Method for regulating and controlling high-point linear fireflooding plane of thick-layer blocky heavy oil reservoir

Abstract

The invention discloses a thick-layer blocky heavy oil reservoir high-point linear fireflooding plane regulation and control method which comprises the following steps: determining an effect condition evaluation standard according to the average daily oil production and huff and puff period of an oil well; region division is carried out through the main control factor boundary of the response condition, and the response intensity becomes weak from the middle to the south and north; on the one hand, on the premise that high-temperature combustion is met, the higher the effect is, and the gas injection strength of the corresponding gas injection well is reduced; and the gas injection strength of the corresponding gas injection well is improved, so that the live wire is promoted to be uniformly propelled. On the other hand, on the premise of meeting normal production of the oil well, the effect is stronger, the cycle huff-puff time of the oil well is prolonged, and the steam injection intensity is reduced; the periodic throughput time is shortened, and the steam injection intensity is improved. By means of the method, the problem that high-point linear fireflooding plane advancing of the thick-layer blocky heavy oil reservoir is not uniform is solved, and a favorable support is provided for increasing the block fireflooding yield and improving the final recovery efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development geology, and in particular to a method for plane control of high-point linear fire drive in thick-layered blocky heavy oil reservoirs. Background Art

[0002] The burial depth of a certain oil reservoir is 1540-1890m. The main oil-bearing lithology is gravel-containing unequal-grained sandstone and conglomerate. The sorting is poor, and it is a medium-high porosity and high permeability reservoir. The average effective thickness of the oil layer is 103.8m, and the vertical concentration is concentrated. The crude oil density at 20℃ is 0.955g / cm 3 The viscosity of the degassed crude oil at 50°C is 3100-4000 mPa·s, which is a blocky ordinary heavy oil reservoir. The oil-bearing area of ​​the block is 1.06 km 2 , oil geological reserves 1030.2×10 4 t. In 1985, a square well pattern and 210m well spacing were used for steam huff and puff development. Before switching to fire drive, the development had lasted for 23 years. The formation pressure was low, the water recovery rate was low, the oil-gas ratio was low, and the economic benefits were poor. After switching to fire drive development, the effect was significantly improved. After three densification adjustments, the current well spacing is 75m. According to the adjustment time of well pattern, well spacing and conversion development mode, it can be roughly divided into the following four development stages: the first stage: 1987-1991 was the 210m well spacing square well pattern mining stage. The second stage: 1992-1997 was the 150m well spacing square well pattern mining stage. The third stage: 1998-2008 was the 105m well spacing mining stage. The fourth stage: 2008 to the present, it is the fire drive development stage, of which 2008-2015 is double-row array fire drive, and 2015 to the present is high-point linear fire drive.

[0003] High-point linear fire drive in thick blocky heavy oil reservoirs is a world-leading technology. The oil layer thickness is 103.8m, which is 6-12 times the thickness of successful fire drive oil layers at home and abroad. The monocline dip is 15-20°. There is no precedent for fire drive development of this type of oil reservoir. Fire drive is affected by linear well arrangement on the plane, and the control is difficult. There is an obvious problem of fire line advance.

[0004] Most of the domestic thin-layer oil reservoirs are fire-driven, and there are few patents on fire-driven plane control. Chinese patent CN108457632B discloses a method and device for controlling oil production by fire-driven, which uses the hydrogen component content as a basis to analyze the combustion state of the production well, and then controls the fire-driven oil production, but does not consider the influence of reservoir physical properties and recovery degree, and does not take measures such as zoning optimization of fire well gas injection intensity and oil well throughput parameters.

[0005] At present, there is a lack of effective plane control technology for high-point linear fire drive in thick-layer massive heavy oil reservoirs. There is no precedent for fire drive in the same type of reservoirs to learn from and compare. The fire line cannot be effectively controlled to ensure uniform advancement of the fire line, which restricts the development effect of high-point linear fire drive in thick-layer massive heavy oil reservoirs and affects the preparation of plane control plans for this type of fire drive. Summary of the invention

[0006] The purpose of the present invention is to provide a method for high-point linear fire drive plane control in thick-layer massive heavy oil reservoirs, establish a high-point linear fire drive plane zoning control technology for thick-layer massive heavy oil reservoirs, ensure the preparation of fire drive plane control plans, guide fire drive plane control, promote uniform advancement of the fire line plane, improve the fire drive development effect, and fill the gap in the high-point linear fire drive plane control method for thick-layer massive heavy oil reservoirs.

[0007] To achieve the above purpose, the technical solution of the present application is: a method for plane control of high-point linear fire flooding in thick-layer blocky heavy oil reservoirs, comprising:

[0008] Determine the evaluation criteria for the effectiveness of the wells based on their average daily oil production and throughput cycle;

[0009] The regional division is carried out by the boundaries of the main controlling factors of the effect status, and the effect intensity changes from strong to weak from the middle to the south and north;

[0010] Fire drive control is carried out in the affected areas.

[0011] Furthermore, the effectiveness status evaluation standards include: strong effectiveness standard: daily oil production>2.5t / d, cycle throughput time>2.0a; medium effectiveness standard: 1.5t / d≤daily oil production≤2.5t / d, 1.2a≤cycle throughput time≤2.0a; weak effectiveness standard: daily oil production<1.5t / d, cycle throughput time<1.2a.

[0012] Furthermore, through the distribution scatter plot, it is known that the average daily oil production (Q), throughput cycle (T) and permeability (K) and recovery degree (R) show a positive correlation.

[0013] Furthermore, the limits of the main controlling factors of the effective conditions are determined as follows: strong effect of oil wells: permeability K>500mD, recovery rate R>17.5%; moderate effect of oil wells: 220≤permeability K≤500mD, 7.0≤recovery rate R≤17.5%; weak effect of oil wells: permeability K<220mD, recovery rate R<7.0%.

[0014] Furthermore, five areas are divided according to the boundaries of the main controlling factors of the effective conditions.

[0015] Furthermore, after dividing the regions, the fire wells corresponding to injection and production in each region are determined based on tracer monitoring and injection-production correspondence analysis.

[0016] Furthermore, for the affected area, when fire drive regulation is carried out, under the premise of meeting high-temperature combustion, if the effect is strong, the gas injection intensity of the corresponding gas injection well is reduced; if the effect is weak, the gas injection intensity of the corresponding gas injection well is increased, thereby promoting uniform advancement of the fire line.

[0017] Furthermore, for the affected area, when fire drive regulation is carried out, on the premise of meeting the normal production of the oil well, if the effect is strong, the cycle throughput time of the oil well is increased and the steam injection intensity is reduced; if the effect is weak, the cycle throughput time is shortened and the steam injection intensity is increased.

[0018] The present invention adopts the above technical scheme, and can achieve the following technical effects: through this method, the problem of uneven plane advancement of high-point linear fire drive in thick-layer blocky heavy oil reservoirs is alleviated, and a basis is provided for the formulation of fire drive control schemes for such oil reservoirs, which fills the gap in the plane control method of high-point linear fire drive in thick-layer blocky heavy oil reservoirs. After the implementation of this method, the single well oil increase is more than 150t, the fire line advancement situation in each zone tends to be balanced, and the area of ​​high-temperature zones above 80° increases by 61%, which provides favorable support for increasing the block fire drive production and improving the final recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a scatter plot of permeability and average daily oil production;

[0020] Figure 2 It is a scatter plot of recovery degree and average daily oil production;

[0021] Figure 3 It is a scatter plot of the permeability and cycle throughput time distribution;

[0022] Figure 4 It is a scatter plot of the distribution of the extraction degree and the cycle throughput time;

[0023] Figure 5 This is the effective area division diagram of block A;

[0024] Figure 6 This is the well temperature distribution diagram before the plane control of fire flooding in block A;

[0025] Figure 7 This is the well temperature distribution diagram after plane control of fire flooding in Block A. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0028] This embodiment provides a method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs, specifically comprising:

[0029] Step 1. Determine the evaluation standard of the effective status according to the average daily oil production and throughput cycle of the oil well;

[0030] Specifically, combined with the production status of oil wells in the block, the evaluation standards for fire flooding strong, medium and weak effects were determined. Among them, the strong effect standard is: daily oil production>2.5t / d, cycle throughput time>2.0a; the medium effect standard is: 1.5t / d≤daily oil production≤2.5t / d, 1.2a≤cycle throughput time≤2.0a; the weak effect standard is: daily oil production<1.5t / d, cycle throughput time<1.2a.

[0031] Figure 1-4 The figure shows the distribution scatter plot of permeability, recovery degree, average daily oil production and cycle throughput time. It can be seen from the figure that permeability is positively correlated with average daily oil production and throughput cycle; recovery degree is also positively correlated with average daily oil production and throughput cycle.

[0032] The effectiveness of fire flooding includes two main controlling factors: permeability (K) and recovery (R). When the permeability is less than 220mD and the recovery is less than 7.0%, the oil well is weakly effective; when the permeability is 220-500mD and the recovery is 7.0%-17.5%, the oil well is moderately effective; when the permeability is greater than 500mD and the recovery is greater than 17.5%, the oil well is strongly effective.

[0033] Step 2. Divide the regions according to the boundaries of the main controlling factors of the effect status, and the effect intensity decreases from strong to weak from the center to the south and north;

[0034] Specifically, Figure 5 As shown, this application is divided into 5 areas; at the same time, based on tracer monitoring and injection-production correspondence analysis, the main injection-production corresponding fire wells in each area are determined;

[0035] Combined with the actual site, the gas injection intensity adjustment parameters of the fire wells are optimized to balance the advancement speed of the fire line in each area. The gas injection intensity of the fire well corresponding to the strong effect area 3 is the lowest, the gas injection intensity of the three fire wells corresponding to the medium-strong effect area 2 and the medium effect area 1 increases by 20, 50, and 150 cubic meters from the middle to the south, and the gas injection intensity of the two fire wells corresponding to the medium effect area 4 and the weak effect area 5 increases by 70 and 200 cubic meters from the middle to the north.

[0036] Step 3. Carry out fire control for the affected area;

[0037] Specifically, the well throughput parameters are optimized to balance the effect of each area. The stronger the effect, the longer the throughput cycle and the lower the steam injection intensity. Among them, the strong effect area 3 has the longest throughput cycle, more than 2 years, and the lowest throughput steam injection intensity, 30-40t / m; the weak effect area 5 has the shortest throughput cycle, 0.9-1.2 years, and the highest throughput steam injection intensity, 60-70t / m.

[0038] Therefore, the plane control method of fire flooding in Block A was determined, which significantly improved the effectiveness of single wells in each area, and the fire line advancement in each area tended to be balanced. The area of ​​high temperature area above 80° increased by 61%. Figure 6-7 shown.

[0039] The present invention comprehensively utilizes relevant technologies such as petroleum geology and seepage mechanics to carry out research on fire drive plane control methods, obtains the effective classification standards of oil wells and the boundaries of main controlling factors, divides the effective areas according to the boundaries, and forms fire drive plane control technology. According to the effective areas, reasonable control is performed to optimize the fire well gas injection intensity adjustment parameters, oil well throughput effect-inducing cycle and steam injection intensity, and balance the fire line advancement speed and effectiveness degree of each area.

[0040] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0041] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs, characterized in that: include: Determine the evaluation criteria for the effectiveness of the wells based on their average daily oil production and throughput cycle; The regional division is carried out by the boundaries of the main controlling factors of the effect status, and the effect intensity changes from strong to weak from the middle to the south and north; Fire drive control is carried out in the affected areas.

2. The method for plane control of high-point linear fire flooding in thick-layer blocky heavy oil reservoirs according to claim 1, characterized in that: The evaluation standards for the effectiveness status include: strong effectiveness standard: daily oil production>2.5t / d, cycle throughput time>2.0a; medium effectiveness standard: 1.5t / d≤daily oil production≤2.5t / d, 1.2a≤cycle throughput time≤2.0a; weak effectiveness standard: daily oil production<1.5t / d, cycle throughput time<1.2a.

3. The method for plane control of high-point linear fire flooding in thick-layer blocky heavy oil reservoirs according to claim 1, characterized in that: The distribution scatter plot shows that the average daily oil production (Q), throughput cycle (T) and permeability (K) and recovery degree (R) show a positive correlation.

4. The method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs according to claim 3, characterized in that: The limits of the main controlling factors for determining the effective conditions include: strong effect of oil wells: permeability K>500mD, recovery rate R>17.5%; medium effect of oil wells: 220≤permeability K≤500mD, 7.0≤recovery rate R≤17.5%; weak effect of oil wells: permeability K<220mD, recovery rate R<7.0%.

5. The method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs according to claim 1 or 4, characterized in that: Based on the boundaries of the main controlling factors of the effective conditions, a total of 5 areas are divided.

6. The method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs according to claim 5, characterized in that: After dividing the areas, the fire wells corresponding to injection and production in each area are determined based on tracer monitoring and injection-production correspondence analysis.

7. The method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs according to claim 1, characterized in that: For the affected area, when conducting fire drive regulation, under the premise of meeting high-temperature combustion, if the effect is strong, the gas injection intensity of the corresponding gas injection well will be reduced; if the effect is weak, the gas injection intensity of the corresponding gas injection well will be increased.

8. The method for plane control of high-point linear fire flooding in thick-layered massive heavy oil reservoirs according to claim 1, characterized in that: For the affected area, when conducting fire flooding regulation, the effect is strong, the cycle throughput time of the oil well is increased, and the steam injection intensity is reduced while ensuring the normal production of the oil well; The effect is weak, shortening the cycle throughput time and increasing the steam injection intensity.

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