position of two semi-cylindrical modules 5042 is stable, and relative movement is not easy, therefore, the width of the crack 5043 formed between the two semi-cylindrical modules 5042 can not change accidentally, the precision of the simulation experiment is higher, and the crack 5043 is formed with the crack 5040 on the inner wall, the crack type leakage model has the structural stability of the leakage model, and meanwhile, the problem that the inner wall of the crack is too smooth and does not conform to the actual condition does not exist, therefore, the data obtained by the simulation experiment is closer to the actual condition.

The slits 5040 are arranged according to the possible distribution condition of the rock core of the stratum, and are preferably radial slits which are arranged at equal intervals in the axial direction of the columnar model body, that is, a single slit 5040 can be a radial straight slit or a radial curved slit, and all the slits 5040 are arranged at equal intervals in the axial direction of the columnar model body; or the slits 5040 are axial slits arranged at equal intervals in the radial direction of the columnar model body, that is, each slit 5040 is arranged in the axial direction of the columnar model body, and all the slits 5040 are arranged at equal intervals in the radial direction of the columnar model body. The two semi-cylindrical modules 5042 are preferably steel modules machined from steel, and the slots 5040 may be integrally machined directly into the steel modules as they are machined.

In one embodiment of the present invention, as shown in fig. 2, the loss model 504 is mounted in the cup 502, and in order to facilitate the axial positioning of the loss model 504 in the cup 502, a positioning step 511 for defining the axial position of the loss model 504 is provided in the cup 502, and the lower lid 501 is at least partially inserted into the cup 502 to press the loss model 504 against the positioning step 511. Cup 502 is preferably formed by machining a steel material, and after the inner cavity of cup 502 is machined, the inner cavity of cup 502 is radially enlarged from the end where lower lid 501 is fitted to form positioning step 511 on the inner wall of the inner cavity.

Preferably, a first sealing ring 506 is arranged on the positioning step 511, and a second sealing ring 507 is arranged between the outer side wall of the lower cup cover 501 and the inner side wall of the cup body 502, so that the leakage-stopping slurry can only flow to the leakage cavity through the leakage model 504, and can not flow through a gap between the outer side of the leakage model 504 and the inner side wall of the cup body 502. Further, a third sealing ring 505 is preferably disposed between upper lid 500 and cup 502 to seal the pressurized chamber 508 except for the gas inlet 509.

Preferably, the cup body 502 is externally covered with a heating jacket 503. In the experiment process, the liquid cup is heated to the temperature of the simulated stratum through the heating sleeve 503, so that the real stratum condition can be more closely met, and the simulated experiment data is more accurate.

The specific operation process of the drilling fluid leakage-proof and plugging effect evaluation experiment system comprises the following steps:

step 1: installing the leakage model 504 into the cup body 502, then installing the lower cup cover 501, and closing the liquid discharge port 510 through the liquid discharge control valve 6;

step 2: the plugging slurry is poured into the pressurizing cavity 508 from one end of the upper cup cover 500, and the upper cup cover 500 and the third sealing ring 506 are arranged on the cup body 502;

and step 3: closing the pressure relief valve 3, opening the pressurizing valve 2 and the outlet of the high-pressure gas cylinder 1, and adjusting the pressure of the gas inlet valve 4 to pressurize the pressurizing cavity 508 through the high-pressure gas cylinder 1;

and 4, step 4: during the experiment, the heating jacket 503 was kept open to allow the temperature inside the cup 502 to approach the formation temperature.

The plugging slurry enters the loss model 504 under pressure and is retained to form plugging. According to the regulation and control of parameters such as the control pressure, the pressurization time and the like of the pressurization valve 2, leakage stoppage effect evaluation indexes such as instantaneous leakage quantity, total leakage quantity, breakthrough pressure of leakage layer breakthrough and the like can be obtained, and a promise book of the plugging rate can be obtained by taking out and observing the leakage model 504, so that the compressibility of the leakage stoppage layer is evaluated.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.