Fault block oil field water drive development effect evaluation method
By calculating the ideal recovery rate and development degree of the fault block oil field, and using the intersection pattern evaluation, the complexity and parameter acquisition problems of the existing technology interrupted block oil field development effect evaluation are solved, and intuitive and accurate development effect evaluation and potential discovery are achieved. .
Patent Information
- Application Number
- CN202310723305.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-19
- Publication Date
- 2024-12-20
AI Technical Summary
The existing results of the evaluation methods for the development of fault block oil fields mostly use the scoring form and have many calculation parameters, making it difficult to obtain the entire evaluation effect, and the complex steps require software to be prepared, which limits the promotion and application of the method.
By calculating the expected recovery rate and setting the development degree or final recovery rate of the development stage under the ideal state of each fault unit in the fault block oil field, the evaluation is performed using the intersection chart plate, and the Serkachev formula and the Arps yield decreasing equation are used to achieve the evaluation. As the basis for calculation, the representation of parameters is simplified and the development effect is intuitively clarified in the form of a graph.
The intuitive and accurate evaluation of the development effect of the fault block oil field has been achieved, the remaining development potential has been clarified, the operation process has been simplified, and the application promotion problem that existing methods are restricted due to the difficulty of obtaining full calculation parameters has been overcome.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of water flooding development effect evaluation, and in particular to a method for evaluating the water flooding development effect of a fault block oil field. Background Art
[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
[0003] Fault block oilfields are composed of multiple oil-bearing fault block units, and the distribution of oil and gas has the characteristic of "enrichment by fault". The oil layer near the fault is thick and has good physical properties, while the oil layer at the edge of the fault block is thin and has poor physical properties. Each oil-bearing fault block is relatively isolated and has its own oil-water system. The geological conditions and development effects vary greatly. In the process of rolling development and adjustment, it is necessary to take the fault block as the evaluation unit and make overall planning and adjustments based on the geological development characteristics of the fault block itself.
[0004] At present, the multi-index comprehensive evaluation method is widely used in the evaluation of block oilfield development effects, which has the following three shortcomings: First, the evaluation results are mostly in the form of scoring, which only gives the relative development effects of each block, but does not give how much potential there is in the block itself; second, there are many calculation parameters and it is difficult to obtain them all. For example, the calculation parameters such as formation pressure and water-absorbing sandstone thickness are not available in all evaluation blocks due to the long test cycle and high detection cost, which affects the evaluation effect; third, many evaluation methods require the compilation of corresponding software or programs due to the large number of parameters and complex steps, which limits their promotion and application to a certain extent.
[0005] Therefore, how to evaluate the development effect of block oilfields, find the gap between the current development level of block units and the ideal development effect, discover problems in production, evaluate the remaining development potential, and provide a theoretical basis for the adjustment of oilfield development technology policies and the formulation of comprehensive adjustment measures. More effective methods for evaluating the development effect of block oilfields are needed.
[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may contain information that does not constitute prior art. Summary of the invention
[0007] In view of this, the present invention provides a method for evaluating the effect of water flooding development in a fault-block oilfield, which solves the problem that the existing multi-index comprehensive evaluation method is limited in application and promotion due to factors such as difficulty in obtaining all calculation parameters.
[0008] To achieve the above-mentioned purpose of the invention, the method for evaluating the effect of water flooding development in a fault-block oilfield comprises:
[0009] Calculate the predicted recovery factor of each fault block unit in the fault block oil field under ideal conditions;
[0010] Calculating the degree of recovery or ultimate recovery factor of the fault block unit at a set development stage;
[0011] An intersection chart is prepared with the predicted recovery rate as the horizontal coordinate and the recovery degree or the ultimate recovery rate as the vertical coordinate;
[0012] The intersection chart is used to evaluate the development effect of each evaluation unit in the fault block oil field at a set development stage.
[0013] In the present disclosure and possible embodiments, the predicted recovery factor is calculated according to the Sherkachev formula.
[0014] In the present disclosure and possible embodiments, the Sherkachev formula is:
[0015]
[0016] Where: E R is the predicted recovery factor under ideal conditions; E d is the water displacement efficiency of the reservoir, %; a is the well pattern index; k is the air permeability, mD; μo is the formation crude oil viscosity, mPa·s; S is the well pattern density, mouth / km 2 .
[0017] In the present disclosure and possible embodiments, the recovery degree is calculated using the cumulative production prediction formula of the Arps production decline equation.
[0018] In the present disclosure and possible embodiments, the method for calculating the recovery degree using the cumulative production prediction formula is:
[0019] Acquire the decrease type of the fault block unit, and select the prediction formula according to the decrease type;
[0020] The prediction formulas are respectively a hyperbolic decreasing formula, an exponential decreasing formula and a harmonic decreasing formula.
[0021] In the present disclosure and possible embodiments, the hyperbolic decreasing formula is:
[0022]
[0023] The exponentially decreasing formula is:
[0024]
[0025] The harmonic decreasing formula is:
[0026]
[0027] Where: k is the set development period of the evaluation block unit, years; m is the current actual development period, years, m is less than k; Rk is the extraction degree in the kth year, %; R m is the actual extraction degree in the mth year, %; Q m is the annual oil production in the mth year, 10 4 t;D m is the annual decline rate in the mth year, %; n is the decline index, f; N is the geological reserves, 10 4 t.
[0028] In the present disclosure and possible embodiments, the method of using the intersection chart to perform the evaluation is:
[0029] When the coordinates of the predicted recovery factor and the degree of recovery or the ultimate recovery factor of the evaluation unit are located on or above y=x, the development effect is evaluated as good, and the farther from y=x, the better the development effect; otherwise, the development effect is evaluated as poor, and the farther from y=x, the worse the development effect.
[0030] The present disclosure has the following beneficial effects:
[0031] The disclosed method for evaluating the effect of water flooding development of a block oil field, on the one hand, utilizes permeability, formation crude oil viscosity, oil recovery efficiency, well network density, geological reserves, recovery degree and decline rate as calculation parameters, which can represent the geological development characteristics of the oil field and are simple and easy to obtain; on the other hand, the predicted recovery rate under ideal conditions and the recovery degree or final recovery rate of the set development stage are calculated according to the Shelkachev formula and the Arps production decline equation, which has a theoretical basis for reservoir engineering; on the third hand, the development effect evaluation is performed in the form of a chart, which can not only clarify the development effect between evaluation units of the block, but also provide the remaining development potential of the block, the evaluation result is intuitive, the process is clear and accurate, the operation is simple and conducive to application and promotion, and the problem of limited application and promotion of the existing multi-index comprehensive evaluation method due to factors such as the difficulty in obtaining all the calculation parameters and the like is effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:
[0033] Figure 1 It is the intersection diagram of the application example of the present disclosure and the evaluation result of the development effect of the evaluation unit. DETAILED DESCRIPTION
[0034] The present disclosure is described below based on embodiments, but it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.
[0035] In addition, those skilled in the art should understand that the drawings are only provided to illustrate the purpose, features and advantages of the present disclosure, and the drawings are not actually drawn to scale.
[0036] At the same time, unless the context clearly requires otherwise, the words "include", "comprises" and similar words throughout the specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, the meaning is "including but not limited to".
[0037] Example
[0038] The method for evaluating the water flooding development effect of a block oilfield in the disclosed embodiment includes step S10: calculating the predicted recovery rate of each block unit in the block oilfield under an ideal state; step S20: calculating the recovery degree or the final recovery rate of the block unit in a set development stage; step S30: making an intersection chart with the predicted recovery rate as the horizontal coordinate and the recovery degree or the final recovery rate as the vertical coordinate; step S40: using the intersection chart to evaluate the development effect of each evaluation unit in the block oilfield in the set development stage.
[0039] Wherein, step S10: calculating the predicted recovery factor of each fault block unit in the fault block oilfield under an ideal state.
[0040] Specifically, the predicted recovery factor of each fault block unit under the ideal state is calculated. The embodiment of the present disclosure uses the recovery factor (E) established by Soviet scholar Sherkachev. R ) and the water displacement efficiency of the reservoir (E d ), well pattern index (a), and well pattern density (S), the relationship between these main influencing parameters is used to calculate the predicted recovery factor under ideal conditions. The relationship is as follows:
[0041]
[0042] Where: E R is the predicted recovery factor under ideal conditions; E d is the water displacement efficiency of the reservoir, %; a is the well pattern index; k is the air permeability, mD; μo is the formation crude oil viscosity, mPa·s; S is the well pattern density, mouth / km 2 .
[0043] Step S20: Calculate the recovery degree or ultimate recovery rate of the block unit in the set development stage.
[0044] The calculation of the recovery degree in the embodiment of the present disclosure is based on the cumulative production prediction formula of the Arps production decline equation. The specific calculation process is:
[0045] Get the decrease type of each fault block unit. If the decrease type is hyperbolic decrease, the corresponding decrease index needs to be collected. If the decrease type is exponential decrease or harmonic decrease, the decrease index is not required.
[0046] The cumulative production prediction formula is selected according to the decline type of each fault block unit, and the cumulative production prediction formulas are respectively a hyperbolic decline formula, an exponential decline formula and a harmonic decline formula.
[0047] The hyperbolic decreasing formula is:
[0048]
[0049] The exponentially decreasing formula is:
[0050]
[0051] The harmonic decreasing formula is:
[0052]
[0053] Where: k is the set development period of the evaluation block unit, years; m is the current actual development period, years, m is less than k; R k is the extraction degree in the kth year, %; R m is the actual extraction degree in the mth year, %; Q m is the annual oil production in the mth year, 10 4 t;D m is the annual decline rate in the mth year, %; n is the decline index, f; N is the geological reserves, 10 4 t.
[0054] The final recovery rate of the embodiment of the present disclosure is the recovery degree at the time node corresponding to the comprehensive water content of the fault block unit being 98%.
[0055] Step S30: creating an intersection chart with the predicted recovery rate of step S10 as the horizontal coordinate and the recovery degree of step S20 or the final recovery rate as the vertical coordinate.
[0056] Step S40: using the intersection chart of step S30 to evaluate the development effect of each evaluation unit in the fault block oilfield at the set development stage.
[0057] The method for evaluating using the intersection chart in the embodiment of the present disclosure is:
[0058] When the coordinates of the predicted recovery rate and recovery degree or the final recovery rate of the evaluation unit are located on or above y=x, it means that the recovery degree or final recovery rate of the evaluation unit in the set stage has reached or exceeded the predicted recovery rate under the ideal state, and the development effect is good. The farther from y=x, the more the recovery rate exceeds the ideal state, and the better the development effect is, that is, the evaluation unit is located in the development effect reaching standard area and the development effect is gradually getting better. For the development effect reaching standard area with good development effect, favorable development factors are found, which is convenient for further guiding the next effective development. On the contrary, when it is located below y=x, it means that the recovery degree or final recovery rate of the evaluation unit in the set stage has not reached the recovery rate under the ideal state, and the development effect is poor. The farther from y=x, the farther from the recovery rate under the ideal state, the worse the development effect is, that is, the evaluation unit is located in the development effect not reaching standard area and the development effect is gradually getting worse, which is the key target of the next step of potential tapping and adjustment. For the non-standard area with poor development effect, when the deviation from y=x is greater, the remaining adjustment potential is also greater. It is necessary to make timely adjustments to the non-standard area according to the main development contradictions.
[0059] Application Examples
[0060] Taking Block A as an example, the water flooding development effect evaluation of the fault block oilfield is carried out. The specific steps are as follows:
[0061] Step 1: Collect dynamic and static data of each fault block unit in Block A, including permeability, formation crude oil viscosity, oil recovery efficiency, well network density, geological reserves, annual oil production, decline type, decline index, current recovery degree, and decline rate.
[0062] Among them, permeability can be measured by indoor experiments or calculated by permeability logging interpretation model. Formation crude oil viscosity can be measured by high-pressure physical property experiments. Oil recovery efficiency can be obtained through indoor experiments. Well density, geological reserves, decline type and other parameters can all be obtained from dynamic data.
[0063] Step 2: Apply the Sherkachev formula based on permeability, formation oil viscosity, oil recovery efficiency and well pattern density. The predicted recovery factor of the fault block unit under ideal conditions is calculated. The specific results are shown in Table 1:
[0064] Table 1A Block Evaluation Unit Parameters
[0065]
[0066] Step 3: Use the Arps production decline equation to calculate the recovery degree or ultimate recovery factor of a block unit at a certain development stage based on geological reserves, annual oil production, decline type, decline index, current recovery degree and decline rate.
[0067] In this example, Block A is a cooperative development block with a development period. When evaluating the development effect, the extraction degree at the end of the development period is needed. Therefore, the extraction degree at the end of the development period is defined as the extraction degree of the set development stage.
[0068] The decline type of each evaluation unit in Block A of this example conforms to the hyperbolic decline. According to the hyperbolic decline prediction formula of the Arps production decline equation, The recovery degree at the end of the development period was calculated, and the specific results are shown in Table 1.
[0069] Step 4: Make an intersection chart with the predicted recovery rate under ideal conditions as the horizontal axis x and the recovery degree as the vertical axis y. Figure 1 .
[0070] Step 5: Based on Figure 1 The intersection chart of the evaluation units is used to evaluate the development effect. Among them, according to the current development level, the a-276-t162 fault block exceeds the ideal recovery level of the fault block at the end of the development period. It is located above the chart y=x and belongs to the development standard area with good development effect. The four fault blocks such as a-69 are located below the chart y=x and belong to the non-standard area with poor development effect. Among them, the a-X61 fault block deviates the farthest from y=x and has the worst development effect. It is also the fault block with the greatest development adjustment potential.
[0071] According to the conventional technical means in this field, for the development areas that meet the standards, favorable development factors can be further found to guide the effective development of other fault blocks. For the areas that do not meet the standards, the factors affecting the development that do not meet the standards can be further found. For example, the reason why the a-X61 and a-69 fault blocks do not meet the standards is that the physical properties are poor and the water injection is not effective. The adjustment countermeasure of boosting water injection can be adopted. The same is true for other areas that do not meet the standards. According to the factors affecting the non-compliance and development contradictions, corresponding adjustment measures can be formulated (Table 2).
[0072] Table 2A Block Comprehensive Adjustment Strategy Table
[0073]
[0074] The above-described embodiments are only embodiments of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present disclosure. It should be noted that, for a person of ordinary skill in the art, without departing from the concept of the present disclosure, several variations, equivalent substitutions, improvements, etc. may be made, all of which fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be subject to the attached claims.
Claims
1. A method for evaluating the effect of water flooding development in fault-block oilfields. It is characterized in that include: Calculate the predicted recovery factor of each fault block unit in the fault block oil field under ideal conditions; Calculating the degree of recovery or ultimate recovery factor of the fault block unit at a set development stage; An intersection chart is prepared with the predicted recovery rate as the horizontal coordinate and the recovery degree or the ultimate recovery rate as the vertical coordinate; The intersection chart is used to evaluate the development effect of each evaluation unit in the fault block oil field at a set development stage.
2. The method for evaluating the effect of water flooding development in a fault-block oil field according to claim 1, Features: The predicted recovery factor is calculated according to the Sherkachev formula.
3. The method for evaluating the effect of water flooding development in a fault-block oil field according to claim 2, It is characterized in that The Shelkachev formula is: Where: E R is the predicted recovery factor under ideal conditions; E d is the water displacement efficiency of the reservoir, %; a is the well pattern index; k is the air permeability, mD; μo is the formation crude oil viscosity, mPa·s; S is the well pattern density, mouth / km 2 .
4. The method for evaluating the effect of water flooding development in a fault-block oil field according to any one of claims 1 to 3, Features: The recovery degree is calculated using the cumulative production prediction formula of the Arps production decline equation.
5. The method for evaluating the effect of water flooding development in a fault-block oil field according to claim 4, It is characterized in that The method for calculating the recovery degree using the cumulative production prediction formula is: Acquire the decrease type of the fault block unit, and select the prediction formula according to the decrease type; The prediction formulas are respectively a hyperbolic decreasing formula, an exponential decreasing formula and a harmonic decreasing formula.
6. The method for evaluating the effect of water flooding development in a fault-block oil field according to claim 5, Features: The hyperbolic decreasing formula is: The exponentially decreasing formula is: The harmonic decreasing formula is: Where: k is the set development period of the evaluation block unit, years; m is the current actual development period, years, m is less than k; R k is the extraction degree in the kth year, %; R m is the actual extraction degree in the mth year, %; Q m is the annual oil production in the mth year, 10 4 t;D m is the annual decline rate in the mth year, %; n is the decline index, f; N is the geological reserves, 10 4 t.
7. The method for evaluating the effect of water flooding development in a fault-block oil field according to any one of claims 1 to 3 or 5 and 6, It is characterized in that The method for performing the evaluation using the intersection chart is: When the coordinates of the predicted recovery factor and the degree of recovery or the ultimate recovery factor of the evaluation unit are located on or above y=x, the development effect is evaluated as good, and the farther from y=x, the better the development effect; otherwise, the development effect is evaluated as poor, and the farther from y=x, the worse the development effect.