CN111894570A - Quantitative evaluation method for flooding degree of old oil reservoir well in middle and later development periods - Google Patents
Quantitative evaluation method for flooding degree of old oil reservoir well in middle and later development periods Download PDFInfo
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Abstract
The invention provides a quantitative evaluation method for the flooding degree of an old oil reservoir well in the middle and later periods of development, which comprises the following steps: carrying out regression analysis on the ratio of the water content to the resistivity, and establishing a relation between the water content and the resistivity ratio; acquiring the current water content Fw of the old well, and acquiring corrected resistivity Rt of the old well according to the relation between the water content and the resistivity ratio; calculating the saturation of the residual oil according to the corrected resistivity Rt of the old well; and quantitatively evaluating the flooding degree of the old well according to the saturation of the residual oil. In the application, in order to eliminate the influence of initial resistivity, a method of resistivity ratio is utilized, a multiple regression method is adopted to simulate the moisture content, and a mathematical model of the moisture content-resistivity ratio is established; and establishing an Archie improved formula model suitable for a high water-cut period and an ultra-high water-cut period by using the water flooding experimental data and the drilling coring experimental data, and correctly calculating the oil saturation of the water flooded layer.
Description
Technical Field
The invention relates to the field of fine research of geological reservoirs in oil field development, in particular to a quantitative evaluation method for the flooding degree of old oil reservoirs in the middle and later periods of development.
Background
In the long-term water flooding development process, due to stratum water propulsion or water flooding development, reservoirs can be flooded to different degrees, so that the properties of the reservoirs in aspects of physical property, oil-containing property, electrical property and the like can be changed to different degrees. At present, most oil reservoirs enter the middle and later stages of development, the condition of water flooding is increasingly serious, how to improve the water-flooding oil extraction efficiency of an oil field is the key point for improving the recovery ratio of residual oil by accurately identifying and quantitatively evaluating the water flooding degree of an old well.
Disclosure of Invention
In order to solve the problem that the evaluation precision of the existing water flooded layer needs to be further improved, the embodiment of the application provides a quantitative evaluation method for the water flooded degree of the old well of the oil reservoir in the middle and later periods of development, and the quantitative evaluation effect of the water flooded layer is improved.
The embodiment of the application provides a quantitative evaluation method for the flooding degree of an old oil reservoir well in the middle and later periods of development, which comprises the following steps:
carrying out regression analysis on the ratio of the water content to the resistivity, and establishing a relation between the water content and the resistivity ratio;
acquiring the current water content Fw of the old well, and acquiring corrected resistivity Rt of the old well according to the relation between the water content and the resistivity ratio;
calculating the saturation of the residual oil according to the corrected resistivity Rt of the old well;
and quantitatively evaluating the flooding degree of the old well according to the saturation of the residual oil.
Performing regression analysis on the ratio of the water content to the resistivity, and establishing a relation between the water content and the resistivity ratio, wherein the relation comprises the following steps:
for the same type of deposited sand, the resistivity of the first bite when it meets the sand is recorded as R0And the initial resistivity of the well drilled in other periods is recorded as RtInitial moisture content is denoted as FwThe sequence according to the drilling time is as follows:
A1(Rt1,Fw1)、A2(Rt2,Fw2)、…、Ai(Rti,Fwi)、…、An(Rtn,Fwn)
resistivity ratio Rt' is:
by carrying out [ R ]t’，Fw]Regression analysis, establishing the relation between the water content and the resistivity ratio, and obtaining:
Rt＝R0-R0·f(Fw)＝R0[1-f(Fw)]
wherein said calculating remaining oil saturation from said corrected old well resistivity Rt comprises:
the calculation formula of the saturation of the residual oil of the braided river channel phase in the high water-cut period is as follows:
wherein φ is porosity; fwThe water content is obtained; r0The rock resistivity of the first drill encountering the sand body; pzThe degree of mineralization of the mixed liquid; m is a cementation index; n is saturatedDegree index; a. b is a coefficient relating to lithology, SwIs the remaining oil saturation.
Wherein, the relation between the water content of the main oil-containing sand body of the meandering stream phase and the specific value of the resistivity is as follows:
Wherein the relation between the water content and the resistivity ratio of the main oil-containing sand body of the delta phase is as follows:
Wherein, the relation between the water content ratio and the resistivity ratio of the main oil-containing sand body of the delta sector phase is as follows:
Wherein, the relationship between the water content of the braided river sand body and the specific value of the resistivity is as follows:
Wherein, still include: and when the existing water content information of the old well does not exist, the water content of the drill in the preset range meeting the same sediment sand body is used as the existing water content of the old well.
Wherein, still include:
and acquiring the resistivity of the new well, calculating the water content of the sand body according to the relation between the water content and the resistivity ratio, and judging the flooding degree according to the water content.
Wherein, the relationship between the water content of the braided river sand body and the specific value of the resistivity is as follows:
The quantitative evaluation method for the flooding degree of the old oil reservoir well in the middle and later periods of development has the following beneficial effects:
aiming at the development problems of oil reservoirs in the middle and later periods of development, the adaptability of an Archie formula of an evaluation model of the oil content of a reservoir is analyzed on the basis of water flooded layer change characteristic analysis and water flooded mechanism research, an Archie formula model provided on the basis of real sandstone is improved, an Archie improved formula model suitable for a high water-cut period and an ultrahigh water-cut period is established, and the oil saturation of a water flooded layer is correctly calculated. By evaluating the actual flooded layer, theoretical research is combined with field application, quantitative evaluation of the flooded layer is provided by using a water content-resistivity ratio method, old well resistivity curve correction and prediction of the flooded degree of a new well are performed, and quantitative evaluation effect of the flooded layer is improved.
Drawings
FIG. 1 is a geological pattern diagram of a water content-resistivity ratio method;
FIG. 2 is a diagram of the intersection of the resistivity ratio of the main sand body of the plaited river phase of the true Wu oil field and the original water content;
FIG. 3a is a cross plot of the ratio of the resistivity of the main sand body to the original water content of the curved flow river phase of the true Wu oil field;
FIG. 3b is a cross plot of the ratio of the resistivity of the dominant sand body to the original water content in the delta phase of the Zhenwu oil field;
FIG. 3c is a cross plot of the ratio of the resistivity of the main sand body to the original water content of the Zhenwu oil field fan delta phase;
FIG. 4 is a schematic diagram of the change of the oil saturation So with the formation resistivity Rt under injected water with different properties;
fig. 5 is a schematic diagram comparing oil saturation interpretation with core.
Detailed Description
The present application is further described with reference to the following figures and examples.
In the following description, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The following description provides embodiments of the invention, which may be combined with or substituted for various embodiments, and this application is therefore intended to cover all possible combinations of the same and/or different embodiments described. Thus, if one embodiment includes feature A, B, C and another embodiment includes feature B, D, then this application should also be considered to include an embodiment that includes one or more of all other possible combinations of A, B, C, D, even though this embodiment may not be explicitly recited in text below.
The following description provides examples, and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements described without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For example, the described methods may be performed in an order different than the order described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.
(1) Evaluation method of flooding degree
In the eighties of the last century, nobility and honour apply logging data such as natural potential, phase difference, depth and lateral direction and the like to change of various factors after a water-flooded oil layer, and the method starts from a theoretical basis, researches on geophysical characteristics and a water-flooded layer explanation model, applies a qualitative and quantitative method to identify the water-flooded layer, and finally uses a stepwise regression method to deduce oil saturation and pore permeation. In 1987, Zhao Wen Guang conducted research on interpretation methods of water flooded layer logging in order to explain the water flooded degree more accurately and quantitatively, and provided a basis for improving the oil field recovery ratio. During the early period of eighties to ninety years, domestic scholars are actively put into flooded layer research work, and a plurality of well logging interpretation models and identification standards are generated on microscopic factors and well logging interpretation methods influencing a flooded layer.
The evaluation technology of the water flooded layer, in 1987, Zengwenchong research obtains a movable water analysis method, and the low-resistance water flooded layer is effectively analyzed and evaluated; in 1996, Yongshi and according to a flooding mechanism, by adopting coring and mercury suppression materials, trying to abandon the use of a resistivity logging curve, establishing a relational model of logging and mercury suppression, explaining and evaluating the water saturation of a flooding layer, and achieving good results. In the nineties of the last century, Liyu et al used the geochemistry technology of oil reservoirs to evaluate the water flooded layer of the old well adjusting well, and used the geochemistry method to research the oil-water distribution of the water flooded layer, so as to provide the theoretical basis, explanation method and application effect for the water-washing degree and water-flooded condition of the oil layer, and as a new technology and method for discriminating the water flooded layer, the geochemistry of the oil reservoir has become the leading edge of the current research. In 1998, the water flooded layer with high water content is evaluated by utilizing a grey system theory by utilizing coring data, oil testing and dynamic development data based on a logging curve, wherein Songzaiqi and Tanzhi are conducted.
The well logging interpretation technology of the water logging layer is characterized in that the water logging layer is interpreted qualitatively and quantitatively by adopting a natural potential baseline shift method, a natural potential amplitude change, a resistivity change, a natural potential and resistivity curve correspondence analysis method and the like for a plurality of oil fields, and the water logging layer can be judged by using the change of the well logging curves such as sound waves, neutron gamma and the like, an excited polarization potential and phase dielectric under special conditions.
First, the conventional well logging data is used to quantitatively explain the water flooded layer
At present, a set of interpretation method for qualitatively distinguishing a flooded layer, quantitatively solving the saturation and water content of residual oil and comprehensively distinguishing the flooding level based on conventional logging data is formed in each oil field in China. In recent years, through the improvement of a logging series and the research of a new interpretation method, the problems of dividing water flooded parts in a thick layer and judging the water flooded grade are preliminarily solved. A number of different methods are applied: the three-time encryption adjustment well of the Daqing oil field is mainly based on conventional logging information, and the technology for evaluating the water flooded layer by researching and applying the conventional logging curve has wide application range and high practical value. The adaptability of a water flooded layer well logging series applied to the current oil field is analyzed, a self-adaptive deconvolution processing technology and a deep and shallow resistivity curve joint inversion technology are provided aiming at the inadaptability of individual curves, and a good foundation is laid for the next step of quantitative calculation of reservoir parameters.
Resistivity interpretation method
Resistivity logging remains an effective method for detecting residual oil saturation in water-driven oil fields. Under the condition of fresh water injection of the water-flooding oilfield, if a relation chart is established by simply using the true resistivity and the water saturation of the formation of the water flooded layer, a U-shaped curve is frequently generated, and the multi-resolution exists when the saturation of the residual oil of the water flooded layer is determined. The method is a thought used before 1942, and if the relation chart is established by using the stratum resistivity index and the water saturation, a U-shaped curve can not appear, and the multi-solution property can be eliminated.
③ method of degree of saturation
The water-flooding oilfield producing zone three-saturation refers to original oil-containing saturation (Soi), residual oil saturation (So) and residual oil saturation (Sor), the three-saturation of the producing zone can be detected by using a modern logging technology, and the relative error of the three-saturation of the producing zone is required to be explained by logging in the world oil industry and cannot exceed 5%. A conventional well logging data interpretation technology in an oilfield flooding development period is researched by combining Beijing Petroleum exploration and development scientific research institute with an oilfield, and an explanation model of water saturation is established by considering the quantitative influence of formation water resistivity, shale content, median particle size and the like on the formation resistivity on the basis of an Archie formula; an oil and water phase permeability explanation model is established by researching the original saturation, the residual oil saturation and the change relation between the residual oil saturation and the producing layer parameters.
In order to improve the calculation precision of the parameters of the water flooded layer, the Daqing oil field provides a method for establishing a reservoir parameter equation according to geological condition constraints, namely: the method comprises the steps of dividing a Sa oil layer, a Glu oil layer and a high oil layer into a surface inner thick layer (larger than or equal to 2.0m), a surface inner thick layer (0.6-2.0 m), a surface inner thin layer (smaller than or equal to 0.6m) and an independent surface outer layer, performing subdivision interpretation on the middle and thick oil layers (an obviously uneven layer with an inner layer interval larger than or equal to 0.3 m), fully utilizing abundant closed coring inspection well data of Daqing oil fields, and establishing reservoir parameter logging interpretation empirical equations by applying a mathematical statistical method.
The well logging interpretation theory is taken as guidance, and the well logging interpretation evaluation model of each parameter is established according to the core analysis data as follows:
porosity: Φ — f (DEN, … …);
median particle size: md ═ f (HAC, … …);
the mud content: vsh ═ f (Md, … …);
air permeability: ka ═ f (Φ, … …);
irreducible water saturation: swi ═ f (Ka, … …);
residual oil saturation: sor ═ f (Swi, … …);
the interpretation model has higher precision, and parameter calculation meets the requirements of next reservoir rock physical facies division and water flooded layer interpretation through the comparison and analysis of data of the closed coring inspection well.
According to the Jianghong well logging research institute, the evaluation and interpretation technology suitable for fresh water mud, stratum water which is fresh water (<3000mg/l) sand mud rock surface and various well (exploration well or development well) reservoir layers is provided by utilizing two aspects of natural potential and induced polarization potential interpretation models and two parameters of stratum water conductivity and cation exchange capacity, so that the water saturation of a water flooded layer is obtained. The water flooding layers of different water flooding types have different changes of water flooding characteristics, logging response characteristics and the like, and corresponding qualitative identification methods are different. According to the characteristics of the water-flooded layer, different qualitative identification methods are adopted under the conditions of fresh water, sewage, side (bottom) water flooding and water washing. When the conventional logging information is used for qualitatively identifying the flooded layer, a proper qualitative identification method is adopted for comprehensive identification according to the specific geological conditions of a research area, in combination with dynamic production information, dynamic production logging information and water absorption or production conditions of adjacent wells, generally, a certain qualitative identification method is taken as a main method, other methods are taken as references, and the principles of 'statically determining dynamic state and dynamically depending on static state' are followed in the qualitative identification of the flooded layer.
In the aspect of a flooding mechanism, forest purity increase is realized through rock physical experiments, a correlation curve of formation resistivity and water saturation is provided when Rwf is greater than, equal to or less than 2.5Rw, an Rt-Rw relation graph is obtained in production practice and experiments, and experimental data are provided for interpretation and research of a flooding layer.
(2) Evaluation method of flooding degree and current foreign research situation
In the middle and later period of the last 70 th century, the former Soviet Union specially studies the distribution of residual oil in the oil field in the later period of flooding through 24 evaluation wells in a Dumaz oil field. John d.huppler has deeply studied the role of core heterogeneity in influencing relative permeability using digital simulation techniques, and in 1998, m.m.chang has divided the measurement methods of residual oil saturation into 3 types, inter-well, single-well and material balance. In 1990 M.K.Verma, aiming at carbonate reservoirs, residual oil evaluation is carried out on the carbonate reservoirs after water flooding by adopting special core analysis, measurement-injection-measurement, material balance and TDT (time domain reflectometry) logging, so that a certain theoretical basis is provided for identifying low-porosity and low-permeability water flooding layers.
In 2001, Hmada et al studied the effect of the illite-smectite mixed layer on the low resistivity reservoir water flooded layer in a micro-mechanism in order to deduce the relationship between specific surface and Swi and Sw. Donaldson uses the change of the area of the capillary pressure hysteresis loop to deduce the relative degree of oil-water wetting of the rock surface in order to establish the relationship between Archie saturation index n and wettability. The russian scholars, danarov, think that a and m in the Archie formula should adopt different parameter values for different lithologies. Different parameter values and rock wettability lead to different saturation indexes due to different temperatures and pressures.
An Archie equation is an empirical formula established in a laboratory aiming at a pure sandstone static model, oil field development is a water flooding process opposite to the oil field development, and particularly in an oil reservoir in a high water cut period and an ultrahigh water cut period, the evaluation accuracy of a water flooded layer in the stage is seriously restricted by the limitation of the resistivity on the reaction capability of high water saturation.
From the current research conditions at home and abroad, the evaluation of a water flooded layer is continuously improved, but the research on the quantitative evaluation of the water flooded degree of an oil reservoir old well in the middle and later stages of development is less, and the problem is mainly caused by neglecting that a series of changes are generated in oil layer parameters, pore structures, fluid distribution and the like in the water flooding development process, so that the calculation result is difficult to truly represent the underground water flooded condition.
Example one
The embodiment of the application provides a quantitative evaluation method for the flooding degree of an old oil reservoir well in the middle and later periods of development, which comprises the following steps: carrying out regression analysis on the ratio of the water content to the resistivity, and establishing a relation between the water content and the resistivity ratio; acquiring the current water content Fw of the old well, and acquiring corrected resistivity Rt of the old well through the relation between the water content and the resistivity ratio; calculating the saturation of the residual oil according to the corrected resistivity Rt of the old well; and quantitatively evaluating the flooding degree of the old well according to the saturation of the residual oil.
The invention aims to explore and research the practical change rule and quantitative interpretation model of the old well water flooded layer of the oil deposit suitable for developing in the middle and later periods, quantitatively evaluate the water flooded layer by using the provided water content-resistivity ratio method, correct the resistivity curve of the old well and predict the water flooded degree of a new well, and improve the quantitative evaluation effect of the water flooded layer.
Example two
The well pattern and well spacing conditions which are perfect in the middle and later stages of oil field development and abundant encryption, adjustment, sidetracking, updating and well inspection data enable a well logging technology to become one of main technologies for evaluating reservoir and fluid-containing saturation change conditions in fine description of oil reservoirs in the time period, and the well logging technology plays a role which cannot be replaced by other methods. The logging information of newly completed wells in the old district contains very rich reservoir information, and the reservoir information contained in the logging information can be mined to the maximum extent by accurately evaluating the reservoir information.
According to the theoretical basis, the relation between the logging information of different periods of the drilling tool on the sand body of the same sediment type is analyzed according to the sand bodies of different sediment types in the research area. The main logging parameters influencing the evaluation of the water flooded layer are resistivity data, and the water content of production data is the real information which can most reflect the dynamic state of the underground fluid of the oil field at present. By establishing the relationship, the aim of quantitative evaluation of the water flooded layer in the research area can be achieved.
In the actual data processing process, the initial resistivity values R of different sand bodies in drilling are found for the same sedimentary facies interpretation layer0In contrast, to eliminate the initial value R0And (3) the effect of improving the resistivity due to the influence of over-large or over-small is realized, and a water content ratio simulation method is adopted to simulate the water content by adopting a proper mathematical method by utilizing a resistivity ratio method, so that a water content-resistivity ratio mathematical model is established. The specific method comprises the following steps:
in fig. 1, A, B, C, D represents different sediment type sand bodies.
For the same type of deposited sand, the resistivity of the first bite when it meets this sand is recorded as R0And the initial resistivity and the initial water content of the well drilled in other periods are recorded as Rt、FwThen, the sequence according to the drilling encounter time is as follows:
A1(Rt1,Fw1)、A2(Rt2,Fw2)、…、Ai(Rti,Fwi)、…、An(Rtn,Fwn)
eliminating the influence of the original resistivity, wherein the resistivity ratio Rt' is as follows:
carrying out [ Rt', Fw ] regression analysis, establishing a relation between the water content and the resistivity ratio, and obtaining:
Rt＝R0-R0·f(Fw)＝R0[1-f(Fw)]
the problem that the above formula can solve:
1. aiming at a new well: if the new well Rt is known, Fw can be calculated by using the formula, so that the flooding degree is judged;
2. aiming at the old well: and (3) knowing the current water content Fw of the old well, correcting the resistivity Rt of the old well, and improving an Archie formula to calculate the saturation of the residual oil so as to judge the current flooding degree of the old well.
Taking a true 12-broken-block braided river sand body as an example, 9 wells drilled in different periods of the sand body are selected, and parameters such as initial resistivity, initial water content and current water content of each well are counted (table 1).
TABLE 1 statistical table of parameters of each well of braided riverway facies sand body in experimental area
According to the data, as shown in fig. 2, the relationship between the resistivity ratio and the original water content is established to obtain the braided river sand:
the formula is converted to obtain:
wherein R is a correlation coefficient of regression analysis and represents the accuracy of the regression formula.
According to the established formula, knowing the resistivity of the sand body of the braided river channel of the new well, the water content of the sand body can be calculated, so that the flooding degree is judged; according to the established formula, the current resistivity of the old well can be reversely deduced through the statistic of the water content of the old well, so that the residual oil saturation of the old well is calculated.
The improvement of the Archie's formula of the water flooded reservoir is described below.
Compared with an oil-gas layer in an exploration phase, a water flooded layer in the water injection development process has the following characteristics: the water flooded layer is the hydrocarbon reservoir in the dynamic development and change process of water flooding oil field, its explanation has very strong timeliness, and it is very different from the hydrocarbon reservoir which is in static state for a long time. The physical parameters (porosity, permeability, water saturation, median particle size and shale content) and the electrical parameters (resistivity and acoustic wave time difference) of the oil layer in the water flooding development process are constantly changed along with the change of injected water and the development of the water flooding development process. The oilfield formation developed by water flooding contains a fluid which is not available in the exploration stage, and the injected fluid itself is changed continuously due to the change of various factors.
Since the reservoir in the development process is different from the reservoir in the exploration phase, the basic characteristics of the interpretation of the water flooded layer are induced: the basic theory and basic model used for hydrocarbon reservoir interpretation are the Archie's formula, which is used under the static condition of oil-driving water, i.e. oil-gas migration and aggregation to form an oil reservoir, while the water flooded layer interpretation needs to research the dynamic change environment of the oil reservoir in water injection development and water drive. A series of fluid changes caused by injected fluid are fully researched, and the change rule of physical parameters and electrical parameters of an oil layer is fully utilized. Therefore, different parameters and even different interpretation models should be used in different development periods to obtain good effects.
On the basis of the analysis of the change characteristics of the previous flooding layer and the research of the flooding mechanism, two main parameters influencing the correct calculation of the residual oil saturation in the middle and later periods of development are considered to be the mixed filtrate resistivity and the reservoir rock resistivity. These two parameters are constantly changing with increasing injected water and different properties of the injected water. By means of the change rule of the two parameters, the Archie formula can be improved.
The method for calculating the oil saturation of the water flooded layer by utilizing the Archie formula in the water flooding development oil field mainly has the following two limitations:
1. as shown in fig. 4, in the flooding layer, the resistivity changes in a "U" shape under the condition of fresh water injection, and in the case of sewage injection, the resistivity changes in a "L" shape, and the relationship between the formation resistivity Rt and the water saturation Sw is that one formation resistivity Rt value corresponds to two water saturation Sw values;
2. the degree of mineralization of the injected water and the formation water is different, resulting in that Rw, which should be a mixed filtrate resistivity, is a variable parameter as the injected water increases.
Therefore, the key to the correctness of the calculation of the oil saturation of the water flooded layer is the calculation of the rock resistivity (Rt) of the reservoir layer.
The method for calculating the reservoir rock resistivity (Rt) has been explained in detail in the foregoing, taking the braided river sand as an example:
an improved model of an Archie formula for calculating the saturation of the residual oil of the braided river channel phase in the high water-cut period is as follows:
wherein, phi is porosity,%; fw is the water content; r0The resistivity of the first drill in the rock meeting the sand body; pz is the mineralization degree of the mixed liquid; m is a cementation index; n is a saturation index; a. b is a coefficient related to lithology.
The old well resistivity correction is described below.
Under the continuous action of injected water, the lithology, physical property, fluid property and electrical characteristic of the underground are changed continuously in the water injection development oil field, the change causes that the old well logging curve cannot truly reflect the property of the current underground reservoir, the cost of secondary logging is high, and the old well logging curve needs to be corrected in order to save the cost. The most important parameter influencing the calculation of the saturation of the residual oil and evaluating the flooding degree is the rock resistivity of the reservoir, so how to utilize the current information becomes very important to correct the resistivity of the old well.
And (3) calculating the resistivity by knowing the current water content through the established fitting formula of the resistivity, the initial resistivity and the original water content, so as to correct the resistivity of the old well. Taking 7 wells such as a true 12 broken block braided riverway true 90 well, a true 108-1 well and the like as examples, the resistivity of the old well is corrected. Using the calculation:
the calculation results are shown in table 2, and it can be seen from the table that the resistivity of the underground formations is reduced to different degrees, the reduction range is related to the current water content of the oil well, the higher the water content is, the greater the resistivity reduction degree is, and vice versa. If the water content of the real 116 well is 0.709 at present, the resistivity is reduced by 1.9 omega m; the water content of the real 124 well reaches 0.941 at present, and the resistivity of the real 124 well is only 6.14 omega-m at present and is reduced by 7.4 omega-m compared with the original resistivity.
According to the method, when existing water content data of the old well does not exist, the existing resistivity cannot be obtained, and the method is to replace the water content of the old well with the water content of the same sediment sand body encountered by adjacent drills so as to obtain the resistivity value and realize the resistivity correction of the old well.
TABLE 2 old well resistivity correction calculation results
| Well name | Horizon | Type of deposition | Time of day | Original resistivity (Rt) | Current Water cut (Fw) | Corrected resistivity (Rt) |
| Side portrait 120 | E2s1 6-2 | Braided river channel | 2005 | 5.84 | 0.980 | 4.87 |
| True 108-1 | E2s1 6-2 | Braided river channel | 1990 | 17 | 0.939 | 6.18 |
| True 116 | E2s1 6-2 | Braided river channel | 1991 | 14.18 | 0.709 | 12.28 |
| True 124 | E2s1 6-2 | Braided river channel | 1994 | 13.56 | 0.941 | 6.14 |
| Real 151 | E2s1 6-2 | Braided river channel | 1996 | 6.09 | 0.951 | 5.82 |
| Vacuum 188 | E2s1 6-2 | Braided river channel | 2009 | 8.67 | 0.933 | 6.38 |
| Real 90 | E2s1 6-2 | Braided river channel | 1987 | 22.89 | 0.915 | 6.91 |
| True inspection 1 | E2s1 6-2 | Braided river channel | 1993 | 12.19 | 0.918 | 6.82 |
| True 11-1 | E2s1 6-2 | Braided river channel | 2007 | 8.5 | 0.926 | 6.57 |
The determination of the flooding degree of the new well is described below
The true inspection 4 well is one inspection well drilled in 2012, closed coring of the system is performed on the well, core saturation is measured, and the latest underground condition can be reflected really. The oil saturation result calculated by using the Archie's improved formula of the research is compared with the measurement result of the saturation of the closed coring core, and the calculation result is generally higher than the measurement result but has consistent variation trend, as shown in FIG. 5, the correlation coefficient between the calculation result and the measurement result reaches more than 0.8. The coincidence rate of the interpretation conclusion and the original interpretation conclusion is 95.2 percent (table 3), which shows that the research conclusion is reliable and can provide scientific basis for the subsequent adjustment and development and the improvement of the recovery ratio of the Zhenwu oil field.
TABLE 3 comparison table of the present well logging interpretation and core analysis oil saturation and the present well logging interpretation conclusion and original interpretation conclusion
In order to eliminate the influence of initial resistivity, a resistivity ratio method is utilized, a multivariate regression method is adopted to simulate the moisture content, and a mathematical model of the moisture content-resistivity ratio is established; and establishing an Archie improved formula model suitable for a high water-cut period and an ultra-high water-cut period by using the water flooding experimental data and the drilling coring experimental data, and correctly calculating the oil saturation of the water flooded layer.
Aiming at the development problems of oil reservoirs in the middle and later periods of development, the adaptability of an Archie formula of an evaluation model of the oil content of a reservoir is analyzed on the basis of water flooded layer change characteristic analysis and water flooded mechanism research, an Archie formula model provided on the basis of real sandstone is improved, an Archie improved formula model suitable for a high water-cut period and an ultrahigh water-cut period is established, and the oil saturation of a water flooded layer is correctly calculated. By evaluating the actual flooded layer, theoretical research is combined with field application, quantitative evaluation of the flooded layer is provided by using a water content-resistivity ratio method, old well resistivity curve correction and prediction of the flooded degree of a new well are performed, and quantitative evaluation effect of the flooded layer is improved.
EXAMPLE III
In the second embodiment, the braided sand is used as an example, and in the present embodiment, the main oil-containing sand of a meandering river, delta, or delta phase is used as an example. In the second embodiment, the relationship between the resistivity ratio of the braided-channel sand and the original water content is established according to the data in table 1, and similarly, as shown in fig. 3, the "water content-resistivity" ratio models of the main oil-containing sand of the meandering stream, delta and delta are respectively established:
the relationship between the water content and the resistivity ratio of the main oil-containing sand body of the meandering stream phase is as follows:
The relation between the water content and the resistivity ratio of the main oil-containing sand body of the delta phase is as follows:
The relation between the water content and the resistivity ratio of the main oil-containing sand body of the fan delta phase is as follows:
From the above formula, when the water content ratio Fw is known, the resistivity ratio Rt can be calculated, i.e., the corrected resistivity can be obtained. From the above equation, Rt ═ f (fw) can be obtained, and f (fw) can be substituted for that in equation 1-1
Thereby obtaining a calculation formula corresponding to the residual oil saturation of the oil-containing sand body.
For the same sedimentary facies interpretation layer, the initial resistivity values R of the same sand body drilled in different periods are different, the initial resistivity values R of different sand bodies drilled in the same period are also different, in order to eliminate the influence of the initial resistivity, a resistivity ratio method is utilized, a multivariate regression method and a water content ratio are adopted for simulation, and a water content-resistivity ratio mathematical model is established; aiming at the two most main parameters of correctly calculating the residual oil saturation, the resistivity of mixed filtrate and the resistivity of reservoir rock are utilized, the water flooding experimental data and the drilling coring experimental data are utilized, a geostatistical analysis method is adopted, an Archie improved formula model suitable for the high water cut period and the ultrahigh water cut period of the research area is established, and the oil saturation of the water flooded layer in the high water cut period of the research area is correctly calculated. The resistivity of the old well is corrected, so that the evaluation coincidence rate of the water flooded layer is improved to 80% from about 60%.
The explanation result verification is described below.
Comparing the water content counted by the production data with the water content data calculated by the interpretation model, wherein the water content error analysis of the well shows that: the average absolute error of the water content is 4.79 percent, and the average relative error is 6.1 percent (table 4); the error of the water content is within the required error range on the whole, the accuracy is high, and the established well logging interpretation model is reasonable and reliable.
Table 4 true wu oil field flooding layer interpretation production data and model calculation data error analysis (partial well)
The method is applied to the research of the water flooding degree of the old well of the oil reservoir in the middle and later stages of development, the recovery ratio of the real oil field is improved by 0.2 percent through comprehensive treatment and excavation, the yield is increased by 3.24 ten thousand tons in 2019 through 2015-. The method has great application potential, can improve the overall recovery ratio of old oil fields by expanding the new method in other oil fields, and has profound significance for stable yield of Jiangsu oil fields and even old areas of east oil fields of China.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A quantitative evaluation method for the flooding degree of an old well of an oil reservoir in the middle and later periods of development is characterized by comprising the following steps:
carrying out regression analysis on the ratio of the water content to the resistivity, and establishing a relation between the water content and the resistivity ratio;
acquiring the current water content Fw of the old well, and acquiring corrected resistivity Rt of the old well according to the relation between the water content and the resistivity ratio;
calculating the saturation of the residual oil according to the corrected resistivity Rt of the old well;
and quantitatively evaluating the flooding degree of the old well according to the saturation of the residual oil.
2. The method for quantitatively evaluating the flooding degree of the old well of the oil reservoir in the middle and later stages of development according to claim 1, wherein the step of performing regression analysis on the water content and the resistivity ratio to establish the relationship between the water content and the resistivity ratio comprises the following steps:
for the same type of deposited sand, the resistivity of the first bite when it meets the sand is recorded as R0And the initial resistivity of the well drilled in other periods is recorded as RtInitial moisture content is denoted as FwThe sequence according to the drilling time is as follows:
A1(Rt1,Fw1)、A2(Rt2,Fw2)、…、Ai(Rti,Fwi)、…、An(Rtn,Fwn)
resistivity ratio Rt' is:
by carrying out [ R ]t’，Fw]Regression analysis, establishing the relation between the water content and the resistivity ratio, and obtaining:
Rt＝R0-R0·f(Fw)＝R0[1-f(Fw)]。
3. the method for quantitatively evaluating the flooding degree of the old well of the middle and later-period oil deposit in development according to claim 2, wherein the step of calculating the saturation degree of the residual oil according to the corrected resistivity Rt of the old well comprises the following steps:
the calculation formula of the saturation of the residual oil of the braided river channel phase in the high water-cut period is as follows:
wherein φ is porosity; fwThe water content is obtained; r0The rock resistivity of the first drill encountering the sand body; pzThe degree of mineralization of the mixed liquid; m is a cementation index; n is a saturation index; a. b is a coefficient relating to lithology, SwIs the remaining oil saturation.
4. The quantitative evaluation method for the water logging degree of the old well of the middle and later-period oil deposit in development according to any one of claims 1 to 3, characterized in that the relationship between the ratio of the water content of the main oil-bearing sand body of the meandering stream phase to the resistivity is as follows:
5. The quantitative evaluation method for the water logging degree of the old well of the middle and later-stage oil deposit in development according to any one of claims 1 to 3, characterized in that the relationship between the water ratio and the resistivity ratio of the main oil-bearing sand body of the delta phase is as follows:
6. The quantitative evaluation method for the flooding degree of the old well of the middle and later-stage oil deposit in development according to any one of claims 1 to 3, characterized in that the relationship between the water ratio and the resistivity ratio of the main oil-bearing sand body of the fandelta phase is as follows:
7. The quantitative evaluation method for the water logging degree of the old well of the oil deposit in the middle and later stages of development according to any one of claims 1 to 3, characterized in that the relationship between the water content rate and the resistivity ratio of the braided river sand body is as follows:
8. The quantitative evaluation method for the flooding degree of the old well of the middle and later-period oil deposit in development according to any one of claims 1 to 3, characterized by further comprising the following steps: and when the existing water content information of the old well does not exist, the water content of the drill in the preset range meeting the same sediment sand body is used as the existing water content of the old well.
9. The quantitative evaluation method for the flooding degree of the old well of the middle and later-period oil deposit in development according to any one of claims 1 to 3, characterized by further comprising the following steps:
and acquiring the resistivity of the new well, calculating the water content of the sand body according to the relation between the water content and the resistivity ratio, and judging the flooding degree according to the water content.
10. The quantitative evaluation method for the water logging degree of the old well of the oil deposit in the middle and later stages of development according to any one of claims 1 to 3, characterized in that the relationship between the water content rate and the resistivity ratio of the braided river sand body is as follows:
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| CN117153289A (en) * | 2023-09-14 | 2023-12-01 | 大庆油田有限责任公司 | Reservoir flooding degree prediction method suitable for narrow and thin sand bodies |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107832574A (en) * | 2017-09-19 | 2018-03-23 | 中国石油天然气集团公司 | A kind of horizontal well Geologic analysis method based on well logging |
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Non-Patent Citations (2)
| Title |
|---|
| 丁圣等: "基于改进型阿奇公式法定量评价水淹层" * |
| 黄帅等: "ZW12断块E_2s_1~6砂组老井水淹快速评价初探" * |
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| CN112983411A (en) * | 2021-03-09 | 2021-06-18 | 中国石油大学(华东) | Method for estimating mixed liquor resistivity by using inspection well data |
| CN117153289A (en) * | 2023-09-14 | 2023-12-01 | 大庆油田有限责任公司 | Reservoir flooding degree prediction method suitable for narrow and thin sand bodies |
| CN117153289B (en) * | 2023-09-14 | 2024-04-05 | 大庆油田有限责任公司 | Reservoir flooding degree prediction method suitable for narrow and thin sand bodies |
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