阅读说明：本技术 一种水平井套管管柱组合结构及其使用方法 (Horizontal well casing pipe column combined structure and using method thereof ) 是由 程忠 宋吉明 卢岩 乔纯上 李旭光 项春生 刘超 于 2020-06-30 设计创作，主要内容包括：本发明提供一种水平井套管管柱组合结构及其使用方法,引鞋、打孔管、水泥伞套管、盲堵套管、打孔套管、浮箍套管、止塞箍套管、套管柱和送入管柱由下至上依次轴向连接；在水泥伞套管的外壁上安装水泥伞；在盲堵套管内浇灌水泥塞；在打孔套管上开设有方位错开的孔洞；在浮箍套管的尾端内部安装单流阀；在止塞箍套管的尾端内部安装止塞箍。在钻井过程中,如果水平井7英寸技术套管未下到预定深度,未能封固8.5英寸着陆井段油气水层的情况下,使用本发明进行补救,可以有效封固着陆井段油气水层的同时确保作业的连续性。(The invention provides a horizontal well casing pipe column combined structure and a using method thereof.A guide shoe, a perforating pipe, a cement umbrella casing, a blind plugging casing, a perforating casing, a floating hoop casing, a stop hoop casing, a casing string and a feeding pipe column are sequentially and axially connected from bottom to top; the outer wall of the cement umbrella sleeve is provided with a cement umbrella; pouring a cement plug in the blind plugging sleeve; holes with staggered directions are arranged on the punching sleeve; a check valve is arranged in the tail end of the float collar sleeve; the stop hoop is arranged in the tail end of the stop hoop sleeve. In the drilling process, if the 7-inch technical casing of the horizontal well is not lowered to the preset depth and cannot seal the oil-gas water layer of the 8.5-inch landing well section, the method is used for remediation, so that the oil-gas water layer of the landing well section can be effectively sealed and the continuity of operation is ensured.)

1. The utility model provides a horizontal well casing pipe string integrated configuration which characterized in that: the guide shoe, the perforating pipe, the cement umbrella casing pipe, the blind plugging casing pipe, the floating hoop casing pipe, the stop hoop casing pipe, the casing string and the feeding pipe string are sequentially and axially connected from bottom to top;

installing a cement umbrella on the outer wall of the cement umbrella casing pipe, wherein the cement umbrella is used for supporting annular well cementation cement slurry and preventing the annular well cementation cement slurry from sinking to pollute a 6-inch horizontal well section production layer;

a cement plug for blocking the downward circulation channel of the well cementing cement slurry passing through the inside of the horizontal well casing pipe column combined structure is poured in the blind plugging casing pipe so as to prevent the well cementing cement slurry from sinking from the inside of the horizontal well casing pipe column combined structure to pollute a 6-inch horizontal well section production layer;

the hole is used for providing a circulation channel from the inside of the horizontal well casing pipe column combined structure to the well bore annular space;

a check valve for preventing rock debris or other foreign matters in a shaft from entering a horizontal well casing pipe column combined structure in the process of descending the horizontal well casing pipe column combined structure is arranged in the tail end of the floating hoop casing pipe to block a flow channel of the horizontal well casing pipe column combined structure, and after well cementing cement slurry is injected, the well cementing cement slurry is prevented from flowing back to influence the well cementing quality;

the stop collar is arranged in the tail end of the stop collar sleeve and used for supporting a sleeve well cementation rubber plug to play a role in well cementation bumping and pressing, so that well cementation cement paste is prevented from replacing empty, and the well cementation quality of the sleeve pipe column combination and the well bore annulus is guaranteed.

2. The horizontal well casing pipe string composite structure according to claim 1, wherein: the guide shoe adopts the float shoe that removes the check valve, the guide shoe plays and provides the guide effect for horizontal well casing pipe string integrated configuration, and the horizontal well casing pipe string integrated configuration of being convenient for goes down to predetermined degree of depth, and the later stage utilizes small-size drilling tool combination to bore the cement stopper of wearing blind plugging sleeve and carries out the drifting in-process, is convenient for bore and opens the hydrocarbon reservoir circulation passageway of 6 inches horizontal well sections.

3. The horizontal well casing pipe string composite structure according to claim 1, wherein: the number of the cement umbrellas is 2, the distance between the cement umbrellas is 4-8m, the cement umbrellas are wrapped by canvas outside the casing elastic centralizer, the cement umbrellas are fixed on the outer wall of the casing of the cement umbrellas through the stop ring, and the outer diameter of the casing elastic centralizer is larger than the inner diameter of a well hole of a 6-inch horizontal well section, so that the cement umbrellas are centered in the 6-inch horizontal well section, and the cement umbrellas support well-cementing cement slurry in an annulus.

4. The horizontal well casing pipe string composite structure according to claim 1, wherein: the thickness of the cement plug is 3-5 m.

5. The horizontal well casing pipe string composite structure according to claim 1, wherein: the sleeve pipe that punches adopts and punches at the sleeve pipe and makes, the hole is from 3-5m departments to the sheathed tube box end evenly distributed that punches of the sheathed tube pin thread end that punches apart from, 6 holes need be punched within 1 meter's distance, and the whole sleeve pipe that punches total number is 6-8, and the diameter of hole is 15mm, and two holes are punched every 0.5m to circumference, and the position of every hole is whole staggers.

6. The horizontal well casing pipe string composite structure according to claim 1, wherein: the number of the floating hoop sleeves is 2, and a sleeve check valve is respectively arranged at the tail end of each floating hoop sleeve to play a double-insurance role.

7. The horizontal well casing pipe string composite structure according to claim 1, wherein: the size of the horizontal well casing pipe column composite structure is 5 inches.

8. A using method of a horizontal well casing pipe column combined structure is characterized by comprising the following steps: the method comprises the following steps:

step 1, when a 7-inch technical casing is not lowered to a preset depth and a landing well section oil gas water layer at the lower end of the 7-inch technical casing is not sealed, in-situ cementing is carried out on the 7-inch technical casing which is not lowered to the preset depth;

step 2, combining a 6-inch horizontal well section directional well tool combination, drilling down to penetrate a cement plug in a 7-inch technical casing and an accessory of the technical casing, drifting to the bottom of an 8.5-inch landing well section, drilling a well hole of the 6-inch horizontal well section according to the designed well hole size until drilling is finished, and tripping out;

and 3, setting a horizontal well casing pipe column combined structure, arranging a packer between the outer wall of the casing string and a 7-inch technical casing, arranging a guide shoe, a perforating pipe and a cement umbrella casing in a borehole of a 6-inch horizontal well section, fully supporting the cement umbrella on the borehole wall of the 6-inch horizontal well section, keeping the horizontal well casing pipe column combined structure centered, and enabling the two cement umbrellas to extend into 8-12m of the borehole of the 6-inch horizontal well section so as to effectively prevent the well cementation cement slurry from sinking in an annulus. Placing a perforated casing in a borehole of an 8.5-inch landing interval, wherein in order to prevent the borehole of a 6-inch horizontal interval from being excited too much by fluid passing through holes of the perforated casing, the holes are placed in the borehole of the 8.5-inch landing interval, and the hole at the bottommost end is 5-8m away from the top of the borehole of the 6-inch horizontal interval;

step 4, performing well cementation operation, namely sequentially passing well cementation cement slurry through a feeding pipe column, a casing string, a stop collar casing, a floating collar casing, a punching casing, a hole in the punching casing, an annulus between the punching casing and the well wall of the 8.5-inch landing well section, an annulus between the floating collar casing and the well wall of the 8.5-inch landing well section, an annulus between the stop collar casing and the well wall of the 8.5-inch landing well section, an annulus between the casing string and a 7-inch technical casing and an annulus between the feeding pipe column and the 7-inch technical casing to establish a circulating channel, so that the flow of the well cementation cement slurry is realized, and the well cementation cement slurry is pressed;

and 5, putting a 3.75-inch small-size drilling tool assembly, and opening a circulation channel of a hydrocarbon reservoir of the 6-inch horizontal well section after drilling, drilling through the stop collar, the casing check valve, the cement plug and the guide shoe.

9. The use method of the horizontal well casing pipe column combined structure according to claim 8, characterized in that: in step 2, the following method may also be employed: firstly, drilling a cement plug in a 7-inch technical casing and an accessory of the technical casing by using a cement plug drilling tool, pulling out the drill after the well is drilled to the bottom of the 8.5-inch landing well section, replacing a directional well tool of a 6-inch horizontal well section, and then drilling a well hole of the 6-inch horizontal well section until the drill is finished.

10. The use method of the horizontal well casing pipe column combined structure according to claim 8, characterized in that: in step 5, the 3.75 inch small-scale drilling assembly employs a 3.75 inch drill bit, 3.125 inch drill collars, and a 2.875 inch drill pipe.

Technical Field

The invention relates to the technical field of petroleum and natural gas and geological drilling engineering, in particular to a horizontal well casing pipe column combined structure and a using method thereof.

Background

In the process of offshore oil development and production, a plurality of oil fields enter the later development stage, the water content of the produced liquid of the oil well is high, the yield is decreased rapidly, in order to improve the crude oil recovery efficiency to the maximum extent, the adjustment well construction by using the low-yield old well sidetrack horizontal well is an effective means for ensuring the yield increase and stable yield of the old oil field. The conventional mode of the marine drilling horizontal well operation is as follows: and (3) windowing by using a 9.625-inch casing of the old well, sidetracking the 8.5-inch well to the top of a target layer for landing, sealing an oil-gas water layer encountered by the landing well section by using a lower 7-inch technical casing, drilling a horizontal well section of the 6-inch well to the completion of drilling, and developing and producing oil gas of the horizontal well section. In the operation process, the condition that the technical casing of the landing well section cannot reach the preset depth frequently occurs, the oil-gas water layer of the landing well section cannot be sealed, the oil-gas water layer of the landing well section and the production layer of the horizontal well section can not mutually flee, the drilling purpose can not be achieved, and the well bore is scrapped when the well bore is serious. Therefore, if the technical casing of the landing well section is not lowered to the preset depth and the oil gas water layer of the landing well section cannot be sealed, measures need to be taken for remediation so as to achieve the purpose of sealing the oil gas water layer of the landing well section. The following two types of remedial measures are currently known:

the first remedial action is: the technical casing is used for in-situ cementing, the well is opened, the next horizontal well section is drilled according to the well bore size of the designed horizontal well section, and a blind pipe and a technical casing which is not sealed and is sealed by a self-sealing device when meeting oil and water are used in the lower well completion pipe column in the well completion stage. At present, in a plurality of oil fields, the oil-gas-water self-sealing packer is used for sealing an oil-gas-water layer when meeting oil and water to remedy the condition that a technical casing pipe does not fall to a preset depth, and comprehensive production data shows that the oil-gas-water self-sealing packer is adopted in a stratum in a specific area, so that the reliability is poor, the oil-gas-water layer cannot be effectively sealed, the water content of a liquid production amount is increased quickly during production, the expectation of a geological oil reservoir cannot be achieved, and the economic benefit of a horizontal well is remarkably reduced.

The second remedial action is: the technical casing is well-fixed in situ, a layer of casing with one-level smaller size is directly supplemented to a target layer, the well-fixing and sealing technology casing is used for directly filling an oil gas water layer of a landing well section which is not sealed, and then the next small-size horizontal well section operation which is one-level smaller than the well size of the originally designed horizontal well section is carried out. This method is only applicable to wellbores having horizontal intervals of 8.5 inches and above. For a borehole of a 6-inch horizontal well section, a 7-inch technical casing is not lowered to a preset depth, if a 5-inch casing with a first-grade smaller size is directly supplemented and well cementation is carried out, then small-size horizontal well section drilling operation is carried out, the situation that small-size directional well tools without matching are used for conducting small-size horizontal well section drilling guiding is met, operation is stopped, construction period is delayed, and cost is increased.

Disclosure of Invention

The invention overcomes the defects in the prior art, the existing remedial measures are only suitable for the well with the horizontal well section of 8.5 inches or more, and the situation that the drilling guidance of the small-size horizontal well section is carried out by using a small-size directional well tool without matching causes the operation stop, the construction period delay and the cost increase is faced, so that the combined structure of the casing pipe and the pipe column of the horizontal well and the use method thereof are provided.

The purpose of the invention is realized by the following technical scheme.

A horizontal well casing pipe column combined structure comprises a guide shoe, a perforating pipe, a cement umbrella casing pipe, a blind plugging casing pipe, a perforating casing pipe, a floating hoop casing pipe, a stop hoop casing pipe, a casing string and a sending pipe column, wherein the guide shoe, the perforating pipe, the cement umbrella casing pipe, the blind plugging casing pipe, the perforating casing pipe, the floating hoop casing pipe, the stop hoop casing pipe, the casing string and the sending pipe column are sequentially and axially connected from bottom to top;

installing a cement umbrella on the outer wall of the cement umbrella casing pipe, wherein the cement umbrella is used for supporting annular well cementation cement slurry and preventing the annular well cementation cement slurry from sinking to pollute a 6-inch horizontal well section production layer;

a cement plug for blocking the downward circulation channel of the well cementing cement slurry passing through the inside of the horizontal well casing pipe column combined structure is poured in the blind plugging casing pipe so as to prevent the well cementing cement slurry from sinking from the inside of the horizontal well casing pipe column combined structure to pollute a 6-inch horizontal well section production layer;

the hole is used for providing a circulation channel from the inside of the horizontal well casing pipe column combined structure to the well bore annular space;

a check valve for preventing rock debris or other foreign matters in a shaft from entering a horizontal well casing pipe column combined structure in the process of descending the horizontal well casing pipe column combined structure is arranged in the tail end of the floating hoop casing pipe to block a flow channel of the horizontal well casing pipe column combined structure, and after well cementing cement slurry is injected, the well cementing cement slurry is prevented from flowing back to influence the well cementing quality;

the stop collar is arranged in the tail end of the stop collar sleeve and used for supporting a sleeve well cementation rubber plug to play a role in well cementation bumping and pressing, so that well cementation cement paste is prevented from replacing empty, and the well cementation quality of the sleeve pipe column combination and the well bore annulus is guaranteed.

The guide shoe adopts the float shoe that removes the check valve, the guide shoe plays and provides the guide effect for horizontal well casing pipe string integrated configuration, and the horizontal well casing pipe string integrated configuration of being convenient for goes down to predetermined degree of depth, and the later stage utilizes small-size drilling tool combination to bore the cement stopper of wearing blind plugging sleeve and carries out the drifting in-process, is convenient for bore and opens the hydrocarbon reservoir circulation passageway of 6 inches horizontal well sections.

The number of the cement umbrellas is 2, the distance between the cement umbrellas is 4-8m, the cement umbrellas are made of canvas covered outside the elastic centralizer of the casing, and the cement umbrellas are fixed on the outer wall of the casing of the cement umbrellas through the stop rings.

The outer diameter of the casing elastic centralizer is larger than the inner diameter of a well hole of a 6-inch horizontal well section, so that the cement umbrella can be centered in the 6-inch horizontal well section, and the cement umbrella can support annular space to fix well cement slurry.

The thickness of the cement plug is 3-5 m.

The sleeve pipe that punches adopts and punches at the sleeve pipe and makes, the hole is from 3-5m departments to the sheathed tube box end evenly distributed that punches of the sheathed tube pin thread end that punches apart from, 6 holes need be punched within 1 meter's distance, and the whole sleeve pipe that punches total number is 6-8, and the diameter of hole is 15mm, and two holes are punched every 0.5m to circumference, and the position of every hole is whole staggers.

The number of the floating hoop sleeves is 2, and a sleeve check valve is respectively arranged at the tail end of each floating hoop sleeve to play a double-insurance role.

The size of the horizontal well casing pipe column composite structure is 5 inches.

A using method of a horizontal well casing pipe column combined structure is carried out according to the following steps:

step 1, when a 7-inch technical casing is not lowered to a preset depth and a landing well section oil gas water layer at the lower end of the 7-inch technical casing is not sealed, in-situ cementing is carried out on the 7-inch technical casing which is not lowered to the preset depth;

step 2, combining a 6-inch horizontal well section directional well tool combination, drilling down to penetrate a cement plug in a 7-inch technical casing and an accessory of the technical casing, drifting to the bottom of an 8.5-inch landing well section, drilling a well hole of the 6-inch horizontal well section according to the designed well hole size until drilling is finished, and tripping out;

step 3, setting a horizontal well casing pipe column combined structure, arranging a packer between the outer wall of a casing pipe and a 7-inch technical casing, arranging guide shoes, a perforating pipe and a cement umbrella casing in a borehole of a 6-inch horizontal well section, fully supporting the cement umbrella on the borehole wall of the 6-inch horizontal well section, keeping the horizontal well casing pipe column combined structure centered, enabling the two cement umbrellas to extend into 8-12m of the borehole of the 6-inch horizontal well section so as to effectively prevent well cementation cement slurry from sinking in an annulus, arranging the perforating casing in the borehole of an 8.5-inch landing well section, and arranging holes in the borehole of the 8.5-inch landing well section and enabling the hole at the bottommost end to be 5-8m away from the top of the borehole of the 6-inch horizontal well section in order to avoid that the fluid is excited by the holes of the perforating casing;

step 4, performing well cementation operation, namely sequentially passing well cementation cement slurry through a feeding pipe column, a casing string, a stop collar casing, a floating collar casing, a punching casing, a hole in the punching casing, an annulus between the punching casing and the well wall of the 8.5-inch landing well section, an annulus between the floating collar casing and the well wall of the 8.5-inch landing well section, an annulus between the stop collar casing and the well wall of the 8.5-inch landing well section, an annulus between the casing string and a 7-inch technical casing and an annulus between the feeding pipe column and the 7-inch technical casing to establish a circulating channel, so that the flow of the well cementation cement slurry is realized, and the well cementation cement slurry is pressed;

and 5, putting a 3.75-inch small-size drilling tool assembly, and opening a circulation channel of a hydrocarbon reservoir of the 6-inch horizontal well section after drilling, drilling through the stop collar, the casing check valve, the cement plug and the guide shoe.

In step 2, the following method may also be employed: firstly, drilling a cement plug in a 7-inch technical casing and an accessory of the technical casing by using a cement plug drilling tool, pulling out the drill after the well is drilled to the bottom of the 8.5-inch landing well section, replacing a directional well tool of a 6-inch horizontal well section, and then drilling a well hole of the 6-inch horizontal well section until the drill is finished.

In step 5, the 3.75 inch small-scale drilling assembly employs a 3.75 inch drill bit, 3.125 inch drill collars, and a 2.875 inch drill pipe.

The invention has the beneficial effects that: under the condition that a 7-inch technical casing of the horizontal well does not reach a preset depth and cannot seal an oil gas water layer of an 8.5-inch landing well section, the shutdown waiting caused by the lack of a small-size directional well tool for drilling and guiding a small-size horizontal well section can be avoided, so that the operation can be continued, and the construction period and the cost are saved; meanwhile, the oil gas water layer of the 8.5-inch landing well section which is not sealed by a 7-inch technical casing can be sealed with excellent reliability by a well cementation means, so that the production economic benefit of the horizontal well is improved; the casing pipe column combination structure is simple, convenient in material taking and processing, low in cost, simple in use method, quick and convenient in field operation and good in application prospect, and can be widely applied to remedial operation of a 7-inch technical casing pipe which is not lowered to a preset depth in a horizontal well on a drilling field.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a method of use of the present invention;

FIG. 3 is a schematic cross-sectional view of the perforated casing of the present invention;

in the figure: the device comprises a guide shoe 1, a perforating pipe 2, a cement umbrella casing 3, a blind plugging casing 4, a perforating casing 5, a floating hoop casing 6, a stop-cock casing 7, a casing string 8, a feeding pipe string 9, a cement umbrella 11, a cement plug 12, a hole 13, a check valve 14, a stop-cock casing 15, a packer 16, a horizontal well section 21 of 6 inches, a landing well section 22 of 8.5 inches and a technical casing 23 of 7 inches.

For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.

Detailed Description

The technical solution of the present invention is further illustrated by the following specific examples.

Example one

A horizontal well casing pipe column composite structure comprises a guide shoe 1, a perforating pipe 2, a cement umbrella casing 3, a blind plugging casing 4, a perforating casing 5, a floating hoop casing 6, a stop hoop casing 7, a casing string 8 and a sending pipe column 9, wherein the guide shoe 1, the perforating pipe 2, the cement umbrella casing 3, the blind plugging casing 4, the perforating casing 5, the floating hoop casing 6, the stop hoop casing 7, the casing string 8 and the sending pipe column 9 are sequentially and axially connected from bottom to top;

a cement umbrella 11 which is used for supporting annular well cementing cement slurry and preventing the annular well cementing cement slurry from sinking to pollute a 21 production layer of a 6-inch horizontal well section is arranged on the outer wall of the cement umbrella casing 3;

a cement plug 12 for blocking a downward circulation channel of the well cementing cement slurry passing through the interior of the horizontal well casing pipe column combined structure is poured in the blind plugging casing 4 so as to prevent the well cementing cement slurry from sinking from the interior of the horizontal well casing pipe column combined structure to pollute a 6-inch horizontal well section 21 production layer;

the hole 13 with staggered directions is formed in the perforating casing 5, and the hole 13 is used for providing a circulation channel from the inside of the horizontal well casing pipe column combined structure to the horizontal well casing pipe column combined structure and a borehole annulus for well cementing cement slurry;

a check valve 14 for preventing rock debris or other foreign matters in a shaft from entering a horizontal well casing pipe column combined structure in the process of descending the horizontal well casing pipe column combined structure is arranged in the tail end of the floating hoop casing 6 to block a flow channel of the horizontal well casing pipe column combined structure, and after well cementing cement slurry is injected, the well cementing cement slurry is prevented from flowing back to influence the well cementing quality;

the stop plug hoop 15 is arranged in the tail end of the stop plug hoop sleeve 7 and used for supporting a sleeve well cementation rubber plug to play a role in well cementation bumping and pressing, so that well cementation cement paste is prevented from replacing empty, and the well cementation quality of a sleeve pipe column combination and a well bore annulus is guaranteed.

Example two

On the basis of the first embodiment, the guide shoe 1 is a float shoe without a check valve, the guide shoe 1 plays a role in providing a guiding effect for the horizontal well casing pipe column combined structure, the horizontal well casing pipe column combined structure can be conveniently lowered to a preset depth, and in the later period, a small-size drilling tool combination is utilized to drill through the cement plug 12 in the blind plugging casing pipe 4 to perform well opening, so that a hydrocarbon reservoir flow channel of the 6-inch horizontal well section 21 can be conveniently drilled through.

The number of the cement umbrellas 11 is 2, the distance between the cement umbrellas 11 is 4-8m, the cement umbrellas 11 are covered with canvas outside the casing elastic centralizer, and the cement umbrellas 11 are fixed on the outer wall of the cement umbrella casing 3 through a stop ring.

The outer diameter of the casing elastic centralizer is larger than the inner diameter of a borehole of the 6-inch horizontal well section 21, so that the cement umbrella 11 can be centered in the 6-inch horizontal well section 21, and the cement umbrella 11 can support annular space to fix cement slurry.

The cement plug 12 has a thickness of 3 to 5 m.

The punching sleeve 5 is made by punching the sleeve, the holes 13 are uniformly distributed from a position 3-5m away from the male buckle end of the punching sleeve 5 to the female buckle end of the punching sleeve 5, 6 holes 13 need to be punched within a distance of 1 m, the punching total number of the whole punching sleeve is 6-8, the diameter of each hole 13 is 15mm, two holes 13 are punched at intervals of 0.5m in the circumferential direction, and the directions of all the holes 13 are staggered.

The number of the floating hoop casings 6 is 2, and a casing check valve 14 is respectively arranged at the tail end of each floating hoop casing 6 to play a double-insurance role.

The horizontal well casing string composite was 5 inches in size.

EXAMPLE III

On the basis of the second embodiment, the use method of the horizontal well casing pipe column combined structure is carried out according to the following steps:

step 1, when a 7-inch technical casing is not lowered to a preset depth and a landing well section oil gas water layer at the lower end of the 7-inch technical casing is not sealed, in-situ cementing is carried out on the 7-inch technical casing which is not lowered to the preset depth;

step 2, combining a 6-inch horizontal well section directional well tool combination, drilling down to penetrate a cement plug in a 7-inch technical casing and an accessory of the technical casing, drifting to the bottom of an 8.5-inch landing well section, drilling a well hole of the 6-inch horizontal well section according to the designed well hole size until drilling is finished, and tripping out;

step 3, setting a horizontal well casing pipe column combined structure, arranging a packer between the outer wall of a casing pipe and a 7-inch technical casing, arranging guide shoes, a perforating pipe and a cement umbrella casing in a borehole of a 6-inch horizontal well section, fully supporting the cement umbrella on the borehole wall of the 6-inch horizontal well section, keeping the horizontal well casing pipe column combined structure centered, enabling the two cement umbrellas to extend into 8-12m of the borehole of the 6-inch horizontal well section so as to effectively prevent well cementation cement slurry from sinking in an annulus, arranging the perforating casing in the borehole of an 8.5-inch landing well section, and arranging holes in the borehole of the 8.5-inch landing well section and enabling the hole at the bottommost end to be 5-8m away from the top of the borehole of the 6-inch horizontal well section in order to avoid that the fluid is excited by the holes of the perforating casing;

step 4, performing well cementation operation, namely sequentially passing well cementation cement slurry through a feeding pipe column, a casing string, a stop collar casing, a floating collar casing, a punching casing, a hole in the punching casing, an annulus between the punching casing and the well wall of the 8.5-inch landing well section, an annulus between the floating collar casing and the well wall of the 8.5-inch landing well section, an annulus between the stop collar casing and the well wall of the 8.5-inch landing well section, an annulus between the casing string and a 7-inch technical casing and an annulus between the feeding pipe column and the 7-inch technical casing to establish a circulating channel, so that the flow of the well cementation cement slurry is realized, and the well cementation cement slurry is pressed;

and 5, putting a 3.75-inch small-size drilling tool assembly, and opening a circulation channel of a hydrocarbon reservoir of the 6-inch horizontal well section after drilling, drilling through the stop collar, the casing check valve, the cement plug and the guide shoe.

In step 2, the following method may also be employed: firstly, drilling a cement plug in a 7-inch technical casing and an accessory of the technical casing by using a cement plug drilling tool, pulling out the drill after the well is drilled to the bottom of the 8.5-inch landing well section, replacing a directional well tool of a 6-inch horizontal well section, and then drilling a well hole of the 6-inch horizontal well section until the drill is finished.

In step 5, the 3.75 inch small-scale drilling assembly employs a 3.75 inch drill bit, 3.125 inch drill collars, and a 2.875 inch drill pipe.

Spatially relative terms, such as "upper," "lower," "left," "right," and the like, may be used in the embodiments for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatial terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "lower" can encompass both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Moreover, relational terms such as "first" and "second," and the like, may be used solely to distinguish one element from another element having the same name, without necessarily requiring or implying any actual such relationship or order between such elements.

The present invention has been described in detail, but the above description is only a preferred embodiment of the present invention, and is not to be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.