A method and device for evaluating the grade of oilfield stratum development status

Abstract

The present invention provides a method and device for evaluating the level of development status of oilfield strata, including: setting the oil saturation enrichment value limit based on geological model establishment and numerical simulation results, respectively calculating the evaluation factor C representing the oil-bearing area coverage rate of oil-bearing sand bodies at the boundaries of each sub-layer, the evaluation factor D representing the superposition rate of oil-bearing sand bodies at the boundaries of interlayers, the evaluation factor R representing the difference in interlayer seepage resistance, the evaluation factor S representing the degree of deviation of interlayer saturation, and the evaluation factor L representing the degree of deviation of interlayer remaining movable reserves, setting the evaluation level of each parameter and the level limit value; constructing a strata evaluation comment set for each factor; calculating the multi-parameter evaluation decision factor LSD, and establishing the strata development stage level according to the maximum membership criterion. The present invention solves the empiricism and ambiguity of the current strata evaluation method, so that the evaluation of the development stage of the strata and the scientific grasp of the timing of strata adjustment can be clarified.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field development status evaluation and stratum adjustment, and in particular, relates to an oil field stratum development status grade evaluation method and device. Background Art

[0002] In the design of oilfield development plan, due to the limitations of factors such as the vertical heterogeneity of the reservoir, the oil production rate requirements and the level of oil production process technology, the oilfield plan design first needs to divide the layer system and form an injection and production well network based on the layer system division; with the continuous deepening of oilfield water injection development, affected by factors such as the vertical and planar heterogeneity of the reservoir, the oil-water viscosity difference, the well network and well spacing, the contradictions between small layers in the layer system are gradually intensified. The subdivision and reorganization of the layer system is a very important technology for the design of oilfield development adjustment plans to improve oil recovery from the perspective of resolving interlayer contradictions.

[0003] In view of the gradually intensified conflicts between small layers in the formation during the waterflooding development process, the evaluation of the current status of the formation and the determination of the timing of formation adjustment are the primary tasks in the design of formation subdivision and reorganization schemes. However, at present, the evaluation of formations and the timing of formation subdivision and reorganization are mainly qualitatively analyzed and evaluated based on the empirical methods of reservoir engineering. A scientific and quantitative formation evaluation method and formation development status level have not yet been formed, and no clear time node has been proposed for the selection of formation adjustment timing. Summary of the invention

[0004] In order to solve the problem that there is no scientific and quantitative formation evaluation method and formation development status grade, the embodiment of the present application provides an oilfield formation development status grade evaluation method and device, which evaluates and recognizes the formation status from a quantitative and graded perspective, solves the technical difficulty that the current formation evaluation quantitative method is missing and it is difficult to scientifically grasp the formation adjustment opportunity, and provides specific and quantitative guidance for understanding the current formation development status and determining the formation adjustment opportunity.

[0005] In a first aspect, the present application provides a method for evaluating the level of oilfield stratum development status, including:

[0006] Establish reservoir geological model;

[0007] Simulating reservoir values ​​using the reservoir geological model;

[0008] Based on the results of reservoir numerical simulation, the oil saturation enrichment value limit is set, and the evaluation factor C representing the oil-bearing area coverage of the oil-bearing sand bodies at the boundary of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundary of the interlayer, the evaluation factor R representing the difference in interlayer seepage resistance, the evaluation factor S representing the degree of deviation of interlayer saturation, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers are calculated respectively, and the evaluation level of each parameter and the level limit value are set;

[0009] Construction of hierarchical evaluation comment sets for each factor;

[0010] The multi-parameter evaluation decision factor LSD is calculated, and the stratum development stage level is established according to the maximum membership criterion.

[0011] Among them, the evaluation factor C that characterizes the oil-bearing area coverage of the oil-bearing sand bodies at the boundaries of each small layer is calculated, including:

[0012] The coverage rate of the critical oil-bearing area is the ratio of the oil-bearing area of ​​each sublayer in the stratum system at a given critical oil saturation to the total oil-bearing area, expressed as:

[0013]

[0014]

[0015] Where: A k is the oil-bearing area of ​​the kth layer; A is the total oil-bearing area, and K is the total number of layers.

[0016] Among them, the evaluation factor D representing the overlap ratio of oil-bearing sand bodies at the boundary between layers is calculated, including:

[0017] The superposition rate of critical oil-bearing sand bodies is the ratio of the superposition area between the sand bodies in each layer within the stratum system where the oil saturation is higher than the critical value to the total area of ​​the two sand bodies when viewed from above.

[0018]

[0019]

[0020] Where: A i , A j They are all elements in the sand body superposition matrix.

[0021] Among them, the evaluation factor R that characterizes the difference in seepage resistance between layers is calculated, including:

[0022] The seepage resistance is the seepage resistance of the grid along the flow direction, that is:

[0023]

[0024] Where: μ is the fluid viscosity, L ijk is the fluid grid length, K ijk is the grid permeability, h ijk is the grid height, b ijk is the grid width;

[0025] The difference in seepage resistance is the coefficient of variation of the plane grid (i, j) in the longitudinal direction, that is:

[0026]

[0027] in:

[0028] Evaluation factors of seepage resistance difference:

[0029] Where: I is the number of grids in the x-direction of the model, and J is the number of grids in the y-direction of the model.

[0030] The evaluation factor S representing the degree of interlayer saturation deviation is calculated, including:

[0031] The saturation deviation degree is the degree to which the current grid saturation deviates from the original oil saturation, which can be expressed as:

[0032]

[0033] in:

[0034] The evaluation factor S of the saturation deviation degree of the layer is calculated by using the coefficient of variation method:

[0035]

[0036] Among them, the evaluation factor L representing the deviation degree of interlayer remaining movable reserves is calculated, including:

[0037] The remaining movable reserves deviation degree is the degree to which the current grid remaining movable reserves size deviates from the original movable reserves, expressed as:

[0038]

[0039] in:

[0040] The evaluation factor S of the deviation degree of the remaining movable reserves of the stratum is calculated by using the coefficient of variation method:

[0041]

[0042] The construction of the hierarchical evaluation comment set of each factor includes:

[0043] The evaluation factors for the new stratum division result are: evaluation factor C for the coverage of oil-bearing area of ​​the boundary oil-bearing sand body, evaluation factor D for the overlap ratio of the boundary oil-bearing sand body between layers, evaluation factor R for the difference of seepage resistance between layers, evaluation factor S for the deviation degree of saturation between layers, and evaluation factor L for the deviation degree of remaining movable reserves between layers.

[0044] For the comment set of hierarchical evaluation, the comment set of each factor is divided into five levels: excellent, good, medium, poor, and extremely poor.

[0045] In a second aspect, the present application provides an oilfield stratum development status evaluation device, comprising:

[0046] Establishing units for establishing reservoir geological models;

[0047] A simulation unit, used for simulating reservoir values ​​using the reservoir geological model;

[0048] The calculation unit is used to set the oil saturation enrichment value limit based on the reservoir numerical simulation results, respectively calculate the evaluation factor C representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factor R representing the difference in seepage resistance between layers, the evaluation factor S representing the degree of deviation of the interlayer saturation, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers, and set the evaluation level of each parameter and the level limit value size;

[0049] Construction unit, used to construct the hierarchical evaluation comment set for each factor;

[0050] The establishment unit is used to calculate the multi-parameter evaluation decision factor LSD and establish the level of stratum development stage according to the maximum membership criterion.

[0051] In a third aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any of the above methods when executed by a processor.

[0052] In a fourth aspect, an embodiment of the present application 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 steps of any of the above methods when executing the program.

[0053] The method and device for evaluating the development status of oilfield strata in the embodiment of the present application have the following beneficial effects:

[0054] The present invention solves the problems that the existing stratum evaluation technology is vague and not specific, and it is difficult to grasp the timing of stratum adjustment. It evaluates the current status of the stratum from a quantitative and graded perspective, solves the technical difficulty that the current stratum evaluation quantitative method is lacking and it is difficult to scientifically grasp the timing of stratum adjustment. It provides specific and quantitative guidance for understanding the current status of stratum development and determining the timing of stratum adjustment. The establishment of this method has very important practical significance for understanding the current stage of oilfield strata and further improving the recovery rate through stratum adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the process of the oilfield stratum development status evaluation method according to the embodiment of the present application;

[0056] Figure 2This is a schematic diagram of the structure of the oilfield stratum development status evaluation device according to an embodiment of the present application;

[0057] Figure 3 This is a schematic diagram of the structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0058] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0059] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present invention, and different embodiments can be replaced or combined, so this application can also be considered to include all possible combinations of the same and / or different embodiments recorded. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, even though the embodiment may not be clearly recorded in the following text.

[0060] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements described without departing from the scope of the present application. Various processes or components may be appropriately omitted, substituted or added to each example. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted or combined. In addition, features described in some examples may be combined in other examples.

[0061] In the design of oilfield development plan, due to the limitations of factors such as the vertical heterogeneity of the reservoir, the oil production rate requirements and the level of oil production process technology, the oilfield plan design first needs to divide the layer system and form an injection and production well network based on the layer system division; with the continuous deepening of oilfield water injection development, affected by factors such as the vertical and planar heterogeneity of the reservoir, the oil-water viscosity difference, the well network and well spacing, the contradictions between small layers in the layer system are gradually intensified. The subdivision and reorganization of the layer system is a very important technology for the design of oilfield development adjustment plans to improve oil recovery from the perspective of resolving interlayer contradictions.

[0062] In view of the gradually intensified conflicts between small layers in the formation during the waterflooding development process, the evaluation of the current status of the formation and the determination of the timing of formation adjustment are the primary tasks in the design of formation subdivision and reorganization schemes. However, at present, the evaluation of formations and the timing of formation subdivision and reorganization are mainly qualitatively analyzed and evaluated based on the empirical methods of reservoir engineering. A scientific and quantitative formation evaluation method and formation development status level have not yet been formed, and no clear time node has been proposed for the selection of formation adjustment timing.

[0063] The first task in designing a comprehensive reservoir adjustment plan is to scientifically evaluate the current status or degree of stratum development, but the current technology in this area is quite weak. (1) The selection of stratum evaluation parameters is not comprehensive enough, and the evaluation parameter system is not perfect enough; (2) The stratum evaluation results have not formed a set of quantifiable and comparable stratum evaluation levels; (3) The stratum evaluation results lack longitudinal quantitative evaluation comparability based on the time axis; (4) The stratum evaluation results before and after stratum subdivision or reorganization lack quantitative comparability.

[0064] Judging from the current research situation at home and abroad, the key to these problems lies in:

[0065] (1) The evaluation and classification methods of the development status of the strata mainly use indicators such as sedimentary microfacies, vertical permeability, saturation, and water content of each small layer in the strata, without considering the distribution and superposition of sand bodies; the indicators use the average value of each small layer in the strata to study the heterogeneity between layers, which conceals the real heterogeneity characteristics between layers;

[0066] (2) At present, the evaluation of the formation system mainly analyzes the current adaptability of the formation system from the perspective of the principles of formation division, and the result is an empirical, sensory and fuzzy formation evaluation based on reservoir engineering methods, but there is no quantitative and hierarchical evaluation result for the formation system evaluation result;

[0067] (3) At present, the stratum evaluation is mainly carried out when adjusting the reservoir engineering plan. However, at each time point in the whole development process, there is no systematic and continuous tracking and evaluation of the stratum status evaluation results at each development history stage, nor is there a change trend of the stratum evaluation quantitative indicators established. The reason is the lack of a continuous quantitative evaluation method for stratum evaluation.

[0068] (4) At present, before and after the design of the formation adjustment plan, the evaluation of the effect of formation reorganization or subdivision is mainly based on the comparison of the index effects before and after the scheme design using reservoir engineering and numerical simulation methods, without analyzing the rationality and improvement of formation division, subdivision or reorganization from the perspective of the change in the quantitative results of formation evaluation indicators. The reason for this is also the lack of a continuous quantitative evaluation method for formation evaluation.

[0069] Based on the above analysis, this application provides a method for evaluating the level of formation development status based on sand body superposition and interlayer parameter differences, involving quantitative and level evaluation areas such as formation development status evaluation, formation stage evaluation, formation adjustment timing, and formation reorganization and subdivision.

[0070] Embodiment 1:

[0071] The method for evaluating the level of development status of oilfield strata in the present application comprises: establishing a reservoir geological model; simulating reservoir values ​​using the reservoir geological model; setting the oil saturation enrichment value limit based on the reservoir numerical simulation results, respectively calculating the evaluation factor C representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factor R representing the difference in seepage resistance between layers, the evaluation factor S representing the degree of deviation of saturation between layers, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers, setting the evaluation level of each parameter and the level limit value size; constructing a strata evaluation comment set for each factor; calculating the multi-parameter evaluation decision factor LSD, and establishing the strata development stage level according to the maximum membership criterion.

[0072] This application can quantify and grade the development status, development stage and adjustment timing of the current reservoir strata, and conduct longitudinal change rules and grade evaluation on the time axis; it can quantify and grade the adjustment effects after the strata are adjusted.

[0073] Embodiment 2

[0074] like Figure 1 As shown, the method for evaluating the level of development status of oilfield formations in the present application includes the following steps: S101, establishing a reservoir geological model; S103, simulating reservoir values ​​using the reservoir geological model; S105, setting the oil saturation enrichment value limit based on the reservoir numerical simulation result, respectively calculating the evaluation factor C representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each sub-layer, the evaluation factor D representing the overlap rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factor R representing the difference in seepage resistance between layers, the evaluation factor S representing the degree of deviation of the saturation between layers, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers, and setting the evaluation level of each parameter and the level limit value size; S107, constructing a formation evaluation comment set for each factor; S109, calculating the multi-parameter evaluation decision factor LSD, and establishing the formation development stage level according to the maximum membership criterion.

[0075] The invention firstly aims at the reservoir, establishes the evaluation factor of the coverage rate of the oil-bearing sand body and the evaluation factor of the overlap rate of the oil-bearing sand body from the perspective of the ratio of the area of ​​the boundary oil-bearing sand body, and the two factors can effectively characterize the mutual relationship and change trend of the enrichment areas between each small layer in the current layer system, and evaluate the rationality and change speed of the current state of the small layer combination in the layer system; uses the interlayer seepage resistance evaluation factor to evaluate the seepage resistance difference, change trend and change speed of each small layer in the current layer system; uses the interlayer saturation and the remaining movable reserve deviation degree as evaluation factors to evaluate the exploitation degree of the small layers in the current layer system; the invention constructs a scientific and quantitative method for layer system evaluation from three perspectives of sand body form, seepage capacity and development status, solves the current difficulties in understanding the current state of the layer system and grasping the timing of layer system adjustment, so that the layer system adjustment can be quantitatively evaluated and the trend change can be achieved, ensuring the purpose of controlling water and stabilizing oil on site in the oil field and continuously improving the recovery rate.

[0076] Step 1: Calculate the evaluation factor C of the oil-bearing area coverage of the oil-bearing sand body at the boundary of the small layer

[0077] The critical oil-bearing area coverage rate refers to the ratio of the oil-bearing area of ​​each sublayer in the stratum system at a given critical oil saturation to the total oil-bearing area, expressed as:

[0078]

[0079]

[0080] Where: A k is the oil-bearing area of ​​the kth layer; A is the total oil-bearing area, and K is the total number of layers;

[0081] The size of the critical oil saturation value is determined by the water content, usually the oil saturation corresponding to 10% water content; for the evaluation factor C, the C value varies in different water-content development stages. In the early stage of oil field development, for the same stratum, the C value is the largest. As the oil field development progresses, the C value shows a monotonically decreasing characteristic. When it is necessary to adjust the stratum, the rate of change of this value is basically stable, thereby evaluating the stage of stratum development.

[0082] Step 2: Evaluation factor D of the overlap ratio of the critical oil-bearing sand bodies,

[0083] The critical oil-bearing sand body overlap ratio refers to the ratio of the overlapped area between the sand bodies in each sub-layer in the stratum system where the oil saturation is higher than the critical value to the total area of ​​the two sand bodies when viewed from above. As a reasonable development stratum system, each sub-layer should have a higher critical oil-bearing sand body overlap ratio. For a total of K layers in the stratum system, the sand body overlap situation is as follows: Matrix Table 1:

[0084] Table 1. Sand body superposition matrix design table

[0085]

[0086]

[0087]

[0088]

[0089] For the evaluation factor D, as the development progresses, the D values ​​vary in different water-content development stages, and the D value shows a monotonically decreasing characteristic. When it is necessary to adjust the formation system, the rate of change of this value is basically stable, thereby evaluating the stage of formation system development.

[0090] Step 3: Evaluation factor R of seepage resistance difference

[0091] The seepage resistance refers to the seepage resistance of the grid along the flow direction, that is:

[0092]

[0093] Where: μ is the fluid viscosity, L ijk is the fluid grid length, K ijk is the grid permeability, h ijk is the grid height, b ijk is the grid width;

[0094] The seepage resistance difference refers to the coefficient of variation of the plane grid (i, j) in the longitudinal direction, that is:

[0095]

[0096] in:

[0097] Evaluation factor of the seepage resistance difference:

[0098] Where: I is the number of grids in the x-direction of the model, and J is the number of grids in the y-direction of the model.

[0099] The larger the evaluation factor R is, the greater the difference in seepage resistance between layers, the stronger the vertical heterogeneity, and the greater the necessity for layer adjustment.

[0100] Step 4: Evaluation factor S of saturation deviation

[0101] The saturation deviation degree refers to the degree to which the current grid saturation deviates from the original oil saturation, which can be specifically expressed as:

[0102]

[0103] in:

[0104] The evaluation factor S of the saturation deviation degree of the layer is calculated by using the coefficient of variation method:

[0105]

[0106] The larger the S value is, the greater the difference in the remaining oil enrichment between layers within the formation, and the stronger the necessity of formation adjustment.

[0107] Step 5: Evaluation of the deviation degree of remaining movable reserves L

[0108] The remaining movable reserves deviation degree refers to the degree to which the current grid remaining movable reserves deviate from the original movable reserves, which can be specifically expressed as:

[0109]

[0110] in:

[0111] The evaluation factor S of the deviation degree of the remaining movable reserves of the stratum is calculated by using the coefficient of variation method:

[0112]

[0113] The larger the value is, the greater the difference in the availability of remaining oil between layers within the formation, and the greater the necessity for formation adjustment.

[0114] Step 6: Construction of hierarchical evaluation comment sets for each factor

[0115] On the one hand, the layer evaluation evaluates the status of the layer itself, which is used to evaluate the division results after the layer division is completed; on the other hand, it evaluates the degree of layer change, which is used to evaluate the degree and speed of layer change in the development stage after the layer division is formally implemented. The degree of change includes the degree of deviation from the layer adjustment before and the degree of change in the future. The closer the deviation is to the future value, the more adjustment is needed. The speed of change is the rate of change of the current parameter. The more stable the speed of change is, the stronger the necessity of layer adjustment is. The construction of the layer comment set is divided into the following two levels:

[0116] (1) A set of evaluation criteria for the results of new stratigraphic division;

[0117] The evaluation factors for the new stratum division result are: evaluation factor C for the coverage of oil-bearing area of ​​the boundary oil-bearing sand body, evaluation factor D for the overlap ratio of the boundary oil-bearing sand body between layers, evaluation factor R for the difference of seepage resistance between layers, evaluation factor S for the deviation degree of saturation between layers, and evaluation factor L for the deviation degree of remaining movable reserves between layers.

[0118] For the comment set of hierarchical evaluation, the comment set of each factor is divided, and the comment set V = 5 categories of (excellent, good, medium, poor, and extremely poor), where excellent represents an excellent hierarchical division result, good represents a good hierarchical division result, medium represents a medium hierarchical division result, poor represents a poor hierarchical division result and it is necessary to re-divide, and extremely poor represents an extremely poor hierarchical division result and the hierarchical division must be re-divided.

[0119] (2) A set of evaluation criteria for the development status of old strata;

[0120] The evaluation factors for the development status of old strata are: evaluation factor C for the coverage of oil-bearing area of ​​boundary oil-bearing sand bodies, evaluation factor D for the overlap ratio of boundary oil-bearing sand bodies between layers, evaluation factor R for the difference of seepage resistance between layers, evaluation factor S for the deviation degree of saturation between layers, and evaluation factor L for the deviation degree of remaining movable reserves between layers.

[0121] For the comment set of layer evaluation, the comment set of each factor is divided into 5 categories, and the comment set V = (excellent, good, medium, poor, and extremely poor). Excellent means that the system is in the early stage of development and does not need to be reorganized. Good means that the current layer division does not need to be reorganized or subdivided. Medium means that the current layer division is basically in a state where it can be divided or not. Poor means that the current layer is at the level where re-division is recommended. Extremely poor means that the layer must be divided and reorganized immediately.

[0122] Step 7: Multi-parameter evaluation decision factor LSD, maximum membership criterion to establish the level of layer development stage

[0123] (1) Domain Construction:

[0124] The factor set is a combination of various parameters that have a major impact on the evaluation object. A total of 5 parameters constitute the factor set, represented by U, where ui represents each influencing factor, and these parameters usually have different degrees of fuzziness:

[0125] U={u i}={u1,u2,u3,u4,u5}

[0126] (2) Membership function selection

[0127] The fuzzy relationship between the factor set U and the comment set V is usually represented by an m×n order fuzzy relationship single factor evaluation matrix R, where each element means the membership of the i-th factor to the j-th comment. The matrix R = {r i1 , r i2 ,…,r i5} is the i-th evaluation factor u i The single factor judgment of is a fuzzy subset of the comment set V:

[0128]

[0129] Select the ascending and descending semi-trapezoidal type to determine the membership function. The larger the membership function is, the better it is to use the ascending semi-trapezoidal distribution. The smaller the membership function is, the better it is to use the descending semi-trapezoidal distribution.

[0130] Ascending half trapezoid:

[0131] Descending half trapezoid:

[0132] Where: r ij is the membership of the i-th factor to the j-th comment, and 0≤r ij ≤1; b is the maximum value of the i-th factor index; a is the minimum value of the i-th factor index.

[0133] (3) Weight set

[0134] The weight set A is a fuzzy subset of the factor set U. ai represents the weight corresponding to each parameter, reflecting the relative importance of each factor. At the same time, the weight of each parameter must satisfy the formula:

[0135] A=λ i ={λ1, λ2, λ3, λ4, λ5}

[0136] λ1+λ2+λ3+λ4+λ5=1

[0137] (4) Maximum membership criterion to determine the level of hierarchical development

[0138] Calculate the multi-parameter evaluation decision factor LSD, the synthesis of the weight vector A and the fuzzy matrix R is the comprehensive membership degree B:

[0139]

[0140] B=A0R=(b1, b2, b3, b4, b5)

[0141] Where: B: comprehensive evaluation result; R: single factor evaluation matrix; 0: fuzzy operator.

[0142] The maximum membership criterion is based on the index corresponding to the largest membership in fuzzy mathematics to determine the level of the evaluation object. If LSD = max(b1, b2, ..., b m ), then find the corresponding level matrix V, which is the target value vj of the comprehensive evaluation, and the level of the evaluation object is the j-th level evaluation model.

[0143] The present invention includes: based on the establishment of geological model and numerical simulation results, setting the oil saturation enrichment value limit, respectively calculating the evaluation factors representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each small layer, the evaluation factors representing the superposition rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factors representing the difference in seepage resistance between layers, the evaluation factors representing the degree of deviation of the saturation between layers, and the evaluation factors representing the degree of deviation of the remaining movable reserves between layers, setting the evaluation level of each parameter and the level limit value, using the multi-parameter fuzzy comprehensive evaluation method to calculate the decision factor for the evaluation of the development status of the stratum system, and using the maximum membership LSD principle to establish the level of the stratum system development stage. The present invention solves the empiricism and ambiguity of the current stratum system evaluation method, so that the evaluation of the development stage of the stratum system and the scientific grasp of the timing of stratum system adjustment can be clarified.

[0144] Embodiment 3

[0145] In order to have a more intuitive understanding of the application effect of the second embodiment, the specific implementation of the present invention is now described by taking the above method as an example.

[0146] The model adopts a positive row and column injection and production well network and sets the ratio of the maximum and minimum vertical heterogeneity to 3. The reorganization of the formation usually does not undergo major adjustments in the medium and low water content stages, and generally occurs in the high and extra-high water content stages. The evaluation of the formation is divided into two parts: one is the formation division evaluation at the time of production, and the other is the formation evaluation at each stage after development.

[0147] (1) The evaluation of the original layer division is mainly aimed at the designed small layers, and the layer combination effect is evaluated:

[0148] ① One of the purposes of stratum division is to exploit multiple layers in the same well. Therefore, the division of stratum requires a certain degree of overlap between the layers. According to the five-level method, the division is equally spaced. It can be seen that the limit values ​​of the oil-bearing area and the overlap rate of the oil-bearing sand body are set as: 0.9, 0.7, 0.5, 0.3;

[0149] ② The second purpose of layer division is to solve the heterogeneity between layers. From the perspective of vertical heterogeneity of reservoir physical properties, homogenization is usually the best. As a set of layers, from the perspective of permeability alone, the ratio of maximum to minimum is usually required to be less than 5. Therefore, the ratio of maximum to minimum is considered to be 2, 3, 4, and 5 as the limit values, corresponding to the coefficient of variation of 0.33, 0.5, 0.6, and 0.67 respectively;

[0150] ③ The third purpose of the stratigraphic division is to make the small layers a unified pressure system, with consistent oil content, so that the original oil saturation should be consistent. Since the oil saturation changes from the original state to the residual oil saturation, the change range is small, and the maximum oil saturation is usually about 2 times the saturation at 98% water content. Therefore, the saturation change multiples are set as 0.9, 0.8, 0.7, and 0.6 as the limit values, corresponding to the coefficients of variation of 0.053, 0.11, 0.17, and 0.25 respectively;

[0151] ④ When the initial strata are combined, the movable reserves are greatly affected by the thickness of the sand bodies in each small layer and the oil-bearing area. Usually, the ratio of the maximum reserve to the minimum reserve of the small layer is within 5. Therefore, the ratio of the maximum to the minimum is 2, 3, 4, and 5 as the limit values, corresponding to the coefficient of variation of 0.33, 0.5, 0.6, and 0.67 respectively.

[0152] (2) Evaluation of the status of the layer system during the development phase

[0153] ① The coverage rate of the oil-bearing area at the boundary of the sand body and the overlap rate of the oil-bearing sand body at the boundary. After the development of the oil field, the coverage rate of the oil-bearing area is less important. The key to whether the formation is reasonable lies in the overlap rate of the oil-bearing sand body at the boundary. The lower the overlap rate, the stronger the necessity of formation adjustment. The limit values ​​are set as: 0.9, 0.7, 0.5, 0.3;

[0154] ② Interlayer heterogeneity of seepage resistance. The initial coefficient of variation of this value is determined by the reservoir permeability. In the later period, as the oil saturation decreases, the seepage resistance changes. For small layers with small seepage resistance, the more water is injected, the smaller the seepage resistance is, and the more necessary the formation adjustment is. The limit values ​​are set as: 0.33, 0.5, 0.6, 0.67;

[0155] ③ Interlayer heterogeneity of saturation. The initial coefficient of variation of this value is basically 0. When the water content of the small layer reaches 100%, the residual oil saturation is 0.5 times the original saturation, and the value becomes 0.5. The larger the value, the stronger the necessity of layer adjustment. The limit values ​​are set as: 0.1, 0.2, 0.3, 0.4;

[0156] ④ Interlayer heterogeneity of movable reserves. The change of this value depends on the initial setting of the formation system and the focus of perforation development. It may become larger or smaller relative to the original value. However, when the formation system is stable, the rate of change of this value decreases, which is suitable for qualitative evaluation.

[0157] For the injection-production well network in opposite rows, the evaluation factor values ​​at different simulation time nodes are studied to conduct a comprehensive evaluation of the formation.

[0158] By using the established formation evaluation method, the formation effect is evaluated at each time node of the opposite row injection and production well network. It can be seen that in the water-free, low water-content and medium water-content stages, the formation evaluation results are above medium, while when the high water content is 0.925 and the injection porosity multiple is 0.773, the formation evaluation result is poor. It can be seen that after this stage, formation contradictions begin to become prominent, which is the opportunity point for formation adjustment. From a technical point of view, it may be necessary to reorganize the formation after this stage.

[0159] This application can quantify and grade the development status, development stage and adjustment timing of the current reservoir strata, and conduct longitudinal change rules and grade evaluation on the time axis; it can quantify and grade the adjustment effects after the strata are adjusted.

[0160] This application effectively guided the evaluation and adjustment of small fault block reservoir strata, effectively reduced the production decline rate of small fault block reservoirs in Jiangsu Oilfield, extended the stable production period of the oilfield, significantly improved the ultimate recovery rate of the reservoir, and achieved significant development effects and benefits.

[0161] like Figure 2 As shown, the present application also provides an oilfield stratum development status evaluation device, comprising:

[0162] Establishing unit 201, used for establishing reservoir geological model;

[0163] The simulation unit 202 is used to simulate reservoir values ​​using a reservoir geological model;

[0164] The calculation unit 203 is used to set the oil saturation enrichment value limit based on the reservoir numerical simulation results, respectively calculate the evaluation factor C representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factor R representing the difference in seepage resistance between layers, the evaluation factor S representing the degree of deviation of the interlayer saturation, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers, and set the evaluation level of each parameter and the level limit value size;

[0165] A construction unit 204 is used to construct a hierarchical evaluation comment set for each factor;

[0166] The establishing unit 205 is used to calculate the multi-parameter evaluation decision factor LSD and establish the level of the stratum development stage according to the maximum membership criterion.

[0167] In the present application, the embodiment of the oilfield stratum development status grade evaluation device is basically similar to the embodiment of the oilfield stratum development status grade evaluation method. For relevant matters, please refer to the introduction of the embodiment of the oilfield stratum development status grade evaluation method.

[0168] Those skilled in the art can clearly understand that the technical solutions of the embodiments of the present invention can be implemented with the help of software and / or hardware. "Unit" and "module" in this specification refer to software and / or hardware that can independently complete or cooperate with other components to complete specific functions, where the hardware can be, for example, FPGA (Field-Programmable Gate Array), IC (Integrated Circuit), etc.

[0169] Each processing unit and / or module of the embodiment of the present invention may be implemented by an analog circuit that implements the functions described in the embodiment of the present invention, or may be implemented by software that executes the functions described in the embodiment of the present invention.

[0170] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the above-mentioned oilfield stratum development status level evaluation method steps are implemented. The computer-readable storage medium may include, but is not limited to, any type of disk, including a floppy disk, an optical disk, a DVD, a CD-ROM, a micro drive, and a magneto-optical disk, a ROM, a RAM, an EPROM, an EEPROM, a DRAM, a VRAM, a flash memory device, a magnetic card or an optical card, a nanosystem (including a molecular memory IC), or any type of medium or device suitable for storing instructions and / or data.

[0171] Figure 3 This is a schematic diagram of the structure of the computer device according to the embodiment of the present application. Figure 3 As shown, the computer device of the present application is, for example, a laptop computer, a desktop computer, a workbench, a personal digital assistant, a server, a blade server, a mainframe computer, and other suitable computers. The computer device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices and other similar computing devices. The computer device of the present application includes a processor 401, a memory 402, an input device 403 and an output device 404. The processor 401, the memory 402, the input device 403 and the output device 404 can be connected by a bus 405 or other means. A computer program is stored on the memory 402, and the computer program can be run on the processor 401, and the processor 401 implements the above-mentioned oilfield formation development status grade evaluation method steps when executing the program.

[0172] The input device 403 can receive input digital or character information, and generate key signal input related to user settings and function control of the data processing computer device, such as a touch screen, a keypad, a mouse, a track pad, a touch pad, an indicator bar, one or more mouse buttons, a trackball, a joystick, etc. The output device 404 may include a display device, an auxiliary lighting device (e.g., an LED), and a tactile feedback device (e.g., a vibration motor). The display device may include, but is not limited to, a liquid crystal display (LCD), a light emitting diode (LED) display, a plasma display, and a touch screen.

[0173] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0174] In the embodiments of the present invention, all functional units may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0175] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating the grade of oilfield stratum development status, characterized in that: include: Establish reservoir geological model; Simulating reservoir values ​​using the reservoir geological model; Based on the results of reservoir numerical simulation, the oil saturation enrichment value limit is set, and the evaluation factor C representing the oil-bearing area coverage of the oil-bearing sand bodies at the boundary of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundary of the interlayer, the evaluation factor R representing the difference in interlayer seepage resistance, the evaluation factor S representing the degree of deviation of interlayer saturation, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers are calculated respectively, and the evaluation level of each parameter and the level limit value are set; The evaluation factor C that characterizes the oil-bearing area coverage of the oil-bearing sand bodies at the boundaries of each sub-layer is calculated, including: The coverage rate of the critical oil-bearing area is the ratio of the oil-bearing area of ​​each sublayer in the stratum system at a given critical oil saturation to the total oil-bearing area, expressed as: Where: A k is the oil-bearing area of ​​the kth layer; A is the total oil-bearing area, and K is the total number of layers; The evaluation factor D that characterizes the overlap ratio of oil-bearing sand bodies at the boundary between layers is calculated, including: The superposition rate of critical oil-bearing sand bodies is the ratio of the superposition area between the sand bodies in each layer within the stratum system where the oil saturation is higher than the critical value to the total area of ​​the two sand bodies when viewed from above. Where: A i , A j All of them are elements in the matrix of sand body superposition; Calculate the evaluation factor R that characterizes the difference in seepage resistance between layers, including: The seepage resistance is the seepage resistance of the grid along the flow direction, that is: Where: μ is the fluid viscosity, L ijk is the fluid grid length, K ijk is the grid permeability, h ijk is the grid height, b ijk is the grid width; The difference in seepage resistance is the coefficient of variation of the plane grid (i, j) in the longitudinal direction, that is: in: Evaluation factors of seepage resistance difference: Where: I is the number of grids in the x-direction of the model, and J is the number of grids in the y-direction of the model; Calculate the evaluation factor S that characterizes the degree of interlayer saturation deviation, including: The saturation deviation degree is the degree to which the current grid saturation deviates from the original oil saturation, which can be expressed as: in: The evaluation factor S of the saturation deviation degree of the layer is calculated by using the coefficient of variation method: Calculate the evaluation factor L that characterizes the deviation degree of interlayer remaining movable reserves, including: The remaining movable reserves deviation degree is the degree to which the current grid remaining movable reserves size deviates from the original movable reserves, expressed as: in: The evaluation factor L of the deviation degree of the remaining movable reserves of the stratum is calculated by using the coefficient of variation method: Construction of hierarchical evaluation comment sets for each factor; The multi-parameter evaluation decision factor LSD is calculated, and the stratum development stage level is established according to the maximum membership criterion.

2. The method for evaluating the development status of oilfield strata according to claim 1, characterized in that: The hierarchical evaluation comment set of each factor is constructed, including: The evaluation factors for the new stratum division result are: evaluation factor C for the coverage of oil-bearing area of ​​the boundary oil-bearing sand body, evaluation factor D for the overlap ratio of the boundary oil-bearing sand body between layers, evaluation factor R for the difference of seepage resistance between layers, evaluation factor S for the deviation degree of saturation between layers, and evaluation factor L for the deviation degree of remaining movable reserves between layers. For the comment set of hierarchical evaluation, the comment set of each factor is divided into five levels: excellent, good, medium, poor, and extremely poor.

3. An oilfield stratum development status evaluation device, characterized in that: include: Establishing units for establishing reservoir geological models; A simulation unit, used for simulating reservoir values ​​using the reservoir geological model; The calculation unit is used to set the oil saturation enrichment value limit based on the reservoir numerical simulation results, respectively calculate the evaluation factor C representing the oil-bearing area coverage rate of the oil-bearing sand bodies at the boundaries of each small layer, the evaluation factor D representing the superposition rate of the oil-bearing sand bodies at the boundaries of the layers, the evaluation factor R representing the difference in seepage resistance between layers, the evaluation factor S representing the degree of deviation of the interlayer saturation, and the evaluation factor L representing the degree of deviation of the remaining movable reserves between layers, and set the evaluation level of each parameter and the level limit value size; The evaluation factor C that characterizes the oil-bearing area coverage of the oil-bearing sand bodies at the boundaries of each sub-layer is calculated, including: The coverage rate of the critical oil-bearing area is the ratio of the oil-bearing area of ​​each sublayer in the stratum system at a given critical oil saturation to the total oil-bearing area, expressed as: Where: A k is the oil-bearing area of ​​the kth layer; A is the total oil-bearing area, and K is the total number of layers; The evaluation factor D that characterizes the overlap ratio of oil-bearing sand bodies at the boundary between layers is calculated, including: The superposition rate of critical oil-bearing sand bodies is the ratio of the superposition area between the sand bodies in each layer within the stratum system where the oil saturation is higher than the critical value to the total area of ​​the two sand bodies when viewed from above. Where: A i , A j All of them are elements in the matrix of sand body superposition; Calculate the evaluation factor R that characterizes the difference in seepage resistance between layers, including: The seepage resistance is the seepage resistance of the grid along the flow direction, that is: Where: μ is the fluid viscosity, L ijk is the fluid grid length, K ijk is the grid permeability, h ijk is the grid height, b ijk is the grid width; The difference in seepage resistance is the coefficient of variation of the plane grid (i, j) in the longitudinal direction, that is: in: Evaluation factors of seepage resistance difference: Where: I is the number of grids in the x-direction of the model, and J is the number of grids in the y-direction of the model; Calculate the evaluation factor S that characterizes the degree of interlayer saturation deviation, including: The saturation deviation degree is the degree to which the current grid saturation deviates from the original oil saturation, which can be expressed as: in: The evaluation factor S of the saturation deviation degree of the layer is calculated by using the coefficient of variation method: Calculate the evaluation factor L that characterizes the deviation degree of interlayer remaining movable reserves, including: The remaining movable reserves deviation degree is the degree to which the current grid remaining movable reserves size deviates from the original movable reserves, expressed as: in: The evaluation factor L of the deviation degree of the remaining movable reserves of the stratum is calculated by using the coefficient of variation method: Construction unit, used to construct the hierarchical evaluation comment set for each factor; The establishment unit is used to calculate the multi-parameter evaluation decision factor LSD and establish the level of stratum development stage according to the maximum membership criterion.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 2 are implemented.

5. 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 program, the steps of the method according to any one of claims 1 to 2 are implemented.

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