Well building method for offshore ultra-deep extended reach well and offshore ultra-deep extended reach well structure

Abstract

The invention discloses an offshore ultra-deep and large-displacement well building method and an offshore ultra-deep and large-displacement well structure. The offshore ultra-deep and large-displacement well building method comprises the steps that firstly, a phi 762 mm guide pipe is opened; secondly, a well hole with the diameter being 660.4 mm is formed, a surface casing with the diameter being 508 mm is put in, and well cementation is conducted; thirdly, a well hole with the diameter being 444.5 mm is drilled, a technical casing with the diameter being 339.7 mm is put in, and well cementation is conducted; fourthly, a well hole with the diameter being 311.2 mm is formed, a production casing with the diameter being 244.5 mm is put into the well hole, and well cementation is conducted; and fifthly, a well hole with the diameter being 215.9 mm is formed, and well completion is conducted. The offshore ultra-deep and large-displacement well structure is manufactured through the offshore ultra-deep and large-displacement well building method, the oil drainage area of an oil reservoir can be effectively increased by applying the offshore ultra-deep and large-displacement well building method, and the marginal oil field yield is improved.

Description

Technical Field

[0001] The present invention relates to the field of offshore oil and gas drilling, and in particular to an offshore ultra-deep extended reach well construction method and an offshore ultra-deep extended reach well structure. Background Art

[0002] The reserves of offshore marginal oil fields are small, and the economic benefits are often poor if conventional new production platforms or underwater production systems are used for development. The extended reach well technology can rely on existing offshore facilities to develop marginal oil fields within a certain distance, and can achieve economical and effective development and utilization of offshore marginal oil field reserves. However, for high-difficulty extended reach wells with a horizontal displacement of more than 7,000m, conventional wellbore structure design (usually Ф152.4mm well section drilling) cannot simultaneously meet the requirements of safe well construction and efficient reservoir development. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for constructing an offshore ultra-deep extended reach well and an offshore ultra-deep extended reach well structure.

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct a method for constructing an offshore ultra-deep extended reach well, comprising:

[0005] One opening Ø762mm conduit;

[0006] Second, a 660.4 mm diameter wellbore was opened, and a 508 mm diameter surface casing was lowered and cemented;

[0007] Open the 444.5mm diameter wellbore three times, run the 339.7mm diameter technical casing, and cement the well;

[0008] Open the Ø311.2mm wellbore four times, run the Ø244.5mm production casing, and cement the well;

[0009] Five wells with a diameter of 215.9 mm were opened and completed.

[0010] In some embodiments, the Ф762 mm conduit is pre-installed obliquely using directional piling.

[0011] In some embodiments, the Ф508mm surface casing is inserted by grouting casing.

[0012] In some embodiments, the Ф339.7 mm technical casing is lowered by partial floating and partial grouting.

[0013] In some embodiments, the Ф244.5 mm production casing is lowered in a fully floating and rotating manner.

[0014] In some embodiments, after the Ф215.9 mm wellbore is drilled, a completion string is lowered.

[0015] The present invention further discloses an offshore ultra-deep large-reach well structure, and the offshore ultra-deep large-reach well structure is manufactured by using the offshore ultra-deep large-reach well construction method described in any of the above embodiments.

[0016] In some embodiments, the offshore ultra-deep large displacement well structure includes a Ф762mm conduit, a Ф660.4mm wellbore formed inside the Ф762mm conduit, a Ф508mm surface casing installed in the Ф660.4mm wellbore, a Ф444.5mm wellbore formed in the Ф508mm surface casing, a Ф339.7mm technical casing installed in the Ф444.5mm wellbore, a Ф311.2mm wellbore formed in the Ф339.7mm technical casing, a Ф244.5mm production casing installed in the Ф311.2mm wellbore, and a Ф215.9mm wellbore formed in the Ф244.5mm production casing.

[0017] In some embodiments, the well inclination angle of the Ф762mm catheter is 3°-7°.

[0018] In some embodiments, the well inclination angle of the Ф508mm surface casing is 40°-60°.

[0019] The implementation of the present invention has the following beneficial effects: the offshore ultra-deep extended displacement well construction method includes: first opening a 762mm diameter conduit; second opening a 660.4mm diameter wellbore and lowering a 508mm diameter surface casing; third opening a 444.5mm diameter wellbore and lowering a 339.7mm diameter technical casing; fourth opening a 311.2mm diameter wellbore and lowering a 244.5mm diameter production casing; and fifth opening a 215.9mm diameter wellbore. The offshore ultra-deep extended displacement well structure is manufactured by the offshore ultra-deep extended displacement well construction method, and the offshore ultra-deep extended displacement well construction method can effectively increase the oil leakage area of ​​the reservoir and improve the marginal oil field production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work. In the drawings:

[0021] Figure 1 is a schematic diagram of a method for constructing an offshore ultra-deep extended reach well in some embodiments of the present invention;

[0022] Figure 2 It is a schematic diagram of an offshore ultra-deep large-reach well structure in some embodiments of the present invention. DETAILED DESCRIPTION

[0023] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0024] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0026] See also Figure 1 The present invention shows a method for constructing an offshore ultra-deep large-displacement well, which can not only meet the construction operations of ultra-deep large-displacement wells with a high water-to-vertical ratio and a high difficulty level with a horizontal displacement exceeding 7000m, but also increase the oil leakage area of ​​the reservoir, and can help the development of offshore marginal oil fields.

[0027] In this embodiment, the offshore ultra-deep extended reach well construction method may include:

[0028] A 762 mm diameter conduit 1 is provided, and the 762 mm diameter conduit is pre-slanted and lowered by directional piling. Specifically, the 762 mm diameter conduit 1 is used to establish a connection channel between the seabed and the production platform. The 762 mm diameter conduit 1 is pre-slanted and lowered by directional piling, which can achieve a certain well inclination angle (well inclination angle is 3°-7°) and relieve the deflection pressure of the subsequent well section.

[0029] A second 660.4mm borehole is opened, a 508mm surface casing 2 is lowered, and cementing is performed. The 508mm surface casing is lowered by grouting, and an insert cementing process is used for cementing operations to seal the 508mm surface casing. Specifically, a second 660.4mm borehole is opened, and a 508mm surface casing 2 is lowered to isolate the unlithified loose strata in the shallow seabed strata. A motor directional method can be used to achieve surface deflection to reduce the dogleg degree of the third opening section and reduce the difficulty of directional deflection. Among them, because the surface well inclination angle is usually less than 60°, the 508mm surface casing 2 is lowered by grouting.

[0030] The Ф444.5mm wellbore was opened three times, and the Ф339.7mm technical casing 3 was lowered and cemented. The Ф339.7mm technical casing was lowered by partial floating and partial grouting, and the cementing operation was carried out by single-stage cementing technology to seal the Ф339.7mm technical casing. Specifically, the Ф444.5mm wellbore was opened three times, and the Ф339.7mm technical casing 3 was lowered to isolate the geological sealing points of the upper well section to ensure the operation window of the subsequent well section. At the same time, the directional well technology was used to increase the well inclination angle to more than 80° to meet the horizontal directional operation of the fourth well section. The Ф339.7mm technical casing 3 was lowered by partial floating + partial grouting, which can improve the lowering ability of the casing in the high-angle well section.

[0031] Four Ф311.2mm wellbores are opened, Ф244.5mm production casing 4 is lowered, and cementing is performed. The Ф244.5mm production casing is lowered in a fully floating and rotating manner, and a single-stage cementing process is used for cementing operations to seal the Ф244.5mm production casing. Specifically, four Ф311.2mm wellbores are opened, and Ф244.5mm production casing 4 is lowered, which is used for ultra-long-distance horizontal well section extension operations and connects to oil and gas reservoirs. This well section is the key to achieving ultra-long-distance horizontal extension, and horizontal extension directional operations can be performed according to design requirements. The Ф244.5mm production casing 4 is lowered in a fully floating + rotating manner, which can effectively reduce the friction between the Ф244.5mm production casing 4 and the ultra-long-distance horizontal wellbore. ;

[0032] The five-hole 215.9mm wellbore 5 and the well completion are used to meet the completion operation requirements in the horizontal well section of the oil and gas reservoir to achieve oil and gas production. Furthermore, after the 215.9mm wellbore 5 is completed, the completion string is lowered to meet the oil field production requirements. Compared with the traditional 152.4mm well section, this well section increases the oil reservoir leakage area by 42% and increases the marginal oil field production.

[0033] like Figure 2 As shown, the present application also discloses an offshore ultra-deep extended reach well structure, which is made by the above-mentioned offshore ultra-deep extended reach well construction method. Compared with the traditional 152.4mm well section drilling, the offshore ultra-deep extended reach well structure increases the oil reservoir leakage area by 42% and improves the marginal oil field production.

[0034] In this embodiment, the offshore ultra-deep large-displacement well structure includes a Ф762mm conduit 1, a Ф660.4mm wellbore formed on the inner side of the Ф762mm conduit 1, a Ф508mm surface casing 2 installed in the Ф660.4mm wellbore, a Ф444.5mm wellbore formed in the Ф508mm surface casing 2, a Ф339.7mm technical casing 3 installed in the Ф444.5mm wellbore, a Ф311.2mm wellbore formed in the Ф339.7mm technical casing 3, a Ф244.5mm production casing 4 installed in the Ф311.2mm wellbore, and a Ф215.9mm wellbore 5 formed in the Ф244.5mm production casing 4.

[0035] In this embodiment, the 762 mm diameter conduit 1 is used to establish a connection channel between the seabed and the production platform. Preferably, the well inclination angle of the 762 mm diameter conduit 1 is 3°-7°. For example, the well inclination angle of the 762 mm diameter conduit 1 is 4°, the well inclination angle of the 762 mm diameter conduit 1 is 5°, and the well inclination angle of the 762 mm diameter conduit 1 is 6°.

[0036] In this embodiment, the Ф508mm surface casing 2 is used to isolate the undiagenerated loose strata of the shallow seabed strata. Preferably, the well inclination angle of the Ф508mm surface casing 2 is 40°-60°, for example, the well inclination angle of the Ф508mm surface casing 2 is 50°.

[0037] In this embodiment, the Ф339.7mm technical casing is used to isolate the geologically necessary sealing points in the upper well section to ensure the operation window of the subsequent well section. Preferably, the well inclination angle of the Ф339.7mm technical casing 3 is greater than 80°, for example, the well inclination angle can be 85° or 90°.

[0038] In this embodiment, the 244.5 mm diameter production casing 4 is used for ultra-long distance horizontal well section extension operation and connecting oil and gas reservoirs. Preferably, the horizontal extension section length of the 244.5 mm diameter production casing 4 is greater than 7000 meters.

[0039] In this embodiment, the Ф215.9mm wellbore 5 is used in the horizontal well section of the oil and gas reservoir to meet the completion operation requirements and achieve oil and gas production. Compared with the traditional 152.4mm well section, this well section increases the oil leakage area of ​​the reservoir by 42% and improves the marginal oil field production.

[0040] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the scope covered by the claims of the present invention.

Claims

1. A method for constructing an ultra-deep extended reach well offshore, characterized in that: include: One opening Ø762mm conduit; Second, a 660.4 mm diameter wellbore was opened, and a 508 mm diameter surface casing was lowered and cemented; Open the 444.5mm diameter wellbore three times, run the 339.7mm diameter technical casing, and cement the well; Open the Ø311.2mm wellbore four times, run the Ø244.5mm production casing, and cement the well; Five wells with a diameter of 215.9 mm were opened and completed.

2. The offshore ultra-deep extended reach well construction method according to claim 1, characterized in that: The Ф762mm conduit is pre-inclined by directional piling.

3. The offshore ultra-deep extended reach well construction method according to claim 1, characterized in that: The Ф508mm surface casing is lowered by grouting.

4. The offshore ultra-deep extended reach well construction method according to claim 1, characterized in that: The Ф339.7 mm technical casing is lowered by partial floating and partial grouting.

5. The offshore ultra-deep extended reach well construction method according to claim 1, characterized in that: The Ф244.5 mm production casing is lowered in a fully floating and rotating manner.

6. The offshore ultra-deep extended reach well construction method according to claim 1, characterized in that: After the Ф215.9 mm wellbore is drilled, a completion string is run into the well.

7. An offshore ultra-deep extended reach well structure, characterized in that: The offshore ultra-deep extended reach well structure is manufactured by the offshore ultra-deep extended reach well construction method described in any one of claims 1 to 6.

8. The offshore ultra-deep extended reach well structure according to claim 7, characterized in that: The offshore ultra-deep extended-reach well structure comprises a Ф762 mm conduit (1), a Ф660.4 mm wellbore formed inside the Ф762 mm conduit (1), a Ф508 mm surface casing (2) installed in the Ф660.4 mm wellbore, a Ф444.5 mm wellbore formed in the Ф508 mm surface casing (2), a Ф339.7 mm technical casing (3) installed in the Ф444.5 mm wellbore, a Ф311.2 mm wellbore formed in the Ф339.7 mm technical casing (3), a Ф244.5 mm production casing (4) installed in the Ф311.2 mm wellbore, and a Ф215.9 mm wellbore (5) formed in the Ф244.5 mm production casing (4).

9. The offshore ultra-deep extended reach well structure according to claim 8, characterized in that: The well inclination angle of the Φ762 mm conduit (1) is 3°-7°.

10. The offshore ultra-deep extended reach well structure according to claim 8, characterized in that: The well inclination angle of the Ф508mm surface casing (2) is 40°-60°.

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