SAGD injection-extraction method for deep ultra-heavy oil reservoir

Abstract

Disclosed are an SAGD injection-extraction method, apparatus and computer device for a deep ultra-heavy oil reservoir. The injection-extraction method comprises: preheating a horizontal well (10) and vertical wells (20) in a vertical-horizontal combined well network, wherein the vertical-horizontal combined well network comprises a horizontal well (10) and a plurality of vertical wells (21, 22), and the plurality of vertical wells are symmetrically distributed on both sides of the horizontal well; determining whether the preheating treatment is finished or not; and when the preheating treatment is finished, alternately injecting steam into at least some of the plurality of vertical wells, and carrying out SAGD oil extraction by utilizing the horizontal well. By means of the injection-extraction method, heat loss caused by the buried depth during extraction of the deep ultra-heavy oil reservoir can be offset; the rising speed and overlying height of steam cavities at individual steam-injecting well points are effectively controlled, thereby preventing single-point breakthrough of steam, which facilitates an improvement in the development of the steam cavities; and extraction of the deep ultra-heavy oil reservoir is achieved, and the extraction ratio of the deep oil reservoir is largely guaranteed.

Description

A SAGD injection-production method for deep ultra-heavy oil reservoirs Technical Field

[0001] The embodiments of this specification relate to the field of oil reservoir development technology, and in particular to a SAGD injection and production method for deep ultra-heavy oil reservoirs. Background Art

[0002] SAGD (Steam Assisted Gravity Drainage) is a cutting-edge technology for developing extra-heavy oil. Its extraction mechanism involves injecting high-dryness steam into a steam injection well. The steam overlays the formation upward, forming a steam cavity. This cavity then expands upward and laterally, exchanging heat with the crude oil in the reservoir. The heated, viscosity-reduced crude oil and steam condensate then drain by gravity into the horizontal production well below, where the steam cavity continues to expand and consumes the crude oil. This technology has been successfully implemented in extra-heavy oil reservoirs and has achieved excellent results. It has significantly reversed the trend of declining annual oil production from steam stimulation, offering high oil recovery rates and low production costs. It is considered one of the thermal recovery technologies with the highest recovery rates.

[0003] However, due to their depth, deep (defined as those buried below 1,000 to 1,500 meters in the ground) ultra-heavy oil reservoirs are generally developed using a huff-and-puff method, which yields a recovery rate of only 25%, despite significant potential for enhanced recovery. Under existing steam injection and insulation processes, the bottomhole steam quality at a well depth of 1,500 meters can only reach 40%. Deep reservoirs have high side and bottom water pressures, necessitating high steam chamber pressures to balance the side and bottom water pressures and prevent water intrusion. This results in SAGD effectively heating the oil layer in the deep reservoir to less than half the heat of the shallower layer, making effective steam chamber formation difficult. High cycles of steam huff-and-puff development lead to severe reservoir heterogeneity, and switching to SAGD steam injection causes the steam chamber to rapidly rise to the oil cap, making balanced expansion of the steam chamber difficult. In other words, existing SAGD development methods are difficult to apply to the development and production of deep ultra-heavy oil reservoirs.

[0004] In view of this, this specification aims to provide a SAGD injection and production method for deep ultra-heavy oil reservoirs.

[0005] Summary of the Invention

[0006] In view of the above problems of the prior art, the purpose of the embodiments of this specification is to provide a SAGD injection and production method for deep ultra-heavy oil reservoirs to solve the problem that the existing SAGD reservoir development injection and production methods are difficult to apply to deep ultra-heavy oil reservoirs.

[0007] In order to solve the above technical problems, the specific technical solutions of the embodiments of this specification are as follows:

[0008] In a first aspect, the embodiments of this specification provide a SAGD injection-production method for a deep ultra-heavy oil reservoir, comprising:

[0009] Preheating the horizontal wells and vertical wells in a vertical-horizontal combination well pattern, wherein the vertical-horizontal combination well pattern includes a horizontal well and a plurality of vertical wells, wherein the plurality of vertical wells are symmetrically distributed on both sides of the horizontal well;

[0010] Determining whether the preheating treatment is completed;

[0011] When the preheating treatment is completed, steam is injected into at least part of the plurality of vertical wells in rotation, and the horizontal wells are used to switch to SAGD oil production.

[0012] In some preferred embodiments, the plurality of vertical wells include at least two first vertical wells and at least two second vertical wells, the first vertical wells and the second vertical wells located on the same side of the horizontal well are alternately arranged, and a pair of vertical wells symmetrically located on both sides of the horizontal well are the first vertical well and the second vertical well, respectively; and the step of alternately injecting steam into at least part of the plurality of vertical wells includes:

[0013] Steam is injected into all the first vertical wells or all the second vertical wells in rotation for a preset time respectively until the oil production of the horizontal well is completed or a preset rotation round is reached.

[0014] In some preferred embodiments, after the preheating treatment is completed, steam is injected into at least part of the plurality of vertical wells in rotation, and the horizontal wells are used to switch to SAGD oil production, including:

[0015] adjusting injection parameters when rotating steam injection into at least a portion of the plurality of vertical wells; and

[0016] The production parameters when converting the horizontal well to SAGD oil production are adjusted.

[0017] In some preferred embodiments, the injection parameters include at least the steam quality, injection rate and injection period of the injected steam, and the production parameters include at least the production-injection ratio and the operating pressure of the steam chamber formed between the horizontal well and the vertical well.

[0018] In some preferred embodiments, adjusting injection parameters when rotating steam injection into at least part of the plurality of vertical wells, and adjusting production parameters when switching to SAGD oil production using the horizontal wells, further comprises:

[0019] Conduct sensitivity analysis on various injection parameters and production parameters;

[0020] According to the results of sensitivity analysis, determine the order of adjustment between each injection parameter and each production parameter;

[0021] The injection parameters and the production parameters are adjusted according to the sequence.

[0022] In some preferred embodiments, the steam quality is adjusted to be greater than 65%, the steam injection rate is adjusted to 120-140 t / d, the production-injection ratio is adjusted to 1.2, the operating pressure is adjusted to 4.5-6 MPa, and the steam injection cycle is adjusted to 2-3 months.

[0023] In some preferred embodiments, determining whether the preheating treatment is completed further includes:

[0024] Obtaining the interwell temperature and interwell formation pressure between the horizontal well and the vertical well;

[0025] Determining whether the interwell temperature reaches a preset temperature and whether the interwell formation pressure reaches a preset pressure;

[0026] If yes, the preheating process is completed.

[0027] In some preferred embodiments, determining whether the preheating treatment is completed further includes:

[0028] Obtaining the underground temperature field distribution between the horizontal wells and the vertical wells through oil well temperature measurement results and / or numerical simulation methods;

[0029] determining whether the horizontal well and the vertical well are thermally connected according to the temperature field distribution;

[0030] If yes, the preheating process is completed.

[0031] In some preferred embodiments, determining whether the preheating treatment is completed further includes:

[0032] Obtaining the crude oil viscosity of the deep ultra-heavy oil reservoir;

[0033] Determining whether the crude oil viscosity is less than or equal to a preset viscosity threshold;

[0034] If yes, the preheating process is completed.

[0035] In some preferred embodiments, determining whether the preheating treatment is completed includes:

[0036] Obtaining the degree of recovery of the deep ultra-heavy oil reservoir after the horizontal well and the vertical well complete the current round of preheating during the preheating process;

[0037] Determining whether the recovery degree is greater than a preset recovery degree threshold;

[0038] If so, obtaining the interwell temperature and interwell formation pressure between the horizontal well and the vertical well;

[0039] Determining whether the interwell temperature reaches a preset temperature and whether the interwell formation pressure reaches a preset pressure;

[0040] If yes, the preheating treatment is completed;

[0041] If not, continue to perform preheating treatment on the horizontal well and the vertical well.

[0042] In some preferred embodiments, the horizontal wells and vertical wells in the vertical-horizontal combination well pattern are preheated by using a throughput preheating method.

[0043] In some preferred embodiments, the throughput warm-up is performed in 2-5 rounds.

[0044] In some preferred embodiments, before preheating the horizontal wells and vertical wells in the vertical-horizontal combination well pattern, the method further comprises:

[0045] Establishing a three-dimensional geological model for the deep ultra-heavy oil;

[0046] Calculating the well spacing between horizontal wells and each vertical well, and between vertical wells in the vertical-horizontal combined well pattern according to the plane grid division of the three-dimensional geological model;

[0047] Calculating the horizontal wells in the vertical-horizontal combination well pattern and the formations where the vertical wells are located based on the vertical grid division of the three-dimensional geological model;

[0048] According to the calculation results, a straight-horizontal combined well pattern is set in the deep ultra-heavy oil reservoir.

[0049] In some preferred embodiments, the straight-horizontal combination well pattern further includes auxiliary drainage wells, which are connected to the horizontal wells to assist in oil production and drainage of the horizontal wells.

[0050] In a second aspect, the embodiments of this specification provide a SAGD injection and production system for a deep ultra-heavy oil reservoir, comprising:

[0051] a processing module for preheating horizontal wells and vertical wells in a vertical-horizontal combination well pattern, wherein the vertical-horizontal combination well pattern includes a horizontal well and a plurality of vertical wells, wherein the plurality of vertical wells are symmetrically distributed on both sides of the horizontal well;

[0052] A judging module, configured to judge whether the preheating process is completed;

[0053] The injection and production module is used to rotate steam injection into at least part of the plurality of vertical wells when the preheating treatment is completed, and utilize the horizontal wells to switch to SAGD oil production.

[0054] In some preferred embodiments, the device further comprises:

[0055] Establishing a module for establishing a three-dimensional geological model of the deep ultra-heavy oil;

[0056] A first calculation module is configured to calculate the well spacing between horizontal wells and each of the vertical wells, and between vertical wells in the vertical-horizontal combined well pattern according to the plane grid division of the three-dimensional geological model;

[0057] A second calculation module is configured to calculate the horizontal wells in the vertical-horizontal combination well pattern and the formations where the vertical wells are located based on the vertical grid division of the three-dimensional geological model;

[0058] The setting module is used to set a straight and horizontal combination well pattern in the deep ultra-heavy oil reservoir according to the calculation results.

[0059] In a third aspect, an embodiment of this specification also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method provided by the above technical solution when executing the computer program.

[0060] In a fourth aspect, an embodiment of this specification further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method provided by the above technical solution is implemented.

[0061] In a fifth aspect, an embodiment of this specification also provides a computer program product, comprising at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to implement the method provided by the above technical solution.

[0062] By adopting the above technical solution, the embodiments of this specification provide a SAGD injection and production method, device and computer equipment for deep ultra-heavy oil reservoirs. By symmetrically arranging multiple vertical wells on both sides of the horizontal well to form a vertical and horizontal combination well pattern, and after preheating the horizontal wells and the vertical wells, steam is injected into at least part of the vertical wells by rotating steam injection, thereby compensating for the heat loss caused by the burial depth during the exploitation of deep ultra-heavy oil reservoirs; effectively controlling the steam cavity rising speed and overburden height of individual steam injection well points, preventing single-point steam breakthrough, and improving the development of the steam cavity; solving the technical difficulty of the existing SAGD exploitation technology in applying to deep ultra-heavy oil reservoirs, realizing the exploitation of deep ultra-heavy oil reservoirs and greatly ensuring the recovery rate of similar deep oil reservoirs.

[0063] In order to make the above and other purposes, features and advantages of the embodiments of this specification more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0065] FIG1 shows a schematic diagram of the steps of a SAGD injection-production method for a deep ultra-heavy oil reservoir provided in an embodiment of this specification;

[0066] FIG2 shows a schematic structural diagram of a straight-horizontal combined well pattern in an embodiment of this specification;

[0067] FIG3 shows a simulated daily oil production curve for exploitation of deep ultra-heavy oil reservoirs using a rotation steam injection method and a continuous steam injection method;

[0068] FIG4 shows a comparison of the recovery degree and cumulative oil-gas ratio of deep ultra-heavy oil reservoirs when using a rotation steam injection method and a continuous steam injection method;

[0069] FIG5 is a schematic diagram showing the steps of adjusting injection parameters and production parameters in an embodiment of this specification;

[0070] FIG6 shows a schematic diagram of the changes in the SAGD oil recovery degree and the cumulative oil-gas ratio of the production well under different simulated steam chamber operating pressures;

[0071] FIG7 shows a daily oil production curve of SAGD oil production of a production well under different simulated steam chamber operating pressures;

[0072] FIG8 shows a schematic diagram of steam cavity development under different simulated steam cavity operating pressures;

[0073] FIG9 shows a simulated daily oil production curve of SAGD oil production of production wells under different steam injection dryness;

[0074] FIG10 shows a schematic diagram of the simulated SAGD oil recovery and cumulative oil-gas ratio changes of production wells under different steam injection dryness;

[0075] FIG11 shows a curve diagram showing the simulated SAGD oil recovery rate and cumulative oil-gas ratio change of production wells under different steam injection dryness;

[0076] FIG12 shows a schematic diagram showing the relationship between different steam injection rates, different steam injection temperatures and bottomhole steam quality under the simulated steam chamber operating pressure of 6 MPa;

[0077] FIG13 shows a graph showing the simulated oil-gas ratio and cumulative oil production curves of SAGD production wells under different production-injection ratios;

[0078] FIG14 shows a schematic diagram of the staged recovery degree and cumulative oil-gas ratio changes of horizontal well SAGD oil production under different simulated rotation steam injection cycles;

[0079] FIG15 is a schematic diagram showing the steps of determining whether the preheating treatment is completed in an embodiment of this specification;

[0080] FIG16 is a schematic diagram showing another step of determining whether the preheating treatment is completed in an embodiment of this specification;

[0081] FIG17 shows a graph showing the relationship between the simulated conversion flooding recovery degree and the average daily oil production;

[0082] FIG18 shows a graph showing the relationship between the simulated rotary flooding recovery degree and the oil-gas ratio;

[0083] FIG19 shows a comparison of the recovery factor and oil-gas ratio at different simulated flooding times;

[0084] FIG20 is a schematic diagram showing the steps of setting a straight-horizontal combination well pattern in a deep ultra-heavy oil reservoir according to an embodiment of this specification;

[0085] FIG21 shows a schematic structural diagram of a SAGD injection-production device for a deep ultra-heavy oil reservoir provided in an embodiment of this specification;

[0086] FIG22 shows a schematic structural diagram of a computer device provided in an embodiment of this specification;

[0087] FIG23 shows a first relationship diagram of bottom hole steam quality changing with well depth at different steam injection rates;

[0088] FIG24 shows a second relationship diagram showing the change of bottom hole steam quality with steam injection rate under different well depth conditions.

[0089] Explanation of the symbols in the accompanying drawings: 10, horizontal well; 20, vertical well; 21, first vertical well; 22, second vertical well; 2110, processing module; 2120, judgment module; 2130, injection and production module; 2202, computer equipment; 2204, processor; 2206, memory; 2208, driving mechanism; 2210, input / output module; 2212, input device; 2214, output device; 2216, presentation device; 2218, graphical user interface; 2220, network interface; 2222, communication link; 2224, communication bus. DETAILED DESCRIPTION

[0090] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this specification.

[0091] It should be noted that the terms "first," "second," and the like in this specification, the claims, and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this specification 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, apparatus, product, or device comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0092] Existing SAGD reservoir development and injection methods are difficult to apply to deep ultra-heavy oil reservoirs. The steam chamber of deep ultra-heavy oil reservoirs is difficult to fully expand and stably drain oil, and cannot meet the requirements of high-dryness injection and large-volume lifting. In order to solve the above problems, the embodiment of this specification provides a SAGD injection and production method and device for deep ultra-heavy oil reservoirs. Figure 1 is a step diagram of a SAGD injection and production method for deep ultra-heavy oil reservoirs provided by the embodiment of this specification. This specification provides method operation steps as described in the embodiment or flow chart, but based on conventional or non-creative labor, more or fewer operation steps may be included. The order of steps listed in the embodiment is only one way of executing the steps among many, and does not represent the only execution order. When the system or device product is executed in practice, it can be executed in the order of the method shown in the embodiment or the accompanying drawings or in parallel.

[0093] It should be noted that the SAGD injection and production method for deep ultra-heavy oil reservoirs provided in the embodiments of this specification is applicable to ultra-heavy oil and super-heavy oil, wherein super-heavy oil refers to a reservoir with a viscosity greater than 10,000 mPa.s, and super-heavy oil refers to a reservoir with a viscosity greater than 50,000 mPa.s; deep refers to a reservoir with a burial depth of 1,000 to 1,500 meters underground.

[0094] Specifically, as shown in FIG1 , the method may include:

[0095] S110: Preheating the horizontal wells and vertical wells in a straight-horizontal combination well pattern, wherein the straight-horizontal combination well pattern includes one horizontal well and multiple vertical wells, and the multiple vertical wells are symmetrically distributed on both sides of the horizontal well.

[0096] As shown in FIG2 , it is a schematic diagram of the structure of the straight-horizontal combination well pattern described in the embodiments of this specification.

[0097] It should be noted that, due to the influence of factors such as topography, the multiple vertical wells are symmetrically distributed on both sides of the horizontal well, which means that the number of vertical wells on both sides of the horizontal well is equal or the difference in the number of vertical wells on both sides is within a preset number difference range; and the distances between a pair of vertical wells symmetrically arranged on both sides of the horizontal well and the horizontal well are equal or the difference in distances is within a preset distance difference range, and it is not necessarily completely symmetrical.

[0098] In the embodiments of this specification, preheating of the horizontal wells and each vertical well in the vertical-horizontal combination well network can be achieved by injecting steam using injection pipes pre-installed in the horizontal wells and each vertical well, and computer control of the opening (including the opening degree) and closing of the injection pipes.

[0099] S120: Determine whether the preheating process is completed.

[0100] S130: When the preheating treatment is completed, steam is injected into at least part of the plurality of vertical wells in rotation, and the horizontal wells are used to switch to SAGD oil production.

[0101] In the embodiments of this specification, after preheating is complete, the horizontal well is used as a production well and the vertical well is used as an injection well. Furthermore, when injecting steam into the vertical well, a rotational steam injection method is employed, whereby steam is first injected into at least a portion of the vertical well for a predetermined period of time, followed by steam injection into at least the remaining portion of the vertical well for a predetermined period of time. This cycle repeats until oil production from the horizontal well is complete. Thus, during the production process of the horizontal well, one vertical well is always used as an injection well for steam injection; however, for the same vertical well, steam injection is intermittent during the production process.

[0102] If continuous steam injection is used for all vertical wells during horizontal well production, the expansion morphology of the steam chambers at different steam injection well points will be quite different due to reservoir heterogeneity and the influence of continuous steam injection at the steam injection well points. The longitudinal expansion speed of the steam chamber formed will gradually accelerate and exceed its lateral expansion speed, and the lateral expansion will mainly occur in the upper part of the steam chamber, while the lateral expansion speed of the lower part of the steam chamber will be very low. The steam chamber rising speed of individual steam injection well points is fast and the overburden height is high, which makes it easy for steam single-point breakthrough to occur. The embodiment of this specification adopts a rotating steam injection method, so that the steam chambers formed by the vertical well currently being steam injected and the two adjacent wells not being steam injected will gradually connect in the horizontal direction and expand into a larger steam chamber, which is conducive to the expansion and development of the steam chamber. With the expansion of the steam chamber, it is conducive to the enhancement of the oil well's oil drainage capacity, and the displacement of crude oil will gradually shift from steam displacement to steam-assisted gravity drainage, which is conducive to SAGD oil production operations.

[0103] The embodiments of this specification provide a SAGD injection and production method for deep ultra-heavy oil reservoirs. The method comprises the following steps: symmetrically arranging multiple vertical wells on both sides of a horizontal well to form a vertical-horizontal combination well pattern; and after preheating the horizontal wells and the vertical wells, performing steam injection on at least some of the vertical wells by rotating steam injection. This method compensates for the heat loss caused by the burial depth during the production of deep ultra-heavy oil reservoirs; effectively controls the steam cavity rising speed and overburden height of individual steam injection well points, prevents single-point steam breakthrough, and improves the development of the steam cavity. This method solves the technical difficulty of applying existing SAGD production technology to deep ultra-heavy oil reservoirs, realizes the production of deep ultra-heavy oil reservoirs, and greatly guarantees the recovery rate of similar deep reservoirs.

[0104] Furthermore, as shown in Figure 2, the multiple vertical wells 20 include at least two first vertical wells 21 and at least two second vertical wells 22. The first vertical wells 21 and the second vertical wells 22 located on the same side of the horizontal well 10 are alternately arranged, and a pair of vertical wells 20 symmetrically separated on both sides of the horizontal well 10 are the first vertical wells 21 and the second vertical wells 22 respectively.

[0105] 2 , the second vertical well 22 is adjacent to any one of the first vertical wells 21 and is arranged relative to the first vertical well 21 and relative to the horizontal well 10 ; similarly, the first vertical well 21 is adjacent to and relative to any one of the second vertical wells 22 .

[0106] Then, in step S130, rotating the steam injection into at least part of the plurality of vertical wells may be further performed as follows:

[0107] Steam is injected into all the first vertical wells or all the second vertical wells in rotation for a preset time respectively until the oil production of the horizontal well is completed or a preset rotation round is reached.

[0108] That is, during one rotation process, only one of any two adjacent vertical wells is in a steam injection state; and only one of a pair of vertical wells symmetrically separated on both sides of the horizontal well is in a steam injection state.

[0109] As shown in Figure 3, a simulated daily oil production curve for deep, ultra-heavy oil reservoirs using the rotating steam injection method provided in the embodiments of this specification and the existing continuous steam injection method is shown. Point A in Figure 3 represents the end point of stable production for the deep, ultra-heavy oil reservoir using the continuous steam injection method, and point B represents the end point of stable production for the deep, ultra-heavy oil reservoir using the rotating steam injection method. The stable production end point refers to the time point when the steam chamber begins to slowly expand downward from the boundaries of the oil reservoir top. As can be seen from Figure 3, during the SAGD injection and production process, the daily oil production of horizontal wells using rotating steam injection is higher than that of horizontal wells using continuous steam injection. Furthermore, the stable production end point of horizontal wells using rotating steam injection is later than that of horizontal wells using continuous steam injection, indicating that horizontal wells using rotating steam injection have longer stable production periods and higher production efficiency.

[0110] Figure 4 compares the recovery rate and cumulative oil-gas ratio of a simulated deep, ultra-heavy oil reservoir using rotating steam injection and continuous steam injection. As shown in Figure 4, the recovery rate and cumulative oil-gas ratio of horizontal wells are higher when rotating steam injection is used in vertical wells than when continuous steam injection is used in vertical wells.

[0111] Therefore, adopting the vertical and horizontal combination well pattern provided in the embodiments of this specification and adopting the rotation steam injection method for each vertical well in the SAGD injection and production development stage is conducive to extending the stable production period of horizontal well deep ultra-heavy oil reservoir exploitation and improving the recovery rate.

[0112] Furthermore, in the embodiment of this specification, step S130: after the preheating treatment is completed, rotating steam injection into at least part of the plurality of vertical wells and utilizing the horizontal wells to switch to SAGD oil production may include:

[0113] Adjusting injection parameters when rotating steam injection into at least part of the plurality of vertical wells, the injection parameters including at least steam quality, steam injection rate, and steam injection period of the injected steam; and

[0114] The production parameters when converting the horizontal well to SAGD oil production are adjusted, and the production parameters at least include the production-injection ratio and the operating pressure of the steam chamber formed between the horizontal well and the vertical well.

[0115] The production-injection ratio is the ratio of the oil production from the horizontal well to the steam injection rate into the vertical well; and the steam chamber operating pressure refers to the pressure at which development occurs in the formation during the SAGD injection-production process. Specifically, the SAGD injection-production method for deep ultra-heavy oil reservoirs provided in the embodiments of this specification regulates the aforementioned injection and production parameters before or during SAGD injection-production in the reservoir to improve the reservoir's recovery factor.

[0116] It should be noted that in some other feasible embodiments, fewer or higher injection and production parameters can be adjusted, or other injection and production parameters can also be adjusted, for example, the steam temperature, superheat and steam injection pressure during steam injection can also be included.

[0117] Specifically, as shown in FIG5 , adjusting the injection parameters when rotating steam injection into at least part of the plurality of vertical wells, and adjusting the production parameters when switching to SAGD oil production using the horizontal wells, further includes:

[0118] S510: Perform sensitivity analysis on each injection parameter and each production parameter.

[0119] Sensitivity analysis can be used to determine the degree to which an input variable affects an output variable. This degree of influence is called the sensitivity coefficient of the input variable. The sensitivity coefficient represents the importance of the input variable to the output variable. The larger the sensitivity coefficient, the greater the impact of the input variable on the output variable, and vice versa.

[0120] In the embodiments of this specification, the input variables are the steam quality, steam injection rate and steam injection period of the above-mentioned injected steam, as well as the production-injection ratio and the operating pressure of the steam chamber; the output variables can be set to one or more of the daily oil production and cumulative oil-steam ratio of the deep ultra-heavy oil reservoir.

[0121] The sensitivity analysis can be established based on the response surface analysis method in the design of experiments (Design of Experiment, DOE). Experimental design is a method for scientifically formulating experimental plans, rationally planning experimental types and times to comprehensively analyze data, which can shorten the experimental cycle, reduce experimental costs, and obtain satisfactory results. There are many methods for DOE: full factorial design, orthogonal experimental design, uniform design, response surface analysis method (RSM), artificial neural network (ANN) and genetic algorithm (GA) etc. In the embodiments of this specification, the sensitivity analysis method adopted is not specifically limited.

[0122] S520: Determine the order of adjustment between the injection parameters and the production parameters based on the sensitivity analysis results.

[0123] That is, the sensitivity coefficients of the above-mentioned input variables relative to the output variables are calculated, and the order of adjustment between the injection parameters and the mining parameters is determined according to the size of the sensitivity coefficients: the larger the sensitivity coefficient, the higher the order, and vice versa.

[0124] S530: Adjusting the injection parameters and the production parameters according to the sequence.

[0125] In the examples of this specification, the deep ultra-heavy oil reservoir has a burial depth of 1400 to 1690 m, an average oil layer thickness of 160 m, a porosity of 18.1%, and a permeability of 1381×10 -3 μm 2 , cumulative oil production of 354,000 tons, cumulative water production of 877,000 tons. A sensitivity analysis of the injection parameters and production parameters of this deep ultra-heavy oil reservoir was conducted, and the sensitivity coefficient relationship of each parameter was obtained as follows:

[0126] The operating pressure of the steam chamber > steam quality > steam injection rate > production-injection ratio > steam injection cycle.

[0127] In the embodiment of this specification, step S520: determining the order of adjusting the injection parameters and the production parameters according to the sensitivity analysis results, can be:

[0128] The injection parameters and production parameters are adjusted in descending order according to the sensitivity coefficient results obtained from the sensitivity analysis.

[0129] It should be noted that the above sensitivity analysis results correspond to the above-mentioned deep ultra-heavy oil reservoir targeted by the embodiments of this specification. For other reservoirs, their sensitivity analysis results may be different from the above-mentioned sensitivity analysis results.

[0130] The steam chamber operating pressure is then adjusted based on the sensitivity analysis results. Figure 6 shows the simulated SAGD oil recovery and cumulative oil-gas ratio for a production well under different steam chamber operating pressures. As shown in Figure 6, as the steam chamber operating pressure increases, the recovery decreases while the cumulative oil-gas ratio increases. However, when the steam chamber operating pressure increases to above 4.0 MPa, the reduction in recovery slows and the cumulative oil-gas ratio decreases.

[0131] Figure 7 shows the simulated daily oil production curves of SAGD production wells at different steam chamber operating pressures. As shown in Figure 7, as the steam chamber operating pressure increases, the SAGD peak daily oil production decreases.

[0132] Figure 8 shows the simulated steam cavity development at different steam cavity operating pressures. As shown in Figure 8, as the operating pressure increases, the steam cavity rises faster, heat loss to the top cover increases, the lateral expansion of the steam cavity decreases, and the swept volume decreases.

[0133] The steam chamber operating pressure affects the amount of heat carried by the steam. High operating pressures reduce the latent heat of vaporization, while low operating pressures make it difficult to guarantee liquid production. Therefore, based on the simulation results in Figures 6 through 8, the steam chamber operating pressure for the deep, ultra-heavy oil reservoir described in the examples herein is ideally controlled within the 4.5-6 MPa range during the SAGD injection-production phase to achieve optimal liquid supply and a high oil-to-gas ratio.

[0134] Furthermore, the steam dryness is adjusted. Figure 9 is a simulated daily oil production curve of SAGD oil production in production wells under different steam injection dryness, and Figure 10 is a schematic diagram of the changes in the recovery degree and cumulative oil-gas ratio of SAGD oil production in production wells under different steam injection dryness. As shown in Figures 9 and 10, with the increase of steam dryness, the daily oil production peak increases, the production time of the SAGD injection and production stage is shortened, and the oil production rate is increased; the latent heat of vaporization increases, the swept volume increases, and the cumulative oil-gas ratio shows an increasing trend. However, after the steam dryness is greater than 65%, the sensitivity of SAGD cumulative oil production to steam dryness decreases; after the dryness exceeds 60%, the recovery degree remains basically stable. Therefore, in the embodiment of this specification, the bottom hole steam dryness is adjusted to be greater than 65%.

[0135] Furthermore, the steam injection rate was adjusted. Figure 11 shows the simulated SAGD oil recovery and cumulative oil-gas ratio curves for production wells at different steam injection densities. As shown in Figure 11, with increasing steam injection rate, the staged recovery and cumulative oil-gas ratio decrease slightly. When the steam injection rate exceeds 120 t / d, the staged recovery and oil-gas ratio remain stable.

[0136] In another feasible embodiment, the gas injection rate can be obtained by the following steps:

[0137] Establishing a first relationship diagram of the change of bottom hole steam quality with well depth under different steam injection rates and a second relationship diagram of the change of bottom hole steam quality with steam injection rate under different well depth conditions;

[0138] The steam quality and steam injection rate of the steam injection steam are determined according to the first relationship diagram and the second relationship diagram.

[0139] Figure 23 shows the first relationship between bottomhole steam quality and well depth at different steam injection rates. Under the same bottomhole pressure, the higher the steam injection rate, the lower the heat loss along the wellbore and the higher the bottomhole quality. The greater the friction loss, the higher the required wellhead injection pressure. For every 10 t / d increase in steam injection rate, the steam pressure increases by approximately 0.7 MPa. As the steam injection rate increases, the bottomhole steam quality increases linearly. A low steam injection rate makes it difficult to maintain bottomhole steam quality. A higher steam injection rate, however, requires a higher injection pressure, which limits the well group's drainage capacity and can easily lead to an injection-production imbalance, impacting development effectiveness.

[0140] As shown in Figure 24, this is a second relationship diagram of the change of bottomhole steam dryness with steam injection rate under different well depth conditions. It can be seen that the bottomhole steam dryness of deep oil reservoirs (burial depth of 1500m) increases linearly with the injection rate in two stages. The inflection point value of the steam injection rate is 150t / d. The steam dryness increases greatly in the first stage (the dryness increases by about 2% for every 10t / d increase in steam injection rate); after exceeding the inflection point value of the injection rate, the steam dryness decreases with the increase of the injection rate.

[0141] Based on the first relationship diagram and the second relationship diagram, it is determined that the steam injection rate is in the range of 120-140t / d.

[0142] Figure 12 shows the relationship between different steam injection rates, injection temperatures, and bottomhole steam quality at a simulated steam chamber operating pressure (6 MPa). Figure 12 shows that, for a constant steam chamber operating pressure and the same injection temperature, bottomhole steam quality increases with increasing injection rate. Similarly, for the same injection rate, bottomhole steam quality increases with increasing injection temperature.

[0143] Therefore, based on FIG. 11 and FIG. 12 , in the embodiment of this specification, the steam injection rate during rotation steam injection in the vertical well is adjusted within the range of 120-140 t / d.

[0144] Figure 13 shows the simulated oil-gas ratio and cumulative oil production curves for SAGD production at different production-injection ratios. As shown in Figure 13, when the production-injection ratio is less than 1.2, bottomhole pressure increases, affecting the expansion of the vapor cavity, reducing the oil drainage rate, and deteriorating production efficiency. When the production-injection ratio exceeds 1.2, the vapor cavity expansion rate changes little, and the cumulative oil production and oil-gas ratio no longer increase. In the examples herein, the production-injection ratio for deep ultra-heavy oil is ultimately adjusted to 1.2 or higher.

[0145] It should be noted that in the embodiments of this specification, the vertical-horizontal combination well pattern includes multiple vertical wells. During SAGD injection and production, multiple vertical wells are in steam injection mode, and the total amount of steam injected into the vertical wells is relatively large. Therefore, to ensure that the injection-production ratio between the oil production of the horizontal wells and the amount of steam injected into the vertical wells is greater than or equal to 1.2, the vertical-horizontal combination well pattern may also be equipped with auxiliary drainage wells (not shown). The auxiliary drainage wells are connected to the horizontal wells to assist in oil production and fluid drainage from the horizontal wells.

[0146] Furthermore, the steam injection cycle is adjusted. Figure 14 is a schematic diagram of the stage recovery degree and cumulative oil-gas ratio changes of horizontal well SAGD oil production under different simulated rotation steam injection cycles. As shown in Figure 14, as the rotation steam injection cycle increases, the stage recovery degree decreases, while the cumulative oil-gas ratio remains stable. Therefore, in the embodiment of this specification, the rotation steam injection cycle of the vertical well is adjusted to 2-3 months. That is, after suspending steam injection into all second vertical wells and injecting steam into all first vertical wells for 2-3 months, suspending steam injection into all first vertical wells and injecting steam into all second vertical wells for 2-3 months, and repeating this process until the horizontal well oil production is completed.

[0147] In summary, the optimized and adjusted injection and sampling parameters in the embodiments of this specification are shown in the following table:

[0148] Injection and production parameter table

[0149] By adjusting the injection parameters and production parameters mentioned above when switching to SAGD injection and production, deep ultra-heavy oil reservoirs can be utilized to the greatest extent, which is beneficial to improving the extraction and development efficiency of deep ultra-heavy oil reservoirs.

[0150] In some preferred embodiments, step S130: after the preheating treatment is completed, rotating steam injection into at least part of the plurality of vertical wells and utilizing the horizontal wells to switch to SAGD oil production may include:

[0151] monitoring a steam chamber formed between the horizontal well and the vertical well;

[0152] According to the monitored development characteristics of the steam chamber, the steam injection process of at least a portion of the vertical well and the conversion of the horizontal well to SAGD oil production are divided into a steam chamber rising stage, a steam chamber expansion stage, and a steam chamber descending stage;

[0153] Injection parameters when rotating steam injection into at least part of the plurality of vertical wells are adjusted in each stage, and production parameters when switching to SAGD oil production using the horizontal wells are adjusted in each stage.

[0154] Since the development characteristics of the steam chamber correspond to the production characteristics of the production well, in the embodiment of this specification, the steam chamber development process is divided into three stages according to the development characteristics of the steam chamber. The development characteristics of the steam chamber and the production characteristics of the production well in these three development stages are as follows:

[0155] (1) Steam chamber rising stage

[0156] The numerical modeling results show that thermal connectivity between the vertical and horizontal wells was established 20 days after steam injection, with the temperature between the two wells exceeding 80°C. The crude oil between the wells exhibited some fluidity. A steam cavity had formed around the wells, but it was relatively small.

[0157] At this time, the steam chamber developed toward the top of the reservoir under the overlying effect, first expanding along the direction of thermal connectivity advantage; the vertical expansion speed of the steam chamber was slightly faster than the planar expansion speed (about 1.1 times); the steam chamber of a single well had gradually risen to the top of the oil layer; the steam chamber was well developed in the direction perpendicular to the horizontal well section, and was locally continuously distributed; while along the horizontal well section, the steam chamber was only a single point in form, without continuous development, which lasted about 15 months.

[0158] According to the temperature profile and crude oil flow vector perpendicular to the horizontal well direction, the height of the steam chamber is relatively small in the early stage, the crude oil is less affected by gravity, and steam displacement is the main method. When the steam chamber rises to the top of the oil layer, gravity drainage becomes obvious. The volume of the steam chamber at this stage is 15m 3 / d, the daily oil production continues to rise to 50t / d. The recovery rate in this stage is low, and the reserve recovery rate is 4-5%.

[0159] (2) Steam chamber expansion stage

[0160] After the steam cavity of a single well reaches the top of the oil layer, it gradually expands laterally and begins to coalesce from a dispersed state. Eventually, the front edge of the cavity reaches the reservoir boundary, forming a series of inverted conical steam cavities with continuous tops. This process lasts for 50 months.

[0161] The temperature profile and crude oil flow vector diagram show that the steam chamber is significantly developed in the upper part of the horizontal well section. Under the action of gravity, the crude oil in the oil layer flows downward along the interface between the steam chamber and the crude oil into the horizontal well. The volume of the steam chamber increases rapidly (50m 3 / d), with daily oil production maintained at a high level and the recovery rate in the reserve utilization stage reaching 16%.

[0162] (3) Steam chamber descending stage

[0163] The steam chamber slowly developed downward from the boundaries of both sides of the oil layer top, and finally the area above the horizontal production well was basically filled with the steam chamber, which took 40 months.

[0164] The gravity drainage height gradually decreases, and the daily oil production also decreases accordingly. When the horizontal well steam breaks through, the oil production will drop sharply to the economic limit. The SAGD process ends, and the recovery rate in the reserve utilization stage is 13%.

[0165] In addition, the injection parameters and production parameters are adjusted in detail according to the steam chamber development characteristics and production characteristics of the production wells in each stage, as shown in the steam chamber development stage and injection and production parameter comparison table:

[0166] Comparison table of steam chamber development stages and injection and production parameters

[0167] By dividing the injection and production stages of steam injection in vertical wells and conversion of horizontal wells to SAGD oil production into three stages according to the development characteristics of the steam cavity, and finely adjusting the injection parameters and production parameters within the three stages, it is beneficial to improve the oil reservoir recovery rate and enhance the mining and development efficiency of deep ultra-heavy oil reservoirs.

[0168] After preheating of the horizontal wells and individual vertical wells in the vertical-horizontal well pattern is complete, the transition to SAGD injection and production can be made. Therefore, determining whether the preheating process is complete is key to transitioning to SAGD injection and production. As shown in FIG15 , in the embodiment of this specification, step S120: determining whether the preheating process is complete may include the following steps:

[0169] S1510: Obtain the interwell temperature and interwell formation pressure between the horizontal well and the vertical well.

[0170] The interwell temperature can be monitored by using a plurality of thermocouples pre-installed at the horizontal wells and the vertical wells, and the formation pressure can be monitored by using a pre-installed pressure monitoring element.

[0171] S1520: Determine whether the interwell temperature reaches a preset temperature and whether the interwell formation pressure reaches a preset pressure.

[0172] For example, the preset temperature may be set to 80° C., and the preset pressure may be set to 4 MPa.

[0173] S1530: If yes, the preheating process is completed.

[0174] That is, when the interwell temperature reaches 80°C or above and the interwell formation pressure is less than 4MPa or below, it is judged that the preheating of the horizontal wells and vertical wells is completed and SAGD development can be switched.

[0175] As shown in FIG16 , in some preferred embodiments, step S120: determining whether the preheating treatment is completed may include the following steps:

[0176] S1610: Acquire the recovery degree of the deep ultra-heavy oil reservoir after the horizontal well and the vertical well complete the current round of throughput preheating during the preheating process.

[0177] In the embodiments of this specification, a throughput preheating method is used to preheat the horizontal and vertical wells in a vertical-horizontal well pattern. Specifically, steam is injected simultaneously into the horizontal wells and all vertical wells for a preheating cycle. The injected steam exchanges heat with the crude oil in the reservoir, reducing its viscosity. The crude oil, along with the condensed water from the steam, flows down by gravity into the horizontal wells for production. One injection and one production cycle completed within this preset cycle is considered a throughput preheating cycle. When the water content of the produced oil-water mixture exceeds a preset water content threshold, the next throughput preheating cycle is considered appropriate.

[0178] S1620: Determine whether the recovery degree is greater than a preset recovery degree threshold.

[0179] The degree of recovery can be calculated by the oil content in the oil-water mixture produced after the preheating of the current round of throughput is completed and the initial oil storage capacity of the deep ultra-heavy oil reservoir.

[0180] Figure 17 plots the relationship between the simulated conversion recovery rate and average daily oil production, and Figure 18 plots the relationship between the simulated conversion recovery rate and oil-gas ratio. As shown in Figures 17 and 18, as the conversion rate increases during SAGD production, the average daily oil production and oil-gas ratio gradually decrease; that is, the later the transition to SAGD injection and production, the lower the recovery factor during the SAGD injection and production phase. For example, in this specification, the conversion rate threshold is set at 30% to ensure a high recovery factor when switching to SAGD injection and production.

[0181] However, if the transition to SAGD injection and production is initiated too early, and preheating of the horizontal and vertical wells is not complete, this can also negatively impact the recovery rate during the SAGD injection and production phase. Therefore, while ensuring recovery, it is also necessary to assess the preheating results.

[0182] S1630: If yes, obtain the interwell temperature and interwell formation pressure between the horizontal well and the vertical well.

[0183] S1640: Determine whether the interwell temperature reaches a preset temperature and whether the interwell formation pressure reaches a preset pressure.

[0184] S1650: If yes, the preheating process is completed.

[0185] The monitoring and determination methods for interwell temperature and interwell formation pressure are the same as those shown in Figure 15 and will not be repeated here. Switching to SAGD production, steam injection is performed in rotation in vertical wells, and oil is produced in horizontal wells.

[0186] Figure 19 compares the recovery factor and oil-gas ratio at different simulated conversion timings. As shown in Figure 19, with the increase in the number of preheating cycles for both horizontal and vertical wells, the recovery factor and oil-gas ratio first increase and then decrease, reaching a peak at two preheating cycles. The stage recovery rate gradually decreases with the increase in preheating cycles. Therefore, based on the simulation results from Figures 17 to 19, in the embodiments of this specification, preheating horizontal and vertical wells for two to five preheating cycles and switching to SAGD when the reservoir recovery reaches approximately 30% can achieve both improved SAGD development effectiveness and economic benefits.

[0187] S1660: If not, the horizontal well and the vertical well need to continue to be preheated.

[0188] If the interwell temperature does not reach the preset temperature and the interwell formation pressure does not reach the preset pressure, it is determined that the preheating treatment is not completed, and the horizontal well and the vertical well need to continue the preheating treatment.

[0189] The method for determining whether the preheating treatment is completed, as shown in FIG16 , provided in an embodiment of this specification, first determines the degree of production, so that when the degree of production has not reached the production degree threshold, the preheating treatment has not been completed, thereby eliminating the need to determine the interwell temperature and interwell formation pressure, and simplifying the operator's supervision operations; and when the degree of production reaches the production degree threshold, the interwell temperature and interwell formation pressure are used to determine, thereby ensuring a high degree of accuracy in determining whether the preheating treatment is completed and ensuring the economy of switching to SAGD injection and production.

[0190] In some other embodiments, other methods may be combined to determine whether the preheating treatment of the horizontal wells and vertical wells in the vertical-horizontal combination well pattern is completed.

[0191] For example, the underground temperature field distribution between the horizontal well and the vertical well may be obtained by using oil well temperature measurement results and / or numerical simulation methods;

[0192] determining whether the horizontal well and the vertical well are thermally connected according to the temperature field distribution;

[0193] If the horizontal well is thermally connected to the vertical well, the preheating treatment is completed.

[0194] For another example, the viscosity of crude oil after preheating treatment in deep ultra-heavy oil reservoirs can also be obtained;

[0195] Determining whether the crude oil viscosity is less than or equal to a preset viscosity threshold;

[0196] If so, it is determined that the preheating process is completed.

[0197] Combining the above judgment methods can improve the accuracy of judging whether the preheating treatment is completed, thereby improving the accuracy of the timing of switching to SAGD injection and production, which is beneficial to improving the development effect and economic benefits of the SAGD injection and production stage.

[0198] As shown in FIG20 , in the embodiment of this specification, before preheating the horizontal wells and vertical wells in the vertical-horizontal combination well pattern in step S110, the method may further include:

[0199] S2010: Establishing a three-dimensional geological model for the deep ultra-heavy oil.

[0200] S2020: Calculate the well spacing between the horizontal wells and each of the vertical wells, and between the vertical wells in the vertical-horizontal combination well network based on the plane grid division of the three-dimensional geological model.

[0201] S2030: Calculate the horizontal wells in the vertical-horizontal combination well pattern and the formations where the vertical wells are located based on the vertical grid division of the three-dimensional geological model.

[0202] S2040: According to the calculation results, a straight-horizontal combination well pattern is set in the deep ultra-heavy oil reservoir.

[0203] By setting up a straight and horizontal combination well pattern suitable for deep ultra-heavy oil reservoirs, SAGD injection and production of deep ultra-heavy oil reservoirs is facilitated.

[0204] Specifically, the height of the vertical well is higher than that of the horizontal well, and the vertical height difference between the horizontal well and the vertical well is 5 to 7 meters.

[0205] The embodiment of this specification optimizes the height of the steam injection well perforation bottom to 5-7 meters from the horizontal well, which is beneficial to preventing single-point steam channeling, thereby further increasing the drainage space.

[0206] As shown in FIG21 , the embodiment of this specification further provides a SAGD injection-production device for a deep ultra-heavy oil reservoir, comprising:

[0207] Processing module 2110 is used to perform preheating treatment on horizontal wells and vertical wells in a vertical-horizontal combination well pattern, wherein the vertical-horizontal combination well pattern includes one horizontal well and multiple vertical wells, wherein the multiple vertical wells are symmetrically distributed on both sides of the horizontal well;

[0208] A judgment module 2120 is used to judge whether the preheating process is completed;

[0209] The injection and production module 2130 is used to rotate the steam injection into at least part of the plurality of vertical wells when the preheating treatment is completed, and utilize the horizontal wells to switch to SAGD oil production.

[0210] Furthermore, the device further comprises:

[0211] Establishing a module for establishing a three-dimensional geological model of the deep ultra-heavy oil;

[0212] A first calculation module is configured to calculate the well spacing between horizontal wells and each of the vertical wells, and between vertical wells in the vertical-horizontal combined well pattern according to the plane grid division of the three-dimensional geological model;

[0213] A second calculation module is configured to calculate the horizontal wells in the vertical-horizontal combination well pattern and the formations where the vertical wells are located based on the vertical grid division of the three-dimensional geological model;

[0214] The setting module is used to set a straight and horizontal combination well pattern in the deep ultra-heavy oil reservoir according to the calculation results.

[0215] The beneficial effects achieved by the device provided in the embodiments of this specification are consistent with the beneficial effects achieved by the above-mentioned method and will not be repeated here.

[0216] As shown in FIG22 , a computer device is provided in an embodiment of this specification. A deep ultra-heavy oil reservoir SAGD injection and production device in this specification can be a computer device in this embodiment, executing the aforementioned method of this specification. The computer device 2202 may include one or more processors 2204, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. The computer device 2202 may also include any memory 2206 for storing any type of information, such as code, settings, data, and the like. For example, and without limitation, the memory 2206 may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, and the like. More generally, any memory may use any technology to store information. Furthermore, any memory may provide volatile or non-volatile retention of information. Furthermore, any memory may represent a fixed or removable component of the computer device 2202. In one embodiment, when the processor 2204 executes associated instructions stored in any memory or combination of memories, the computer device 2202 may perform any operation of the associated instructions. The computer device 2202 also includes one or more drive mechanisms 2208 for interacting with any storage, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0217] The computer device 2202 may further include an input / output module 2210 (I / O) for receiving various inputs (via input devices 2212) and for providing various outputs (via output devices 2214). A specific output mechanism may include a presentation device 2216 and an associated graphical user interface (GUI) 2218. In other embodiments, the input / output module 2210 (I / O), input devices 2212, and output devices 2214 may not be included, and the computer device 2202 may simply be a computer device in a network. The computer device 2202 may further include one or more network interfaces 2220 for exchanging data with other devices via one or more communication links 2222. One or more communication buses 2224 couple the components described above together.

[0218] The communication link 2222 may be implemented in any manner, for example, via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 2222 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0219] Corresponding to the method shown in Figures 1, 5, 15 to 16 and 20, an embodiment of this specification also provides a computer-readable storage medium, which stores a computer program, and when the computer program is run by a processor, it executes the steps of the above method.

[0220] The embodiments of this specification also provide a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to execute the method shown in Figures 1, 5, 15 to 16 and 20.

[0221] An embodiment of this specification also provides a computer program product, comprising at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to implement the method shown in Figures 1, 5, 15 to 16 and 20.

[0222] It should be understood that in the various embodiments of this specification, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0223] It should also be understood that in the embodiments of this specification, the term "and / or" is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this specification generally indicates that the associated objects are in an "or" relationship.

[0224] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the composition and steps of each example according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this specification.

[0225] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0226] In the several embodiments provided in this specification, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or can be an electrical, mechanical or other form of connection.

[0227] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of this specification.

[0228] In addition, the functional units in the various embodiments of this specification may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0229] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this specification is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this specification. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0230] Specific embodiments are used in this specification to illustrate the principles and implementation methods of this specification. The description of the above embodiments is only used to help understand the methods and core ideas of this specification. At the same time, for those skilled in the art, based on the ideas of this specification, there will be changes in the specific implementation methods and application scope. In summary, the contents of this specification should not be understood as limiting this specification.

Claims

1. A SAGD injection and production method for deep ultra-heavy oil reservoirs, characterized in that: include: Preheating the horizontal wells and vertical wells in a straight-horizontal combination well pattern, wherein the straight-horizontal combination well pattern includes a horizontal well and a plurality of vertical wells, wherein the plurality of vertical wells are symmetrically distributed on both sides of the horizontal well; Determining whether the preheating treatment is completed; When the preheating treatment is completed, steam is injected into at least part of the plurality of vertical wells in rotation, and the horizontal wells are used to switch to SAGD oil production.

2. The method according to claim 1, characterized in that The plurality of vertical wells include at least two first vertical wells and at least two second vertical wells, the first vertical wells and the second vertical wells located on the same side of the horizontal well are alternately arranged, and a pair of vertical wells symmetrically separated on both sides of the horizontal well are the first vertical well and the second vertical well respectively; The step of rotating the steam injection into at least a portion of the plurality of vertical wells further comprises: Steam is injected into all the first vertical wells or all the second vertical wells in rotation for a preset time respectively until the oil production of the horizontal well is completed or a preset rotation round is reached.

3. The method according to claim 1, characterized in that After the preheating treatment is completed, steam is injected into at least part of the plurality of vertical wells in rotation, and the horizontal wells are used for SAGD oil production, further comprising: adjusting injection parameters when rotating steam injection into at least a portion of the plurality of vertical wells; and The production parameters when converting the horizontal well to SAGD oil production are adjusted.

4. The method according to claim 3, characterized in that Injecting steam into at least part of the plurality of vertical wells in rotation, and utilizing the horizontal wells to switch to SAGD oil production, further comprises: monitoring a steam chamber formed between the horizontal well and the vertical well; According to the monitored development characteristics of the steam chamber, the steam injection into at least part of the vertical well and the injection and production process of the horizontal well to SAGD oil production are divided into a steam chamber rising stage, a steam chamber expansion stage and a steam chamber descending stage; Injection parameters when rotating the steam injection into at least part of the plurality of vertical wells are adjusted in each stage, and production parameters when switching to SAGD oil production using the horizontal wells are adjusted in each stage.

5. The method according to claim 3 or 4, characterized in that: The injection parameters at least include the steam quality, injection speed and injection period of the injected steam, and the production parameters at least include the production-injection ratio and the operating pressure of the steam chamber formed between the horizontal well and the vertical well.

6. The method according to claim 3 or 4, characterized in that: Adjusting the injection parameters when rotating the steam injection into at least part of the plurality of vertical wells, and adjusting the production parameters when switching to SAGD oil production using the horizontal wells, further comprises: Conduct sensitivity analysis on various injection parameters and production parameters; According to the results of sensitivity analysis, determine the order of adjustment between various injection parameters and various production parameters; The injection parameters and production parameters are adjusted according to the sequence.

7. The method according to claim 6, characterized in that According to the sensitivity analysis results, the order of adjustment between the injection parameters and the production parameters is determined, further including: The injection parameters and production parameters are adjusted in descending order according to the sensitivity coefficient results obtained from the sensitivity analysis.

8. The method according to claim 5, characterized in that The steam dryness is adjusted to be greater than 65%, the steam injection rate is adjusted to 120-140 t / d, the production-injection ratio is adjusted to 1.2, the operating pressure is adjusted to 4.5-6 MPa, and the steam injection cycle is adjusted to 2-3 months.

9. The method according to claim 5, characterized in that The steam injection rate is obtained by the following steps: Establishing a first relationship diagram of the bottom hole steam quality changing with the well depth under different steam injection speeds and a second relationship diagram of the bottom hole steam quality changing with the steam injection speed under different well depth conditions; The steam quality and the steam injection rate of the steam injection steam are determined according to the first relationship diagram and the second relationship diagram.

10. The method according to claim 1, characterized in that Determining whether the preheating treatment is completed further includes: Acquiring the interwell temperature and interwell formation pressure between the horizontal well and the vertical well; Determining whether the inter-well temperature has reached a preset temperature and whether the inter-well formation pressure has reached a preset pressure; If yes, the preheating process is complete.

11. The method according to any one of claims 1 or 10, characterized in that: Determining whether the preheating treatment is completed further includes: Obtaining the underground temperature field distribution between the horizontal well and the vertical well through oil well temperature measurement results and / or numerical simulation methods; According to the temperature field distribution, determining whether the horizontal well and the vertical well are thermally connected; If yes, the preheating process is complete.

12. The method according to claim 11, characterized in that Determining whether the preheating treatment is completed further includes: Obtaining the crude oil viscosity of the deep ultra-heavy oil reservoir; Determining whether the viscosity of the crude oil is less than or equal to a preset viscosity threshold; If yes, the preheating process is complete.

13. The method according to claim 1, characterized in that Determining whether the preheating treatment is completed includes: Acquire the recovery degree of the deep super-heavy oil reservoir after the horizontal well and the vertical well complete the current round of preheating during the preheating process; Determining whether the recovery degree is greater than a preset recovery degree threshold; If yes, then obtaining the interwell temperature and interwell formation pressure between the horizontal well and the vertical well; Determining whether the inter-well temperature has reached a preset temperature and whether the inter-well formation pressure has reached a preset pressure; If yes, the preheating treatment is completed; If not, the horizontal well and the vertical well continue to be preheated.

14. The method according to claim 13, characterized in that The horizontal wells and vertical wells in the vertical-horizontal combination well pattern are preheated by using the huff-and-puff preheating method.

15. The method according to claim 14, characterized in that The number of rounds of throughput preheating is 2-5 rounds.

16. The method according to claim 1, characterized in that Before preheating the horizontal wells and vertical wells in the vertical-horizontal combination well pattern, the method further comprises: Establishing a three-dimensional geological model for the deep ultra-heavy oil; Calculating the well spacing between horizontal wells and each of the vertical wells, and between vertical wells in the vertical-horizontal combined well pattern according to the plane grid division of the three-dimensional geological model; Calculating the horizontal wells in the vertical-horizontal combination well pattern and the formations where the vertical wells are located according to the vertical grid division of the three-dimensional geological model; According to the calculation results, a straight and horizontal combined well pattern is set in the deep ultra-heavy oil reservoir.

17. The method according to claim 16, characterized in that The vertical height difference between the horizontal well and the vertical well is 5 to 7 meters.

18. The method according to claim 16, characterized in that The straight-horizontal combination well pattern also includes auxiliary drainage wells, which are connected to the horizontal wells to assist in oil production and drainage of the horizontal wells.

19. A deep super heavy oil SAGD injection and production device, characterized in that: include: A processing module, used for preheating horizontal wells and vertical wells in a straight-horizontal combination well pattern, wherein the straight-horizontal combination well pattern comprises a horizontal well and a plurality of vertical wells, wherein the plurality of vertical wells are symmetrically distributed on both sides of the horizontal well; A judging module, used for judging whether the preheating process is completed; The injection and production module is used for rotatingly injecting steam into at least part of the plurality of vertical wells when the preheating treatment is completed, and utilizing the horizontal wells to switch to SAGD oil production.

20. The device according to claim 19, characterized in that The device also includes: Establishing a module for establishing a three-dimensional geological model for the deep extra-heavy oil; A first calculation module is used to calculate the well spacing between the horizontal wells and each of the vertical wells, and between the vertical wells in the vertical-horizontal combination well pattern according to the plane grid division of the three-dimensional geological model; A second calculation module is used to calculate the horizontal wells in the vertical and horizontal combined well pattern and the formations where the vertical wells are located according to the vertical grid division of the three-dimensional geological model; The setting module is used to set a straight and horizontal combination well pattern in the deep super heavy oil reservoir according to the calculation results.

21. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 18 is implemented.

22. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 18 is implemented.

23. A computer program product, characterized in that The method comprises at least one instruction or at least one program, wherein the at least one instruction or the at least one program is loaded and executed by a processor to implement the method according to any one of claims 1 to 18.

Images