Method for finding fish and reconstructing channel by opening window on side wall

Abstract

The invention discloses a method for finding fish and rebuilding a channel by windowing a side wall. The method comprises the following steps: assembling a fish finding assembly; the fish finding assembly is lowered into the oil-water well, the drilling machine is started, and the fish finding assembly is used for cutting the sleeve deviating from the center of the well hole; and a tracing pipe column is inserted until the tracing pipe column falls into the casing pipe through the fish top, the fish recycling assembly is recycled, and casing milling and casing taking construction continues to be conducted through the casing milling barrel. Compared with the prior art, the method has the advantages that operation is easy, the success rate is high, the problem that in the casing taking and replacing process, the success rate of fish top finding through a conventional fish finding technology is low is solved, the well occupying period is greatly shortened, the safety coefficient of overhaul casing taking and replacing construction is greatly increased, and the method is suitable for large-scale popularization and application. The accident that the oil-water well is scrapped due to the fact that the fish top cannot be found can be effectively avoided, and therefore the application effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum well repairing operations, and particularly relates to a method for opening windows on a side wall to find fish and rebuild a channel. Background Art

[0002] During the production process of oil and water wells in oil fields, due to the ground subsidence, sometimes the shallow casing will be twisted and deformed, thus affecting the normal production of oil and water wells, and even forcing them to stop production. At this time, it is necessary to carry out overhaul and replacement of casing. The construction method of overhaul and replacement of casing refers to inserting a tracer string into the casing, and then using a casing milling barrel to perform casing milling and reconnection. In recent years, in the overhaul and replacement of casing for shallow casing twisted and deformed wells, it was found that the inner diameter of the casing milling barrel was limited by the diameter of the surface casing, and the casing with severe twisting and deformation would be cut off and lose fish. At this time, it is necessary to find the fish top. In this industry, the fish top refers to the part of the casing broken after cutting in the oil and water well. The conventional method of finding fish is to use a wall hook, but because the wall hook has a limited range of detection in the oil and water well, even if the fish top is found, the strength of putting the cut casing back to the correct position is limited, which will not only result in a low success rate of finding fish, but also have serious safety hazards, and may even cause the oil and water well to be scrapped. Summary of the invention

[0003] In order to solve the above problems, the object of the present invention is to provide a method for opening windows in side walls to find fish and rebuild a passage.

[0004] In order to achieve the above object, the method for opening a window in a side wall to find fish and rebuild a passage provided by the present invention comprises the following steps performed in sequence:

[0005] 1) When the casing in the oil and water well is eccentrically cut and the fish is lost, and the fish top needs to be retrieved, the construction personnel first assemble the fish finding assembly, which includes a drill collar, an eccentric short-circuit and a window milling shoe; wherein the drill collar, the eccentric short-circuit and the window milling shoe are all hollow structures, and the upper end of the drill collar is connected to the drilling rig; the upper and lower ends of the eccentric short-circuit are respectively threadedly connected to the lower end of the drill collar and the upper end of the window milling shoe;

[0006] 2) Lower the fish-finding assembly into the oil and water well, and after the lower end of the fish-finding assembly passes through the fish top and encounters resistance, start the drilling rig to make the fish-finding assembly rotate at high speed, and use the lower end of the window milling shoe to cut the casing that deviates from the center of the wellbore, and the cut casing falls into the well. After cutting, the part where the casing is broken, i.e., the fish top, will be located inside the window milling shoe, thereby successfully achieving fish collection;

[0007] 3) Insert the tracer string downward from the upper end of the drill collar until the tracer string passes through the fish top and falls into the casing. Retrieve the fish assembly and continue to use the casing milling barrel to perform casing milling and casing removal construction.

[0008] In step 1), the lower end of the window milling shoe is in an outer trumpet shape.

[0009] In step 1), the maximum eccentricity of the eccentric short circuit is 30 degrees.

[0010] The method for opening windows on the side wall to find fish and rebuild the passage provided by the present invention has the following beneficial effects:

[0011] This method is simple to operate and has a high success rate. It solves the problem of low success rate in retrieving the fish top using conventional fish finding technology during casing replacement, greatly shortens the well occupation period, greatly improves the safety factor of overhaul casing replacement construction, and can effectively avoid accidents in which oil and water wells are scrapped due to failure to retrieve the fish top. Therefore, the application effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of a fish-finding device used in the method for finding fish by opening windows in side walls and reconstructing a passage provided by the present invention. DETAILED DESCRIPTION

[0013] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] like Figure 1 As shown, the method for opening a window on the side wall to find fish and rebuild a passage provided by the present invention comprises the following steps performed in sequence:

[0015] 1) When the casing in the oil and water well is eccentrically cut and the fish is lost, and the fish top needs to be retrieved, the construction personnel first assemble the fish finding assembly, which includes a drill collar 1, an eccentric short circuit 2 and a window milling shoe 3; wherein the drill collar 1, the eccentric short circuit 2 and the window milling shoe 3 are all hollow structures, and the upper end of the drill collar 1 is connected to the drilling rig; the upper and lower ends of the eccentric short circuit 2 are respectively threadedly connected to the lower end of the drill collar 1 and the upper end of the window milling shoe 3;

[0016] The lower end of the window-cutting milling shoe 3 is in an outer trumpet shape, which is more conducive to cutting the twisted casing and quickly collecting fish.

[0017] The maximum eccentricity of the eccentric short circuit 2 can reach 30 degrees. Under the condition that it can be lowered into the wellbore, the maximum eccentricity is met as much as possible to improve the fish finding effect.

[0018] 2) lowering the fish-finding assembly into the oil and water well, and after the lower end of the fish-finding assembly passes through the fish top and encounters resistance, the drilling rig is turned on to make the fish-finding assembly rotate at high speed, and the casing deviating from the center of the wellbore is cut by the lower end of the window milling shoe 3, and the cut casing falls into the well, and the part where the casing is broken after cutting, i.e., the fish top, will be located inside the window milling shoe 3, thereby successfully achieving fish collection;

[0019] 3) Insert the tracer string downward from the upper end of the drill collar 1 until the tracer string passes through the fish top and falls into the casing, retract the fish assembly, and continue to use the casing milling barrel to perform casing milling and casing removal construction.

[0020] In the present invention, the purpose of setting the eccentric short circuit 2 is to expand the fish finding range and facilitate the window milling shoe 3 to cut the casing far away from the center of the wellbore.

[0021] Example:

[0022] Well conditions of an oil and water well: the deepest point of casing deformation is 236m, and the surface casing is 162m. Due to severe casing distortion and a tracer string stuck in the well, internal tracing is impossible. The casing is milled to 167.30m and the footage is slow and there is drill jumping. The casing milling barrel is pulled out to salvage the casing, and it is found that the 16th casing was cut obliquely, resulting in the loss of fish.

[0023] Construction method: Make a lead stamp to confirm that the fish top has deviated from the center line of the casing, and use the side wall window opening method provided by the present invention to find the fish and rebuild the channel, and successfully find the fish top. The technical parameters are set as: pressurization 5-10kN;

[0024] Recommended speed: 30-60 rpm;

[0025] Maximum processing direction: 30° away from the center line;

[0026] Recommended displacement: 400-600L / min.

Claims

1. A method for finding fish and reconstructing a channel by opening windows in a side wall, characterized in that: The method for opening a window on the side wall to find fish and rebuild a passage comprises the following steps performed in sequence: 1) When the casing in the oil and water well is eccentrically cut and the fish is lost, and the fish top needs to be retrieved, the construction personnel first assemble the fish finding component, which includes a drill collar (1), an eccentric short-circuit (2) and a window milling shoe (3); wherein the drill collar (1), the eccentric short-circuit (2) and the window milling shoe (3) are all hollow structures, and the upper end of the drill collar (1) is connected to the drilling rig; the upper and lower ends of the eccentric short-circuit (2) are respectively threadedly connected to the lower end of the drill collar (1) and the upper end of the window milling shoe (3); 2) lowering the fish-finding component into the oil and water well, and after the lower end of the fish-finding component passes through the fish top and encounters resistance, starting the drilling rig to make the fish-finding component rotate at high speed, and using the lower end of the window-opening milling shoe (3) to cut the casing that deviates from the center of the wellbore, the cut casing falls into the well, and the part of the casing where the casing is cut off after cutting, i.e., the fish top, will be located inside the window-opening milling shoe (3), thereby successfully achieving fish collection; 3) Insert the tracer string downward from the upper end of the drill collar (1) until the tracer string passes through the fish top and falls into the casing, retract the fish assembly, and continue to use the casing milling barrel to perform casing milling and casing removal construction.

2. The method for finding fish and reconstructing a channel by opening windows in the side wall according to claim 1, characterized in that: In step 1), the lower end of the window milling shoe (3) is in an outer bell-mouth shape.

3. The method for finding fish and reconstructing a channel by opening windows in the side wall according to claim 1, characterized in that: In step 1), the maximum eccentricity of the eccentric short circuit (2) is 30 degrees.

Images