Internal spiral conduit bearing capacity reinforcing device and method for using the same

A bearing capacity reinforcing device. The bearing capacity reinforcing device comprises: a reinforcing mechanism having a reinforcing body and a reinforcing disc connected to a lower portion of the reinforcing body, a plurality of reinforcing rib plates being spaced apart in a circumferential direction of the reinforcing body and connected to the reinforcing disc; wherein the reinforcing disc is provided with a plurality of accommodating spaces which are spaced apart in a circumferential direction thereof and provided therein with a movable sector plate, respectively, and the reinforcing disc at each of the accommodating spaces is provided with a perforated portion which can be blocked by the sector plate; and a connecting portion having a male buckle end connected to a lower end of the reinforcing body, and a female buckle end connected to an upper end of the reinforcing body. The present disclosure can increase the area of action between the riser or the surface conduit and the seabed soil, thereby increasing the bearing capacity of the conduit to ensure the safety and high efficiency of on-site exploration and development operations.

TECHNICAL FIELD

The present disclosure relates to the technical field of offshore oil and gas drilling and completion, and in particular to a bearing capacity reinforcing device and a method for using the same.

BACKGROUND ART

As China increases the efforts in the oil and gas exploration and development, the oil and gas exploration regions gradually turn from the land to the offshore shallow and deep water regions, which are also the regional focuses for the future oil and gas development.

The drilling and completion, and production operations in the offshore shallow water region cannot be performed without a water separation and a support to the surface blowout preventer (BOP) or the Christmas tree by a riser; while the drilling and completion, and production operations in the offshore deep water region cannot be performed without a support to the subsea blowout preventer (BOP) or the Christmas tree by a surface conduit. The bearing capacity of the riser or the surface conduit for the upper blowout preventer (BOP) or the Christmas tree mainly comes from a resistance between a side face of an outer wall of the conduit and the seabed soil and a resistance between an end face of a bottom of the conduit and the seabed soil. The magnitude of the bearing capacity is related to an area of action between the conduit and the seabed soil, i.e., the bearing capacity increases as a driving depth, and/or a diameter and a wall thickness, of the conduit increase.

However, due to the technical and cost constraints, it is usually impossible to set the conduit too deep, which leads to a phenomenon that the conduit often sinks sharply due to insufficient bearing capacity during the subsequent operation. As a result, the drilling and completion, and production operations cannot be carried out normally, while causing a large amount of economic losses and even a marine ecological environment pollution.

Therefore, the bearing capacity of the riser or the surface conduit is the key in the drilling and completion, and production operations of the offshore oil and gas fields, and it influences the operation progress and success of a well.

SUMMARY OF THE DISCLOSURE

An objective of the present disclosure is to provide abearing capacity reinforcing device and a method for using the same, so as to increase an effective area of action between a riser or a surface conduit and the seabed soil, thereby increasing a bearing capacity of the conduit and ensuring the safety and high efficiency of on-site exploration and development operations.

The above objective of the present disclosure can be achieved by the following technical solutions:

The present disclosure provides a bearing capacity reinforcing device, comprising:

a reinforcing mechanism having a reinforcing body and a reinforcing disc connected to a lower portion of the reinforcing body, a plurality of reinforcing rib plates being spaced apart in a circumferential direction of the reinforcing body and connected to the reinforcing disc; wherein the reinforcing disc is provided with a plurality of accommodating spaces which are spaced apart in a circumferential direction thereof and provided therein with a movable sector plate, respectively, and the reinforcing disc at each of the accommodating spaces is provided with a perforated portion which can be blocked by the sector plate; and

a connecting portion having a male buckle end connected to a lower end of the reinforcing body, and a female buckle end connected to an upper end of the reinforcing body.

The present disclosure further provides a method for using the bearing capacity reinforcing device aforementioned, comprising:

step S1: seating the bearing capacity reinforcing device on a female buckle of a conduit placed on a rotary table surface, and performing a buckling operation;

step S2: adjusting positions of a plurality of sector plates of the bearing capacity reinforcing device to ensure that each of the sector plates does not block a plurality of perforated portions on the reinforcing disc;

step S3: lifting up another conduit, seating a male buckle of the another conduit in a female buckle end of the bearing capacity reinforcing device, and performing a buckling operation;

step S4: setting a combined structure of the bearing capacity reinforcing device and a conduit string, until a driving depth of the conduit reaches a design depth; and

step S5: setting an operating tool into the bearing capacity reinforcing device, and adjusting the positions of the plurality of sector plates so that the plurality of sector plates can block the plurality of perforated portions on the reinforcing disc.

The bearing capacity reinforcing device and the method for using the same in the present disclosure has the following characteristics and advantages:1. The bearing capacity reinforcing device is located at a middle and/or a tail of a conduit, and may be plurally connected between the conduits at intervals at the same time, or may be singularly connected between the conduits, i.e., the bearing capacity reinforcing device may be used repeatedly for multiple times, or used singularly or plurally at the same time, so as to increase the bearing capacity of the conduit to the greatest extent, while the problem of difficulty in setting the device will not occur; during use, the present disclosure can reduce the driving depth of the conduit, and save the operation time and cost, thus achieving the advantages of a simple structure, a low cost, a convenient use, an easy operation and a high reliability.2. The effective area of action between the string and the seabed soil is increased by using the bearing capacity reinforcing device, which can improve the bearing capacities of the riser in the offshore shallow water region and the surface conduit in the offshore deep water region, and prevent the riser or the surface conduit from sinking due to insufficient bearing capacity in the later operation process and resulting in the wellhead instability and abnormal drilling and completion operations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The technical solutions in the embodiments of the present disclosure will be clearly and completely described as follows with reference to the drawings in the embodiments of the present disclosure. Obviously, those described are merely parts, rather than all, of the embodiments of the present disclosure. Based on the embodiments of the present disclosure, any other embodiment obtained by a person skilled in the art without paying any creative labor should fall within the protection scope of the present disclosure.

As illustrated inFIGS.1to3, the present disclosure provides a bearing capacity reinforcing device, comprising a reinforcing mechanism1and a connecting portion2, wherein the reinforcing mechanism1has a reinforcing body11and a reinforcing disc12connected to a lower portion of the reinforcing body11, a plurality of reinforcing rib plates13being spaced apart in a circumferential direction of the reinforcing body11and connected to the reinforcing disc12; wherein the reinforcing disc12is provided therein with a plurality of accommodating spaces121which are spaced apart in a circumferential direction thereof and provided therein with a movable sector plate122, respectively, and the reinforcing disc12at each of the accommodating spaces121is provided with a perforated portion123which can be blocked by the sector plate122; the connecting portion2has a male buckle end21connected to a lower end of the reinforcing body11, and a female buckle end22connected to an upper end of the reinforcing body11.

In order to solve the problem that the operation safety and efficiency are affected by the wellhead subsidence due to the insufficient bearing capacity of the riser or the surface conduit, the present disclosure designs a bearing capacity reinforcing device to increase the effective area of action between the riser or the surface conduit and the seabed soil, thereby increasing the bearing capacity of the conduit and ensuring the safety and high efficiency of on-site exploration and development operations.

Specifically, the connecting portion2has a male buckle end21and a female buckle end22; the female buckle end22is in threaded connection with the upper end of the reinforcing body11, located at a center of an upper end face of the reinforcing body11, and may be connected to the male buckle end of the riser or the surface conduit in a threaded sealing manner; the male buckle end21is in threaded connection with a lower end of the reinforcing body11, located at a center of a lower end face of the reinforcing body11, and may be connected to the female buckle end of the riser or the surface conduit in a threaded sealing manner. The connecting portion2is mainly connected to the conduit (i.e., the riser or the surface conduit) by threads. In other embodiments of the present disclosure, the male buckle end21and the female buckle end22of the connecting portion2may also be connected to the reinforcing body11in any fixed sealing manner besides the welded connection, which is not limited herein.

The reinforcing mechanism1is a main body of the bearing capacity reinforcing device, having the reinforcing body11in a substantially cylindrical shape; the reinforcing disc12is connected to an outer wall of a lower portion of the reinforcing body11, and substantially annular, with an outer diameter larger than that of the connecting portion2, and an inner diameter consistent with that of the connecting portion2. In the present disclosure, the reinforcing disc12is provided with a plurality of accommodating spaces121which are spaced apart in a circumferential direction thereof and substantially in a sector shape.

In the present disclosure, each of the accommodating spaces121of the reinforcing disc12is provided with a plurality of perforated portions123in a circumferential direction of the reinforcing disc12; the perforated portions123are communicated with the accommodating space121, run through upper and lower end faces of the reinforcing disc12, and can effectively reduce the setting resistance to the bearing capacity reinforcing device of the present disclosure.

Specifically, the perforated portion123comprises a plurality of through-holes1231spaced apart in a radial direction of the reinforcing disc12, with diameters thereof sequentially increased in a radial outward direction of the reinforcing disc12to ensure an overall strength of the reinforcing disc12. In this embodiment, six perforated portions123are spaced apart in a circumferential direction of the reinforcing disc12, each having two through-holes1231spaced apart in a radial direction of the reinforcing disc12; of course, in other embodiments, four, eight or any other number of perforated portions123may be spaced apart in the circumferential direction of the reinforcing disc12, each having one, three or more through-holes1231spaced apart in the radial direction of the reinforcing disc12, which are not limited herein.

Further, each of the accommodating spaces121of the reinforcing disc12is provided with a sector plate122in the circumferential direction of the reinforcing disc12; the sector plates122may be rotated at a certain angle in the accommodating space121under the action of an external force, so that the sector plates122can completely cover the plurality of perforated portions123on the reinforcing disc12; the number of the sector plates122is consistent with the number of the perforated portions123arranged in the circumferential direction of the reinforcing disc12; in a normal working state, the sector plate122is located in the accommodating space121of the reinforcing disc12; a height of the accommodating space121is consistent with a thickness of the sector plate122, so as to ensure that the sector plate122does not accidentally move in the accommodating space121; a width D of the accommodating space121is larger than a width d of the sector plate122; a shape of the accommodating space121is substantially consistent with a shape of the sector plate122, so as to ensure that the sector plate122will not cover the plurality of through-holes1231on the perforated portion123under normal conditions, thereby ensuring that the effective area of action between the bearing capacity reinforcing device of the present disclosure and the soil is minimum, and reducing the setting resistance to the bearing capacity reinforcing device. In this embodiment, the width D of the accommodating space121is twice the width d of the sector plate122, and the width d of the sector plate122is slightly larger than the diameter of each of the through-holes1231at the corresponding accommodating space121.

In order to ensure that the reinforcing disc12has a certain shear strength, in the present disclosure, assuming that a shear strength of the reinforcing disc12is M, a diameter of the through-hole1231is d, a weight of the riser or the surface conduit on the bearing capacity reinforcing device is G, a weight capacity of the riser or the surface conduit is F, and a safety factor when the reinforcing disc12does not undergo a shear deformation is k, then a calculation formula of a thickness t of the reinforcing disc12is:

In the embodiment of the present disclosure, an annular groove14is formed on an inner sidewall of the reinforcing body11, an annular body15is rotatably provided in the annular groove14, and inner ends of the plurality of sector plates122are connected to the annular body15. The inner ends of the plurality of sector plates122are connected to an outer wall of the annular body15at an equal interval in a circumferential direction of the annular body15, and drive the plurality of sector plates122to move synchronously when the annular body15rotates.

Further, as illustrated inFIG.4, an inner annular wall of the annular body15is provided with a plurality of keyways151spaced apart in a circumferential direction thereof. By setting a specific downhole tool, the annular body15may be rotated by the keyways151, thereby driving the plurality of sector plates122to rotate to completely cover the plurality of perforated portions123on the reinforcing disc12. In this embodiment, a design rotation angle of the annular body15is about 30 degrees.

Since the interior of the reinforcing disc12is solid except the accommodating space121where the sector plate122is movable, on the one hand, the strength of the reinforcing disc12is ensured, and on the other hand, the movable range of the sector plate122is limited.

The plurality of reinforcing rib plates13are spaced apart in the circumferential direction of the reinforcing body11. In the present disclosure, the reinforcing rib plate13comprises an upper rib plate131and a lower rib plate132. In this embodiment, the upper rib plate131is a flat plate in a right-angled trapezoidal shape, which is in welded connection with the upper surface of the reinforcing disc12and the female buckle end22, and an accommodating space121is provided between every adjacent two of the upper rib plates131. The upper rib plates131mainly enhance the connection strength between the female buckle end22and the reinforcing body11. The lower rib plate132is a rod in a rectangular shape or a flat plate in a right-angle trapezoidal shape, which is in welded connection with a lower surface of the reinforcing disc12and the male buckle end21, and an accommodating space121is provided between every adjacent two of the lower rib plates132. The lower rib plates132mainly enhance a shearing action of the reinforcing body11on the lower soil, so that the bearing capacity reinforcing device of the present disclosure can be more easily set after being combined with a conduit string, while the connection strength between the male buckle end21and the reinforcing body11is also enhanced. The plurality of upper rib plates131and the plurality of lower rib plates132of the reinforcing rib plates13are uniformly distributed at equal intervals on the upper and lower end faces of the reinforcing disc12.

In the embodiment of the present disclosure, an inner wall of the reinforcing body11is provided with an annular accommodating groove16that is formed between the reinforcing body11and the male buckle end21of the connecting portion2, wherein an axis of the annular accommodating groove16is provided coaxially with an axis of the reinforcing body11, and the annular accommodating groove16provides a space for an operating tool set into the reinforcing mechanism1.

As illustrated inFIGS.5and6, a working process of the bearing capacity reinforcing device for internal spiral conduits is as follows:

step S1: seating the bearing capacity reinforcing device on a female buckle41of a conduit4(i.e., a riser or a surface conduit) placed on a rotary table surface3in a sequence that a male buckle end21of a connecting portion2is lower and a female buckle end22thereof is upper, and performing a buckling operation;

step S2: adjusting positions of sector plates122of the bearing capacity reinforcing device to ensure that each of the sector plates122is in the accommodating space121of the reinforcing disc12, without being freely movable, and covers the plurality of perforated portions123on the reinforcing disc12;

step S3: cleaning the female buckle end22of the connecting portion2and applying a thread compound thereto, lifting up a new conduit5(i.e. a riser or a surface conduit), seating a male buckle51of the conduit5in the female buckle end22of the connecting portion2of the bearing capacity reinforcing device, and performing a buckling operation;

step S4: setting a combined structure of the bearing capacity reinforcing device and a conduit string10(including the conduit5and the conduit4), and continuing to connect a new conduit and/or a new bearing capacity reinforcing device according to actual needs until a driving depth of the conduit4reaches a design depth;

step S5: setting an operating tool7from a top end of the conduit into the bearing capacity reinforcing device, and adjusting the positions of the plurality of sector plates122to ensure that the sector plates122can completely cover the plurality of perforated portions123on the reinforcing disc12.

The bearing capacity reinforcing device of the present disclosure is located at a middle and/or a tail of a conduit, and may be plurally connected between the conduits at intervals at the same time, or may be singularly connected between the conduits, i.e., the bearing capacity reinforcing device may be used repeatedly for multiple times, or used singularly or plurally at the same time, so as to increase the bearing capacity of the conduit to the greatest extent, while the problem of difficulty in setting the device will not occur; during use, the present disclosure can reduce the driving depth of the conduit, and save the operation time and cost, thus achieving the advantages of a simple structure, a low cost, a convenient use, an easy operation and a high reliability.

As illustrated inFIGS.1to6, the present disclosure further provides a method for using the bearing capacity reinforcing device for internal spiral conduits as described above, comprising:

step S1: seating the bearing capacity reinforcing device on a female buckle41of a conduit4(i.e., a riser or a surface conduit) placed on a rotary table surface3, and performing a buckling operation;

step S2: adjusting positions of a plurality of sector plates122of the bearing capacity reinforcing device to ensure that each of the sector plates122does not block a plurality of perforated portions123on the reinforcing disc12;

step S3: lifting up another conduit5, seating a male buckle51of the another conduit5in a female buckle end22of the bearing capacity reinforcing device, and performing a buckling operation;

step S4: setting a combined structure of the bearing capacity reinforcing device and a conduit string10(including the conduit5and the conduit4), until a driving depth of the conduit4reaches a design depth; and

step S5: setting an operating tool7into the bearing capacity reinforcing device, and adjusting the positions of the plurality of sector plates122so that the plurality of sector plates122can block the plurality of perforated portions123on the reinforcing disc12.

In step S1, the bearing capacity reinforcing device is seated on the female buckle41of the conduit4(i.e., a riser or a surface conduit) placed on the rotary table surface3in a sequence that a male buckle end21of a connecting portion2is lower and a female buckle end22thereof is upper, and then the buckling operation is performed.

Before step S3is performed, the female buckle end22of the connecting portion2is cleaned and a thread compound is applied thereto.

In step S4, it may continue to connect a new conduit and/or a new bearing capacity reinforcing device to the combined structure of the bearing capacity reinforcing device and the conduit string10, according to actual needs.

During use, the present disclosure can reduce the driving depth of the conduit, and save the operation time and cost, thus achieving the advantages of a simple structure, a low cost, a convenient use, an easy operation and a high reliability.

Those described above are just several embodiments of the present disclosure. A person skilled in the art can make various changes or modifications to the embodiments of the present disclosure according to the content disclosed by the application document, without deviating from the spirit or scope of the present disclosure.