CN110630234B - Steam injection method for heavy oil thermal recovery well - Google Patents
Steam injection method for heavy oil thermal recovery well Download PDFInfo
- Publication number
- CN110630234B CN110630234B CN201810644067.7A CN201810644067A CN110630234B CN 110630234 B CN110630234 B CN 110630234B CN 201810644067 A CN201810644067 A CN 201810644067A CN 110630234 B CN110630234 B CN 110630234B
- Authority
- CN
- China
- Prior art keywords
- steam
- section
- injection
- horizontal
- well section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/164—Injecting CO2 or carbonated water
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
Abstract
The invention provides a steam injection method for a heavy oil thermal production well. The thermal production well comprises a vertical well section and a horizontal well section connected with the vertical well section, and the steam injection method comprises the following steps: step S10: judging the utilization degree of each part of the horizontal well section; step S20: injecting steam into the horizontal well section; step S30: steam is continuously injected into the portion of the horizontal wellbore section having a low mobility level, and an inert gas is injected into the portion of the horizontal wellbore section having a high mobility level. By applying the technical scheme of the invention, the problem of poor exploitation effect caused by unbalanced utilization degree of the thick oil thermal exploitation horizontal well in the prior art can be solved.
Description
Technical Field
The invention relates to the technical field of oil extraction in oil fields, in particular to a steam injection method for a heavy oil thermal production well.
Background
At present, a steam huff and puff mode is mostly adopted for exploiting the thick oil thermal recovery horizontal well. The theoretical basis of improving the development effect by utilizing the throughput of the horizontal well is that the long horizontal section can increase the contact area of steam and an oil layer and increase the oil drainage area. The thickened oil thermal recovery horizontal well generally adopts an open hole sieve tube well completion mode, namely, a horizontal section of the horizontal well is drilled into an oil layer without any well cementation measure, so that an open hole shaft is formed. Slotted screens are run in the open hole wellbore in the full wellbore interval and very few wells are run in dead legs without slots. And the fluids such as crude oil, water and the like flow into the open hole shaft from the oil layer, then flow into the sieve tube through the gaps on the slotted sieve tube, and then are lifted to the ground.
In the actual production process, the phenomenon of obviously unbalanced horizontal section utilization can occur after the steam huff-puff exploitation of the thick oil thermal recovery horizontal well is carried out for multiple times, namely, a part of well sections absorb more steam and produce more oil, which is also called as a single-section plunging phenomenon, and the rest of well sections absorb less steam and even do not absorb steam, so that the well sections produce less oil and even do not produce oil, thereby seriously affecting the exploitation effect of the horizontal well.
Disclosure of Invention
The invention mainly aims to provide a steam injection method for a heavy oil thermal recovery well, which aims to solve the problem of poor recovery effect caused by unbalanced utilization degree of a heavy oil thermal recovery horizontal well in the prior art.
In order to achieve the above object, the present invention provides a steam injection method for a thick oil thermal recovery well, the thick oil thermal recovery well comprises a vertical well section and a horizontal well section connected with the vertical well section, the steam injection method comprises: step S10: judging the utilization degree of each part of the horizontal well section; step S20: injecting steam into the horizontal well section; step S30: steam is continuously injected into the portion of the horizontal wellbore section having a low mobility level, and an inert gas is injected into the portion of the horizontal wellbore section having a high mobility level.
Further, the horizontal wellbore section includes a first horizontal wellbore section connected to the vertical wellbore section and a second horizontal wellbore section connected to the first horizontal wellbore section, wherein the mobilization degree of the first horizontal wellbore section is higher than that of the second horizontal wellbore section, and after the step S20, the step S30 includes: steam injection continues into the second horizontal leg while steam injection into the first horizontal leg is stopped and inert gas injection into the first horizontal leg is stopped.
Further, the steam injection method also comprises the step of putting an injection-production string into the heavy oil thermal production well, wherein the injection-production string comprises: one end of the injection and production oil pipe is positioned in the vertical well section, the other end of the injection and production oil pipe extends into the second horizontal well section, and one end of the injection and production oil pipe, which is far away from the vertical well section, is provided with an injection and production hole; the sieve tube is sleeved outside the injection and production oil tube; the packer is arranged between the outer wall surface of the injection and production oil pipe and the inner wall surface of the sieve pipe to divide a gap between the inner wall surface of the sieve pipe and the outer wall surface of the injection and production oil pipe into a first area and a second area, wherein the first area corresponds to the first horizontal well section, the second area corresponds to the second horizontal well section, steam is injected into the second horizontal well section through the injection and production hole and the second area, and steam or inert gas is injected into the first horizontal well section through the first area.
Furthermore, the injection-production string further comprises a steam injection auxiliary pipe, one end of the steam injection auxiliary pipe is located in the vertical well section, the other end of the steam injection auxiliary pipe is communicated with the first area, and the steam injection auxiliary pipe is isolated from the second area.
Further, between step S10 and step S20, the steam injection method further includes the steps of: and determining the steam injection amount of the steam injected into the first horizontal well section and the steam injection amount of the steam injected into the second horizontal well section according to the exploitation degree of the first horizontal well section and the second horizontal well section.
Further, in step S20, the steam injection method further includes: and judging whether the steam quantity of the steam injected into the first horizontal well section reaches a first preset value or not, if so, executing the step that the steam injection auxiliary pipe stops injecting the steam into the first horizontal well section, and the steam injection auxiliary pipe injects inert gas into the first horizontal well section, and if not, executing the step that the steam injection auxiliary pipe injects the inert gas into the first horizontal well section after the steam quantity injected into the first horizontal well section by the steam injection auxiliary pipe reaches the first preset value.
Further, the injection-production string further comprises: at least one part of the sucker rod is positioned in the vertical well section, and the sucker rod is arranged in the oil injection production pipe; and the injection and production dual-purpose pump is arranged in the injection and production oil pipe and is connected with one end of the sucker rod close to the horizontal well section.
Further, the heavy oil thermal recovery well also comprises a deflecting well section for connecting the vertical well section and the horizontal well section, and the injection-production pipe column further comprises: the shaft is arranged in the horizontal well section and sleeved on the periphery of the sieve tube; a casing, a portion of the casing being located within the vertical wellbore section and a remainder of the casing being located within the whipstock wellbore section; a hanger positioned within the whipstock section and disposed between the inner wall surface of the casing and the outer wall surface of the screen to connect the screen to the casing.
Furthermore, the heavy oil thermal recovery well also comprises an inert gas supply device, the inert gas supply device is positioned outside a well head of the thermal recovery well, and the inert gas supply device is connected with the steam injection auxiliary pipe so as to inject inert gas into the first horizontal well section.
Further, the inert gas is nitrogen or carbon dioxide or methane or natural gas.
Further, after the step S30, the steam injection method further includes sequentially performing the following steps; step S40: soaking the thick oil thermal recovery well; step S50: performing an oil recovery step for recovering oil from the first horizontal wellbore section and the second horizontal wellbore section; step S60: step S10 is repeatedly executed.
By applying the technical scheme of the invention, the utilization degree of each part of the horizontal well section is judged firstly, then steam is injected into the well sections with different utilization degrees simultaneously, and the horizontal well section with high utilization degree can finish steam injection earlier than the horizontal well section with low utilization degree due to strong steam absorption capacity. When the horizontal well section with high utilization degree finishes steam injection, inert gas is injected into the horizontal well section instead, steam is continuously injected into the horizontal well section with low utilization degree, the inert gas can improve the pressure of the horizontal well section with high utilization degree after entering the horizontal well section with high utilization degree, and the gas solubility of the inert gas is low, so that the compression resistance is strong, the steam is difficult to enter the horizontal well section with high utilization degree when the steam is continuously injected into the horizontal well section with low utilization degree, and the purpose of fully injecting steam into the horizontal well section with low utilization degree is achieved. Therefore, through the setting, the problem that the horizontal well section of the heavy oil thermal production well in the prior art is not good in production effect due to the unbalanced drawing degree can be effectively solved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 shows a schematic flow diagram of a steam injection method for a heavy oil thermal production well according to the present invention; and
fig. 2 shows a schematic structural view of a heavy oil thermal production well according to an embodiment of the present invention.
Wherein the figures include the following reference numerals:
1. a wellbore; 2. a screen pipe; 3. injecting and producing holes; 4. a centralizer; 5. a packer; 6. injecting and extracting oil pipes; 7. a hanger; 8. a dual-purpose pump for injection and production; 9. a sleeve; 10. a sucker rod; 11. a steam injection auxiliary pipe; 13. a first region; 14. a second region; 15. and an inert gas supply device.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
As shown in fig. 1, an embodiment of the present invention provides a steam injection method for a thick oil thermal production well, the thick oil thermal production well includes a vertical well section and a horizontal well section connected to the vertical well section, the steam injection method includes:
step S10: judging the utilization degree of each part of the horizontal well section;
step S20: injecting steam into the horizontal well section;
step S30: steam is continuously injected into the portion of the horizontal wellbore section having a low mobility level, and an inert gas is injected into the portion of the horizontal wellbore section having a high mobility level.
In the prior art, after steam huff and puff mining of a heavy oil thermal production well for multiple rounds, an obvious phenomenon of unbalanced horizontal section utilization can occur, namely, a part of well sections absorb more steam and produce more oil, and the oil production condition of the horizontal well sections is also called as a single-section plunging phenomenon; and the remaining horizontal well sections absorb little or no steam, so that the well sections produce little or no oil, thereby seriously affecting the exploitation effect of the horizontal well.
In order to solve the problems, the application provides a steam injection method for a heavy oil thermal production well. The technical scheme of this application at first judges the degree of using of each part of horizontal well section, then uses the well section of degree difference earlier and pours into steam into simultaneously, uses the high horizontal well section of degree into because the steam absorption ability is strong, can be earlier than and use the low horizontal well section of degree to accomplish and annotate steam. When the horizontal well section with high utilization degree finishes steam injection, inert gas is injected into the horizontal well section instead, steam is continuously injected into the horizontal well section with low utilization degree, the inert gas can improve the pressure of the horizontal well section with high utilization degree after entering the horizontal well section with high utilization degree, and the gas solubility of the inert gas is low, so that the compression resistance is strong, the steam is difficult to enter the horizontal well section with high utilization degree when the steam is continuously injected into the horizontal well section with low utilization degree, and the purpose of fully injecting steam into the horizontal well section with low utilization degree is achieved. Therefore, through the setting, the problem that the horizontal well section of the heavy oil thermal production well in the prior art is not good in production effect due to the unbalanced drawing degree can be effectively solved.
As shown in fig. 2, in an embodiment of the present invention, the horizontal wellbore section comprises a first horizontal wellbore section connected to the vertical wellbore section and a second horizontal wellbore section connected to the first horizontal wellbore section, wherein the mobilization degree of the first horizontal wellbore section is higher than that of the second horizontal wellbore section, and after step S20, step S30 comprises: steam injection continues into the second horizontal leg while steam injection into the first horizontal leg is stopped and inert gas injection into the first horizontal leg is stopped.
Specifically, in the embodiment of the present invention, the horizontal well section of the heavy oil thermal recovery well is divided into the first horizontal well section and the second horizontal well section, and the steam injection method of the present application is described by taking the example that the mobility degree of the first horizontal well section is higher than that of the second horizontal well section.
In this application, because the degree of using of first horizontal well section is higher than the degree of using of second horizontal well section, consequently, at the in-process of injecting steam to the horizontal well section, the steam-absorbing capacity of first horizontal well section is high, and the steam-absorbing speed is fast, and the steam-absorbing capacity of second horizontal well section is low, and the steam-absorbing speed is slow. After the steam injection of the first horizontal well section is completed, the steam injection of the second horizontal well section is continued to reach the steam injection amount of the second horizontal well section. However, if the steam injection of the first horizontal well section is stopped, and the steam injection of the second horizontal well section is continued, the steam injected into the second horizontal well section flows to the first horizontal well section through the gap of the sieve tube 2, so that the steam injection efficiency of the second horizontal well section is lower, the steam absorption degree is worse, and the oil recovery effect of the second horizontal well section is further influenced. Therefore, in the present application, after the steam injection of the first horizontal wellbore section is completed, the inert gas is injected into the first horizontal wellbore section to increase the pressure of the first horizontal wellbore section. Because inert gas's solubility is low, resistance to compression ability chamber can effectively prevent the steam of pouring into the second horizontal well section when the steam is annotated to the second horizontal well section to flow into first horizontal well section to reach the purpose of segmentation steam injection, improve the steam injection efficiency of second horizontal well section, and then improve the oil recovery effect of second horizontal well section.
In the embodiment of the invention, the steam injection method further comprises the step of putting an injection-production string into the heavy oil thermal production well, and as shown in figure 2, the injection-production string comprises an injection-production oil pipe 6, a sieve pipe 2 and a packer 5. One end of the injection and production oil pipe 6 is positioned in the vertical well section, the other end of the injection and production oil pipe 6 extends into the second horizontal well section, and one end of the injection and production oil pipe 6, which is far away from the vertical well section, is provided with an injection and production hole 3; the sieve tube 2 is sleeved outside the injection and production oil tube 6; the packer 5 is arranged between the outer wall surface of the injection and production oil pipe 6 and the inner wall surface of the sieve pipe 2 to divide a gap between the inner wall surface of the sieve pipe 2 and the outer wall surface of the injection and production oil pipe 6 into a first area 13 and a second area 14, wherein the first area 13 corresponds to a first horizontal well section, the second area 14 corresponds to a second horizontal well section, steam is injected into the second horizontal well section through the injection and production holes 3 and the second area 14, and steam or inert gas is injected into the first horizontal well section through the first area 13.
In the present application, the screen 2 is a slotted screen.
The sectional steam injection process in the prior art generally needs to arrange packers in and outside a sieve tube, and a seamless sieve tube is arranged at the arrangement position of the packers, so that the horizontal well section can be really divided into mutually independent sections. However, the setting of the packer (external packer) and the setting of the non-slotted screen pipe outside the screen pipe are both completed in the well completion, and the external packer is expensive in manufacturing cost and high in sectional steam injection cost. At present, most of produced thermal recovery horizontal wells are not provided with external pipe packers and blind pipes, but the phenomenon of unbalanced steam absorption among all well sections of the produced horizontal wells after the produced horizontal wells are taken out and taken in by a plurality of rounds of single wells is obvious, the problem of single-section outburst is serious, and the recovery effect of the horizontal wells is seriously influenced. It is therefore desirable to perform staged steam injection on these horizontal wells to improve production.
In this application, the packer 5 is placed between the injection and production tubing 6 and the screen 2, thereby dividing the space between the outer wall of the injection and production tubing 6 and the inner wall of the screen 2 into a first zone 13 and a second zone 14. Because the screen pipe 2 is provided with the gaps, when steam is injected into the second area 14, the steam can flow to the area between the screen pipe 2 and the shaft 1 from the gaps on the screen pipe 2 and then enters the first area 13 through the gaps on the screen pipe 2, and because the utilization degree of the second horizontal well section is low, the steam absorption efficiency of the second horizontal well section is reduced, and the phenomenon of unbalanced steam absorption of each well section of the horizontal well is caused. In this application, after steam injection is completed in the first horizontal well section, inert gas is injected into the first horizontal well section through the injection and production hole 3 located in the first area 13, so that the pressure in the first area 13 is increased, the pressure in the first horizontal well section is increased, steam located in the second horizontal well section cannot enter the first horizontal well section, and then segmented steam injection of the horizontal well is realized.
Preferably, centralizer 4 is set up after going into packer 5 in this application to fix packer 5, guarantee the separation effect of packer 5.
Preferably, the end of the injection and production oil pipe 6 far away from the vertical well section in the application is connected with a perforated pipe, and the perforated pipe is provided with the injection and production hole 3. Of course, in an alternative embodiment not shown in the drawings of the present invention, the injection and production hole 3 may be directly formed in the injection and production tubing 6.
In the embodiment of the present invention, as shown in fig. 2, the injection-production string further comprises a steam injection auxiliary pipe 11, one end of the steam injection auxiliary pipe 11 is located in the vertical well section, the other end of the steam injection auxiliary pipe 11 is communicated with the first area 13, and the steam injection auxiliary pipe 11 is isolated from the second area 14.
Specifically, steam is injected into the second horizontal shaft section through the injection and production holes 3 in the second area 14, and steam or inert gas is injected into the first horizontal shaft section through the steam injection auxiliary pipe 11 communicated with the first area 13. According to the arrangement, the steam injection and production oil pipe 6 or the steam injection auxiliary pipe 11 is adopted to respectively inject steam or inert gas into the first horizontal well section and the second horizontal well section, so that the segmented steam injection of the thermal recovery horizontal well is further ensured.
As shown in fig. 1, in the embodiment of the present invention, between step S10 and step S20, the steam injection method further includes the steps of: and determining the steam injection amount of the steam injected into the first horizontal well section and the steam injection amount of the steam injected into the second horizontal well section according to the exploitation degree of the first horizontal well section and the second horizontal well section.
After the staff judges the utilization degree of each part of the horizontal well section of the thermal recovery horizontal well according to the oil layer thickness, the length of the thermal recovery horizontal well, the steam throughput wheel number and the recovery degree of the oil well, the injected steam quantity is set according to the condition of each part of the horizontal well section. Specifically, taking the first horizontal well section and the second horizontal well section as an example, since the utilization degree of the first horizontal well section is high and the utilization degree of the second horizontal well section is low, in the previous production, the oil output of the first horizontal well section is large, the residual oil amount is small, the oil output of the second horizontal well section is small, and the residual oil amount is large. Therefore, staff can set up the steam injection volume that the steam injection volume of first horizontal well section is less than the steam injection volume of second horizontal well section according to the different situation of two well sections when setting for the steam injection volume of first horizontal well section and second horizontal well section, under the prerequisite that the steam injection volume of guaranteeing individual horizontal well section is sufficient, reduce extravagantly.
In addition, the working personnel can also further set the amount of inert gas needed to be injected into the first horizontal well section, and the sum of the time of injecting steam into the first horizontal well section and the time of injecting inert gas into the first horizontal well section is equal to the time of injecting steam into the second horizontal well section.
As shown in fig. 1, in the embodiment of the present invention, in step S20, the steam injection method further includes: and judging whether the steam quantity of the steam injected into the first horizontal well section reaches a first preset value, if so, stopping injecting the steam into the first horizontal well section, and injecting inert gas into the first horizontal well section through the steam injection auxiliary pipe 11, and if not, continuously injecting the steam into the first horizontal well section.
In the process of injecting steam into the first horizontal well section, whether the injected steam quantity reaches a first preset value is judged, if the injected steam quantity reaches the first preset value, steam injection into the first horizontal well section is stopped, inert gas is injected into the first horizontal well section instead, so that the pressure of the first horizontal well section is improved, the steam injected into the second horizontal well section is prevented from flowing to the first horizontal well section, the steam injection quantity of the second horizontal well section is ensured, and segmented steam injection of the horizontal well section is realized.
As shown in fig. 2, in the embodiment of the present invention, the injection-production string further includes a sucker rod 10 and an injection-production dual-purpose pump 8. At least one part of the sucker rod 10 is positioned in the vertical well section, and the sucker rod 10 is arranged in the injection and production oil pipe 6; and the injection and production dual-purpose pump 8 is arranged in the injection and production oil pipe 6 and is connected with one end of the sucker rod 10 close to the horizontal well section.
In the application, the sucker rod 10 is connected with the injection and production dual-purpose pump 8, and in the steam injection stage, the injection and production dual-purpose pump 8 is used for pumping steam to the injection and production oil pipe 6; in the oil production stage, the injection and production dual-purpose pump 8 is used for taking oil from the injection and production oil pipe 6, and the oil is pumped out by the sucker rod 10.
In an embodiment of the invention, as shown in fig. 2, the thermal production well further comprises a deviated interval for connecting the vertical interval and the horizontal interval, and the injection-production string further comprises a wellbore 1, a casing 9 and a hanger 7. The shaft 1 is arranged in the horizontal well section and sleeved on the periphery of the sieve tube 2; a portion of the casing 9 is located in the vertical wellbore section and the remainder of the casing 9 is located in the whipstock wellbore section; the hanger 7 is located in the whipstock section and the hanger 7 is disposed between the inner wall surface of the casing 9 and the outer wall surface of the screen 2 to connect the screen 2 to the casing 9.
The sieve tube 2 is fixedly arranged in the shaft 1, so that the sieve tube 2 is fixedly arranged in the shaft 1.
In an embodiment of the invention, as shown in fig. 2, the thermal production well further comprises an inert gas supply device 15, the inert gas supply device 15 is located outside the wellhead of the thermal production well, and the inert gas supply device 15 is connected with the steam injection sub-pipe 11 to inject inert gas into the first horizontal well section.
The degree of exploitation of the first horizontal shaft section is higher in the present application than the degree of exploitation of the second horizontal shaft section, and therefore the inert gas supply means 15 is connected to the auxiliary steam injection pipe 11 co-directional to the first zone 13 for injecting inert gas into the first horizontal shaft section.
Of course, in an embodiment of the invention not shown in the drawings, the thermal production well of the present application further comprises a steam supply device, which is connectable to both the injection and production tubing 6 and the steam injection secondary 11, and which is connected only to the injection and production tubing 6 when inert gas is injected into the first horizontal well section through the steam injection secondary 11.
The inert gas in this application is nitrogen or carbon dioxide or methane or natural gas.
Preferably, the inert gas injected in the embodiment of the present invention is nitrogen. In the process of huff and puff production of the thermal production well, inert gases such as nitrogen and the like are filled, so that the effects of discharging assistance and saving steam are achieved, and no side effect is caused on the production of the oil well. All of the above gases have the characteristics of being insoluble in water and having strong compression resistance, and in the alternative embodiment not shown in the present invention, the gases having the above characteristics are all within the protection scope of the present invention.
Further, after step S30, the steam injection method further includes the steps of:
step S40: soaking the thick oil thermal recovery well;
step S50: an oil recovery step of recovering oil from the first horizontal well section and the second horizontal well section;
step S60: step S10 is repeatedly executed.
Specifically, after steam injection is completed on the horizontal well section of the thermal production well, the thermal production well is stewed for 2 to 7 days, so that the heat of the steam injected into the horizontal well section is diffused to the deep part of the oil layer as far as possible, and the oil production is improved. And (3) extracting oil from the horizontal well section after the well is shut in, wherein the injection and production effect of the injection and production oil pipe 6 is changed from the injection effect during steam injection into the extraction effect, and crude oil flows into the injection and production oil pipe 6 through an injection and production hole 3 arranged at the end part of the injection and production oil pipe 6, is pumped out under the power effect of the injection and production dual-purpose pump 8 and is pumped out of the well through a sucker rod 10. The injection and production dual-purpose pump 8 is used for fluid lifting of the whole well section in the oil production process.
After oil extraction is finished, step S10 is repeatedly executed, the utilization degree of each part of the horizontal well section is judged, if the utilization degree is the same as that of the previous round, the processes of steam injection and inert gas injection are executed according to the steps of the previous round, and well stewing and extraction are carried out after the steam injection is finished; if the judgment is different from the previous judgment, the inert gas supply device 15 is connected with the injection and production oil pipe 6 only when the inert gas is injected.
Researches find that two reasons exist for uneven steam absorption of the thickened oil thermal recovery horizontal well, namely, the friction resistance in the pipe of the steam injection oil pipe; the second is the permeability difference of the reservoir itself.
The influence of friction resistance in the pipe is embodied in that the steam forms friction resistance with the pipe wall in the flowing process of the steam in the horizontal section sieve pipe, so that the pressure difference between the steam and an oil layer in the sieve pipe is different on the whole horizontal section, the pressure difference at the outlet position of the steam injection pipe is large, and the pressure difference at the position far away from the outlet position of the steam injection pipe is small. According to Darcy's law, the flow velocity with large pressure difference is large, and the flow velocity with small pressure difference is small. Therefore, the friction in the tube causes uneven steam suction in the horizontal section.
The permeability difference of the oil reservoirs means that the permeability of the oil reservoirs passing through the horizontal section is different and has a certain difference, and some wells have great difference. This difference in permeability also causes an imbalance in vapor draw in the horizontal section, according to darcy's law.
The technological measures for solving the unbalance of the horizontal section steam absorption include two types of multi-point steam injection and sectional steam injection.
In the multipoint steam injection process, a plurality of steam injection valves are arranged in the sieve tube at the horizontal section so as to reduce the influence of flow friction in the sieve tube on the steam suction uniformity. The process is generally effective for common heavy oil reservoir horizontal wells with relatively low crude oil viscosity in the early production period.
The sectional steam injection process is to set a packer in the horizontal section, divide the horizontal section into two or more mutually independent sections and form mutually independent steam cavities during steam injection. The steam injection quantity of each section is controlled to improve the steam absorption uniformity of the horizontal section, and the development effect of the horizontal well is improved. The process can be used for horizontal wells of common heavy oil reservoirs, extra heavy oil reservoirs and super heavy oil reservoirs, and can also be used for horizontal wells which are already formed into single-section plunging.
The sectional steam injection process generally needs to arrange packers inside and outside a sieve tube, and a seamless tube (namely a blind tube) is required to be arranged at the arrangement position of the packers, so that the horizontal section can be really divided into mutually independent sections. However, the placement of the outer packer outside the screen and the placement of the seamless pipe are both accomplished during completion and the outer packer is expensive to manufacture. The vast majority of thermal recovery horizontal wells that have been put into production at present do not have external casing packers and blind pipes. The phenomenon of unbalanced steam absorption of the produced horizontal wells after the multiple rounds of single-well huff and puff is obvious, the problem of single-section outburst is serious, the exploitation effect of the horizontal wells is seriously influenced, and sectional steam injection is urgently needed to be carried out on the horizontal wells so as to improve the exploitation effect.
For realizing segmented steam injection on a thermal production horizontal well without a blind pipe and a pipe-free external packer, the arrangement of the pipe-in packer in a sieve pipe is not enough because a blind pipe section and the pipe-out packer are not provided. As shown in fig. 2, the packer 5 is set in the screen 2, although the screen 2 is divided into two sections, a first zone 13 and a second zone 14. However, the annulus between the screen 2 and the open hole wellbore 1 is not sealed off. When steam is injected, the steam of the first horizontal well section can flow to the second horizontal well section through the annular space, and the steam of the second horizontal well section can also flow to the first horizontal well section, so that the segmented steam injection is ineffective.
The technical scheme in the application is realized by the following modes:
the principles of the present application are illustrated by way of example in the thermal production well configuration of fig. 2. The in-pipe packer 5 in fig. 2 divides the space inside the screen 2 into two mutually independent sections, a first zone 13 and a second zone 14, and a centralizer is placed to fix the packer 5. The first region 13 is arranged corresponding to the first horizontal shaft section, and the second region 14 is arranged corresponding to the second horizontal shaft section. The first horizontal well section of the horizontal well is assumed to be a strong steam absorption section in the production history of the well through analysis, and can also be called a strong utilization section. The residual oil of the section is less, but the steam absorption capacity is strong, and the steam injection amount of the section needs to be reduced; the second horizontal well section is a weak steam absorption section in the production history of the well, or a weak exploitation section, the section has more residual oil but poor steam absorption capacity, and the steam absorption amount of the section needs to be increased. The operation is carried out according to the well structure in fig. 2, the steam injection and production oil pipe 6 injects steam for the second horizontal well section, and the steam injection auxiliary pipe 11 injects steam for the first horizontal well section. During steam injection, due to the poor steam suction capacity of the second horizontal interval, a part of the steam may flow into the first horizontal interval through the outer annular space of the screen 2 and possible blow-by channels in the reservoir. When the steam injection of the first horizontal shaft section is completed, the steam injection of the second horizontal shaft section needs to be continued, and the steam flowing to the first horizontal shaft section through the passages has a larger proportion.
In the invention, when the steam absorption amount of the first horizontal well section reaches the designed steam amount, steam injection to the first horizontal well section is stopped, and steam injection to the second horizontal well section is continued. In order to prevent steam of the second horizontal well section from flowing into the first horizontal well section through the annular space outside the sieve tube and a possible cross flow channel in an oil layer, inert gas such as nitrogen is injected immediately after the steam injection of the first horizontal well section is stopped, and the pressure of the first horizontal well section is increased. Because inert gases such as nitrogen and the like have low solubility and strong compression resistance, although steam is continuously injected in the second horizontal well section, injected steam is difficult to enter the first horizontal well section which is injected with nitrogen, thereby achieving the purpose of segmented steam injection. Of course, if the second horizontal well section of the horizontal well is judged to be the strong steam absorption section in the production history of the horizontal well, only the nitrogen injection end needs to be replaced by the second horizontal well section, and the rest is unchanged.
In actual production, it is difficult to accurately judge the position of the strong steam absorption section. And if the segmented steam injection effect of the first round after segmented steam injection is poor, the position judgment of the strong steam absorption section of the horizontal well is inaccurate. In the next round of steam injection parameter design, the nitrogen injection well section is replaced by the other end, and the separate injection pipe column does not need to be adjusted.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects: the method comprises the steps of firstly judging the utilization degree of each part of the horizontal well section, then simultaneously injecting steam into the well sections with different utilization degrees, and completing steam injection in the horizontal well section with high utilization degree earlier than the horizontal well section with low utilization degree due to strong steam absorption capacity. When the horizontal well section with high utilization degree finishes steam injection, inert gas is injected into the horizontal well section instead, steam is continuously injected into the horizontal well section with low utilization degree, the inert gas can improve the pressure of the horizontal well section with high utilization degree after entering the horizontal well section with high utilization degree, and the gas solubility of the inert gas is low, so that the compression resistance is strong, the steam is difficult to enter the horizontal well section with high utilization degree when the steam is continuously injected into the horizontal well section with low utilization degree, and the purpose of fully injecting steam into the horizontal well section with low utilization degree is achieved. Therefore, through the setting, the problem that the horizontal well section of the heavy oil thermal production well in the prior art is not good in production effect due to the unbalanced drawing degree can be effectively solved.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A steam injection method for a thick oil thermal production well is characterized in that the thick oil thermal production well comprises a vertical well section and a horizontal well section connected with the vertical well section, and the steam injection method comprises the following steps:
step S10: judging the utilization degree of each part of the horizontal well section;
step S20: injecting steam into the horizontal well section;
step S30: continuing to inject steam into the low-mobility portion of the horizontal wellbore section and injecting inert gas into the high-mobility portion of the horizontal wellbore section;
wherein the horizontal wellbore section comprises a first horizontal wellbore section connected to the vertical wellbore section and a second horizontal wellbore section connected to the first horizontal wellbore section, wherein the volume usage of the first horizontal wellbore section is greater than the volume usage of the second horizontal wellbore section, after the step S20, the step S30 comprises: continuing to inject steam into the second horizontal leg while stopping the injection of steam into the first horizontal leg and injecting an inert gas into the first horizontal leg, the steam injection method further comprising, between the step S10 and the step S20:
and determining the steam injection amount of the steam injected into the first horizontal well section and the steam injection amount of the steam injected into the second horizontal well section according to the exploitation degree of the first horizontal well section and the second horizontal well section.
2. The steam injection method of claim 1, further comprising the step of running an injection and production string into the heavy oil thermal production well, the injection and production string comprising:
an injection and production oil pipe (6), wherein one end of the injection and production oil pipe (6) is positioned in the vertical well section, the other end of the injection and production oil pipe (6) extends into the second horizontal well section, and one end, far away from the vertical well section, of the injection and production oil pipe (6) is provided with an injection and production hole (3);
the sieve tube (2) is sleeved outside the injection and production oil tube (6);
the packer (5) is arranged between the outer wall surface of the injection and production oil pipe (6) and the inner wall surface of the sieve pipe (2) to separate a gap between the inner wall surface of the sieve pipe (2) and the outer wall surface of the injection and production oil pipe (6) into a first area (13) and a second area (14), wherein the first area (13) corresponds to the first horizontal well section, the second area (14) corresponds to the second horizontal well section, steam is injected into the second horizontal well section through the injection and production hole (3) and the second area (14), and steam or inert gas is injected into the first horizontal well section through the first area (13).
3. A steam injection method according to claim 2, wherein the injection and production string further comprises a steam injection secondary pipe (11), one end of the steam injection secondary pipe (11) being located within the vertical well section, the other end of the steam injection secondary pipe (11) being in communication with the first zone (13) and the steam injection secondary pipe (11) being isolated from the second zone (14).
4. The steam injection method according to claim 3, wherein in the step S20, the steam injection method further comprises: and judging whether the steam quantity of the steam injected into the first horizontal well section reaches a first preset value, if so, executing the step that the steam injection auxiliary pipe (11) stops injecting the steam into the first horizontal well section, and the steam injection auxiliary pipe (11) injects inert gas into the first horizontal well section, and if not, executing the step that the steam injection auxiliary pipe (11) injects the inert gas into the first horizontal well section after waiting for the steam injection auxiliary pipe (11) to inject the steam quantity into the first horizontal well section to reach the first preset value.
5. The steam injection method according to claim 2, wherein the injection-production string further comprises:
a sucker rod (10), at least a portion of the sucker rod (10) being located within the vertical well section, and the sucker rod (10) being disposed within the injection and production tubing (6);
and the injection and production dual-purpose pump (8) is arranged in the injection and production oil pipe (6) and is connected with one end, close to the horizontal well section, of the sucker rod (10).
6. The steam injection method according to claim 2, wherein the heavy oil thermal production well further comprises a deflecting well section for connecting the vertical well section and the horizontal well section, the injection and production string further comprising:
the shaft (1) is arranged in the horizontal well section and sleeved on the periphery of the sieve tube (2);
a casing (9), a portion of the casing (9) being located within the vertical wellbore section and a remaining portion of the casing (9) being located within the whipstock wellbore section;
a hanger (7) located within the whipstock section, the hanger (7) being disposed between an inner wall surface of the casing (9) and an outer wall surface of the screen (2) to connect the screen (2) to the casing (9).
7. A method according to claim 3, characterized in that the heavy oil thermal recovery well further comprises an inert gas supply device (15), the inert gas supply device (15) being located outside the wellhead of the thermal recovery well, the inert gas supply device (15) being connected to the steam injection sub (11) for injecting inert gas into the first horizontal wellbore section.
8. A method according to any one of claims 1 to 7, wherein the inert gas is nitrogen or carbon dioxide or methane or natural gas.
9. The steam injection method according to any one of claims 2 to 7, wherein after the step S30, the steam injection method further comprises the steps of:
step S40: soaking the thickened oil thermal production well;
step S50: a step of recovering oil from the first and second horizontal well sections;
step S60: the step S10 is repeatedly performed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810644067.7A CN110630234B (en) | 2018-06-21 | 2018-06-21 | Steam injection method for heavy oil thermal recovery well |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810644067.7A CN110630234B (en) | 2018-06-21 | 2018-06-21 | Steam injection method for heavy oil thermal recovery well |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110630234A CN110630234A (en) | 2019-12-31 |
| CN110630234B true CN110630234B (en) | 2021-11-02 |
Family
ID=68966289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810644067.7A Active CN110630234B (en) | 2018-06-21 | 2018-06-21 | Steam injection method for heavy oil thermal recovery well |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110630234B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113847003A (en) * | 2020-06-28 | 2021-12-28 | 中国石油天然气股份有限公司 | Method for uniformly using horizontal section of thickened oil horizontal well |
| CN114790879B (en) * | 2021-01-26 | 2023-09-26 | 中国石油天然气股份有限公司 | Underground exploitation method and system for steam assisted gravity drainage of fractured reservoir |
| CN115247543B (en) * | 2021-04-28 | 2024-04-09 | 中国石油化工股份有限公司 | Fixed-point segmented water shutoff and dislocation accurate steam injection method for horizontal well of heavy oil reservoir |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201090200Y (en) * | 2007-09-18 | 2008-07-23 | 中国石油天然气股份有限公司 | Nitrogen gas foam generator |
| CN102011573A (en) * | 2010-12-20 | 2011-04-13 | 中国海洋石油总公司 | Method for uniformly injecting multi-component thermal fluid in horizontal well |
| WO2013106205A1 (en) * | 2012-01-10 | 2013-07-18 | Conocophillips Company | Heavy oil production with em preheat and gas injection |
| CN105332672A (en) * | 2015-11-17 | 2016-02-17 | 中国石油集团长城钻探工程有限公司 | Multi-element composite water-control oil-enhancement method for extracting oil |
| CN105863588A (en) * | 2016-04-28 | 2016-08-17 | 重庆科技学院 | Balanced injection and recovery method of thickened oil thermal recovery horizontal well |
| CN107288601A (en) * | 2017-08-17 | 2017-10-24 | 芜湖通全科技有限公司 | A kind of oil field HTHP cleans gas injection system |
-
2018
- 2018-06-21 CN CN201810644067.7A patent/CN110630234B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201090200Y (en) * | 2007-09-18 | 2008-07-23 | 中国石油天然气股份有限公司 | Nitrogen gas foam generator |
| CN102011573A (en) * | 2010-12-20 | 2011-04-13 | 中国海洋石油总公司 | Method for uniformly injecting multi-component thermal fluid in horizontal well |
| WO2013106205A1 (en) * | 2012-01-10 | 2013-07-18 | Conocophillips Company | Heavy oil production with em preheat and gas injection |
| CN105332672A (en) * | 2015-11-17 | 2016-02-17 | 中国石油集团长城钻探工程有限公司 | Multi-element composite water-control oil-enhancement method for extracting oil |
| CN105863588A (en) * | 2016-04-28 | 2016-08-17 | 重庆科技学院 | Balanced injection and recovery method of thickened oil thermal recovery horizontal well |
| CN107288601A (en) * | 2017-08-17 | 2017-10-24 | 芜湖通全科技有限公司 | A kind of oil field HTHP cleans gas injection system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110630234A (en) | 2019-12-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110630234B (en) | Steam injection method for heavy oil thermal recovery well | |
| CN104514535B (en) | Thermal oil production pipe column for injection-production in the same well for vertical well and oil production method thereof | |
| RU2015156402A (en) | METHOD OF IMPROVED PRODUCTION OF HYDROCARBONS USING MULTIPLE ARTIFICIALLY EDUCATED CRACKS | |
| CN103939071B (en) | A kind of horizontal well steam flooding well web frame and steam drive method | |
| CN101892827B (en) | Optimized steam injection technology for horizontal well in segments | |
| CA2744749C (en) | Basal planer gravity drainage | |
| RU2007148901A (en) | CAVITY DRILLING SYSTEM | |
| CN103321622A (en) | Sand draining and oil extracting method in manner of integrating injection and extraction for thermal producing well and device thereof | |
| CN105863588B (en) | A kind of heavy crude heat extraction horizontal well equilibrium note mining method | |
| CN109025940B (en) | CO for tight oil reservoir2Fracturing oil displacement integrated oil extraction method | |
| CN105822252A (en) | Well cementation pipe column combination and well cementation method | |
| CN103470221B (en) | Method made by the connection that pump was taken out and examined to oil pipe under underbalance, no killing well gaslift, axle | |
| CN111946300A (en) | Same-well same-layer multi-lateral self-injection-production downhole fluid separation self-driving well and production method | |
| EA012022B1 (en) | Method for developing hydrocarbon accumulations | |
| CN110593846A (en) | Gas well gas-liquid separate production well completion pipe string | |
| RU2533465C1 (en) | Well completion and operation method for underground gas storage in water-bearing formation with inhomogeneous lithologic structure | |
| CN111520116B (en) | Oil-gas lifting device and method for high oil-gas ratio oil field | |
| CN112990629B (en) | Unconventional oil and gas reservoir exploitation method and unconventional oil and gas reservoir exploitation system | |
| CN203783536U (en) | High-pressure gas injection and deep pumping integrated pipe column for ultra-deep well | |
| RU2738615C1 (en) | Method for simultaneous separate production of oil from two formations of one well by production string | |
| RU2425961C1 (en) | Well operation method | |
| CN211448541U (en) | Horizontal well leak-stopping water-plugging pipe column | |
| CN205858270U (en) | A kind of selectivity cementing unit | |
| RU79935U1 (en) | CONSTRUCTION OF A MULTIPLE WELL FOR SIMULTANEOUS OPERATION OF MULTIPLE RESURSES OF DIFFERENT PRODUCTIVITY | |
| RU2724715C1 (en) | Operating method of water-flooded oil formation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |