Horizontal well cementation sand prevention structure
By setting roughened surfaces and guide grooves on the casing, along with leakage gaps, the problem of uneven cement filling in horizontal wells was solved, achieving uniform cement slurry filling, reducing the risk of cavity formation, and improving formation isolation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-10
- Publication Date
- 2026-04-07
AI Technical Summary
In horizontal wells, uneven filling of cement in the annulus between the casing and the wellbore can lead to the formation of cavities, which can affect the formation sealing effect.
A roughened surface and a guide groove are set on the casing, along with a grout leakage notch, to guide the cement grout to fill evenly and reduce the formation of cavities.
It improves the uniformity of cement grout filling, reduces cavity area, and lowers the risk of formation sealing failure.
Smart Images
Figure CN224093381U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of oil exploitation, and more particularly to a horizontal well cementing sand control structure. BACKGROUND
[0002] After drilling, in order to isolate complex formations (such as water layer, low pressure layer), control sand and water channeling, a commonly used completion method is casing perforation completion, which is to lower casing into the oil well, then inject cement into the annulus between the casing and the well wall, and after the cement solidifies, a stable barrier is formed in the oil well, and finally a perforating gun is used to perforate the casing and the cement ring to form an oil and gas passage; to prevent sand plugging, a sand control screen can be installed in the perforated section, and gravel can be filled between the sand control screen and the perforated section wall to double-filter sand and gravel.
[0003] However, in a horizontal well, due to the horizontal placement of the casing, when cement is injected into the annulus between the casing and the well wall, the cement is easily unevenly filled under the action of gravity, specifically, the upper cement slurry flows fast but is not easy to hang the cement, and the lower cement slurry is easy to form a gap due to retention, when the cavity is relatively large, it will lead to failure of formation isolation and interlayer fluid channeling.
[0004] In order to solve the above problems, people have been seeking an ideal technical solution. SUMMARY
[0005] The utility model discloses to the deficiency of prior art, and a horizontal well cementing sand control structure is provided, which is more easy to fill evenly when pouring cement and is not easy to form a large cavity.
[0006] In order to achieve the above object, the utility model adopts the technical scheme of a horizontal well cementing sand control structure, which comprises an oil well and a casing arranged in the horizontal direction, the casing is sleeved in the oil well, the annulus between the oil well and the casing is filled with a cement ring, the upper surface of the casing is provided with a rough surface, and the lower surface and both sides of the casing are provided with smooth surfaces.
[0007] Beneficial effects: the upper surface of the casing is provided with a rough surface, which can increase the flow resistance of the upper cement slurry, reduce the filling speed difference between the upper and lower cement slurries, reduce the gap formed by the retention of the lower cement slurry, and more easily hang the cement, thereby more easily filling evenly when pouring in the horizontal well.
[0008] Based on the above, three axially extending grooves are formed on the rough surface, one of which is located at the top end of the rough surface, and the remaining two are symmetrically arranged on both sides.
[0009] Beneficial effects: the three grooves have the effect of guiding the upper cement slurry to flow in the axial direction, reducing the tendency of accumulation to the bottom, so that the cement slurry filling can be more uniform.
[0010] Based on the above, the slurry leakage gap is arranged above the tail pipe of the casing, and the flow guide chute is arranged at the bottom of the inner wall of the tail pipe of the casing.
[0011] Beneficial effects: the slurry leakage gap and the flow guide chute cooperate with each other to guide the cement slurry to overflow towards the obliquely upper part of the tail pipe, so that at the slurry inlet position, more cement slurry flows into the upper part and less cement slurry flows into the lower part, and the upper cement slurry continuously collects to the lower part during the running process; thus, the lower cement flows faster and is less likely to be retained, and the upper cement is more likely to hang on the upper surface of the casing and is less likely to form a larger cavity.
[0012] Based on the above, it further comprises a plurality of sand control screens, a plurality of perforated sections are arranged on the casing, and the sand control screens are installed in each perforated section one by one, and the annulus between the sand control screens and the perforated sections is filled with gravel.
[0013] Beneficial effects: the sand control screen and the gravel form a double-layer filtering structure, which facilitates filtering of the sand-producing oil layer. BRIEF DESCRIPTION OF DRAWINGS
[0014] Fig. 1 is a structural schematic view of the horizontal well cementing sand control structure in the utility model.
[0015] Fig. 2 is a top view of the casing in the utility model.
[0016] Fig. 3 is a longitudinal sectional view of the tail pipe of the casing in the utility model.
[0017] In the figure: 1. oil well; 2. casing; 3. sand control screen; 4. cement sheath; 5. roughened surface; 6. gravel; 7. groove; 8. slurry leakage gap; 9. flow guide chute; 21. perforated section. DETAILED DESCRIPTION
[0018] The technical scheme of the utility model will be described in further detail below through specific embodiments.
[0019] For example, Figs. 1-3As shown, a horizontal well cementing sand control structure comprises an oil well 1, a casing 2 and a plurality of sand control screens 3 arranged horizontally, the casing 2 is sleeved in the oil well 1, a cement sheath 4 is filled in the annulus between the oil well 1 and the casing 2, the upper surface of the casing 2 is provided with a rough surface 5, and the lower surface and both sides of the casing 2 are provided with smooth surfaces; a plurality of perforated sections 21 are arranged on the casing 2, and the sand control screens 3 are correspondingly arranged in each perforated section 21, and a gravel 6 is filled in the annulus between the sand control screens 3 and the perforated sections 21, so that the sand control screens 3 and the gravel 6 form a double-layer filtering structure, facilitating the filtration of the sand-producing oil layer.
[0020] Three axial grooves 7 are arranged on the rough surface 5, one groove 7 is arranged at the top end of the rough surface 5, and the remaining two grooves 7 are symmetrically arranged on both sides; a slurry leakage gap 8 is arranged above the tail pipe of the casing 2, and a flow guide chute 9 is arranged on the inner wall of the bottom of the tail pipe of the casing 2, and the flow guide chute 9 is inclined upward toward the tail pipe.
[0021] Working principle:
[0022] When the cement slurry is input from the tail pipe, the slurry leakage gap 8 and the flow guide chute 9 can guide the cement slurry to overflow obliquely upward from the tail pipe, at the slurry input position, more cement slurry flows into the upper part and less cement slurry flows into the lower part, and the upper part of the cement slurry continuously converges to the lower part during the running process, so that the lower part of the cement flows faster and is less likely to be retained, and the upper part of the cement is more and is more likely to fill the upper surface of the casing 2; the rough surface 5 can increase the flow resistance of the upper part of the cement slurry, reduce the flow rate difference between the upper and lower parts of the cement slurry, and reduce the voids formed by the retention of the lower part of the cement slurry, and on the other hand, the rough surface 5 is more likely to retain the cement; the three grooves 7 have the effect of guiding the upper part of the cement slurry to flow axially, reducing the tendency to accumulate at the bottom; thus, when the cement sheath 5 is poured in the horizontal well, the cement slurry is more likely to be uniformly filled and is less likely to form a larger cavity; through the test of the ultrasonic imaging logging instrument, the cavity area of the cement slurry structure used by the applicant can be reduced by 60%-80% compared with the traditional cement slurry structure, greatly reducing the risk of formation sealing failure.
[0023] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent substitutes; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application.
Claims
1. A horizontal well cementing and sand control structure, characterized in that: It includes an oil well and a casing arranged in a horizontal direction. The casing is fitted inside the oil well. The annulus between the oil well and the casing is filled with a cement ring. The upper surface of the casing is provided with a roughened surface, and the lower surface and both sides of the casing are provided with smooth surfaces.
2. The horizontal well cementing and sand control structure according to claim 1, characterized in that: The roughened surface has three grooves extending along the axial direction, one of which is located at the top of the roughened surface, and the remaining two grooves are symmetrically arranged on both sides.
3. The horizontal well cementing and sand control structure according to claim 2, characterized in that: The sleeve has a grout leakage notch above the tail end of the sleeve, and a guide groove is provided at the bottom of the inner wall of the tail end of the sleeve. The guide groove is inclined upward towards the tail end of the sleeve.
4. The horizontal well cementing and sand control structure according to any one of claims 1-3, characterized in that: It also includes several sand screens, each with several perforated sections. The sand screens are installed in each of the perforated sections in a corresponding manner, and the annulus between the sand screen and the perforated section is filled with gravel.