CN108915676B

CN108915676B - Movable fluid invasion profile imaging method for tight reservoir pores

Info

Publication number: CN108915676B
Application number: CN201810803065.8A
Authority: CN
Inventors: 陈义国; 贺永红; 张佳琪; 马芳侠; 李晓路; 孟旺才; 刘护创; 杨超; 刘延哲; 张庆; 邓南涛; 吴凤; 李广涛; 王超; 马二平; 张洪美
Original assignee: Shaanxi Yanchang Petroleum Group Co Ltd
Current assignee: Shaanxi Yanchang Petroleum Group Co Ltd
Priority date: 2018-07-20
Filing date: 2018-07-20
Publication date: 2021-09-14
Anticipated expiration: 2038-07-20
Also published as: CN108915676A

Abstract

The invention provides a compact reservoir pore movable fluid invasion profile imaging method based on array induction logging resistivity data. A method for imaging a movable fluid invasion profile of a compact reservoir pore comprises the following steps: step (1): correcting data; step (2): interpolation resampling; and (3): color graduation: the S ' (x ', y ') is scaled by color, and the resistivity values are scaled from dark to light in the order of increasing resistivity values, thereby forming a moving fluid invasion profile image. The method provided by the invention overcomes the defects of shallow depth, low acquisition rate and poor representativeness of imaging logging, a rock core experimental method and a nuclear magnetic resonance T2 spectrum detection, and can visually display the pore connectivity and the movable fluid distribution characteristics of the compact reservoir within a radial 120-inch depth range.

Description

Movable fluid invasion profile imaging method for tight reservoir pores

Technical Field

The invention provides a compact reservoir pore movable fluid invasion profile imaging method based on array induction logging resistivity data.

Background

With the global energy demand increasing, the dense oil exploration draws more and more attention from the industry. The compact reservoir layer is mainly made of fine-superfine sandstone, has compact physical property, narrow pore throat, high impurity base content and strong diagenesis, and leads to strong spatial heterogeneity. The evaluation of compact reservoir pore connectivity and movable fluid distribution characteristics is the key of compact reservoir quality evaluation, and influences the exploration and development of compact oil. At present, only laboratory core sample test and nuclear magnetic resonance logging can be used for evaluating movable fluid in tight reservoir pores, but the applicability of the prior art is restricted due to low acquisition rate, long interpretation period and strong heterogeneity of tight reservoir space.

Foreign schlumberger FMI, atlas STAR, harlibertn EMI and domestic EILOG, ERMI and other electrical imaging logging equipment mainly collects resistivity through the well periphery density, applies digital image processing, and evaluates the pore, crack and structural characteristics of the well periphery interface. Because the equipment collects the resistivity through the density of the well, the detection depth is shallow (less than 5cm), and the connectivity of the deep pores of the stratum and the distribution characteristics of the movable fluid are difficult to reflect.

The array induction logging has a longitudinal sampling interval of 0.125M, three working modes of 1, 2 and 4 feet, and can measure resistivity values of formations at depths of 10, 20, 30, 60, 90 and 120 inches from the well bore (taking the working mode of 1 foot as an example, six resistivity curves of M1R1, M1R2, M1R3, M1R6, M1R9 and M1RX can be measured). The logging method is low in cost and high in acquisition rate, oil layer identification is mainly carried out according to the longitudinal difference of the actually measured resistivity values at present, and the specific expression is that the resistivity value of a water layer is low, the resistivity value of an oil layer is high, the excavation degree of geological information contained in the resistivity difference of different radial detection depths is insufficient, and meanwhile, the conventional radial resistivity curve is poor in superposition display intuitiveness. Therefore, the geological information contained in the array induction resistivity measured value and the resistivity relative value of each detection depth is mined, and the research on the pore connectivity of the tight reservoir and the movable fluid evaluation method is of great value.

Under the action of drilling pressure, the drilling fluid displaces movable fluid along the formation communication pores and gradually invades the formation, and the more the communication pores are developed, the more the drilling fluid is invaded, such as a relatively high-permeability reservoir; the less well-communicating pore development occurs in formations with less drilling fluid invasion, such as relatively hypotonic reservoirs and mudstone formations. Due to the property difference between the drilling fluid and the formation pore fluid, the resistivity of the circumferentially communicated pores and the resistivity of the non-communicated pores are differentiated, and the specific expression is that the higher the pore communication degree is, the more the drilling fluid is invaded into a reservoir stratum, the smaller the resistivity value is, and the more obvious the difference between the resistivities of different radial detection depths is; the lower the pore communication degree of the reservoir, the less the invasion drilling fluid amount, the larger the resistivity value, and the smaller the difference between the resistivities at different radial detection depths.

At present, in a laboratory, the pore mobile fluid is mainly measured by core sample centrifugation and constant-speed mercury pressing, or the pore mobile fluid is evaluated by utilizing nuclear magnetic resonance logging T2 spectral data. Because of strong spatial heterogeneity of a compact reservoir, even the same reservoir has obvious pore connectivity difference due to lithologic change, a core sample has no universal representativeness, and the application is restricted; the nuclear magnetic resonance logging T2 spectrum can be used for evaluating pore mobile fluid according to oil and water relaxation signal characteristics, but the logging cost is high, the acquisition rate is low, the representativeness is poor, specialized software is required for processing, the interpretation period is long, and the application is limited.

The existing Schlumberger FMI, atlas STAR, Harlibertn EMI, domestic EILOG, ERMI and other electric imaging logging equipment collects data through the resistivity at the periphery of a well, evaluates the pores and structural characteristics of the interface at the periphery of the well, and due to the influence of the skin effect, the larger the density of the collected data is, the smaller the detection depth is (the detection depth of the existing imaging equipment is less than 5cm), and the connectivity of the pores at the deep part of a stratum and the distribution characteristics of movable fluid are difficult to reflect.

Disclosure of Invention

The technical scheme of the invention is as follows:

a method for imaging a movable fluid invasion profile of a compact reservoir pore comprises the following steps:

step (1): and (3) data correction: carrying out data correction on the resistivity value of the induction logging of the whole well array, wherein the correction range of the resistivity value of the whole well is 0-255, namely the minimum resistivity value is corrected to be 0, and the maximum resistivity value is corrected to be 255;

step (2) interpolation resampling: taking the radial detection depth as an x coordinate, wherein x is less than or equal to 120 in; taking the corrected resistivity as a y coordinate as an interpolation sample point S (x, y); in order to ensure that the display proportion of an imaging graph is coordinated, visual and exquisite, the radial sampling interval and the longitudinal sampling interval are consistent or close to each other as much as possible; because the longitudinal sampling interval of the array induction logging data is 0.125m, the radial maximum detection depth 120in is equally divided into 23 parts, 24 parts or 25 parts respectively in the uniform equal division process, and the corresponding radial sampling interval is 0.133m, 0.127m or 0.122m respectively; at 24 equal divisions, the radial sampling interval is 0.127m, which is closest to the longitudinal sampling interval, and the imaging effect is optimal, so 24 equal divisions are preferred; utilizing the interpolation sample point data, taking the equally divided radial detection depth value as an interpolation resampling x ' coordinate, applying a piecewise linear interpolation method, taking a resistivity value after interpolation resampling as a y ' coordinate, and resampling to obtain S ' (x ', y ');

and (3): color graduation: the color of S ' (x ', y ') is scaled, and the resistivity values are scaled from dark to light in the order of increasing, i.e., RGB (0:0:0) for black and RGB (255:255:255) for white, to form a moving fluid invasion profile.

The invention has the technical effects that:

the method provided by the invention is based on the array induction logging resistivity data, a digital image processing technology is applied, a movable pore fluid invasion profile in the radial 120-in range of a compact reservoir is formed through data correction, interpolation resampling and color scale processing, geological information contained in radial difference of the array induction logging resistivity is mined, the defects of low acquisition rate and poor representativeness of a rock core experimental method and a nuclear magnetic resonance T2 spectrum are overcome, the radial detection depth is larger than that of peripheral imaging technologies such as FMI, STAR and the like, and the pore connectivity and movable fluid distribution characteristics in the radial 120-in range of the compact reservoir can be visually displayed. The deeper the color of the image of the invasion profile is, the smaller the representative resistivity value is, the more the mud invasion amount is, the better the pore connectivity is, and the more the mobile fluid content is; the brighter the color of the invasion profile image, the larger the resistivity value and the less the mud invasion, indicating the poorer the pore connectivity and the less mobile fluid content.

Drawings

FIG. 1 is a graph of the processing result of Zh067 according to the present invention.

Detailed Description

As shown in fig. 1, the Zh067 well array induction logging data is processed to form a pore mobile fluid invasion profile imaging diagram (fig. 1, 6 th) in the radial 120in range of the tight reservoir, and a nuclear magnetic resonance experiment is performed on the well core sample to measure the mobile fluid saturation of the core sample (fig. 1, 5 th). Comparing and analyzing the movable fluid invasion imaging section and the nuclear magnetic resonance experiment data result, wherein the darker the movable fluid invasion section is, the higher the corresponding nuclear magnetic resonance movable fluid saturation is; the brighter the color of the moving fluid invasion section is, the lower the saturation of the corresponding nuclear magnetic resonance moving fluid is, and the coincidence degree of the two is higher. The 'tight reservoir pore movable fluid invasion profile imaging graph' formed by the method can visually reflect pore connectivity and movable fluid distribution characteristics in the radial 120-in range of the tight reservoir; the defects that the imaging logging detection depth is less than 5cm, and the connectivity of deep pores of the stratum and the distribution characteristics of movable fluid are difficult to reflect are overcome; compared with rock core assay and other means, the method has the advantages of short interpretation period and high acquisition degree, and has important popularization and application values.

Claims

1. A movable fluid invasion profile imaging method for compact reservoir pores is characterized by comprising the following steps: the method comprises the following steps:

step (1): and (3) data correction: carrying out data correction on the resistivity value of the induction logging of the whole well array, wherein the correction range of the resistivity value of the whole well is 0-255;

step (2): interpolation and resampling: taking the radial detection depth as an x coordinate, wherein x is less than or equal to 120 in; taking the corrected resistivity as a y coordinate as an interpolation sample point S (x, y); uniformly dividing the radial maximum detection depth equally to ensure that the radial sampling interval is consistent with or close to the longitudinal sampling interval as much as possible; utilizing the interpolation sample point data, taking the equally divided radial detection depth value as an interpolation resampling x ' coordinate, applying a piecewise linear interpolation method, taking a resistivity value after interpolation resampling as a y ' coordinate, and resampling to obtain S ' (x ', y ');

and (3): color graduation: the S ' (x ', y ') is scaled by color, and the resistivity values are scaled from dark to light in the order of increasing resistivity values, thereby forming a moving fluid invasion profile image.

2. The tight reservoir pore mobile fluid invasion profiling imaging method of claim 1, wherein: in the step (2), 120in is evenly divided into 23, 24 or 25 parts, and the corresponding radial sampling interval is 0.133m, 0.127m or 0.122m respectively.

3. The tight reservoir pore mobile fluid invasion profiling imaging method of claim 2, wherein: in the step (1), in the data correction process of the resistivity value of the whole well array induction logging, the resistivity minimum value is corrected to be 0, and the resistivity maximum value is corrected to be 255.

4. The tight reservoir pore mobile fluid invasion profiling method of claim 3, wherein: in step (3), in the color calibration process, 0 corresponds to black for RGB (0:0:0), and 255 corresponds to white for RGB (255:255: 255).