Well spacing method, system and equipment in middle and later periods of gas reservoir development and storage medium

Abstract

The invention discloses a well spacing method, system and equipment in the middle and later periods of gas reservoir development and a storage medium, and the method comprises the following steps: S1, selecting a gas reservoir of which the water drive and the thickness meet the requirement and the reservoir is strong heterogeneity, and selecting a horizontal well for deployment when a primary well pattern of the gas reservoir cannot meet the development requirement of the stage or the recoverable reserves in the middle and later periods of development are greater than or equal to 50%; s2, if the high-permeability strip does not exist in the gas reservoir, the horizontal well is deployed close to the top of the reservoir; if the high-permeability strip exists in the gas reservoir, the longitudinal deployment position of the horizontal well is determined according to the position of the high-permeability strip; s3, determining the direction of the horizontal well in combination with geomechanics and fracture depiction; s4, calculating the length of the horizontal well under the condition that the productivity ratio of the vertical well is more than 1.5; and S5, horizontal well spacing is conducted according to the longitudinal deployment positions, directions and lengths of the horizontal wells in the steps S2 to S4. The effective well spacing adjustment strategy in the middle and later periods is achieved, and the gas reservoir recovery efficiency is effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of gas reservoir development, and relates to a method, system, equipment and storage medium for well arrangement in the middle and late stages of gas reservoir development. Background Art

[0002] A gas reservoir in the Tarim Basin is a very thick, abnormally high-pressure water-containing gas reservoir with a reservoir thickness of 300 to 400 meters. The physical properties are mainly medium-pore and medium-high permeability reservoirs. High-permeability strips and faults are developed inside the gas reservoir. The geological conditions are complex and the water characteristics of single wells vary greatly. The heterogeneity between the reservoir units of this gas reservoir is serious, the permeability range is large, and the coefficient of variation is 0.8 to 3.4. The actual gas production profile test shows that, affected by the reservoir heterogeneity, the output of the gas well mainly comes from the high-permeability strips. Later, as the gas wells see water, the edge and bottom water also have the characteristics of invading and migrating along the high-permeability strips. According to statistics, the thickness of the main production layer accounts for 21%, and the production contribution reaches 83.7%. The gas reservoir is generally non-uniformly flooded, and the flooding is most serious in the east. The saturation test data over the years show that with the progress of development, half of the perforated section of a water-seeking well in the east has not been flooded ( Figure 1 ), which seriously affects the development effect of gas reservoirs, and the gas reservoirs need to be adjusted urgently. The output of this type of gas reservoir is mainly in high-permeability strips, and its seepage mechanism and reserve utilization are crucial to the later development adjustment. The thick and water-containing gas reservoirs are affected by the heterogeneity of the reservoir, and the output is mainly in high-permeability strips. In the later stage, the edge and bottom water also have the characteristics of invading and migrating along the high-permeability strips, showing the phenomenon of non-uniform flooding. For this type of gas reservoir, how to efficiently develop, make effective adjustments, and improve the recovery rate of gas reservoirs is crucial, but there is no method for efficient development of this type of gas reservoir in the existing research, and there is no method for deploying new wells to improve the recovery rate based on the development characteristics of this type of gas reservoir. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method, system, equipment and storage medium for well layout in the middle and late stages of gas reservoir development, so as to realize an effective well layout adjustment strategy in the middle and late stages and effectively improve the recovery rate of gas reservoirs.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for well layout in the middle and late stages of gas reservoir development includes the following processes:

[0006] S1, select a gas reservoir with water drive, thickness that meets the requirements and strong heterogeneity. When the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, select horizontal wells for deployment;

[0007] S2, if there is no high permeability strip in the gas reservoir, the horizontal well is deployed close to the top of the reservoir; if there is a high permeability strip in the gas reservoir, the vertical deployment position of the horizontal well is determined according to the position of the high permeability strip;

[0008] S3, combining geomechanics and fracture characterization to determine the direction of horizontal wells;

[0009] S4, calculate the length of the horizontal well when the vertical well productivity ratio is above 1.5;

[0010] S5, deploying horizontal wells according to the longitudinal deployment position, direction and length of the horizontal wells in S2-S4.

[0011] Preferably, in S1, a gas reservoir with a water invasion replacement coefficient greater than or equal to 0.15 is selected from water-driven gas reservoirs.

[0012] Preferably, in S1, when the reservoir thickness is greater than or equal to 100 m, the thickness meets the requirement.

[0013] Preferably, in S1, strong heterogeneity means that the coefficient of variation of permeability is greater than 0.7.

[0014] Preferably, in S2, geological research data including seismic data, stratigraphic comparison, lateral distribution comparison of reservoir physical properties, high permeability zones and reservoir characterization are used. If there is no high permeability zone in the gas reservoir, the closer the horizontal well is deployed to the top of the reservoir, the better the reservoir is, and the permeability is greater than or equal to the average permeability of the top reservoir segment; if there is a high permeability zone in the gas reservoir, when the high permeability zone is located at the top, considering the water avoidance above and below the gas reservoir, the horizontal well is deployed in the medium permeability reservoir below the high permeability zone, and the permeability is greater than or equal to the average permeability of the top reservoir segment; when the high permeability zone is located in the middle or lower part of the gas reservoir, the closer the horizontal well is deployed to the top of the reservoir, the better the reservoir is, and the permeability is greater than or equal to the average permeability of the top reservoir segment.

[0015] Preferably, in S3, in a direction that is beneficial to wellbore stability, horizontal wells are arranged in a profile with good quality, a signal-to-noise ratio greater than 3, a well error less than 1%, and no faults in the seismic data, and the angle between the horizontal section direction and the direction of the maximum horizontal principal stress is controlled to be 70° to 90°.

[0016] Preferably, the calculation process of the horizontal well length is:

[0017]

[0018]

[0019] In the above formula:

[0020]

[0021]

[0022] J h / J v =[Ln(r ev / r w )] / [Ln(r eh / r w,eff )]

[0023] In the above formula: r w,eff is the radius of the vertical wellbore with the same production as the horizontal well; RR is the replacement ratio; r w is the radius of the vertical wellbore; r ev is the vertical well supply radius; L is the horizontal section length; ΔE R is the recovery factor improvement of horizontal wells compared to vertical wells, which is taken as 0.05; β is the square root of the ratio of horizontal to vertical permeability; h is the oil layer thickness; r eh is the average supply radius of the horizontal well; A o is the single well control area of ​​horizontal well; J h is the gas production index of horizontal well; J v is the vertical well gas production index.

[0024] A well layout system for the middle and late stages of gas reservoir development, comprising:

[0025] The selection module is used to select gas reservoirs with water drive, thickness that meets the requirements, and strong heterogeneity. When the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or when the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, horizontal wells are selected for deployment;

[0026] A vertical position determination module is used to determine the vertical deployment position of the horizontal well according to whether there is a high permeability strip in the gas reservoir and the position of the high permeability strip;

[0027] Direction determination module, used to determine the direction of horizontal wells by combining geomechanics and fracture characterization;

[0028] The length calculation module is used to calculate the length of the horizontal well when the vertical well productivity ratio is above 1.5;

[0029] The well layout module is used to layout the horizontal wells according to the longitudinal deployment position, direction and length of the horizontal wells in the above modules.

[0030] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for well layout in the middle and late stages of gas reservoir development are implemented.

[0031] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for well layout in the middle and late stages of gas reservoir development.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention adopts horizontal wells. Compared with vertical wells, horizontal wells have a large water avoidance height, a smaller risk of water breakthrough, more uniform water invasion, a long stable production period, and are conducive to improving gas reservoir recovery. The higher the horizontal section position, the later the water breakthrough time. Horizontal wells are preferentially deployed in high structural parts. Horizontal wells fully consider reservoir protection during drilling and completion, and effectively release production capacity. After adopting the well layout method of the present invention, a gas field in the Tarim Oilfield has a horizontal well in the top medium permeability layer. Affected by reservoir pollution, the well was put into production on November 30, 2022, with a daily gas production of 824,000 cubic meters / day, no water production, stable production, and good effect. It is estimated that the cumulative gas production of a single well is 2.523 billion cubic meters, increasing the gas reservoir recovery rate by 1%. In addition, the other two horizontal wells proposed by the study have also been drilled. Practice has proved that the innovative research results are established, highly operational, and can be effectively promoted and applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the production logging comparison chart of the Eastern A10 Well over the years of the present invention;

[0035] Figure 2 The formation pressure profile of a single well in gas reservoir A over the years of the present invention;

[0036] Figure 3 It is a double logarithmic curve diagram of pressure recovery of Well A01 of the present invention;

[0037] Figure 4 A schematic diagram of gas flow during stable mining of high and low permeability layers of the present invention;

[0038] Figure 5 A comparison chart of daily gas production in different regions of the present invention;

[0039] Figure 6 This is a comparison chart of remaining reserves in different regions of the present invention;

[0040] Figure 7 It is the model diagram of high and low permeability layers of the present invention;

[0041] Figure 8 The high and low osmotic pressure difference of the present invention (hypertonic 100mD, hypotonic 1mD);

[0042] Fig. 9 It is a comparison diagram of the cross-flow rate under different KH ratios of the present invention;

[0043] Fig.10 This is a flow chart of the well layout method in the middle and late stages of gas reservoir development of the present invention;

[0044] Fig.11 Comparison of water invasion profiles of vertical wells and horizontal wells in the gas field of the present invention;

[0045] Fig.12 A schematic diagram of the vertical position of the horizontal well deployment of the present invention;

[0046] Fig.13 This is a diagram showing the water production demonstration results of the horizontal wells deployed at different vertical positions according to the present invention;

[0047] Fig.14 This is a north-south stratigraphic comparison diagram of the present invention;

[0048] Fig.15 This is a diagram showing the water production demonstration results of different perforation layers in the horizontal well of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0050] It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to directions in the drawings, and the words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0052] The method for well layout in the middle and late stages of development described in the present invention mainly solves the technical problem that due to the influence of factors such as reservoir heterogeneity, the thick and water-bearing gas reservoir has the characteristics of non-uniform water flooding, low gas reservoir recovery rate and how to effectively utilize the residual gas in the later stage. The present invention firstly uses the formation pressure profile of a single well over the years to show ( Figure 2 ), the formation pressure drop values ​​of each single well at different time points tend to be consistent, the formation pressure drop is relatively balanced, and there is no local large pressure drop area from west to east, indicating that the reservoir is well connected laterally and has a high degree of horizontal production. In recent years, with the intensification of water invasion, the formation pressure at the edge is significantly greater than that in the middle.

[0053] At the same time, the well test data showed that the gas reservoir interlayer had no sealing properties and good vertical connectivity. A01 well was perforated 4m for testing, and the well test analysis showed that more than 100m of reservoir was involved in production ( Figure 3 ), judging from the curve shape, the KH / KV value is small, indicating that the longitudinal connectivity is good.

[0054] The MDT test results of the inspection well and the pass well in the target layer of the gas reservoir show that the pressure gradient of the reservoir is basically consistent in the vertical direction, indicating that with the production of the high permeability layer, the pressure of the low permeability layer also decreases, and there is a phenomenon of gas supply from the low permeability layer to the high permeability layer. The reserves of the low permeability layer can be effectively utilized during the production process.

[0055] The plane and vertical are connected as a whole, the vertical gradient is consistent, and the whole is mobilized. On this basis, combined with the geological and dynamic characteristics of this type of gas reservoir, a mathematical model of low permeability layer-high permeability layer-wellbore coupled seepage is established.

[0056] Considering the single-phase gas flow in porous media, ignoring the nonlinearity and slippage of the gas flow process, the gas flow conforms to Darcy's seepage law:

[0057]

[0058] Where v is the gas seepage velocity, p is the fluid pressure in the matrix pores, and k m is the matrix permeability, μ is the gas viscosity, ρ is the gas density, g is the gravitational acceleration, and H is the reservoir depth.

[0059] Considering the influence of reservoir permeability anisotropy, the permeability anisotropy matrix can be expressed as:

[0060]

[0061] In the formula, k mx is the matrix permeability in the x direction, k my is the matrix permeability in the y direction, β k is the permeability anisotropy angle.

[0062] Based on the gas flow mass conservation principle, the gas flow mass conservation equation is:

[0063]

[0064] In the formula, φ m is the matrix porosity, Q s It is the source and sink term.

[0065] Combining the Darcy flow equation and the gas flow mass conservation equation, the matrix gas flow continuity equation is:

[0066]

[0067] Since gas has strong compressibility and low viscosity, in order to effectively reduce the nonlinearity of the gas seepage equation and comprehensively characterize the gas's pressure, viscosity, compressibility factor and other characteristics, pseudo-pressure is introduced to process other seepage equations.

[0068]

[0069] In the formula, p 0 is the original formation pressure, and Z is the gas compression factor.

[0070] Substitute the pseudo-pressure into the gas seepage continuity equation and arrange the pseudo-pressure form of matrix gas seepage:

[0071]

[0072] In the formula, C t is the total formation compressibility for gas flow.

[0073] Due to the large difference in physical properties between the high permeability layer and the low permeability layer, the high permeability layer is the main source of gas during the production process. The pressure in the high permeability layer decreases rapidly, and under the pressure difference between the high and low permeability layers, the low permeability layer will gradually flow toward the high permeability layer. The continuity equation for gas seepage in the high permeability layer is:

[0074]

[0075] In the formula, is the matrix porosity of the high permeability layer, is the matrix permeability of the high permeability layer, ψ h is the pseudo pressure of matrix gas in the hyperpermeability layer, H h is the reservoir depth of the high permeability layer, Q c It is the gas crossflow term between high permeability layer and low permeability layer.

[0076]

[0077] The continuity equation of gas flow in low permeability layer is:

[0078]

[0079] In the formula, is the matrix porosity of the low permeability layer, is the matrix permeability of the low permeability layer, ψ l is the pseudo pressure of matrix gas in the low permeability layer, H l is the reservoir depth of the low permeability layer.

[0080] The seepage boundary conditions between high permeability layer and low permeability layer are expressed as follows.

[0081] The bottom flow pressure at the high permeability layer-low permeability layer wellbore is fixed:

[0082]

[0083] The gas pressure at the boundary between the high permeability layer and the low permeability layer is the same:

[0084] ψ l =ψ h (Formula 11)

[0085] The outer boundary of the reservoir is a constant pressure outer boundary:

[0086]

[0087] The finite difference method is used to discretize the high permeability layer-low permeability layer seepage equation to obtain the five-diagonal numerical discrete equations of other seepage:

[0088]

[0089] The output of high permeability layer is mainly radial flow, and the fluid flows from the far well area to the near well area, and then flows into the wellbore; due to the poor physical properties of the low permeability layer, the gas volume that directly flows into the wellbore is limited, and due to the rapid drop in pressure in the high permeability layer, the pressure difference between the high and low permeability layers increases. In addition to a certain contribution to the wellbore near the bottom of the well, the direction of seepage in the far well area is basically from low permeability to high permeability. Therefore, a seepage process from low permeability to high permeability and high permeability to the wellbore is formed ( Figure 4 ). Through the production of high permeability layer, the overall reserves of gas reservoir are utilized. During the whole seepage process, the pressure of wellbore is the lowest, the high permeability layer is second, and the low permeability layer is the highest. This also leads to the priority of edge and bottom water intrusion into the high permeability layer with the lowest pressure, resulting in non-uniform water invasion of gas reservoir.

[0090] Based on the study of mathematical models of seepage, a numerical model was established to simulate the coupled seepage process of low permeability layer-high permeability layer-wellbore. A single well model of Well A1 was separated from the actual geological model of the gas field, and the physical property data was interpreted using the logging results (Table 1), so as to conceptualize the impact of high permeability zones on development. The reserves of the entire single well model are 147×10 8 m 3 , of which the low permeability layer in the perforated layer accounts for 40×10 8 m 3 , the hyperosmotic layer accounts for 46×10 8 m 3 , the unperforated section accounts for 61×10 8 m 3 (Table 2).

[0091] Table 1 Statistics of porosity and permeability of the production layer of Well A1

[0092]

[0093]

[0094] Table 2 Statistics of reserves zoning of single well geological model of Well A1

[0095] area <![CDATA[Water volume (10 8 m 3 )]]> <![CDATA[Gas storage (10 8 m 3 )]]> total 2.45 147 Unperforated Area-Zone 1 1.48 61 Perforated low permeability zone-zone 2 0.44 40 Perforated high permeability zone-zone 3 0.53 46

[0096] The numerical simulation results show that the gas production of the well is basically all produced through the high permeability section, and the daily gas production of the low permeability section accounts for less than 5%. However, the remaining gas in different areas (perforated high permeability area, low permeability area and unperforated area) basically decreases synchronously and the trend is consistent, indicating that the low permeability section and the unperforated section finally flow into the perforated high permeability section through interlayer crossflow, and the pressure drop in each section is consistent ( Figure 5 , Figure 6 ). The mechanism analysis of Well A1 confirmed that the production of high permeability strips achieved the overall utilization of the gas reservoir, and the calculation results were basically consistent with the profile test results.

[0097] In order to further study the influence of interlayer crossflow size and reservoir characteristics on crossflow, a three-layer conceptual model of a single well was established based on the actual parameters of the gas field, with the top and bottom layers being low permeability layers and the middle being high permeability layers ( Figure 7 The permeability ratio of the low-permeability layer to the high-permeability layer is divided into three cases: 1:10, 1:100, and 1:1000. The thickness ratio is divided into three cases: 2:1, 4:1, and 10:1. The permeability of the low-permeability layer is divided into three cases: 1mD, 10mD, and 20mD.

[0098] The simulation results show that the cross-flow between high and low permeability layers only requires a very small production pressure difference. When the permeability of the high permeability layer is 100mD and the permeability of the low permeability layer is 1mD, the interlayer seepage pressure difference is distributed between 0.002 and 0.004MPa. When the KH of the high permeability layer / KH of the low permeability layer>10, the increase in the KH ratio has little effect on the cross-flow rate ( Figure 8 , Fig. 9 ).

[0099] The single well gas production profile calculated by numerical simulation is basically consistent with the actual measurement. The numerical simulation pressure profile shows that during the production of a single high-permeability strip, the gas reservoir pressure decreases as a whole and is vertically balanced, which is consistent with the actual situation.

[0100] The seepage mechanism of partially opening a single well during the development of this type of extremely thick heterogeneous water-bearing gas reservoir: the gas reservoir is mainly produced by perforating the high permeability strip of the reservoir with a single well, but the remaining gas in different areas (perforated high permeability area, low permeability area and unperforated area) is basically reduced synchronously, indicating that the low permeability section and the unperforated section finally flow into the high permeability section for production through interlayer crossflow, and the pressure drop of each section is consistent. The output of the high permeability section alone can achieve the overall utilization of the gas reservoir. The extremely thick gas reservoir has a multi-stage coupled seepage mechanism of low permeability layer to high permeability layer and high permeability layer to wellbore flow. As the development proceeds, the high permeability strip will become the main channel for water invasion in the later stage, resulting in non-uniform water invasion of the gas reservoir. In view of the problem of non-uniform water invasion of gas reservoirs, a reasonable development technology policy needs to be formulated.

[0101] In view of the problem of non-uniform water invasion in this type of gas reservoir, as the development progresses, the water invasion intensifies, the number of water-seeking wells increases year by year, and the production capacity drops sharply after the gas wells see water. Therefore, in the middle and late stages of the development of this type of gas reservoir, it is urgent to deploy new wells to supplement the gas reservoir production capacity and maintain the long-term high and stable production of this type of gas reservoir; on the other hand, the number of water-seeking wells in the gas reservoir increases, and the remaining gas cannot be effectively used, so it is necessary to add new wells and increase the number of gas outlets. Fig.10 As shown, the strategy of adding new wells to this type of gas reservoir is discussed below:

[0102] S1, select a gas reservoir with water drive, thickness that meets requirements and strong heterogeneity. When the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or when the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, select horizontal wells for deployment.

[0103] S2, determine the vertical deployment position of the horizontal well according to whether there is a high permeability strip in the gas reservoir and the location of the high permeability strip.

[0104] S3, combining geomechanics and fault characterization to determine the direction of the horizontal well.

[0105] S4, calculate the length of the horizontal well when the vertical well productivity ratio is greater than 1.5.

[0106] (1) Gas reservoir type: For gas-driven gas reservoirs and water-driven gas reservoirs, select water-driven gas reservoirs and evaluate the water invasion replacement coefficient of the gas reservoir, ω = (We-WpBw) / (G p Bgi).

[0107] W e —Water intrusion, ×10 4 m 3 W p —Cumulative water production, ×10 8 m 3 .

[0108] B w —Formation water volume coefficient, dimensionless.

[0109] B gi —Original natural gas volume coefficient, dimensionless.

[0110] G p —Cumulative natural gas production, 10 8 m 3 .

[0111] ω—water intrusion substitution coefficient, dimensionless.

[0112] Select secondary active and active water-driven gas reservoirs with water invasion replacement coefficient greater than or equal to 0.15; select thick gas reservoirs with reservoir thickness greater than or equal to 100m, which have room for adjustment in the later stage; select severe heterogeneous reservoirs for reservoir heterogeneity.

[0113] Permeability variation coefficient V k It is used to measure the dispersion of several statistical values ​​relative to their average value. The calculation formula is as follows:

[0114]

[0115] K i ——The permeability value of a sample in the layer i=1, 2, 3,…, n.

[0116] ——The average permeability of all samples in the layer.

[0117] n is the number of samples in a layer.

[0118] Select the permeability variation coefficient V k If it is greater than 0.7, it is a severely heterogeneous reservoir.

[0119] (2) Development stage: This stage is selected in the middle and late stages of development, when the recoverable reserves of a gas reservoir are greater than or equal to 50%, or when the development of a gas reservoir requires the preparation of an adjustment plan and the improvement of the gas reservoir recovery rate, that is, when the primary well network cannot meet the development needs of this stage.

[0120] (3) Well type: Based on the clarification of the seepage mechanism of this type of gas reservoir, the following is an optimization of the well layout principle. The gas reservoir is in the middle and late stages of development, the gas-water interface rises year by year, and the remaining gas is concentrated at the top of the gas reservoir. If a vertical well is deployed, the water avoidance height is limited and the production capacity is low. Therefore, considering the influence of water avoidance and production capacity factors, it is more advantageous to deploy horizontal wells. Compared with vertical wells, horizontal wells have a large water avoidance height, a lower risk of water breakthrough, more uniform water invasion, and a long stable production period, which is conducive to improving the recovery rate of gas reservoirs. Fig.11 Therefore, horizontal wells are selected for deployment.

[0121] (4) Vertical position: A homogeneous model similar to the reservoir and structural characteristics of this type of gas field is established to carry out the optimization of the vertical position of horizontal wells. The horizontal well sections are divided into three different vertical positions: high, medium and low. Fig.12 The simulation results show that the higher the horizontal section is, the later the water breakthrough time is. Horizontal wells are preferentially deployed in high structural parts, such as Fig.13 shown.

[0122] First, using geological research data including seismic data, stratigraphic comparison, lateral distribution comparison of reservoir physical properties, high permeability strips and reservoir characterization, if there is no high permeability strip in the gas reservoir, the horizontal well is deployed in the better reservoir at the top of the reservoir, the closer to the top the better, and the permeability is greater than or equal to the average permeability of the top reservoir section (excluding the high permeability strip); if there is a high permeability strip in the gas reservoir, when the high permeability strip is located at the top, considering the water avoidance above and below the gas reservoir, the horizontal well is designed to be deployed in the medium permeability reservoir below the high permeability strip, and the permeability is greater than or equal to the average permeability of the top reservoir section (excluding the high permeability strip section); when the high permeability strip is located in the middle or lower part, just like when there is no high permeability strip in the gas reservoir, the horizontal well is deployed in the good reservoir at the top of the reservoir, the closer to the top the better, and the permeability is greater than or equal to the average permeability of the top reservoir section.

[0123] (5) Horizontal section direction: The vertical strata are determined, and combined with geomechanics and fault characterization research, the horizontal wells are arranged in a direction that is conducive to wellbore stability. The seismic data is of good quality, with a signal-to-noise ratio greater than 3, a well error of less than 1%, and no faults. The horizontal wells are arranged in a section with an angle between the horizontal section direction and the direction of the maximum horizontal principal stress of 70° to 90°.

[0124] (6) Horizontal well length: Studies have shown that under the same geological and mining technology limits, the replacement ratio is the ratio of the initial production of horizontal wells to vertical wells, the ratio of cumulative production and the ratio of controlled areas. This study modified the modified replacement ratio calculation formula proposed by SD Joshi, and the results are shown in the following formula, which covers the calculation equations for indicators such as "vertical wellbore radius with equivalent horizontal well production", horizontal well single well control area, and horizontal well to vertical well gas production index ratio:

[0125]

[0126]

[0127] In the above formula:

[0128]

[0129]

[0130] J h / J v =[Ln(r ev / r w )] / [Ln(r eh / r w,eff )]

[0131] In the above calculation equations:

[0132] r w,eff —The radius of the vertical wellbore with equivalent production to the horizontal well, m.

[0133] RR—Replacement ratio.

[0134] r w —Vertical wellbore radius, m.

[0135] r ev —Vertical well supply radius, m.

[0136] L—horizontal section length, m.

[0137] ΔE R —The recovery rate of horizontal wells is increased compared to that of vertical wells, which is taken as 0.05.

[0138] β—square root of the ratio of horizontal to vertical permeability.

[0139] h—oil layer thickness, m.

[0140] r eh —Average supply radius of horizontal wells, m.

[0141] A o —Controlled area of ​​single horizontal well, km 2 .

[0142] J h —Horizontal well gas production index, 10 4 m 3 / (d·MPa 2 ).

[0143] J v —Vertical well gas production index, 10 4 m 3 / (d·MPa 2 ).

[0144] By solving the above formula, the calculation of the open flow rate can achieve the corresponding vertical well production capacity ratio of more than 1.5. In addition, during the drilling and completion process of horizontal wells, reservoir protection should be fully considered to effectively release production capacity.

[0145] According to the above method, the actual A gas reservoir in Tarim is taken as an example for analysis. The heterogeneity between the reservoir units in this gas field is serious, the permeability range is large (114-121627), and the coefficient of variation is 0.8-3.4. The seepage mechanism of the gas reservoir has been clarified through mechanism research and dynamic verification, and the well layout strategy is also effective. The specific implementation is 1. First, through seismic research, through the seismic profile of the well, the horizontal well trajectory cannot pass through the fault, and the twisting of the phase axis near the target point is not obvious, and the fault is not developed. 2. Through the detailed description of the gas reservoir, make a comparison map of the physical properties of the target layer of the horizontal well, from Fig.14It can be seen from the target layer comparison diagram that the sandstone section at the top of the formation has a high permeability zone with a permeability of 310.2mD. This section should be avoided. The medium permeability layer in the middle and upper part of the first section of Ba is preferably deployed, with a permeability of 39.1mD, about 40m away from the top, and from Fig.15 The numerical simulation results show that the wells are deployed in the sandstone section, and the water breakthrough time of the horizontal wells is much earlier than that deployed in the middle and upper part of the first section of the Ba. Therefore, while ensuring the production capacity of a single well, avoiding the high-permeability zone development area can effectively extend the water-free gas production period and maximize the gas reservoir recovery rate. 3. Considering the stability of the well wall and avoiding faults, the preferred deployment direction is northwest. 4. Through analogy and gas reservoir engineering demonstration, the length of the horizontal section is 500m. Based on the above research, it is preferred that the horizontal section of the horizontal well is 33m away from the top surface, 500m long, and 48° northwest of the north for implementation.

[0146] The following are device embodiments of the present invention, which can be used to perform method embodiments of the present invention. For details not disclosed in the device embodiments, please refer to the method embodiments of the present invention.

[0147] In yet another embodiment of the present invention, a well deployment system for mid-to-late stage of gas reservoir development is provided. The well deployment system for mid-to-late stage of gas reservoir development can be used to implement the above-mentioned well deployment method for mid-to-late stage of gas reservoir development. Specifically, the well deployment system for mid-to-late stage of gas reservoir development includes a selection module, a longitudinal position determination module, a direction determination module and a length calculation module.

[0148] Among them, the selection module is used to select gas reservoirs with water drive, thickness that meets requirements and strong heterogeneity. When the primary well network of the gas reservoir cannot meet the development needs of this stage, or the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, horizontal wells are selected for deployment.

[0149] The vertical position determination module is used to determine the vertical deployment position of the horizontal well according to whether there is a high permeability strip in the gas reservoir and the position of the high permeability strip.

[0150] The direction determination module is used to determine the direction of horizontal wells by combining geomechanics and fracture characterization.

[0151] The length calculation module is used to calculate the length of horizontal wells when the vertical well productivity ratio is above 1.5.

[0152] The well layout module is used to layout horizontal wells according to the longitudinal deployment position, direction and length of the horizontal wells in the above modules.

[0153] In another embodiment of the present invention, a terminal device is provided, the terminal device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGAs), or other processors. GateArray, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions to implement corresponding method processes or corresponding functions; the processor described in the embodiment of the present invention can be used for the operation of the well layout method in the middle and late stages of gas reservoir development, including: S1, selecting a gas reservoir with water drive, thickness that meets the requirements and a reservoir with strong heterogeneity, and when the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or when the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, selecting horizontal wells for deployment; S2, if there is no high permeability strip in the gas reservoir, the horizontal well is deployed close to the top of the reservoir; if there is a high permeability strip in the gas reservoir, the vertical deployment position of the horizontal well is determined according to the position of the high permeability strip; S3, combining geomechanics and fracture characterization, determining the direction of the horizontal well; S4, calculating the length of the horizontal well under the condition that the vertical well production capacity ratio is greater than 1.5; S5, according to the vertical deployment position, direction and length of the horizontal well in S2-S4, horizontal well layout is performed.

[0154] In another embodiment, the present invention further provides a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory.

[0155] The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for well layout in the middle and late stages of gas reservoir development in the above-mentioned embodiment; one or more instructions in the computer-readable storage medium are loaded by the processor and the following steps are executed: S1, select a gas reservoir with water drive, thickness that meets requirements and reservoir with strong heterogeneity, and when the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, select horizontal wells for deployment; S2, if there is no high permeability belt in the gas reservoir, the horizontal well is deployed close to the top of the reservoir; if there is a high permeability belt in the gas reservoir, the vertical deployment position of the horizontal well is determined according to the position of the high permeability belt; S3, determine the direction of the horizontal well in combination with geomechanics and fracture characterization; S4, calculate the length of the horizontal well under the condition that the vertical well production capacity ratio is greater than 1.5; S5, arrange the horizontal well according to the vertical deployment position, direction and length of the horizontal well in S2-S4.

[0156] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0157] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0158] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0159] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0160] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0161] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A method for well layout in the middle and late stages of gas reservoir development, characterized in that: The process includes: S1, select a gas reservoir with water drive, thickness that meets the requirements and strong heterogeneity. When the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, select horizontal wells for deployment; S2, if there is no high permeability zone in the gas reservoir, the horizontal wells are deployed close to the top of the reservoir; If there is a high permeability zone in the gas reservoir, the vertical deployment position of the horizontal well is determined according to the location of the high permeability zone; S3, combining geomechanics and fracture characterization to determine the direction of horizontal wells; S4, calculate the length of the horizontal well when the vertical well productivity ratio is above 1.5; S5, deploying horizontal wells according to the longitudinal deployment position, direction and length of the horizontal wells in S2-S4.

2. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: In S1, gas reservoirs with water invasion replacement coefficient greater than or equal to 0.15 are selected from water-driven gas reservoirs.

3. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: In S1, when the reservoir thickness is greater than or equal to 100 m, the thickness meets the requirements.

4. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: In S1, strong heterogeneity is when the coefficient of variation of permeability is greater than 0.

7.

5. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: In S2, geological research data including seismic data, stratigraphic comparison, lateral distribution comparison of reservoir physical properties, high permeability zones and reservoir characterization are used. If there is no high permeability zone in the gas reservoir, the closer the horizontal well is deployed to the top of the reservoir, the better the reservoir is, and the permeability is greater than or equal to the average permeability of the top reservoir segment; if there is a high permeability zone in the gas reservoir, when the high permeability zone is at the top, considering the water avoidance above and below the gas reservoir, the horizontal well is deployed in the medium permeability reservoir below the high permeability zone, and the permeability is greater than or equal to the average permeability of the top reservoir segment; when the high permeability zone is located in the middle or lower part of the gas reservoir, the closer the horizontal well is deployed to the top of the reservoir, the better the reservoir is, and the permeability is greater than or equal to the average permeability of the top reservoir segment.

6. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: In S3, in the direction that is beneficial to the stability of the wellbore, horizontal wells are arranged in the sections with good quality of seismic data, signal-to-noise ratio greater than 3, well error less than 1%, and no faults, and the angle between the horizontal section direction and the direction of the maximum horizontal principal stress is controlled to be 70°~90°.

7. The method for well layout in the middle and late stages of gas reservoir development according to claim 1, characterized in that: The calculation process of horizontal well length is: In the above formula: J h / J v =[Ln(r ev / r w )] / [Ln(r eh / r w,eff )] In the above formula: r w,eff is the radius of the vertical wellbore with the same production as the horizontal well; RR is the replacement ratio; r w is the radius of the vertical wellbore; r ev is the vertical well supply radius; L is the horizontal section length; ΔE R is the recovery factor improvement of horizontal wells compared to vertical wells, which is taken as 0.05; β is the square root of the ratio of horizontal to vertical permeability; h is the oil layer thickness; r eh is the average supply radius of the horizontal well; A o is the single well control area of ​​horizontal well; J h is the gas production index of horizontal well; J v is the vertical well gas production index.

8. A well layout system for the middle and late stages of gas reservoir development, characterized in that: include: The selection module is used to select gas reservoirs with water drive, thickness that meets the requirements, and strong heterogeneity. When the primary well pattern of the gas reservoir cannot meet the development needs of this stage, or when the recoverable reserves in the middle and late stages of development are greater than or equal to 50%, horizontal wells are selected for deployment; A vertical position determination module is used to determine the vertical deployment position of the horizontal well according to whether there is a high permeability strip in the gas reservoir and the position of the high permeability strip; Direction determination module, used to determine the direction of horizontal wells by combining geomechanics and fracture characterization; The length calculation module is used to calculate the length of the horizontal well when the vertical well productivity ratio is above 1.5; The well layout module is used to layout the horizontal wells according to the longitudinal deployment position, direction and length of the horizontal wells in the above modules.

9. 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 steps of the method for well deployment in the middle and late stages of gas reservoir development are implemented as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for well deployment in the middle and late stages of gas reservoir development are implemented as described in any one of claims 1 to 7.

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