CN114893120A - Method for forming technical casing with single borehole diameter underground by using resin - Google Patents

Abstract

The invention relates to the technical field of oil drilling, in particular to a method for forming a technical casing with a single borehole diameter underground by using resin. The method comprises the following steps: (1) drilling an open hole section in a complex stratum; (2) carrying out reaming on all or part of the open hole section; (3) placing the middle lower part of the central pipe into the open hole section by using a drilling tool, and applying a drillable centralizer on the central pipe to ensure that the resin pipe is centered to form a central framework in the open hole section; (4) taking high-temperature resistant delayed coagulation resin as a raw material, and ensuring that the resin is solidified between the outer wall of a central pipe framework in the well and the inner wall of an open hole section to form a ring-shaped resin solid material; (5) waiting for setting for 12-24 hours, drilling a central pipe and a resin solid material by adopting a pilot drill, and forming a section of resin casing with a single borehole diameter in the open hole section. The invention utilizes resin material and a drillable central pipe to form a resin casing with a single borehole diameter underground, thereby solving the temporary sealing problem of complex intervals.

Description

A method of using resin to form a technical casing of a single well diameter downhole

technical field

The invention relates to the technical field of oil drilling, in particular to a method for forming a technical casing with a single well diameter downhole by using resin.

Background technique

For complex formations such as rock layers encountered during the drilling process, casing is often required for open-hole sealing. But the casing sequence of a well is always affected by casing size, wellbore size, casing strength, length, pressure bearing capacity, etc.; There is a problem with the size design, and it is not possible to run additional multi-layer casings. In this case, it is necessary to temporarily seal the formation by using liquid materials such as mud and plugging materials, auxiliary materials such as liquid additives, and auxiliary technologies. This type of auxiliary technology has a low pressure bearing capacity and is often difficult to meet the needs of drilling. Therefore, there is a need to develop a new process that can provide casing performance, but also provide the same wellbore size as the original wellbore to provide temporary sealing for complex formations.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for forming a casing with a single well diameter downhole by using resin, to overcome the deficiencies of the prior art. Resin casing with strata cemented together to solve the problem of temporary sealing of complex sections.

The technical scheme adopted by the present invention to solve its technical problems is:

A method of using resin to form a casing of a single well diameter downhole, comprising the steps of:

(1) Start drilling from the upper casing shoe, drill in complex formations, and drill out the open hole section;

(2) Carry out reaming operation on all or part of the open-hole well section, and the diameter of the open-hole well section after reaming is 2±0.2 inches larger than the casing diameter in the conventional formation;

(3) Select the center pipe of appropriate size, use the drilling tool to place the center pipe in the open hole section after reaming, and use a drillable centralizer on the pipe body of the center pipe to ensure that the center pipe is centered. A central skeleton is formed in the subsequent open-hole section;

(4) Using high temperature-resistant and setting-retarding resin as raw material to ensure that the high-temperature setting-retarding resin is solidified between the outer wall of the downhole central pipe skeleton and the annulus of the open hole section to form an annular resin solid material;

(5) After setting for 12-24 hours, the center pipe and solid resin material are drilled with a pilot bit of the same size as that used to drill the open-hole section, to form a new hole of the same size as the original wellbore, that is, in the open-hole well The segment forms a single-diameter resin casing;

The above method can ensure that a new wellbore is drilled at the center of the downhole resin solid material without drilling deviation, avoid the partial well section of the open-hole well section sealed with resin without resin layer protection, and ensure the protection of complex formations. Sealing effect.

Further, in the step (3), the length of the central pipe is 200±100 m longer than the length of the well section that needs to be plugged in the open-hole well section.

Further, in the step (3), the central tube is a resin tube, or a nylon tube, or an aluminum alloy tube that can be drilled. Dropping is required prior to sealing with resin.

Further, in the step (3), the method of selecting the center pipe is: select a 7-inch-(9-5/8)-inch center pipe in a 12-1/4-inch wellbore, and the outer diameter of its coupling is 8- 12-inch, the tensile capacity of the thread is not less than 200kN; in the 8-1/2-inch wellbore, use a 5-1/2-inch-7-inch center pipe, and the outer diameter of the coupling is 6-inch-(8-1/2) inch, the tensile capacity of the thread is not less than 150kN.

Further, in the step (3), a resin centralizer capable of drilling is selected for the centralizing tool, and the maximum outer diameter of the centralizing tool does not exceed the outer diameter of the drill bit for drilling the open hole section.

Further, in the step (4), the high temperature-resistant and retarded resin is resistant to a high temperature of 80-160°.

Further, in the step (4), the high temperature-resistant and retarded resin is selected from the high-temperature-resistant and retarded unsaturated polyester resin, epoxy resin, vinyl unsaturated resin or cyanate ester with a temperature resistance of up to 120-160°C. resin.

Further, in the step (4), the initial thickening time of the high temperature resistant retarding resin is 4-6 hours, the compressive strength of the high temperature resistant retarding resin after curing can reach 70-130MPa, and the high temperature resistant retarding resin can reach 70-130MPa. The performance of the resin is stable and does not react with common acids, alkalis and salts. In order to improve the characteristics of high temperature resistant and retarded resins, commonly used additives can be added to enhance the performance.

Further, in the step (4), the density of the high temperature-resistant and retarded resin can be adjusted between 1.10 and 2.50, which is required to be no less than the density of the mud used for drilling the formation in the open-hole section; the high-temperature resistant and retarded resin The viscosity can be adjusted between 40-200mPa.s, and the fluidity of the high-temperature-resistant and retarded resin liquid is required to match the viscosity of the mud used for drilling the open-hole section.

Further, in the step (4), the designed volume of the resin solid material is an annulus volume of an additional 50 meters of casing-center pipe annulus to the annulus volume of the open hole section to be sealed.

The beneficial effects of the present invention are: compared with the prior art, a method of using resin to form a casing with a single well diameter downhole has the following advantages: low cost, controllable risks, using resin materials, and drilling The center pipe is formed into a resin casing with a certain wall thickness and cemented with the formation. The cooperation of the center pipe, the centralizer of the resin material and the pilot bit can ensure that the drilling is not deviated, and avoid the failure of some sections of the open hole section. The protection of the resin layer ensures that a single-diameter resin casing is formed in the open-hole section, which solves the problem of temporary sealing of complex sections.

Description of drawings

Fig. 1 is the process principle diagram of the present invention;

Among them, 1 upper casing casing, 2 complex formation, 3 open hole section, 4 open hole section after reaming, 5 casing, 6 center pipe, 7 drillable centralizer, 8 resin solid material, 9 collar Eye drill.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

In the embodiment shown in FIG. 1 , a method for forming a casing with a single well diameter downhole by using resin is performed downhole, the well depth is 2000-3000 meters, the temperature range is 60-100°C, and the pressure range is 20-60MPa; The well depth is 3000-4000 meters, the temperature range is 80-120℃, and the pressure range is 30-80MPa; the well depth is greater than 4000 meters, the temperature is greater than 100℃, and the pressure is greater than 40MPa.

A method for forming a casing with a single borehole downhole by using a resin comprises the following steps:

(1) Drilling is carried out from the upper casing casing shoe 1 to the complex formation 2, and the open hole section 3 is drilled;

(2) Reaming is performed on all or part of the open-hole well section, and the diameter of the open-hole well section 4 after reaming is 2±0.2 inches larger than the diameter of the casing 5 in the conventional formation;

(3) Select the center pipe 6 of suitable size, use the drilling tool to put the center pipe into the open hole section after reaming, and use the drillable centralizer 7 on the pipe body of the center pipe to ensure that the center pipe is centered. A central skeleton is formed in the open hole section after reaming;

(4) Using high-temperature-resistant and setting-retarding resin as the raw material to ensure that the high-temperature-resisting and setting-retarding resin is solidified between the outer wall of the downhole central skeleton and the annulus of the open hole section to form a solid annular resin solid material 8;

(5) Wait for 12-24 hours to set, and use the pilot bit 9 of the same size as the drill bit used to drill the open hole section to drill the center pipe and resin solid material to form a new hole with the same size as the original wellbore. The open hole section forms a single-diameter resin casing;

The above method can ensure that a new wellbore is drilled at the center of the downhole resin solid material, and no drilling deviation occurs, avoiding the connection of part of the open-hole well section with the original stratum, resulting in no resin layer protection, and ensuring the protection of complex strata. Sealing effect.

In this embodiment, in the step (3), the length of the central pipe is 200±100 m longer than the length of the open hole section. In the step (3), the central tube is a resin tube, or a nylon tube, or an aluminum alloy tube that can be drilled. Drop the hand before resin sealing. In the step (3), the method of selecting the center pipe is as follows: select a 7-inch-(9-5/8)-inch center pipe in the 12-1/4 wellbore, and the outer diameter of the coupling is 8-12 inches, and the thread is 8-12 inches. The tensile strength is not less than 200kN; in the 8-1/2 wellbore, a 5-1/2 inch-7 inch center pipe is selected, and the outer diameter of the coupling is 6-(8-1/2) inch, and the tensile strength of the thread is The capacity is not less than 150kN. In the step (3), the maximum outer diameter of the resin material centralizer does not exceed the outer diameter of the drill bit for drilling the open hole section.

In this embodiment, in the step (4), the high temperature-resistant and retarded resin is resistant to a high temperature of 80-160°. In the step (4), the high temperature-resistant and setting-retarding type resin is selected from vinyl unsaturated resin with temperature resistance up to 120-160°C, or cyanate resin with temperature resistance of 80-120°C, or epoxy resin. In the step (4), the initial thickening time of the high temperature resistant retarding resin is 4-6 hours, the strength of the high temperature resistant retarding resin after curing can reach 70-130MPa, and the performance of the high temperature resistant retarding resin is stable, It does not react with common acids, alkalis, and salts. In order to improve the properties of high temperature-resistant and retarded resins, common additives can be added to enhance performance. In the step (4), the density of the high-temperature-resistant and setting-retarding resin can be adjusted between 1.10 and 1.50, which is required to be no less than the density of the mud used for drilling the open-hole section; Adjusted between 40-100mPa.s, it is required that the fluidity of the high-temperature-resistant and setting-retarding resin liquid matches the viscosity of the mud used to drill the formation in the open hole interval. In the step (4), the designed volume of the resin solid material is the casing-center pipe annulus volume of 50 meters in addition to the annulus volume of the open hole section to be sealed.

In this embodiment, the other on-site constructions follow common casing cementing procedures.

The above-mentioned specific embodiments are only specific cases of the present invention, and the scope of patent protection of the present invention includes but is not limited to the product forms and styles of the above-mentioned specific embodiments. Appropriate changes or modifications made shall fall within the scope of patent protection of the present invention.

Claims (10)

1. a kind of method that utilizes resin to form the casing of single well diameter downhole, it is characterized in that: comprise the steps: (1) Start drilling from the upper casing shoe, drill in complex formations, and drill out the open hole section; (2) Carry out reaming operation on all or part of the open-hole well section, and the diameter of the open-hole well section after reaming is 2±0.2 inches larger than the casing diameter in the conventional formation; (3) Select the center pipe of appropriate size, use the drilling tool to place the center pipe in the open hole section after reaming, and use a drillable centralizer on the pipe body of the center pipe to ensure that the center pipe is centered. A central skeleton is formed in the subsequent open-hole section; (4) Using high temperature-resistant and retarded resin as raw material to ensure that the high-temperature retarded resin is solidified between the outer wall of the downhole central skeleton and the annulus of the open hole section to form an annular resin solid material; (5) After setting for 12-24 hours, use a pilot bit of the same size as the drill bit used to drill the open hole section to drill the center pipe and solid resin material to form a new hole the same size as the original wellbore. The open-hole section forms a single-diameter resin casing. 2 . The method according to claim 1 , characterized in that in the step (3), the length of the central pipe is longer than that in the open-hole well section and needs to be blocked or blocked. 3 . The length of the reinforced well section is greater than 200±100m. 3. A method for forming a casing with a single well diameter downhole by using resin according to claim 1, wherein in the step (3), the central pipe is a resin pipe or a nylon pipe, Or an aluminum alloy tube that can be drilled. 4. A method of using resin to form a casing with a single well diameter downhole according to claim 1, characterized in that: in the step (3), the method of selecting the center pipe is: at 12-1/4 7-inch-(9-5/8)-inch center pipe is used in wellbore of 1-inch, the outer diameter of the coupling is 8-12 inches, and the tensile capacity of the thread is not less than 200kN; 1/2 inch-7 inch center pipe, the outer diameter of the coupling is 6 inch-(8-1/2) inch, and the tensile capacity of the thread is not less than 150kN. 5 . The method of using resin to form a casing with a single hole diameter downhole according to claim 1 , wherein in the step (3), the maximum value of the outer diameter of the centralizer made of the resin material is not equal to or equal to 5 . Exceeds the outer diameter of the drill bit that drilled the open hole section. 6 . The method of using resin to form a casing with a single well diameter downhole according to claim 1 , wherein in the step (4), the high-temperature-resistant and setting-retarding resin is resistant to high temperature of 80-160°. 7 . 7. A method for forming a casing with a single well diameter downhole by using resin according to claim 1 or 6, characterized in that: in the step (4), the high temperature-resistant and setting-retarding resin is selected as a high-temperature-resisting setting retarder. One or more of unsaturated polyester resin, epoxy resin, vinyl unsaturated resin or cyanate resin. 8 . The method according to claim 1 or 6 , wherein the method for forming a casing with a single well diameter downhole by using resin is characterized in that: in the step (4), the initial thickening time of the high-temperature-resistant and setting-retarding resin is After 4-6 hours, the compressive strength of the high-temperature-resistant retarder resin can reach 70-130MPa. 9 . The method of using resin to form a casing with a single well diameter downhole according to claim 1 or 6 , wherein in the step (4), the density of the high-temperature-resistant and setting-retarding resin can be within 1.10 Adjusted between -2.50, it is required to be no less than the density of the mud used to drill the formation in the open hole section; the viscosity of the high temperature resistant and setting retarding resin can be adjusted between 40-200mPa.s. The fluidity matches the viscosity of the mud used to drill the open hole formation. 10. A method for forming a casing with a single hole diameter downhole by using resin according to claim 1 or 6, characterized in that: in the step (4), the designed volume of the resin solid material is required to be sealed The annulus volume of the open hole section is additionally 50 meters of casing-centre annulus volume.

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