WO2017193504A1

WO2017193504A1 - Thickened oil horizontal well completion string capable of achieving subsection extraction

Info

Publication number: WO2017193504A1
Application number: PCT/CN2016/097426
Authority: WO
Inventors: 贺昶明
Original assignee: 四川行之智汇知识产权运营有限公司
Priority date: 2016-05-11
Filing date: 2016-09-28
Publication date: 2017-11-16
Also published as: CN105952388A

Abstract

Disclosed is a thickened oil horizontal well completion string capable of achieving subsection extraction. The horizontal well completion string comprises a production sleeve (1). Two primary screen pipes (4) are connected to a horizontal section of the production sleeve (1). An oil drawing pipe (7) is fixed into a vertical section of the production sleeve (1) through a packer (6). The horizontal end of the oil drawing pipe (7) freely extends in the horizontal well section formed by the two primary screen pipes (4) and a sleeve (2). A horizontal section of the oil drawing pipe (7) is provided with a secondary screen pipe (11). A screen hole of the secondary screen pipe (11) comprises a shrinkage section (113), a straight section (112) and an impact section (111). The inner diameter of the shrinkage section (113) is reduced gradually outwards in the radial direction of the secondary screen pipe. The inner diameter of the impact section (111) is reduced gradually outwards in the radial direction of the secondary screen pipe (11). In the horizontal well, two outer-pipe packers (3) enable an open well (9) to be divided into three parts. That is, oil liquid in the horizontal well enters the periphery of the oil drawing pipe (7) through the two primary screen pipes (11). At this moment, the oil liquid entering from the two primary screen pipes (11) is conveyed into the upper portion of the vertical section of the production sleeve (1) through the end of the oil drawing pipe (7) and the secondary screen pipe (11) on the horizontal section of the oil drawing pipe (7) respectively, and then subsection extraction of a horizontal well is achieved. The thickened oil horizontal well completion string capable of achieving subsection extraction can minimize the solid content of the oil liquid entering into the oil drawing pipe, and can ensure oil recovery efficiency of the horizontal well at a later stage in the extraction process.

Description

Heavy oil horizontal well completion string

Technical field

The invention belongs to the technical field of horizontal well production, and particularly relates to a heavy oil horizontal well completion string which can be segmentally mined.

Background technique

Heavy oil is an important part of petroleum hydrocarbon energy, and its characteristics are as follows:

(1) The colloid and bitumen content in heavy oil is high, and the light fraction is small. And with colloid and asphaltenes

The relative density and viscosity of the heavy oil increased accordingly.

(2) The viscosity of heavy oil is particularly sensitive to temperature, and the viscosity drops sharply with increasing temperature. And the greater the viscosity of the crude oil, the more obvious this change.

(3) There are many heteroatoms such as sulfur, oxygen and nitrogen in heavy oil.

(4) The paraffin content in heavy oil is generally low, but there are also very few oil fields that are “double high oil fields”, that is, high asphaltene content and high paraffin content, characterized by high viscosity and high freezing point crude oil.

(5) In the same heavy oil reservoir, the nature of crude oil often varies greatly between wells in different vertical oil layers and wells on the plane.

With the continuous improvement of horizontal well drilling and completion technology, horizontal wells are beneficial to increase single well production, increase recoverable reserves and improve oil recovery. Currently, horizontal well development technology is applied to various types of reservoirs. For homogeneous sandstone or carbonate reservoirs, traditional openhole completions, primary screen completions, and perforation completions can cause problems for horizontal well development. Due to the long production level, affected by the frictional resistance of the wellbore, the production pressure difference of the whole horizontal section is different, the pressure difference between the heel and the end is the largest, and the pressure difference between the toe ends is the smallest, which eventually leads to uneven production of the horizontal section and even appears. The situation that the toe end does not produce liquid greatly affects the development effect of the horizontal well.

Summary of the invention

The invention provides a heavy oil horizontal well completion pipe string which can be segmentally mined, reduces the production pressure difference of the heel end, enlarges the production pressure difference of the toe end, and realizes the relatively uniform output of the horizontal section, thereby realizing the horizontal well section mining.

The invention is implemented by the following technical solutions:

A heavy oil horizontal well completion string that can be mined in sections, including an L-shaped production casing, the horizontal section of the production casing is connected with two primary screens, and the casing is disposed between the two primary screens, An L-shaped oil suction pipe is fixed in the vertical section of the production casing by a packer, and an inner pipe packer is installed in the casing, and the horizontal end of the oil suction pipe is composed of two of the primary sieve pipes and the casing The horizontal well section is freely extended, and the horizontal section of the oil sucking pipe is provided with a secondary screen, the secondary screen is connected to the primary screen of the horizontal section of the production casing, and two are installed outside the casing. An out-of-tube packer, and two of the out-of-tube packers divide the open-eye into three parts; the screen of the second-stage screen includes a narrowed section that is sequentially connected radially outward along the secondary screen, and straight The segment and the impact segment, the inner diameter of the reduced section decreases radially outward along the secondary screen, and the inner diameter of the impact section decreases radially outward along the secondary screen.

In the prior art, in the thermal recovery process of heavy oil, the longer the horizontal section of the horizontal well, the greater the frictional resistance along the horizontal toe end, and finally the uneven production of the horizontal section, that is, the heel end of the horizontal section and The production pressure difference of the toe end is different, which seriously affects the oil recovery efficiency of the horizontal well. To solve this problem, the present invention divides the naked eye into three parts in the horizontal well through two outer packers, that is, the oil in the horizontal well respectively The two primary screens enter the pumping pipe; at this time, the oil entering from the two primary screens is transported to the upper part of the vertical section of the production casing through the end of the pumping pipe and the secondary screen on the horizontal section of the pumping pipe. In the middle, the section mining of the horizontal well is completed. The invention utilizes sectional mining to reduce the frictional resistance of the liquid produced at the toe end of the horizontal well, enlarge the production pressure difference of the toe end, increase the frictional resistance of the horizontal well and the production fluid, and reduce the production pressure of the heel end. Poor, the horizontal production of the liquid is relatively evenly produced, effectively solving the uneven production of the horizontal section caused by the conventional horizontal well completion method, and even the toe end The problem of non-liquid production is to achieve balanced production of horizontal sections and improve the development of horizontal wells. And the oil in the open hole near the end of the production casing passes through the primary screen and the secondary screen to filter, so that the solid phase content of the oil finally entering the pumping pipe is minimized, and the horizontal completion is washed in the later stage of oil recovery. During well operation, the washing fluid is injected into the production casing, and the oil suction pipe, the primary sieve pipe and the secondary sieve pipe are cleaned by the washing fluid to ensure the oil recovery efficiency of the horizontal completion in the later mining process;

Wherein, when the washing fluid enters the oil sucking pipe from the production casing, the resistance of the washing fluid in the oil sucking pipe is relatively large due to the large pressure of the oil layer, and the washing is performed for the two primary screens. The well fluid is injected into the primary screen near the side of the production casing by the secondary screen on the horizontal section of the pumping pipe. At this time, the washing fluid is sprayed out of the primary screen directly opposite the secondary screen to realize the dredging. The effect of the mesh hole on the primary screen is difficult to achieve. Therefore, the inventors have improved the screen hole of the secondary screen, that is, the screen hole of the secondary screen includes a narrow section, a straight section and an impact section which are sequentially connected. The inner diameter of the narrowing section and the impact section are all decreased along the radial direction of the secondary screen, while the inner diameter of the straight section remains unchanged. When the washing fluid overflows from the oil suction pipe, the washing fluid passes through the circulation. After the cross section suddenly becomes smaller, the flow velocity will increase continuously, and the acceleration will be accelerated again in the impact section by the gentle transition in the straight section. At the same time, the pressure in the horizontal well in the horizontal well is relatively normal to the ordinary sieve. The hole is low, that is, it overflows from the impact section. The well fluid begins to flush the primary screen while maintaining its high speed state, while the solid phase particles that are blocked on the secondary screen and the primary screen are washed away by the washing fluid with strong impact force, so that the secondary screen and The primary screen maintains the smoothness of its mesh openings.

The lengths of the reduced section, the straight section, and the impact section in the radial direction of the secondary screen are sequentially increased. The length of the narrowing section, the straight section and the impact section in the radial direction of the secondary screen is directly related to the jetting speed of the washing fluid on the secondary screen, that is, the speed of the washing fluid in the sieve hole is accelerated, and the primary sieve is The impact force of the tube is larger, and the length of the narrow section, the straight section and the impact section in the present invention increases along the radial direction of the secondary screen, so that the acceleration time of the washing fluid in the sieve hole The extension ensures that the impulse of the well washing liquid can completely remove the solid phase particles on the primary screen and the secondary screen to ensure stable output of the produced liquid in the later stage of horizontal completion.

Also included is a lost hand that is connected to the upper end of the packer by a thread. After the hand is connected to the packer, it can be directly connected with the pumping string in the technical casing. At the same time, the packer separates the vertical part of the first section of the oil pipe into upper and lower parts, and the oil hole is opened in the lower part. The hand is located at the upper part, so that the product fluid flowing in the first stage of the primary screen is directly mixed with the liquid phase flowing in from the second section of the oil pipe after flowing into the oil hole, and is concentrated in the hand and is taken out of the well. outer.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The oil in the open hole near the end of the production sleeve of the invention is filtered through the primary screen and the secondary screen, so that the solid phase content of the oil finally entering the pumping pipe is minimized, and the horizontal completion is performed in the late stage of oil recovery. During the well washing operation, the washing fluid is injected into the production casing, and the oil suction pipe, the primary sieve pipe and the secondary sieve pipe are cleaned by the washing fluid to ensure the oil recovery efficiency of the horizontal completion in the later mining process.

DRAWINGS

The drawings are intended to provide a further understanding of the embodiments of the present invention, and are not intended to limit the embodiments of the invention. In the drawing:

Figure 1 is a schematic structural view of the present invention;

Figure 2 is a schematic view showing the structure of the secondary screen.

Marked in the drawing and the corresponding part name:

1-production casing, 2-casing, 3-tube outer packer, 4-primary screen, 5-handle, 6-packer, 7-oil pipe, 8-in-tube packer, 9- Open-hole, 10-technical casing, 11-secondary screen, 111-impact section, 112-straight section, 113-reduced section, A-heel end, B-toe end.

detailed description

The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. As a limitation of the invention.

Example 1

As shown in Figures 1 to 2, the present embodiment comprises an L-shaped production casing 2, the horizontal section of which is connected to two primary screens, and the casing 2 is arranged between the two primary screens. An L-shaped oil suction pipe 7 is fixed in the vertical section of the production casing 2 by a packer 6, and an inner pipe packer 8 is installed in the casing 2, and the horizontal end of the oil suction pipe 7 is two The horizontal screen formed by the primary screen and the casing 2 is freely extended, and the horizontal section of the oil suction pipe 7 is provided with a secondary screen 11 which is opposite to the horizontal section of the production casing 2 Connected primary screen, two outboard packers 3 are mounted outside the casing 2, and the two outboard packers 3 divide the open eye 9 into three parts; the screen of the secondary screen 11 The hole includes a narrowing section 113, a straight section 112 and an impact section 111 which are sequentially connected radially outward along the secondary screen 11, and the inner diameter of the reducing section 113 decreases radially outward along the secondary screen 11, the impact section The inner diameter of 111 decreases radially outward along the secondary screen 11.

In the prior art, in the thermal recovery process of heavy oil, the longer the horizontal section of the horizontal well, the greater the frictional resistance along the horizontal end of the toe end B of the horizontal well, and finally the uneven production of the horizontal section, that is, the horizontal section The production pressure difference between the end A and the toe end B is different, which seriously affects the oil recovery efficiency of the horizontal well. To solve this problem, the present invention divides the naked eye 9 into three parts in the horizontal well through the two outer tube packers 3, namely The oil in the horizontal well enters the pumping pipe 7 through two primary screens respectively; at this time, the oil entering from the two primary screens passes through the end of the oil suction pipe 7 and the secondary screen 11 on the horizontal section of the oil suction pipe 7, respectively. It is conveyed to the upper part of the vertical section of the production casing 2 to complete the section mining of the horizontal well. The invention utilizes the sectional mining to reduce the frictional resistance of the liquid produced at the toe end of the horizontal well, enlarges the production pressure difference of the toe end B, and increases the frictional resistance of the horizontal well A and the liquid A, and reduces the friction. Production pressure difference with the end A, real Now the production of liquid in the horizontal section is relatively evenly produced, which effectively solves the problem of uneven production of liquid in the horizontal section caused by the completion of the conventional horizontal well completion method, and even the problem of non-liquid production at the toe end B, achieving balanced production of liquid in the horizontal section and increasing water. The development effect of Pingjing. And the oil in the open hole 9 near the end of the production casing 2 is filtered through the primary screen and the secondary screen 11, so that the solid phase content of the oil finally entering the suction pipe 7 is minimized, and at the later stage of the oil recovery. When the completion is used for the well washing operation, the washing fluid is injected into the production casing 2, and the oil sucking pipe 7, the primary screen and the secondary screen 11 are cleaned by the washing fluid to ensure the horizontal completion in the later mining process. Oil recovery efficiency;

Wherein, when the washing fluid enters the oil suction pipe 7 from the production casing 2, the resistance of the washing fluid in the oil suction pipe 7 is relatively large due to the large pressure of the oil layer, and the two primary screens are correspondingly Said that the washing fluid is injected into the primary screen near the side of the production casing 2 by the secondary screen on the horizontal section of the oil suction pipe 7, at which time the washing fluid is directed to the primary screen directly opposite the secondary screen. The effect of ejecting to achieve the unblocking of the mesh holes in the primary screen is difficult to achieve. Therefore, the inventors have improved the screen openings of the secondary screen 11, that is, the screen holes of the secondary screen 11 include the narrowing sections 113 which are sequentially connected. The straight section 112 and the impact section 111, while the inner diameter of the narrow section 113 and the impact section 111 are all decreased outward in the radial direction of the secondary screen 11, while the inner diameter of the straight section 112 remains unchanged when the well is washed When overflowing from the oil suction pipe 7, the flow rate of the washing fluid will increase continuously after passing through the flow cross section, and the acceleration in the impact section 111 is again accelerated by the gentle transition in the straight section 112, and At the same time, the pressure in the horizontal well is equivalent to the pressure in the secondary screen 11 compared to the ordinary sieve. That is, the washing fluid finally overflowing from the impact section 111 starts to wash the primary screen while maintaining its high speed state, and the solid phase particles blocked on the secondary screen 11 and the primary screen are strongly impacted. The well washing liquid is washed away, so that the secondary screen 11 and the primary screen maintain the smoothness of the mesh.

Preferably, in the narrowing section 113, the straight section 112 and the impact section 111 are in two The length of the stage screen 11 in the radial direction is sequentially increased. The length of the narrowing section 113, the straight section 112 and the impact section 111 in the radial direction of the secondary screen 11 is directly related to the jetting speed of the washing fluid on the secondary screen 11, that is, the speed of the washing fluid in the screen is accelerated. More, the impact on the primary screen is greater, and in the present invention, the length of the narrow section 113, the straight section 112 and the impact section 111 increases along the radial direction of the secondary screen 11, so that the washing fluid is sieved. The acceleration time in the hole is prolonged, and the impulse at the time of the injection of the washing liquid can completely remove the solid phase particles on the primary screen and the secondary screen 11, thereby ensuring the stable output of the production liquid in the later stage of horizontal completion.

This embodiment further includes a lost hand 5, which is connected to the upper end of the packer 6 by a thread. After the lost hand 5 is connected with the packer 6, it can directly interface with the sucker 7 column in the technical casing 10, and the packer 6 blocks the vertical portion of the first section of the oil pipe into upper and lower parts. The oil hole is opened at the lower part, and the hand 5 is located at the upper portion, so that the product liquid flowing in the first stage primary sieve tube is directly mixed with the liquid phase flowing in from the second stage oil pipe after being flowed into the oil hole, and concentrated in After losing the hand 5, he was taken out of the well.

The specific embodiments of the present invention have been described in detail with reference to the preferred embodiments of the present invention. All modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

A heavy oil horizontal well completion string that can be mined in sections, comprising an L-shaped production casing (1), characterized in that: the horizontal section of the production casing (1) is connected with two primary screens (4), The sleeve (2) is disposed between the two primary screens (4), and an L-shaped oil suction pipe (7) is fixed in the vertical section of the production casing (1) by a packer (6). An in-tube packer (8) is installed in the casing (2), and the horizontal end of the oil sucking pipe (7) is freely extended in the horizontal section formed by the two primary screens (4) and the casing (2) a horizontal screen (11) is provided on the horizontal section of the oil suction pipe (7), and the secondary screen (11) of the secondary screen (11) is connected to the horizontal section of the production casing (1) Two out-of-tube packers (3) are installed outside the casing (2), and the two outer-out packers (3) divide the open-eye (9) into three parts; the secondary screen The sieve hole of (11) includes a reduced section (113), a straight section (112) and an impact section (111) which are sequentially connected radially outward along the secondary screen (11), and the inner diameter of the reduced section (113) The secondary screen (11) is radially outwardly decreasing, and the inner diameter of the impact section (111) decreases radially outward along the secondary screen (11).
The method of claim 1, wherein the reduced section (113), the straight section (112), and the impact section (111) are in a secondary screen ( 11) The length in the radial direction is sequentially increased.
The segmentable-harvestable heavy oil horizontal well completion string according to claim 1, further comprising: a lost hand (5), the lost hand (5) passing through the upper end of the thread and the packer (6) connection.