WO2011069340A1

WO2011069340A1 - Oil-gas well structure for facilitating extracting downhole filter string and method for extracting string

Info

Publication number: WO2011069340A1
Application number: PCT/CN2010/002015
Authority: WO
Inventors: 裴柏林; 房娜
Original assignee: 安东石油技术（集团）有限公司
Priority date: 2009-12-11
Filing date: 2010-12-10
Publication date: 2011-06-16
Also published as: NO346845B1; CN101701517B; CA2783392A1; GB2489161B; NO20120798A1; GB201211951D0; CN101701517A; US20120279716A1; GB2489161A

Abstract

An oil-gas well structure for facilitating extracting a downhole filter string and a method for extracting the downhole filter string from the oil-gas well are provided. The oil-gas well structure includes a borehole wall (1) of the oil-gas well and a downhole filter string (2) lowered into the oil-gas well. The end of the downhole filter string (2) close to the wellhead is fixedly connected with the borehole wall (1). An annulus is formed between the downhole filter string (2) and the borehole wall (1), and the annulus is filled with ultra light particles, wherein, the density of ultra light particles approaches to or is equal to the density of the carrier fluid which carries the ultra light particles. The method for extracting the downhole filter string includes the following steps: 1) establishing channels; 2) injecting the carrier fluid for ultra light particles so as to remove the ultra light particles from the annulus completely; 3) extracting the downhole filter string. The structure can conveniently extract the downhole filter string from the oil-gas well, thus facilitating the replacement and maintenance of the downhole filter string and the parameter regulation of the flow-control filter.

Description

Easy to pull out the downhole filter string

Oil and gas well structure and pipe column extraction method

Field of the Invention This invention relates to the field of petroleum extraction and, in particular, to an oil and gas well structure that facilitates the extraction of a downhole filter string and a method of extracting a downhole filter string from the oil and gas well. Oil and gas wells here refer to generalized production wells in oil and gas field development, including oil wells, gas wells, natural gas wells, injection wells, etc. Background technique

The completion structures of most mechanical sand control wells include oil and gas wells and downhole filter columns in oil and gas wells. Vertical and horizontal wells, inclined wells, high-angle wells and horizontal wells. As shown in Fig. 1, reference numeral 1 in Fig. 1 indicates a well wall, reference numeral 2 indicates a downhole filter string, and reference numeral 3 indicates an annulus between the downhole filter string and the well wall, attached Figure 4 indicates the packer that suspends the downhole filter string. The downhole filter column here is a generalized downhole filter column, which can be used in various forms, such as: The first case is a non-throttle function downhole filter column, and then the throttling function downhole filter tube The column is just a sand control filter, also known as a sand control tube. The second type is a filter with a flow control function, that is, a flow control filter column, also called a flow control screen. The flow control filter has a flow control function and has a filtering function. The filtering function sometimes prevents the turbulent flow of the granulating medium outside the flow control filter from entering the wellbore, and also prevents the formation sand from entering the wellbore. . The flow control function of the flow control filter also has a throttling function.

A downhole filter string is one that has one or more downhole filters connected in series. For example, if a sand pipe with a total length of 300 meters is placed in a horizontal well, 30 sand pipes of about 10 meters are connected in series.

In the oil and gas wells that flow into the downhole filter column, the downhole filter column is stored outside In either case, one case is that the downhole filter column is artificially filled with gravel, the gravel includes quartz sand or ceramsite; the other case is that there is no filler outside the downhole filter column, if the downhole filter column There is no filling outside. After the production of the sand well for a period of time, the produced formation sand will also fill the annulus between the filter column and the wall of the well. As shown in Figure 1, Figure 5 shows the filtration under the well. Formation sand or artificially filled gravel accumulated outside the column. Whether it is naturally filled formation sand or artificially filled gravel, it will cause great resistance to the downhole filter string, making the downhole filter string in the oil and gas well difficult to remove, especially the well of the downhole filter column. For high-angle wells and horizontal wells, it is almost impossible to pull out the downhole filter string.

However, in many cases it is necessary to pull out the downhole filter string, as in the following cases:

1. Need to repair the damaged downhole filter string or replace the downhole filter column;

2. The extracted downhole filter string needs to be reused to save a lot of expenses;

3. When using the flow control filter column, in the production process, pull out the flow control filter column, you can easily adjust the flow control parameters of the flow control filter column to adapt to the flow requirements of different development stages, improve Oil and gas well production efficiency.

There is currently no oil and gas well structure that facilitates the removal of the downhole filter string and a particularly effective method of extracting the downhole filter string from the oil and gas well. Summary of the invention

The technical problem to be solved by the present invention is to provide an oil and gas well structure that facilitates the extraction of the downhole filter string and a method of extracting the downhole filter string from the oil and gas well.

In order to solve the above problems, the present invention adopts the following technical solutions:

The present invention relates to an oil and gas well structure for facilitating the extraction of a downhole filter string, comprising a wellbore wall and a downhole filter string inserted into the oil and gas well, the downhole filter The end of the pipe string near the wellhead is the upper end of the filter pipe string, the upper end of the filter pipe string is fixedly connected with the well wall, and an annular space is formed between the downhole filter pipe string and the well wall; the downhole filter pipe string and The annulus between the well walls is filled with ultra-light particles, wherein the ultra-light particles have a density close to or equal to the density of the ultra-light particle carrying liquid, and the ultra-light particle carrying liquid is used for carrying the ultra-light particles. The liquid in the annulus or backflushed from the ultra-light particles carries out the liquid of the annulus.

The density difference between the ultralight particles and the ultralight particle carrier fluid ranges from -0.35 to +0.35, inclusive.

Preferably, the density difference between the ultra-light particles and the ultra-light particle carrying liquid ranges from -0.3 to +0.3, inclusive.

The ultra-light particles are particles having an average particle diameter of 0.05 to 1.2 mm and a true density of 0.7 to 1.3 g/cm ³ .

Preferably, the ultra-light particles are particles having an average particle diameter of 0.05 to 0.8 mm and a true density of 0.94 to 1.08 g/cm ³ .

Preferably, the ultra-light particles are high molecular polymer particles.

Preferably, the ultra-light particles are high-density polyethylene particles having an average particle diameter of 0.05 to 0.8 mm and a true density of 0.90 to 0.98 g/cm ³ .

Alternatively, the ultra-light particles are polypropylene and polyvinyl chloride polymer particles having an average particle diameter of 0.05 to 0.8 mm and a true density of 0.7 to 1.3 g/cm ³ .

Alternatively, the ultra-light particles are styrene and divinylbenzene crosslinked copolymer particles having an average particle diameter of 0.05 to 0.8 mm and a true density of 0.94 to 1.08 g/cm ³ .

The invention also discloses a method for proposing a downhole filter string from the oil and gas well structure for facilitating the extraction of a downhole filter string, the method comprising the steps of:

1) Establish a channel: open the annulus between the upper end of the downhole filter string and the well wall;

2), recoiling the carrying liquid to empty the ultra-light particles: injecting an ultra-light particle carrying liquid into the downhole filter column for carrying back the ultra-light particles from the annulus; 3) Pull out the downhole filter string.

When the downhole filter column is a flow control filter column, the step of emptying the ultra-light particles by the recoil carrier liquid is connected by using a liquid injection pipe and a downhole filter pipe column, directly injecting into the control flow filter column Light particle carrying liquid, due to the flow control function of the flow control filter column, the injection liquid is injected into the ultralight particles from the control flow pipe column, and the underground fluid is filtered through the upper filter pipe column. The ultra-light particles accumulated outside the column are emptied.

When the downhole filter column is a flow control filter column, the step of emptying the ultra-light particles by the recoil carrier liquid is to insert the liquid injection pipe into the downhole filter pipe column, and the liquid injection pipe is used for injecting the liquid; The lower part of the injection pipe has an opening, and the upper part of the opening of the injection pipe is provided with a sealing ring, the outer diameter of the sealing ring is substantially the same as the inner diameter of the downhole filter column, and the liquid injection method is a segmented injection: the liquid injection pipe Stepping from the top of the downhole filter string to the bottom of the downhole filter column for segmented injection, segmenting the ultra-light particles outside the downhole filter column, outside the previous section of the downhole filter column near the wellhead After the ultra-light particles are emptied, the injection tube is further inserted into the downhole filter column for a period of time until the downhole filter tube column is completely emptied; or the injection tube can be continuously moved to inject the liquid until the well filter column is emptied outside the column. Ultra-light particles.

When the downhole filter column is a non-throttled downhole filter column, the step of flushing the ultra-light particles by the recoil carrier liquid is to insert the injection pipe into the downhole filter column, and the injection pipe is used for injection. The liquid injection pipe has an opening at a lower portion thereof, and a sealing ring is disposed at an upper portion of the opening of the liquid injection pipe, and an outer diameter of the sealing ring is substantially the same as an inner diameter of the downhole filter pipe string, and the liquid injection method is a segment injection: The injection pipe is gradually advanced from the top of the downhole filter pipe string to the bottom of the downhole filter pipe column for segmental injection, and the ultra-light particles outside the downhole filter pipe column are segmented and emptied, and the former section of the downhole filter near the wellhead is used. After the ultra-light particles outside the column are emptied, the injection tube is further inserted into the downhole filter column for a period of time until the downhole filter column is completely emptied. The injection tube can be moved by continuously moving the injection tube until the empty filter column is emptied. Light particles.

Preferably, the ultralight particle carrier liquid of the present invention is water or an aqueous solution.

The invention utilizes ultra-light particle carrying liquid with a density of about 1 g/cm ^{3 to} select ultra-light particles with a real density and a density of the carrying liquid very close, so that the carrier liquid can easily carry ultra-light particles to the downhole filter. The annulus between the string and the borehole wall fills and fills the annulus between the downhole filter string and the borehole wall, a portion of the carrier fluid enters the downhole filter string and returns to the ground, and a portion of the carrier fluid passes through the borehole wall. Infiltrating into the formation; eventually forming a completion structure filled with ultra-light particles in the annulus between the downhole filter string and the wellbore.

At the same time, the ultra-light particles occupy the annulus between the downhole filter string and the borehole wall, and also block the accumulation of formation sand within the annulus between the downhole filter string and the borehole wall.

The invention selects particles with an average particle diameter of 0.05-1.2 mm and a true density of 0.7-l, 3 g/cm ³ as ultra-light particles filled in the annulus between the downhole filter column and the well wall, when it is necessary to propose a downhole When the filter string is used, the ultra-light particles accumulated outside the downhole filter column can be easily emptied. Since the density of the ultra-light particles and the density of the carrier liquid are very close, the carrier liquid of the low-speed cycle can be easily ultra-light. The particles are brought to the surface to empty the annulus outside the downhole filter column, so that the downhole filter column can be easily extracted from the well. Meet the requirements for proposing a downhole filter string.

The method of the invention is simple and feasible, overcomes the difficulty in extracting the downhole filter column in the oil well, facilitates the production, and the cleaned ultra-light particles can be reused, thereby greatly reducing the production cost. DRAWINGS

Figure 1 is a schematic view of the completion structure of the background art.

2 is a schematic view of a completion structure according to Embodiment 1 of the present invention.

3 is an ultra-light outside the column of the recoil empty filter according to Embodiment 2 of the present invention; Schematic diagram of the flow path of the particles carrying the particles.

Fig. 4 is a schematic view showing the flow path of the ultra-light particles carrying the ultra-light particles outside the column of the backflushing filter according to the third embodiment of the present invention.

Fig. 5 is a schematic view showing the flow path of the ultra-light particles carrying the ultra-light particles outside the column of the backflushing filter according to the fourth embodiment of the present invention.

FIG. 6 is a schematic view showing the structure of an oil and gas well after emptying ultra-light particles according to the present invention. detailed description

Example 1

As shown in FIG. 2, the present invention provides an oil and gas well structure for facilitating the extraction of a downhole filter string, including an oil and gas well wall 1 and a downhole filter string 2 that is lowered into the oil and gas well, the downhole filter string A packer 4 for suspending the downhole filter string is disposed between one end of the wellhead and the well wall, and an annular space is formed between the downhole filter string and the well wall; between the downhole filter string and the well wall The annulus is filled with ultra-light particles 6.

Embodiment 1 Controlled flow filter column extraction method

As shown in FIG. 2, the completion structure according to Embodiment 1, wherein the ultra-light particles are polypropylene and polyvinyl chloride having an average particle diameter of 0.05-0.8 mm and a true density of 0.7-1.3 g/cm ³ . High molecular polymer particles.

As shown in FIG. 3, the downhole filter column is a flow control filter column 2, and the downhole filter column is provided with a flow control filter 2-1; the method for lifting the downhole filter column is as follows:

1) Open the packer that suspends the downhole filter string. For packers that can be unpacked, the open method is to lift the packer and the packer automatically unblocks. For a rotatable decapsulator, rotate the packer and the packer automatically unseals. After the decapsulation, there is a gap between the packer and the well wall, and the gap becomes a fluid circulation passage.

2), the recoil carrying liquid empties the ultra-light particles: the injection pipe column is connected with the downhole filter pipe column to directly inject the carrier liquid into the control flow filter column, because the flow control filter tube The flow control of the column, the carrier liquid is uniformly injected into the ultra-light particles from the various sections of the downhole filter column through the flow control filter; the direction of the arrow in Figure 3 is the method of carrying liquid flow.

3), empty: The ultra-light particles are carried out of the well by the carrying liquid until the ultra-light particles accumulated outside the downhole filter column are emptied; the structure of the oil and gas well after emptying is shown in Fig. 6.

4) Pull out the downhole filter string.

Embodiment 3 Controlled flow filter column extraction method

As shown in FIG. 2, the completion structure according to Embodiment 1, wherein the ultra-light particles are styrene and divinylbenzene having an average particle diameter of 0.05-0.8 mm and a true density of 0.94-1.08 g/cm ³ . Crosslinking copolymer particles.

As shown in FIG. 4, the downhole filter column is a flow control filter column 2, and the downhole filter column is provided with a flow control filter 2-1; the downhole filter column is lifted by:

1) Open the packer that suspends the downhole filter string. For packers that can be unpacked, the open method is to lift the packer and the packer automatically unblocks. For a rotatable decapsulator, rotate the packer and the packer automatically unseals. There is a gap between the packer and the well wall after unsealing, and the gap becomes a fluid circulation passage.

2), the recoil carrier liquid empties the ultra-light particles: the liquid injection pipe 7 is inserted into the downhole filter pipe string, and the liquid injection pipe is used for injecting liquid; the liquid injection pipe has an opening at the bottom, and a sealing seal is arranged at the upper part of the opening. 8. The outer diameter of the sealing ring is substantially the same as the inner diameter of the downhole filter string. The liquid injection method is a segmented injection: the injection pipe is gradually advanced from the top of the downhole filter pipe column to the bottom of the downhole filter pipe column. The segmented liquid injection and the partial emptying of the ultra-light particles outside the downhole filter column. Due to the action of the sealing ring, the sealing ring can inject the liquid carrying the injection pipe into the downhole filter column to block the lower side of the sealing ring. The concentrated carrier liquid impacts the deposition of ultra-light particles. When the ultra-light particles outside the upper filter column near the wellhead are emptied, the injection pipe is further inserted into the downhole filter column to the next section until underground. The ultra-light particles outside the filter column are completely emptied; this also avoids the carrier liquid from acting on the ultra-light particles that initiate the deposition, A large amount of carrier liquid. The direction of the arrow in Figure 4 is the flow direction of the carrier fluid. The dashed line in Figure 4 indicates that the injection tube is progressively deep into the sub-filter column for in-situ injection. The manner in which the injection pipe penetrates the downhole filter column can be a continuous hook-and-height approach. The continuously injecting tube is continuously injected, and the ultra-light particles are emptied and the depth is continuously increased until the ultra-light particles outside the downhole filter column are completely emptied. The direction of the arrow in Figure 4 is the method of carrying liquid flow

4) Pull out the downhole filter string.

Example 4 Method for extracting downhole filter column without throttling function

2, as completion of the structure of embodiment 1, wherein the lightweight particles having an average particle size of 0.1-0.5 mm, a true density of 0.94g / cm ³ High-density polyethylene particles.

As shown in FIG. 5, the downhole filter column is a non-throttled downhole filter column 2, and the method for lifting the downhole filter column is as follows:

1), opening a downhole filter column near the annulus between the end of the wellhead and the well wall, establishing a fluid circulation channel at an upper portion of the annulus between the end of the downhole filter column near the wellhead and the well wall; The unpacked packer is opened by a packer and the packer is automatically unsealed. For a rotatably decapsulated packer, the packer is rotated and the packer is automatically unsealed. After the decapsulation, there is a gap between the packer and the well wall, and the gap becomes a fluid circulation passage.

2), the recoil carrying liquid empties the ultra-light particles: the liquid injection pipe 7 is inserted into the downhole filter pipe string, and the liquid injection pipe is used for injecting liquid; the top of the liquid injection pipe is provided with a sealing ring 8, the sealing ring The outer diameter of the outer diameter of the downhole filter column is basically the same. The sealing ring of the injection pipe is slightly lower at the outlet port 9 of the injection pipe. The injection method is a segmented injection: the injection pipe is made of a downhole filter. The top of the pipe string is gradually drilled deep into the bottom of the downhole filter pipe column for segmented injection, and the ultra-light particles outside the downhole filter pipe column are emptied by the segment. The function of the sealing ring, the sealing ring can inject the liquid carrying pipe into the downhole filter pipe string to block the lower side of the sealing ring in the downhole filter pipe string, and the carrier liquid is difficult to enter the upper side of the sealing ring, thus, Where the upper side is emptied, there will be no more incoming liquid from the filter string, and the concentrated carrying liquid will empty the ultra-light particles that need to be emptied. When the upper section of the downhole filter column near the wellhead is emptied, the ultra-light particles are emptied. After that, the liquid injection pipe is further inserted into the downhole filter pipe column until the underground filter pipe column is completely emptied; this also avoids the running of the liquid, saves a large amount of carrier liquid, and maintains a high flush and ultralight The flow rate of the particles. The direction of the arrow in Fig. 5 is the flow direction of the carrier liquid. The dashed line in the figure indicates that the injection tube is gradually infiltrated into the downhole filter column. The manner in which the injection pipe penetrates the downhole filter column can be intermittently deep. The intermittently moving injection tube is continuously infused until the ultra-light particles outside the downhole filter column are completely emptied.

4) Pull out the downhole filter string.

The carrier liquid described in Examples 2-4 may be water or an aqueous solution of a commonly used additive for oil fields in water.

The method of the invention is simple and feasible, overcomes the difficulty in extracting the downhole filter column in the oil and gas well, facilitates the production, and the cleaned ultra-light particles can be reused, thereby greatly reducing the production cost.

The particle density in this patent refers to the true density of the particles.

This patent also includes the secondary injection of a finer downhole filter string into the original downhole filter string in a well where a downhole filter string is already present. This includes the case of a well in the casing perforating well, the well in the lower perforated pipe, and the lower filter column in the well.

It should be noted that the above-described embodiments are merely illustrative of the invention and are not intended to limit the embodiments. Other variations or modifications of the various forms may be made by those skilled in the art in light of the above description. There is no need and no way to exhaust all of the implementations. And Obvious changes or variations resulting therefrom are still within the scope of the invention.

Claims

1. An oil and gas well structure for facilitating the extraction of a downhole filter string, comprising a wellbore wall and a downhole filter string in the oil and gas well, the filter column of the downhole being near the wellhead and being a filter column An upper end, a fixed connection between the upper end of the filter string and the well wall, and an annular space formed between the downhole filter string and the well wall; wherein: the ring between the downhole filter string and the well wall The empty interior is filled with ultra-light particles, the density of the ultra-light particles is close to or equal to the density of the ultra-light particle carrying liquid, and the ultra-light particle carrying liquid is used for carrying ultra-light particles into the annulus or The ultra-light particles are backflushed to bring out the liquid of the annulus.

2. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 1, wherein the ultralight particles are particles having an average particle diameter of 0.05 to 1.2 mm and a true density of 0.7 to ^1.3 g/cm ³ . .

3. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 2, wherein: the ultralight particles have an average particle diameter of 0.05-0.8 mm and a true density of 0.94-1.08 g/ Particles of cm ³ .

4. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 2 or 3, wherein: the ultralight particles are high molecular polymer particles.

5. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 2, wherein: the ultralight particles have an average particle diameter of 0.05-0.8 mm and a true density of 0.90-0.98 _g / High density polyethylene pellets of cm ³ .

6. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 2, wherein: the ultralight particles have an average particle diameter of 0.05-0.8 mm and a true density of 0.7-1.3 g/ Cm ³ polypropylene and polyvinyl chloride polymer particles.

7. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 4, wherein: the ultralight particles have an average particle diameter of 0.05-0.8 mm and a true density of 0.94-1.08 _g / Cm ³ styrene and diethyl benzene crosslinked copolymer particles.

8. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 1, wherein: the density difference between the ultralight particles and the ultralight particle carrier fluid is from -0.35 to +0.35 Within the scope of the endpoint.

9. The oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 8, wherein: the density difference between the ultralight particles and the ultralight particle carrier fluid is from -0.3 to +0.3 Within the scope of the endpoint.

10. A method of proposing a downhole filter string in an oil and gas well structure for facilitating the extraction of a downhole filter string according to any of claims 1-9, wherein: the method comprises the steps of:

2), recoiling the carrier liquid to empty the ultra-light particles: injecting an ultra-light particle carrying liquid into the downhole filter column for carrying back the ultra-light particles from the annulus;

3) Pull out the downhole filter string.

11. The method for proposing a downhole filter string from an oil and gas well structure for facilitating extraction of a downhole filter string, according to claim 10, wherein: said downhole filter string is a flow control filter tube The column, the step of emptying the ultra-light particles by the recoil carrier liquid is connected by using the liquid injection pipe and the downhole filter pipe column, and directly injecting the ultra-light particle carrier liquid into the control flow filter pipe column.

12. The method for proposing a downhole filter string from an oil and gas well structure for facilitating the extraction of a downhole filter string according to claim 10, wherein: the step of emptying the ultralight particles by the recoil carrier liquid is The injection pipe is inserted into the downhole filter pipe, and the liquid injection pipe is injected; the lower part of the injection pipe has an opening, and the upper part of the opening of the injection pipe is provided with a sealing ring, the outer diameter of the sealing ring and the underground The inner diameter of the filter column is basically the same, and the liquid injection method is a segmented injection.

13. A method of proposing a downhole filter string from an oil and gas well structure for facilitating the extraction of a downhole filter string, according to any of claims 10-12, wherein: said ultralight particulate carrier fluid is Water or an aqueous solution.