阅读说明：本技术 基于无阻流量的含气饱和度校正方法和装置 (Gas saturation correction method and device based on unimpeded flow ) 是由 张克非 李呈呈 林正良 胡华锋 于 2019-10-09 设计创作，主要内容包括：本申请公开了基于无阻流量的含气饱和度校正方法和装置。该方法包括：基于地质信息和工程先验信息确定工区内无阻流量与含气饱和度之间的关系；确定无阻流量和含气饱和度估计值之间的关系曲线；根据无阻流量计算每口井的含气饱和度估计值；根据测井数据得到每口井的原始含气饱和度平均值；基于含气饱和度估计值和原始含气饱和度平均值,得到每口井的含气饱和度校正系数；采用含气饱和度校正系数对每口井的原始含气饱和度进行校正。根据本申请,可以获得与开发生产资料及地质认识相符的含气饱和度曲线,能有效指导含气性预测等后续一系列工作,在气藏发育地区具有极大的推广应用价值。(The application discloses a gas saturation correction method and device based on unimpeded flow. The method comprises the following steps: determining the relation between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information; determining a relationship curve between the unobstructed flow and the estimated value of gas saturation; calculating a gas saturation estimated value of each well according to the unobstructed flow; obtaining the average value of the original gas saturation of each well according to the logging data; obtaining a gas saturation correction coefficient of each well based on the estimated value of the gas saturation and the average value of the original gas saturation; and correcting the original gas saturation of each well by using a gas saturation correction coefficient. According to the method and the device, a gas saturation curve which is consistent with development and production data and geological knowledge can be obtained, a series of follow-up work such as gas bearing prediction can be effectively guided, and the method and the device have great popularization and application values in gas reservoir development areas.)

1. A method for correcting gas saturation based on unobstructed flow, the method comprising:

determining the relation between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information;

determining a relation curve between the unobstructed flow and the estimated value of the gas saturation according to the relation between the unobstructed flow and the gas saturation;

calculating a gas saturation estimated value of each well according to the unobstructed flow;

obtaining the average value of the original gas saturation of each well according to the logging data;

obtaining a gas saturation correction coefficient of each well based on the estimated value of the gas saturation and the average value of the original gas saturation;

and correcting the original gas saturation of each well by using a gas saturation correction coefficient.

2. The method of claim 1, further comprising:

and determining whether to correct the original gas saturation according to the relation between the unobstructed flow of each well in the work area and the average value of the original gas saturation.

3. The method of claim 1, wherein determining the relationship between unobstructed flow and gas saturation in the work area based on geological information and engineering prior information comprises:

and determining the corresponding value range of the gas saturation when the unimpeded flow is in different value ranges.

4. The method of claim 1, wherein deriving an average of raw gas saturation for each well from the well log data comprises:

and aiming at each well, calculating the arithmetic mean of the original gas saturation measured by the logging data at each sampling point of the target layer to obtain the average value of the original gas saturation.

5. The method of claim 1, wherein determining a relationship between the unobstructed flow rate and the estimated gas saturation comprises:

the relationship between the unobstructed flow and the estimated value of gas saturation is fitted based on the estimated value of gas saturation as a power function of the unobstructed flow.

6. An unobstructed flow based gas saturation correction apparatus, the apparatus comprising:

the prior information acquisition unit is used for determining the relation between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information;

the relation curve determining unit is used for determining a relation curve between the unobstructed flow and the estimated value of the gas saturation according to the relation between the unobstructed flow and the gas saturation;

the estimated value calculation unit is used for calculating the estimated value of the gas saturation of each well according to the unobstructed flow;

the original average value calculating unit is used for obtaining the original gas saturation average value of each well according to the logging data;

the correction coefficient determining unit is used for obtaining the gas saturation correction coefficient of each well based on the estimated value of the gas saturation and the average value of the original gas saturation;

and the correcting unit is used for correcting the original gas saturation of each well by adopting the gas saturation correction coefficient.

7. The apparatus of claim 6, further comprising:

and the data evaluation unit is used for determining whether to correct the original gas saturation according to the relation between the unobstructed flow of each well in the work area and the average value of the original gas saturation.

8. The apparatus according to claim 6, wherein the prior information obtaining unit is specifically configured to:

and determining the corresponding value range of the gas saturation when the unimpeded flow is in different value ranges.

9. The apparatus according to claim 6, wherein the raw average calculating unit is specifically configured to:

and aiming at each well, calculating the arithmetic mean of the original gas saturation measured by the logging data at each sampling point of the target layer to obtain the average value of the original gas saturation.

10. The apparatus according to claim 6, wherein the relationship curve determining unit is specifically configured to:

the relationship between the unobstructed flow and the estimated value of gas saturation is fitted based on the estimated value of gas saturation as a power function of the unobstructed flow.

Technical Field

The invention belongs to the field of oil exploration, and particularly relates to a saturation correction method based on unimpeded flow and a saturation correction device based on unimpeded flow.

Background

Gas saturation, which refers to the volume of natural gas in a reservoir as a percentage of the volume of interconnected pores in the original state. In oil exploration, the gas saturation is a very important parameter, and the method has great guiding significance for a series of works such as gas saturation prediction and the like. At present, the gas saturation is mostly calculated according to an Archie formula, and because parameters such as the formation water mineralization and the like in the formula are difficult to obtain, well logging interpreters can only calculate according to experience, the calculation of the gas saturation is often not accurate enough.

Therefore, a technical solution capable of obtaining more accurate gas saturation is needed.

Disclosure of Invention

In view of the above, the present application provides a method capable of correcting existing gas saturation. The application also provides a corresponding device.

According to an aspect of the application, a method for correcting gas saturation based on unobstructed flow is provided, and the method comprises the following steps: determining the relation between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information; determining a relation curve between the unobstructed flow and the estimated value of the gas saturation according to the relation between the unobstructed flow and the gas saturation; calculating a gas saturation estimated value of each well according to the unobstructed flow; obtaining the average value of the original gas saturation of each well according to the logging data; obtaining a gas saturation correction coefficient of each well based on the estimated value of the gas saturation and the average value of the original gas saturation; and correcting the original gas saturation of each well by using a gas saturation correction coefficient.

In one possible embodiment, the method further comprises: and determining whether to correct the original gas saturation according to the relation between the unobstructed flow of each well in the work area and the average value of the original gas saturation.

In one possible implementation, the determining a relationship between unobstructed flow and gas saturation in a work area based on geological information and engineering prior information includes: and determining the corresponding value range of the gas saturation when the unimpeded flow is in different value ranges.

In one possible embodiment, the obtaining an average value of the original gas saturation of each well according to the well logging data comprises: and aiming at each well, calculating the arithmetic mean of the original gas saturation measured by the logging data at each sampling point of the target layer to obtain the average value of the original gas saturation.

In one possible embodiment, the determining a relationship between the unobstructed flow and the estimated gas saturation includes: the relationship between the unobstructed flow and the estimated value of gas saturation is fitted based on the estimated value of gas saturation as a power function of the unobstructed flow.

According to another aspect of the application, there is provided a gas saturation correction apparatus based on an unobstructed flow, the apparatus comprising: the prior information acquisition unit is used for determining the relation between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information; the relation curve determining unit is used for determining a relation curve between the unobstructed flow and the estimated value of the gas saturation according to the relation between the unobstructed flow and the gas saturation; the estimated value calculation unit is used for calculating the estimated value of the gas saturation of each well according to the unobstructed flow; the original average value calculating unit is used for obtaining the original gas saturation average value of each well according to the logging data; the correction coefficient determining unit is used for obtaining the gas saturation correction coefficient of each well based on the estimated value of the gas saturation and the average value of the original gas saturation; and the correcting unit is used for correcting the original gas saturation of each well by adopting the gas saturation correction coefficient.

In a possible embodiment, the apparatus further comprises: and the data evaluation unit is used for determining whether to correct the original gas saturation according to the relation between the unobstructed flow of each well in the work area and the average value of the original gas saturation.

In a possible implementation manner, the prior information obtaining unit is specifically configured to: and determining the corresponding value range of the gas saturation when the unimpeded flow is in different value ranges.

In a possible implementation, the raw average calculating unit is specifically configured to: and aiming at each well, calculating the arithmetic mean of the original gas saturation measured by the logging data at each sampling point of the target layer to obtain the average value of the original gas saturation.

In a possible implementation, the relationship curve determining unit is specifically configured to: the relationship between the unobstructed flow and the estimated value of gas saturation is fitted based on the estimated value of gas saturation as a power function of the unobstructed flow.

According to the method, on the basis of the positive correlation relation between the unimpeded flow and the gas saturation, the mean value correction is carried out on the basis of the normal gas saturation curve calculation under the condition that the variance of the gas saturation curve is not changed, the gas saturation curve which is consistent with development and production data and geological understanding is obtained, a series of follow-up work such as gas saturation prediction can be effectively guided, and the method has great popularization and application values in a gas reservoir development area.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application, as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

FIG. 1 illustrates a flow diagram of a method for unobstructed flow based gas saturation correction according to an embodiment of the application.

FIG. 2 shows a correction path diagram according to an exemplary embodiment of the present application.

FIG. 3 illustrates a block diagram of a gas saturation correction apparatus based on an unobstructed flow according to an embodiment of the application.

FIG. 4 shows histograms of unobstructed flow and raw gas saturation for different producing wells of a work area prior to correction.

FIG. 5 illustrates a plot of the relationship between unobstructed flow and estimated gas saturation values from geological information and engineering prior information in a work area.

FIG. 6 shows histograms of unobstructed flow and gas saturation for different producing wells of a work area corrected according to the present application.

Detailed Description

Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Please refer to fig. 1. FIG. 1 illustrates a flow diagram of a method for unobstructed flow based gas saturation correction according to an embodiment of the application. As shown, the method includes the following steps.

And 102, determining the relation between the unobstructed flow A and the gas saturation sg in the work area based on the geological information and the engineering prior information.

The relationship between the unobstructed flow a and the gas saturation sg is here obtained by the staff of the work area according to previous empirical summaries. Because the relation between the unobstructed flow A and the gas saturation sg is determined by adopting the experiences summarized by the staff through the exploration and the knowledge (namely the knowledge of geological information and engineering prior information) of the working area for years, the obtained relation between the unobstructed flow A and the gas saturation sg can accurately express the actual condition of the working area, and a good foundation is laid for the subsequent correction.

In one possible implementation, step 102 may include determining a range of values of the gas saturation sg corresponding to the unobstructed flow rate a at different ranges of values. In other words, the empirically derived relationship between the unobstructed flow rate a and the gas saturation sg may be an approximate range correspondence.

And step 104, determining a relation curve between the unobstructed flow A and the estimated value sg _ ave of the gas saturation according to the relation between the unobstructed flow A and the gas saturation sg.

In one possible implementation, the relationship between the unobstructed flow rate a and the estimated gas saturation value sg _ ave may be fitted based on the estimated gas saturation value sg _ ave as a power function of the unobstructed flow rate a.

The unimpeded flow rate A is the yield obtained by the open wellhead open blowout method and can be used for measuring the production capacity of gas wells and comparing the production capacity among the gas wells, so that the unimpeded flow rate A and the gas saturation sg are positively correlated. On the basis, the inventor carries out further research and deeply analyzes data collected from a plurality of work areas, finds that the relation between the gas saturation and the unimpeded flow A can be accurately expressed by taking the gas saturation as a power function of the unimpeded flow A. Therefore, a relationship curve between the two can be fitted based on this.

And 106, calculating the estimated value sg _ ave of the gas saturation of each well according to the unobstructed flow A.

For each well, the non-resistance flow rate a may be substituted into the relationship between the non-resistance flow rate a and the estimated gas saturation value sg _ ave obtained in step 104 to obtain an estimated gas saturation value sg _ ave of the well.

And step 108, obtaining the average value sg _ orign _ ave of the original gas saturation of each well according to the logging data.

In one possible implementation, for each well, the arithmetic mean of the original gas saturation sg _ orign measured by the well logging data at each sampling point of the target stratum is obtained to obtain the average value sg _ orign _ ave of the original gas saturation.

And step 110, obtaining a gas saturation correction coefficient sg _ check of each well based on the gas saturation estimated value sg _ ave and the original gas saturation average value sg _ orign _ ave.

Sg _ check can be given as sg _ ave-sg _ orign _ ave.

And step 112, correcting the original gas saturation of each well by using the gas saturation correction coefficient.

After the original gas saturation is corrected, histograms of the unobstructed flow and the corrected gas saturation of different gas producing wells can be made to confirm that the corresponding relationship between the unobstructed flow and the gas saturation conforms to positive correlation.

In the embodiment, on the basis of the positive correlation relationship between the unimpeded flow and the gas saturation, the average value correction is carried out on the basis of the normal gas saturation curve calculation under the condition of ensuring that the variance of the gas saturation curve is not changed, the gas saturation curve conforming to development and production data and geological knowledge is obtained, a subsequent series of work such as gas saturation prediction can be effectively guided, and the method has great popularization and application values in a gas reservoir development area

In a possible implementation manner, before the step 102, it may be determined whether to correct the gas saturation sg _ orign according to a relationship between the unobstructed flow rate a and the gas saturation sg _ orign of each well in the work area. For example, histograms of the unobstructed flow a and the original average value sg _ orign _ ave of gas saturation of different gas producing wells can be made, and if the unobstructed flow a and the original average value sg _ orign _ ave of gas saturation are in positive correlation, the original gas saturation sg _ orign can be considered to be basically accurate and no correction can be made; if the two do not match a positive correlation, the original gas saturation sg orign can be considered as erroneous and can be corrected.

FIG. 2 shows a correction path diagram according to an exemplary embodiment of the present application. As shown, the actual relationship (204) of the unobstructed flow and the gas saturation can be obtained from geological information of the work area and engineering prior information (202). The unobstructed flow rate (206) is brought into an actual relationship (204) between the unobstructed flow rate and the gas saturation to obtain an estimated value sg _ ave of the gas saturation for each well (208). An average value sg _ orign _ ave of the original gas saturation is obtained (212) from the original gas saturation (210). The sg _ ave (208) and the sg _ orign _ ave (212) are subtracted to obtain the gas saturation correction coefficient sg _ check (214). The original gas saturation (210) is corrected using sg check (214) to obtain a corrected gas saturation (216).

FIG. 3 illustrates a block diagram of a gas saturation correction apparatus based on an unobstructed flow according to an embodiment of the application. As shown, the apparatus includes an a priori information acquisition unit 302, a relationship curve determination unit 304, an estimated value calculation unit 306, a raw average value calculation unit 308, a correction coefficient determination unit 310, and a correction unit 312.

The prior information obtaining unit 302 is configured to determine a relationship between the unobstructed flow and the gas saturation in the work area based on the geological information and the engineering prior information.

The relation curve determining unit 304 is configured to determine a relation curve between the unobstructed flow and the estimated value of the gas saturation according to the relation between the unobstructed flow and the gas saturation.

The estimated value calculation unit 306 is used for calculating the estimated value of the gas saturation of each well according to the unobstructed flow.

The raw average calculation unit 308 is used for obtaining the raw gas saturation average of each well according to the well logging data.

The correction factor determination unit 310 is configured to obtain a gas saturation correction factor for each well based on the estimated gas saturation value and the average value of the original gas saturation.

The correction unit 312 is configured to correct the original gas saturation for each well using a gas saturation correction factor.

In a possible embodiment, the apparatus further comprises: and the data evaluation unit is used for determining whether to correct the original gas saturation according to the relation between the unobstructed flow of each well in the work area and the average value of the original gas saturation.

In a possible implementation manner, the prior information obtaining unit is specifically configured to: and determining the corresponding value range of the gas saturation when the unimpeded flow is in different value ranges.

In a possible implementation, the raw average calculating unit is specifically configured to: and aiming at each well, calculating the arithmetic mean of the original gas saturation measured by the logging data at each sampling point of the target layer to obtain the average value of the original gas saturation.

In a possible implementation, the relationship curve determining unit is specifically configured to: fitting a relationship between unobstructed flow and estimated value of gas saturation based on estimated value of gas saturation as power function of unobstructed flow

Application example

In the application example, based on the work area logging interpretation result, histograms of the unobstructed flow a and the original gas saturation sg _ orign of different gas wells in the work area are obtained, as shown in fig. 4. As can be seen from fig. 4, the resulting unobstructed flow rate a and the gas saturation sg orign are not positively correlated, and therefore, it can be considered that the gas saturation sg orign in fig. 2 needs to be corrected.

In this example, after the operator in the work area surveys and recognizes the work area for a long period of time, the unobstructed flow rate a and the gas saturation sg in the work area are considered to have the following relationship:

when the unimpeded flow A is larger than 10, the gas saturation sg is larger than 70%;

when 3< unobstructed flow A <10, 55% < gas saturation sg < 70%;

when the unobstructed flow a is <3, 40% < gas saturation sg < 55%.

Based on the above relationship and based on the power function of the estimated value sg _ ave of gas saturation as the unobstructed flow rate a, a relationship curve between the unobstructed flow rate a and the estimated value sg _ ave of gas saturation (i.e. the gas saturation indicated by the ordinate in fig. 5) is obtained as shown in fig. 5: sg _ ave ═ 32 a^1/6+20. Then the non-resistance flow A of each well is brought into sg _ ave ═ 32 × A^1/6+20, and obtaining an estimated value sg _ ave of the gas saturation of each well.

In addition, for each well, the arithmetic mean of the original gas saturation sg _ orign measured by the logging data at each sampling point of the target layer is obtained, the original gas saturation mean value sg _ orign _ ave is obtained, sg _ check is made to be sg _ ave-sg _ orign _ ave, and a gas saturation correction coefficient sg _ check of each well is obtained.

And correcting the original gas saturation sg orign of each well by adopting a gas saturation correction coefficient sg _ check, so that mean value correction can be performed under the condition that the variance of an original gas saturation curve is not changed. Histograms of the unobstructed flow a and the corrected gas saturation sg _ padded of different gas producing wells can be made according to the correction result, as shown in fig. 6. As can be seen from fig. 6, the gas saturation sg _ checked corrected according to the present application has a good positive correlation corresponding relationship with the unobstructed flow rate a, and conforms to geological knowledge.

The present application may be a system, method and/or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to implement various aspects of the present application.

The computer readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or electrical signals transmitted through electrical wires.

Various aspects of the present application are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.

Having described embodiments of the present application, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein were chosen in order to best explain the principles of the embodiments, the practical application, or technical improvements to the techniques in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.