Efficient development method for converting steam huff and puff old area into VHSD development area to supplement energy

Abstract

The invention discloses an efficient development method for converting a steam huff and puff old area into a VHSD development area to supplement energy. The method comprises the following steps: determining position information of a VHSD development area adjacent to a steam huff and puff development area according to a development area distribution condition in a target mining range; the VHSD development area comprises at least one steam injection well and a production well; according to the position information, the stratigraphic dip angle of the VHSD development area is determined; according to the stratigraphic dip angle of the VHSD development area, a gas injection well of the VHSD development area is determined; and according to the gas injection well and the steam injection well, the VHSD development area is pressurized. By the adoption of the technical scheme, the formation pressure of the VHSD development area is rapidly recovered, steam overflow is effectively restrained, the oil-steam ratio of the VHSD development area is greatly increased, and finally a VHSD development area efficient energy supplement and steam huff and puff old area gas drive collaborative development mode is formed.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas extraction, and in particular to an efficient energy supplement development method for converting an old steam-throwing area into a VHSD development area. Background Art

[0002] Thermal recovery is the most widely used method for heavy oil development. This includes steam stimulation, steam flooding, steam-assisted gravity drainage, and fire flooding. Steam stimulation is the most important method for heavy oil development in my country. Currently, nearly all established heavy oil production areas utilize steam stimulation in the early stages of development, but later adopt steam-assisted gravity drainage (VHSD) for development.

[0003] Most VHSD development zones were developed by converting existing steam stimulation zones. Areas with reservoir thicknesses below the required standards continue to be developed using steam stimulation or steam flooding, resulting in separate development zones within the same block, with VHSD zones and steam stimulation operating differently. The differences in operating methods between the VHSD zone and the steam stimulation zone lead to regional pressure imbalances. This creates high-pressure areas within the VHSD zone, leading to significant steam overflow into the steam stimulation zone. This results in formation pressure recovery in the VHSD zone falling far short of expectations. This significant steam overflow also significantly reduces the oil-to-gas ratio, necessitating an efficient energy replenishment method to quickly restore formation pressure in the VHSD zone and reduce steam overflow. Summary of the Invention

[0004] The present invention provides a method for efficiently developing an old steam huff-and-puff area by converting it into a VHSD development area, so as to solve the problem of low oil-gas ratio when producing oil and gas through steam-assisted gravity drainage.

[0005] According to one aspect of the present invention, a method for efficiently developing an old steam throughput area into a VHSD development area is provided, the method comprising:

[0006] Determine the location information of the VHSD development zone adjacent to the steam stimulation development zone based on the distribution of development zones within the target mining area; wherein the distribution of development zones includes the distribution location information of development zones corresponding to different mining methods within the target mining area;

[0007] determining a stratum dip angle of the VHSD development zone according to the location information of the VHSD development zone;

[0008] Determining a gas injection well in the VHSD development area according to the formation dip angle in the VHSD development area;

[0009] The VHSD development area is pressurized according to the gas injection well and the steam injection well.

[0010] According to the technical solution of the embodiment of the present invention, by determining the location information of the VHSD development zone adjacent to the steam stimulation development zone based on the distribution of development areas within the target mining range, determining the gas injection wells in the VHSD development zone based on the formation inclination of the VHSD development zone, and pressurizing the VHSD development zone based on the gas injection wells and steam injection wells, the formation pressure in the VHSD development zone is quickly restored, steam overflow is effectively suppressed, and the oil-gas ratio in the VHSD development zone is greatly improved, ultimately forming a collaborative development model of efficient energy replenishment in the VHSD development zone and gas drive in the old steam stimulation area.

[0011] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 This is a flow chart of a method for efficiently developing a steam throughput old area into a VHSD development area according to the first embodiment of the present invention;

[0014] Figure 2 A schematic diagram of a VHSD development zone to which an embodiment of the present invention is applicable when steam huff-and-puff wells in the peripheral area of ​​the VHSD development zone are selected as gas injection wells;

[0015] Figure 3 A schematic diagram of a VHSD development area when the steam stimulation wells in the peripheral area of ​​the structural high portion to which the embodiment of the present invention is applicable are gas injection wells;

[0016] Figure 4 A schematic diagram of a cross section of a VHSD development area when the steam stimulation wells in the peripheral area of ​​the structural high portion to which the embodiment of the present invention is applicable are gas injection wells;

[0017] Figure 5 This is a flow chart of another method for efficiently developing steam throughput old areas into VHSD development areas for energy replenishment according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0019] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0020] Example 1

[0021] Figure 1 The present invention provides a flow chart of a method for efficiently developing a steam-throwing old area into a VHSD development area. This embodiment is applicable to situations where steam overflow occurs in a VHSD development area during oil and gas collection. Figure 1 As shown, the pressurization method of the VHSD development zone of this embodiment may include the following steps:

[0022] S110. Determine location information of a VHSD development zone adjacent to a steam stimulation development zone based on distribution of development zones within the target mining area.

[0023] The development area distribution includes the distribution location information of the development areas corresponding to different mining methods within the target mining range; the VHSD development area includes at least one steam injection well and production well.

[0024] The target exploitation area may be an oil and gas exploitation area. The steam stimulation development area may be an area where oil and gas are exploited through steam stimulation. The VHSD development area may be an area where oil and gas are exploited through steam-assisted gravity drainage.

[0025] The VHSD development zone was proposed based on the technical concepts of steam drive and steam-assisted gravity drainage, combining the characteristics of my country's geological reservoirs and heavy oil development methods. It adopts a well pattern combining steam injection and horizontal wells. Vertical wells serve as injection wells to continuously inject high-dryness steam into the oil layer, and horizontal wells are arranged at the bottom of the oil layer as production wells to achieve gravity drainage development. It has become the most effective successor development technology in the later stage of steam stimulation.

[0026] When oil and gas production is carried out through the VHSD development zone, steam injection is required in the early stage of the VHSD development zone, but the VHSD development zone is often used in the later stage of steam stimulation, resulting in serious steam leakage. In addition, since the development method of the VHSD development zone is different from that of the steam stimulation development zone, the pressure in the VHSD development zone and the steam stimulation development zone is different, resulting in pressure imbalance in the entire area.

[0027] When determining the VHSD development area, it is necessary to determine the areas for oil and gas exploitation using different exploitation methods based on the distribution of development areas within the target exploitation range, thereby determining the location information of the VHSD development area adjacent to the steam stimulation development area.

[0028] S120. Determine the stratum dip angle of the VHSD development area based on the location information.

[0029] S130. Determine a gas injection well in the VHSD development area based on the formation dip angle in the VHSD development area.

[0030] Gas injection wells may be wells used to inject gas into the area surrounding the VHSD development.

[0031] The formation dip angle can be the angle between the downward direction of the maximum dip line of the rock layer and the projection of the layer on the horizontal plane.

[0032] After obtaining the location information of the VHSD development zone, the specific location of the VHSD development zone can be determined, thereby obtaining the formation dip angle of the VHSD development zone based on previous seismic data or drilling data of the VHSD development zone.

[0033] Since formation dips may vary in different VHSD development areas, and different formation dips will lead to different gas injection well selection results, this application does not restrict the acquisition of formation dips.

[0034] In an optional solution, determining the gas injection wells in the VHSD development area based on the formation dip in the VHSD development area may include steps A1-A2:

[0035] Step A1: If the formation dip is less than a preset dip threshold, the steam stimulation wells in the peripheral area of ​​the VHSD development zone are determined as gas injection wells.

[0036] Step A2: Otherwise, the steam stimulation wells in the peripheral area of ​​the structural high portion in the VHSD development area are determined as gas injection wells.

[0037] The preset inclination angle threshold may be a preset threshold value for distinguishing between two gas injection well selection methods.

[0038] Figure 2 A schematic diagram of a VHSD development zone to which an embodiment of the present invention is applicable when steam huff-and-puff wells in the peripheral area of ​​the VHSD development zone are selected as gas injection wells. Figure 3 A schematic diagram of a VHSD development area when the steam stimulation wells in the peripheral area of ​​the structural high portion to which the embodiment of the present invention is applicable are gas injection wells. Figure 4 A schematic diagram of a cross section of a VHSD development area when the steam stimulation wells in the peripheral area of ​​the structural high portion to which the embodiment of the present invention is applicable are gas injection wells.

[0039] See also Figure 2 、 Figure 3 as well as Figure 4 ,The preset dip threshold can be set in advance through the work experience of ,explorers or according to the actual situation of the VHSD development ,area.

[0040] When the formation dip is less than a preset dip threshold, the steam stimulation wells in the peripheral area of ​​the VHSD development zone will be determined as gas injection wells.

[0041] When the formation dip is greater than or equal to a preset dip threshold, the steam stimulation wells in the peripheral area of ​​the structural high portion in the VHSD development area are determined as gas injection wells.

[0042] Optionally, in addition to the formation dip, the judgment can also be made based on the height difference of the formation structure in the VHSD development area and the preset formation height.

[0043] For example, when the preset formation height is 10 m and the height difference of the formation structure in the VHSD development zone is less than 10 m, the steam stimulation wells in the peripheral area of ​​the VHSD development zone are determined to be gas injection wells.

[0044] When the height difference of the stratum structure in the VHSD development area is greater than 10m, the steam stimulation wells in the peripheral area of ​​the structural high part in the VHSD development area are determined as gas injection wells.

[0045] S140, boost the pressure of the VHSD development area based on the gas injection wells and steam injection wells.

[0046] Since the development of the VHSD development area includes three phases, namely, hot-dip preheating, steam flooding and stable gravity drainage, steam injection will be carried out through steam injection wells during the hot-dip preheating phase to achieve inter-well connectivity between vertical wells and horizontal wells.

[0047] Gas is injected through gas injection wells to reduce gas channeling of the injected steam.

[0048] According to the technical solution of the embodiment of the present invention, by determining the location information of the VHSD development zone adjacent to the steam stimulation development zone based on the distribution of development areas within the target mining range, determining the formation dip of the VHSD development zone based on the location information, determining the gas injection wells in the VHSD development zone based on the formation dip of the VHSD development zone, and pressurizing the VHSD development zone based on the gas injection wells and steam injection wells, rapid recovery of the formation pressure in the VHSD development zone is achieved, steam overflow is effectively suppressed, and the oil-gas ratio of the VHSD development zone is greatly improved, ultimately forming a collaborative development model of efficient energy replenishment in the VHSD development zone and gas drive in the old steam stimulation zone.

[0049] Example 2

[0050] Figure 5 The present invention provides a flowchart of another method for efficiently developing a VHSD development zone by converting an old steam-throwing area into a VHSD development zone. This embodiment further optimizes the process of pressurizing the VHSD development zone according to the gas injection well and the steam injection well in the above embodiment. This embodiment can be combined with various optional solutions in one or more of the above embodiments. Figure 5 As shown, the method for converting an old steam throughput area into a VHSD development area for energy replenishment and efficient development in this embodiment may include the following steps:

[0051] S210. Determine location information of a VHSD development zone adjacent to the steam stimulation development zone based on distribution of development zones within the target mining area.

[0052] S220. Determine the stratum dip angle of the VHSD development area based on the location information.

[0053] S230. Determine the gas injection wells in the VHSD development area based on the formation dip angle in the VHS development area.

[0054] S240. Inject steam into the steam injection well and monitor the pressure in the VHSD development area.

[0055] S250: If the pressure reaches a preset pressure threshold, gas injection into the gas injection well is increased to increase the pressure of the VHSD development area.

[0056] After the injection wells are identified, steam injection is carried out during the preheating phase of the VHSD development area. The pressure in the VHSD development area is continuously monitored during the steam injection. Once the pressure reaches the preset threshold, gas injection is resumed through the injection wells. This reduces steam outflow and increases the pressure in the VHSD development area through gas injection.

[0057] Optionally, in order to quickly reach the preset pressure threshold, a larger injection method can be selected at the initial injection stage, such as an injection rate of 1 to 5 × 10 4 Nm 3 / d.

[0058] In an optional solution, if the pressure reaches a preset pressure threshold, gas injection into the gas injection well is increased to increase the pressure of the VHSD development area, which may include steps B1-B2:

[0059] Step B1: If the pressure reaches a preset pressure threshold, gas is injected into the gas injection well to obtain a gas wall barrier around the VHSD development area.

[0060] Among them, the air wall barrier is used to reduce the overflow of steam injected during the throughput preheating stage.

[0061] Step B2: Pressurize the VHSD development area based on the air wall barrier.

[0062] The gas wall barrier can be generated by injecting gas, thereby blocking the steam when it overflows and reducing the degree of steam overflow.

[0063] As gas is injected into the gas injection well, a gas wall barrier is generated through steam, thereby reducing the overflow of the injected steam in the VHSD development area, so that the pressure in the VHSD development area can be maintained at a certain pressure for a longer period of time.

[0064] In one alternative, pressurizing the VHSD development area based on the air wall barrier may include steps C1-C2:

[0065] Step C1: Determine the steam overflow rate of the injected steam in the VHSD development area based on the air wall barrier.

[0066] Step C2: pressurizing the VHSD development area according to the steam overflow rate and the preset pressure threshold.

[0067] The steam overflow rate can be the degree to which the steam injected into the VHSD development zone overflows per unit time after the gas wall barrier is constructed, and can be determined by the pressure change in the VHSD development zone.

[0068] The efficiency of steam injection into the steam injection well is adjusted by adjusting the steam overflow rate and the preset pressure threshold, thereby pressurizing the VHSD development area.

[0069] In an optional solution, pressurizing the VHSD development area according to the steam overflow rate and the preset pressure threshold may include steps D1-D2:

[0070] Step D1: Determine the steam injection and escape balance efficiency of the steam injected into the VHSD development area based on the steam escape rate and a preset pressure threshold.

[0071] Step D2: adjusting the steam injection rate of the VHSD development zone according to the steam injection and dissipation balance efficiency, and pressurizing the VHSD development zone.

[0072] The steam injection and escape balance efficiency can be the rate at which steam is injected into the steam injection well to ensure that the pressure position of the VHSD development area is at a preset pressure threshold.

[0073] By using the steam overflow rate and the preset pressure threshold, the steam injection rate of the steam injection well can be adjusted so that the steam injected into the steam injection well is balanced with the steam injection and escape efficiency, thereby making the pressure position of the VHSD development area at the pressure threshold.

[0074] According to the technical solution of the embodiments of the present invention, steam is injected into the steam injection well and the pressure of the VHSD development zone is monitored. If the pressure reaches a preset pressure threshold, gas injection into the gas injection well is increased to pressurize the VHSD development zone. This ensures that the pressure in the VHSD development zone is close to the preset pressure threshold, thereby ensuring that the pressure in the VHSD development zone can be fixed at a specific value, thereby reducing the impact on other collection areas.

[0075] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0076] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for efficiently developing an old steam throughput area into a VHSD development area, characterized in that: include: Determine the location information of the VHSD development zone adjacent to the steam stimulation development zone based on the distribution of development zones within the target mining area; wherein the distribution of development zones includes the distribution location information of development zones corresponding to different mining methods within the target mining area; determining a stratum dip angle of the VHSD development area based on the location information; Determining a gas injection well in the VHSD development area according to the formation dip angle in the VHSD development area; The VHSD development area is pressurized according to the gas injection well and the steam injection well.

2. The method according to claim 1, characterized in that Determining a gas injection well in the VHSD development area according to the formation dip in the VHSD development area includes: If the formation dip is less than a preset dip threshold, determining the steam huff-and-puff well in the peripheral area of ​​the VHSD development zone as the gas injection well; Otherwise, the steam stimulation well in the peripheral area of ​​the structural high portion in the VHSD development area is determined as the gas injection well.

3. The method according to claim 2, characterized in that According to the gas injection well and the steam injection well, the VHSD development area is pressurized, including: injecting steam into the steam injection well and monitoring the pressure of the VHSD development area; If the pressure reaches the preset pressure threshold, gas injection into the gas injection well is increased to increase the pressure of the VHSD development area.

4. The method according to claim 3, characterized in that If the pressure reaches the preset pressure threshold, gas injection into the gas injection well is increased to pressurize the VHSD development area, including: If the pressure reaches the preset pressure threshold, gas is injected into the gas injection well to form a gas wall barrier around the VHSD development area; wherein the gas wall barrier is used to reduce the overflow of the steam injected during the throughput preheating stage; The VHSD development area is pressurized according to the air wall barrier.

5. The method according to claim 4, characterized in that Pressurizing the VHSD development area according to the air wall barrier, including: determining a steam escape rate for injected steam in the VHSD development area based on the gas wall barrier; The VHSD development area is pressurized according to the steam overflow rate and the preset pressure threshold.

6. The method according to claim 5, characterized in that Pressurizing the VHSD development area according to the steam overflow rate and the preset pressure threshold, including: Determining a steam injection and escape balance efficiency of steam injected into the VHSD development area based on the steam escape rate and the preset pressure threshold; According to the steam injection and dissipation balance efficiency, the steam injection rate of the VHSD development zone is adjusted to pressurize the VHSD development zone.

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