CN111485875B - Method for evaluating saturation degree of isochronous residual oil - Google Patents
Method for evaluating saturation degree of isochronous residual oil Download PDFInfo
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Abstract
The invention provides an isochronal residual oil saturation evaluation method, for a well layer which is not flooded with water, the water saturation is calculated by using the water production rate when the water production rate is developed, and the water saturation is calculated by using resistivity logging when the water production rate is not developed; for a well layer which is put into production after flooding, obtaining residual oil saturation according to the water production rate at the evaluation moment on the basis of a water production rate and water saturation curve or statistical relationship obtained by a relative permeability experiment; for a well layer which is not put into production after flooding but has a logging curve at an evaluation moment, establishing a qualitative identification method and a quantitative evaluation method of residual oil saturation based on logging response characteristics at different flooding stages, and then carrying out evaluation on the residual oil saturation of the flooding layer; judging the flooding condition of a well layer which is not put into production after flooding and has early logging operation according to the development effect condition of an adjacent well, and interpolating to obtain the saturation of the residual oil; and comprehensively drawing a contour map of the isochronism residual oil saturation distribution of a certain layer of the evaluation block at a certain time.
Description
Technical Field
The invention relates to the technical field of petroleum and natural gas geology and exploration and development engineering, in particular to a quantitative evaluation method for isochronal residual oil saturation of a development block.
Background
In the prior art, after an oil-gas reservoir is developed for the second time and the third time, evaluation of the residual oil saturation of a single well and distribution of the residual oil saturation in the longitudinal direction and the transverse direction are very important for adjusting a development scheme. At present, well logging curves and test data are commonly used for carrying out qualitative identification of a water flooded layer and quantitative evaluation of water saturation. Logging is carried out to evaluate the residual oil saturation of a water flooded layer, and the method is mainly a quantitative evaluation method for the residual oil saturation established on the basis of logging response characteristics of different water flooded stages, and has a very large limitation in specific implementation: for a given well, the logging curve is a static curve, and the logging response such as resistivity of the static curve only reflects the state of the formation saturation during logging, for example, the completion logging curve only reflects the state at that time in 2001. If the water is not flooded, the original water saturation is obtained, the residual oil saturation in a certain period (for example, after 2002) after the development cannot be evaluated, and the water saturation generally becomes higher and higher.
In the prior art, the principle of quantitatively estimating the saturation of the remaining oil in the water flooded layer based on test data is to estimate the saturation of the remaining oil in the water flooded layer from the water production rate according to the relationship between the water production rate and the water saturation based on a relative permeability curve. The basic condition for implementing the method is that the water production rate data after single-layer development is necessary, but the method has the advantage of dynamic and can reflect the water saturation of the stratum in real time. At present, if no water production rate data exists, the water saturation condition at the evaluation moment is difficult to reflect by estimating the residual oil saturation degree only according to a logging curve and possibly measuring results several years ago.
The limitations of the two methods result in that the residual oil saturation and the distribution thereof obtained at the time of evaluating the residual oil saturation of the oil and gas reservoir at present are not equal, the distribution of the residual oil saturation of the oil and gas reservoir in the plane and the longitudinal direction at a certain stage of development of the oil and gas reservoir cannot be quantitatively described, the effect of the current development scheme cannot be effectively evaluated, the adjustment of the subsequent development scheme cannot be guided, and great technical defects exist. Therefore, it is necessary to develop a quantitative evaluation method of isochronal remaining oil saturation of a block based on two methods. The literature research finds that the definition of the isochronal residual oil saturation of the development block and the evaluation method thereof are not reported in the literature.
Disclosure of Invention
The invention aims to provide an isochronal residual oil saturation evaluation method to solve the technical problem.
In order to achieve the above object, in one aspect, the present invention provides an isochronal remaining oil saturation evaluation method, including: the evaluation process comprises the following steps:
in the well layer which is not flooded with water, the water saturation is calculated by using the water production rate of the developed water production rate, and the water saturation is calculated by using resistivity logging of the well layer which is not developed;
for a well layer which is put into production after flooding, obtaining residual oil saturation according to the water production rate at the evaluation moment on the basis of a water production rate and water saturation curve or statistical relationship obtained by a relative permeability experiment;
for a well layer which is not put into production after flooding but has a logging curve at an evaluation moment, establishing a qualitative identification method and a quantitative evaluation method of residual oil saturation based on logging response characteristics at different flooding stages, and then carrying out evaluation on the residual oil saturation of the flooding layer;
judging the flooding condition of a well layer which is not put into production after flooding and has early logging operation according to the development effect condition of an adjacent well, and interpolating to obtain the saturation of the residual oil;
and comprehensively drawing a contour map of the isochronism residual oil saturation distribution of a certain layer of the evaluation block at a certain time.
Further, for the situation that the flooding is judged according to the second development situation, the third development situation and the flooding layer well logging qualitative identification, the flooding is not produced, the evaluation time lags the well logging time, and the evaluation process of the oil-water saturation is as follows:
step c1, acquiring reservoir geology and oil well parameters; in this process, various parameters are obtained, such as: logging curves, oil testing data, production dynamic data, water injection data and geological stratification data;
step c2, determining whether the well layer is flooded according to the reservoir geology and the oil well parameters obtained in the step c 1; if yes, go to step c3, otherwise, go to step c 8;
step c3, judging whether the well layer is in production, if not, performing step c4, and if so, jumping to the step c 7;
step c4, judging whether the logging and the evaluation are equal, if not, performing step c5, and if so, performing step c 6;
step c5, determining saturation by adopting oil-water well distribution relation and adjacent well effect condition interpolation;
step c6, calculating saturation by adopting a conventional logging evaluation method for a water flooded layer;
c7, matching the productivity, and calculating the saturation according to the water content at the evaluation moment;
step c8, judging whether the well layer is in production, if so, performing capacity matching, performing step c9, and if not, performing step c 10;
step c9, calculating saturation according to the water yield;
step c10, calculating the water saturation according to Archie formula by resistivity logging, wherein the water saturation is actually the original water saturation and is equal to the residual oil saturation in value;
and step c11, drawing a contour map of the oil saturation of the block at the same time according to the steps c5, c6, c7, c8, c9 and c 10.
Further, for the situation of determining flooding according to the second development situation, the third development situation and the flooding layer well logging qualitative identification, the well layer which is developed in the production is calculated by using the water production rate at the evaluation moment to obtain the water saturation; the calculation process of the water saturation comprises the following steps:
step a1, calculating reservoir geological parameters;
step a2, setting an initial value fw1 of the formation water content;
step a3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment;
step a4, calculating the water saturation of the reservoir according to an Archie's formula;
step a5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi);
step a6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting parameters such as water saturation Sw, mixed liquid resistivity Rwz, water content Fw and the like, if not, setting Fw1 to Fw2, and carrying the steps in step a3 again for judgment.
And further, calculating the water saturation by using a conventional flooding layer well logging evaluation method for a production stratum which is not produced and has the same well logging time as the evaluation time according to the secondary development condition, the tertiary development condition and the flooding layer well logging qualitative identification judgment of the flooding condition.
Further, for the condition that the flooding is not judged according to the secondary development condition and the third development condition, the well layer which is developed in the production is already developed, the water yield is used for calculating to obtain the water saturation, and the water yield at the evaluation moment is used for calculating to obtain the residual oil saturation.
Further, the calculation process of the remaining oil saturation is as follows:
step a1, calculating reservoir geological parameters;
step a2, setting an initial value fw1 of the formation water content;
step a3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment;
step a4, calculating the water saturation of the reservoir according to an Archie's formula;
step a5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi);
step a6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting parameters such as water saturation Sw, mixed liquid resistivity Rwz, water content Fw and the like, if not, setting Fw1 to Fw2, and carrying the steps in step a3 again for judgment.
Further, for the condition that the non-flooding is judged according to the secondary development condition and the third development condition, for the non-developed well layer, resistivity logging is adopted to calculate the water saturation according to an Archie formula, wherein the water saturation is actually the original water saturation, and the value is equal to the residual oil saturation.
Further, the evaluation process for quantitatively evaluating the saturation degree of the residual oil in the water flooded layer by logging of the undeveloped well comprises the following steps:
step b1, screening key wells; the basis for screening wells in the process is as follows: geological data such as slice analysis, core description and the like, logging data, core analysis data, supplementary test data, conventional logging data, oil testing and water content data and the like;
b2, acquiring the relationship among lithology, physical property, electrical property and oil-containing property of the reservoir according to the screened key wells;
b3, establishing a argillaceous content evaluation model, if the model is not suitable, returning to the step b2, and if the model is suitable, performing the step b 4;
b4, establishing a reservoir porosity evaluation model, a permeability evaluation model and an oil saturation evaluation model, and determining the formation water resistivity by using water analysis data;
b5, calculating to obtain single-well longitudinal porosity, permeability and water saturation distribution data according to the models established in the step b4 and the obtained parameters;
b6, combining the data obtained by calculation in the step b5 with the oil testing data to establish an oil gas water layer identification plate and a standard;
and b7, judging whether the oil gas water layer identification chart and the standard obtained in the step b6 are suitable for other wells except the key well, if not, returning to the step b4, and if so, obtaining the well logging explanation of the old well.
Further, the process of quantitatively estimating the saturation degree of the residual oil in the water flooded layer by using production test data comprises the following steps:
acquiring the relation between saturation and water yield according to experiment supplementary test data;
acquiring single-layer development water yield data according to the production dynamic data;
and acquiring the single-layer real-time saturation according to the relation between the saturation and the water yield and the single-layer development water yield data.
Further, determining saturation by interpolation of distribution relation of oil-water wells and adjacent well affected conditions, calculating saturation by a conventional logging evaluation method of a water flooded layer, calculating saturation according to the water yield at the evaluation moment, calculating saturation according to the water yield, calculating water saturation according to an Archie formula, and acquiring an isochronal oil saturation contour map of the block by the five saturation calculation methods.
Compared with the prior art, the method for evaluating the saturation of the residual oil at the same time has the advantages that the method can quantitatively describe the distribution of the saturation of the residual oil at a certain stage in the plane and the longitudinal direction during the development of the oil-gas reservoir, and reflects the water saturation condition at the evaluation moment. The method comprises the steps of determining saturation by interpolation of distribution relation of oil-water wells and adjacent well affected conditions, calculating saturation by a conventional logging evaluation method of a water flooded layer, calculating saturation according to water yield at evaluation time, calculating saturation according to water yield, calculating water saturation according to an Archie formula, and obtaining an isochronal oil saturation contour map of a block by the five saturation calculation methods, so that the quantitative evaluation method of the isochronal residual oil saturation of the block can be provided.
In particular, the evaluation process of the present invention comprises: for a well layer which is not flooded with water, developing the water production rate, calculating the water saturation by using the water production rate, and calculating the water saturation by using resistivity logging which is not developed; for a well layer which is put into production after flooding, obtaining residual oil saturation according to the water production rate at the evaluation moment on the basis of a water production rate and water saturation curve or statistical relationship obtained by a relative permeability experiment; for a well layer which is not put into production after flooding but has a logging curve at an evaluation moment, establishing a qualitative identification method and a quantitative evaluation method of residual oil saturation based on logging response characteristics at different flooding stages, and then carrying out evaluation on the residual oil saturation of the flooding layer; judging the flooding condition of a well layer which is not put into production after flooding and has early logging operation according to the development effect condition of an adjacent well, and interpolating to obtain the saturation of the residual oil; and comprehensively drawing a contour map of the isochronism residual oil saturation distribution of a certain layer of the evaluation block at a certain time.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a schematic diagram of a well log for quantitatively evaluating remaining oil saturation of a water flooded layer in a well under development of an embodiment of the present invention;
FIG. 2 is a cross-plot of water production rate and mixed liquor mineralization degree in accordance with an embodiment of the present invention;
FIG. 3 is a cross plot of saturation and water production rate for an embodiment of the present invention;
FIG. 4a is a diagram illustrating the effect of logging to quantitatively evaluate the saturation of the remaining oil in the water flooded layer in the embodiment A of the present invention;
FIG. 4b is a diagram of the early production dynamics of well development in accordance with example A of the present invention;
FIG. 5a is a diagram illustrating the effect of quantitative evaluation of the saturation of the remaining oil in the water flooded layer by well logging in embodiment B of the present invention;
FIG. 5B is a graph of the early production dynamics of well development in accordance with example B of the present invention;
FIG. 6a is a diagram of the effect of quantitative evaluation of the remaining oil saturation of a water flooded layer by well logging in embodiment C of the present invention;
FIG. 6b is a graph of the early production dynamics of well development in accordance with example C of the present invention;
FIG. 7 is a schematic diagram of quantitative evaluation of remaining oil saturation of a water flooded layer by logging of an undeveloped well in accordance with an embodiment of the present invention;
FIG. 8 is a schematic diagram of a quantitative estimation of remaining oil saturation in a flooded layer using production test data in accordance with an embodiment of the present invention;
FIG. 9a is a graph of production dynamics for single-seam mining of a well in accordance with an embodiment of the present invention;
FIG. 9b is a graph of well saturation versus water production rate in accordance with an embodiment of the present invention;
FIG. 9c is a graph of oil saturation calculated from test data for a well according to an embodiment of the present invention at a corresponding time;
the logging time for this well was 2000 years, while the production dynamics for single-seam mining began at 2009 with less data for whole block single-seam mining.
FIG. 10 is a schematic diagram of a method for isochronal remaining oil saturation evaluation according to an embodiment of the present invention.
Detailed Description
Preferred embodiments of the invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the invention, and do not limit the scope of the invention.
The isochronal residual oil saturation evaluation method provided by the embodiment of the invention comprises the following evaluation processes:
for a well layer which is not flooded with water, developing the water production rate, calculating the water saturation by using the water production rate, and calculating the water saturation by using resistivity logging which is not developed;
for a well layer which is put into production after flooding, obtaining residual oil saturation according to the water production rate at the evaluation moment on the basis of a water production rate and water saturation curve or statistical relationship obtained by a relative permeability experiment;
for a well layer which is not put into production after flooding but has a logging curve at an evaluation moment, establishing a qualitative identification method and a quantitative evaluation method of residual oil saturation based on logging response characteristics at different flooding stages, and then carrying out evaluation on the residual oil saturation of the flooding layer;
judging the flooding condition of a well layer which is not put into production after flooding and has early logging operation according to the development effect condition of an adjacent well, and interpolating to obtain the saturation of the residual oil;
and comprehensively drawing a contour map of the isochronism residual oil saturation distribution of a certain layer of the evaluation block at a certain time.
Specifically, the situation that the water flooding is not judged according to the secondary development situation and the third development situation is divided into two situations: the water saturation is calculated by the water production rate which is changed along with time, and the water saturation is calculated by the water production rate at the evaluation moment, namely the residual oil saturation.
Referring to fig. 1, a schematic diagram of a logging quantitative evaluation of remaining oil saturation of a water flooded layer of a well developed by the embodiment of the present invention is shown, and a calculation process of water saturation is as follows:
step a1, calculating reservoir geological parameters;
step a2, setting an initial value fw1 of the formation water content;
step a3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment;
step a4, calculating the water saturation of the reservoir according to an Archie's formula;
step a5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi);
step a6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting parameters such as water saturation Sw, mixed liquid resistivity Rwz, water content Fw and the like, if not, setting Fw1 to Fw2, and carrying the steps in step a3 again for judgment.
FIG. 4a is a diagram showing the effect of the well logging on the quantitative evaluation of the saturation of the residual oil in the water flooded layer in the embodiment A of the present invention; FIG. 4b is a diagram of the early production dynamics of well development in accordance with example A of the present invention; FIG. 5a is a diagram illustrating the effect of quantitative evaluation of the saturation of the remaining oil in the water flooded layer by well logging in embodiment B of the present invention; FIG. 5B is a graph of the early production dynamics of well development in accordance with example B of the present invention; FIG. 6a is a diagram of the effect of quantitative evaluation of the remaining oil saturation of a water flooded layer by well logging in embodiment C of the present invention; FIG. 6b is a diagram of the early production dynamics of well development in accordance with example C of the present invention. The logging time of the A, B, C well in fig. 4-6 is earlier, and only the early data in the dynamic production data corresponds to the logging data better, i.e. the data marked by the red frame cannot reflect the current state of the formation saturation, and it can be seen in the figure that the water content is constantly changed.
Specifically, for an undeveloped well formation, the water saturation is calculated using resistivity logging according to the Archie's formula, which is effectively the original water saturation, numerically equal to the remaining oil saturation.
Fig. 7 is a schematic diagram for quantitatively evaluating the saturation degree of residual oil in a water flooded layer by logging in an undeveloped well according to an embodiment of the present invention; the evaluation process for quantitatively evaluating the saturation degree of the residual oil in the water flooded layer by logging of the undeveloped well comprises the following steps:
step b1, screening key wells; the basis for screening wells in the process is as follows: geological data such as slice analysis, core description and the like, logging data, core analysis data, supplementary test data, conventional logging data, oil testing and water content data and the like;
b2, acquiring the relationship among reservoir lithology, physical property, electrical property and oil-containing property according to the screened key wells;
b3, establishing a argillaceous content evaluation model, if the model is not suitable, returning to the step b2, and if the model is suitable, performing the step b 4;
b4, establishing a reservoir porosity evaluation model, a permeability evaluation model and an oil saturation evaluation model, and determining the formation water resistivity by using water analysis data;
b5, calculating to obtain single-well longitudinal porosity, permeability and water saturation distribution data according to the models established in the step b4 and the obtained parameters;
b6, combining the data obtained by calculation in the step b5 with the oil testing data to establish an oil gas water layer identification plate and a standard;
and b7, judging whether the oil gas water layer identification chart and the standard obtained in the step b6 are suitable for other wells except the key well, if not, returning to the step b4, and if so, obtaining the well logging explanation of the old well.
FIG. 8 is a schematic diagram of a method for quantitatively estimating remaining oil saturation of a flooded layer using production test data according to an embodiment of the present invention; the process of quantitatively estimating the saturation of the residual oil in the water flooded layer by using production test data in the embodiment comprises the following steps:
acquiring the relation between saturation and water yield according to experiment supplementary test data;
acquiring single-layer development water yield data according to the production dynamic data;
and acquiring the single-layer real-time saturation according to the relation between the saturation and the water yield and the single-layer development water yield data.
FIG. 9a is a graph of production dynamics for a single well layer production in accordance with an embodiment of the present invention; FIG. 9b is a graph of well saturation versus water production rate in accordance with an embodiment of the present invention; FIG. 9c is a graph of oil saturation calculated from test data for a well according to an embodiment of the present invention at a corresponding time; the logging time for this well was 2000 years, while the production dynamics for single-seam mining began at 2009 with less data for whole block single-seam mining. The effect graph of quantitative evaluation of the saturation of the residual oil in the water flooded layer by using the well test data shows that the resistivity logging is adopted to calculate the water saturation according to the Archie formula, the water saturation is actually the original water saturation, the value is equal to the saturation of the residual oil, and the calculation result is accurate.
Specifically, the flooding condition is judged according to the second development condition, the third development condition and the flooding layer well logging qualitative identification, and the method is divided into three conditions: well formations in production have been developed and water saturation calculated using water production rates at the time of evaluation. For those skilled in the art, calculating the remaining oil saturation by using production test and experimental data instead of logging method can avoid the problem that the resistivity of the mixed liquid is difficult to be accurately determined.
The calculation process of the water saturation comprises the following steps:
further, the calculation process of the remaining oil saturation is as follows:
step a1, calculating reservoir geological parameters;
step a2, setting an initial value fw1 of the formation water content;
step a3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment;
step a4, calculating the water saturation of the reservoir according to an Archie's formula;
step a5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi);
step a6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting parameters such as water saturation Sw, mixed liquid resistivity Rwz, water content Fw and the like, if not, setting Fw1 to Fw2, and carrying the steps in step a3 again for judgment.
Specifically, in a producing zone which is not produced by flooding and has the logging time the same as the evaluation time, the water saturation is calculated by using a conventional flooding zone logging evaluation method.
Specifically, the logging time is delayed after the flooding is not produced and the evaluation time, a logging curve is completely unavailable, and the oil-water saturation is determined by directly adopting the distribution relation of an oil-water well and interpolating according to the effect condition of an adjacent well. For those skilled in the art, the oil-water saturation is determined as a frequently occurring condition by directly adopting the distribution relation of oil-water wells and interpolating according to the receiving conditions of adjacent wells.
Referring to FIG. 10, a schematic diagram of a method for isochronal remaining oil saturation evaluation according to an embodiment of the present invention is shown; and for the third situation, the logging curve is completely unavailable when the water logging is not produced and the evaluation time lags the logging time, and the oil-water saturation is determined by directly adopting the distribution relation of the oil-water well and interpolating according to the effect situation of the adjacent well.
The evaluation process of the oil-water saturation comprises the following steps:
step c1, acquiring reservoir geology and oil well parameters; in this process, various parameters are obtained, such as: logging curves, oil testing data, production dynamic data, water injection data and geological stratification data;
step c2, determining whether the well layer is flooded according to the reservoir geology and the oil well parameters obtained in the step c 1; if yes, go to step c3, otherwise, go to step c 8;
step c3, judging whether the well layer is in production, if not, performing step c4, and if so, jumping to the step c 7;
step c4, judging whether the logging and the evaluation are equal, if not, performing step c5, and if so, performing step c 6;
step c5, determining saturation by adopting oil-water well distribution relation and adjacent well effect condition interpolation;
step c6, calculating saturation by adopting a conventional logging evaluation method for a water flooded layer;
c7, matching the productivity, and calculating the saturation according to the water content at the evaluation moment;
step c8, judging whether the well layer is in production, if so, performing capacity matching, performing step c9, and if not, performing step c 10;
step c9, calculating saturation according to the water yield;
step c10, calculating the water saturation according to Archie formula by resistivity logging, wherein the water saturation is actually the original water saturation and is equal to the residual oil saturation in value;
and step c11, drawing a contour map of the oil saturation of the block at the same time according to the steps c5, c6, c7, c8, c9 and c 10.
Specifically, the logging curve is completely unavailable when the flooding is not produced and the time lag logging time is evaluated, and the oil-water saturation is determined by directly adopting the distribution relation of an oil-water well and interpolating according to the effect condition of an adjacent well. The method comprises the steps of determining saturation by interpolation of distribution relation of oil-water wells and adjacent well affected conditions, calculating saturation by a conventional logging evaluation method of a water flooded layer, calculating saturation according to water yield at evaluation time, calculating saturation according to water yield, calculating water saturation according to Archie formula, and obtaining an isochronal oil saturation contour map of a block by the five saturation calculation methods.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. The isochronal residual oil saturation evaluation method is characterized by comprising the following steps of evaluating oil-containing water saturation according to a secondary or tertiary development condition, a water flooded layer logging qualitative identification judgment water flooded condition, a production condition and a logging and evaluation time isochronal condition;
step c1, obtaining reservoir geology and oil well parameters; in this process, various parameters are obtained, which are: logging curves, oil testing data, production dynamic data, water injection data and geological stratification data; step c2, determining whether the well layer is flooded according to the reservoir geology and the oil well parameters obtained in the step c 1; if yes, go to step c3, otherwise, go to step c 8; step c3, judging whether the well layer is in production, if not, performing step c4, and if so, jumping to the step c 7; step c4, judging whether the logging and the evaluation are equal, if not, performing step c5, and if so, performing step c 6;
step c5, determining saturation by adopting oil-water well distribution relation and adjacent well effect condition interpolation; step c6, calculating saturation by adopting a conventional logging evaluation method for a water flooded layer; c7, matching the productivity, and calculating the saturation according to the water content at the evaluation moment; step c8, judging whether the well layer is in production, if so, performing capacity matching, performing step c9, and if not, performing step c 10; step c9, calculating saturation according to the water yield; step c10, calculating the water saturation according to Archie formula by resistivity logging, wherein the water saturation is actually the original water saturation and is equal to 1-residual oil saturation in value; and c11, drawing a contour map of the oil saturation of the block at the same time according to the step c5, the step c6, the step c7, the step c8, the step c9 and the step c 10.
2. The isochronal residual oil saturation evaluation method according to claim 1, wherein for a well layer flooded in production, the water saturation is calculated by using the water production rate at the evaluation time; the calculation process of the water saturation comprises the following steps: step A1, reservoir geological parameters are calculated; step A2, setting an initial value fw1 of the water content of the stratum; step A3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment; step A4, calculating the water saturation of the reservoir according to an Archie's formula; step A5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi); step A6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting the water saturation Sw, the mixed liquid resistivity Rwz and the water content Fw parameter, if not, setting Fw1 to Fw2, and carrying the steps in step A3 again for judgment.
3. The method of claim 1, wherein for a well zone that is not flooded and is in production, the water saturation is calculated using the water production rate, the residual oil saturation is calculated using the water production rate at the time of evaluation,
the calculation process of the residual oil saturation degree comprises the following steps: step a1, calculating reservoir geological parameters; step a2, setting an initial value fw1 of the formation water content; step a3, calculating the resistivity of the reservoir mixed liquor according to the water yield and the mixed liquor resistivity model obtained by the experiment; step a4, calculating the water saturation of the reservoir according to an Archie's formula; step a5, inversely calculating the water content of the reservoir fw2, wherein the calculation formula is fw2 ═ f (Sw, Swi); step a6, calculating whether the absolute value of the difference between the reservoir water content Fw2 and the initial water content Fw1 is less than 0.05, judging the formula to be ABS (Fw2-Fw1) <0.05, if so, outputting the water saturation Sw, the mixed liquid resistivity Rwz and the water content Fw parameter, if not, setting Fw1 to Fw2, and carrying the steps in step a3 again to judge.
4. The method for isochronal residual oil saturation evaluation according to claim 1, wherein for a well layer which is not flooded with water and is not in production, resistivity logging is used to calculate the water saturation according to the Archie formula, which is actually the original water saturation, and is numerically equal to 1-residual oil saturation;
the evaluation process for quantitatively evaluating the saturation degree of the residual oil in the water flooded layer when the oil is not flooded in the production well comprises the following steps: step b1, screening key wells; the basis for screening wells in the process is as follows: the geological data is slice analysis, core description, logging data, core analysis data, supplementary test data, conventional logging data, oil testing data and water content data;
b2, acquiring the relationship among reservoir lithology, physical property, electrical property and oil-containing property according to the screened key wells; b3, establishing a argillaceous content evaluation model, if the model is not suitable, returning to the step b2, and if the model is suitable, performing the step b 4; b4, establishing a reservoir porosity evaluation model, a permeability evaluation model and an oil saturation evaluation model, and determining the formation water resistivity by using water analysis data; b5, calculating to obtain single-well longitudinal porosity, permeability and water saturation distribution data according to the models established in the step b4 and the obtained parameters; b6, combining the data obtained by calculation in the step b5 with the oil testing data to establish an oil gas water layer identification plate and a standard; and b7, judging whether the oil gas water layer identification chart and the standard obtained in the step b6 are suitable for other wells except the key well, if not, returning to the step b4, and if so, obtaining the well logging explanation of the old well.
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