A method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic methods

Abstract

The present invention relates to the field of oil and gas field development and applied geophysics, and specifically to a method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic data. The method comprises the following steps: designing active and passive seismic combined oil and gas reservoir monitoring acquisition parameters according to the target area range of oil and gas reservoir monitoring; continuous acquisition of passive seismic data and phased acquisition of active seismic data; processing each phase of active seismic data; using each phase of active seismic processing results as constraints to process passive seismic data; performing dynamic monitoring and interpretation of oil and gas reservoirs; and adjusting development plans according to the interpretation results. The method of the present invention combines active seismic and passive seismic data to achieve higher-precision monitoring of oil and gas reservoir dynamics, reduce monitoring costs, and make up for the deficiencies of the prior art.

Description

Technical Field

[0001] The invention relates to the field of oil and gas field development and applied geophysics, and in particular to a method for dynamically monitoring oil and gas reservoirs by combining active and passive seismic operations. Background Art

[0002] Reservoir dynamic monitoring is to establish a quantitative, precise and dynamic reservoir model during the reservoir development process, and predict the performance of reservoir development through reservoir numerical simulation, optimize the development plan, find remaining oil and improve oil and gas recovery. At present, the main method of dynamic monitoring of oil and gas reservoirs in the industry is to directly measure the parameters of oil and gas reservoirs using permanent downhole measuring instruments, such as a downhole reservoir monitor disclosed in CN211422629U, which includes an upper joint, a circuit board, a pressure sensor, a lower joint, a resistivity tomography device, a power supply unit, an acquisition and control unit, a wire guide tube, a thread, a wellbore casing and a production pipe; the upper joint is arranged at the upper end of the production pipe, the lower joint is arranged at the lower end of the production pipe, the production pipe is connected to the upper pipe and the lower pipe through a thread, the edge of the production pipe is provided with a wire guide tube, and the other edge is provided with a circuit board; the pressure sensor is fixed at the bottom end of the upper joint, the pressure sensor is electrically connected to the circuit board through the wire guide tube, and the wellbore casing is sleeved on the outside of the production pipe and is separated from the production pipe by a gap. CN102758617A discloses a method for fine temperature logging using distributed optical fiber; the measured oil and gas parameters include pressure, stratified flow, remaining oil distribution, oil-water interface, etc.

[0003] Reservoir geophysics technology is developed on the basis of exploration geophysics technology. Reservoir geophysics serves oil and gas development. The use of geophysical technology for dynamic monitoring of oil and gas reservoirs is an important technical guarantee for accurately, reliably and dynamically understanding the changes in underground oil and gas reservoir characteristics and optimizing development plans.

[0004] Chinese invention patent CN109471170B discloses a seismic data processing method and device, the seismic data processing method comprising: when the acquisition azimuths of the first seismic data body and the second seismic data body after seismic mutual equalization processing are different, performing a two-azimuth acquisition footprint attenuation processing on the first seismic data body after seismic mutual equalization processing, and performing a two-azimuth acquisition footprint attenuation processing on the second seismic data body after seismic mutual equalization processing; performing a pre-stack two-azimuth amplitude change with offset distance AVO mutual equalization processing on the first seismic data body and the second seismic data body after the two-azimuth acquisition footprint attenuation processing.

[0005] Chinese invention patent CN103149587B discloses a random coupled four-dimensional seismic inversion reservoir monitoring method and device based on grid points. The method includes: a random coupled four-dimensional seismic inversion method based on grid points, obtaining the change of wave impedance through two coupled random three-dimensional seismic inversions; repeating the above steps to obtain multiple wave impedance change data bodies; obtaining a probability body of wave impedance change in any interval based on the multiple wave impedance change data bodies; and monitoring reservoir changes using the probability body of wave impedance change in any interval.

[0006] Chinese invention patent CN101872024B discloses a method for well site deployment using time-lapse seismic, which includes the following steps: 1) obtaining seismic data at two different time points according to the methods of steps a and b: a. determining basic formation parameters of the area to be tested; making a reservoir profile of the area to be tested, and establishing a formation profile module based on the reservoir profile; obtaining three data bodies of P-wave velocity, S-wave velocity and density according to the basic formation parameters and the formation profile module; b. performing AVO forward modeling to obtain superimposed seismic data of various incident angles; 2) processing the two seismic data to obtain the difference in seismic data; 3) inverting the difference in seismic data to obtain P-wave impedance difference, S-wave impedance difference, density difference and P-S wave velocity ratio difference; 4) predicting changes in reservoir parameters; 5) deploying well sites.

[0007] At present, the main time-lapse seismic method is active time-lapse seismic, which relies on artificially excited seismic waves to obtain underground oil and gas reservoir information. Active time-lapse seismic has the advantages of high precision and high certainty, but it also has the disadvantages of high cost and is not suitable for dynamic monitoring of oil and gas reservoirs. It has not been widely used in actual production. Therefore, a simpler and more effective method of oil and gas reservoir dynamics is currently needed. Summary of the invention

[0008] The main purpose of the present invention is to provide a method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic. The method of the present invention combines active seismic and passive seismic to achieve higher-precision monitoring of oil and gas reservoir dynamics, reduce monitoring costs, and make up for the shortcomings of the prior art.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic methods, which comprises the following steps:

[0011] Design active and passive seismic combined oil and gas reservoir monitoring acquisition parameters according to the target area of ​​oil and gas reservoir monitoring;

[0012] Continuous acquisition of passive seismic data and phased acquisition of active seismic data;

[0013] Process each period of active seismic data;

[0014] The passive seismic data are processed using the active seismic processing results of each period as constraints;

[0015] Conduct dynamic monitoring and interpretation of oil and gas reservoirs;

[0016] Adjust the development plan based on the interpretation results.

[0017] Furthermore, the active and passive seismic combined oil and gas reservoir monitoring acquisition parameters include: the longitudinal and lateral spacing and number of ground detectors; the longitudinal and lateral spacing and number of ground seismic sources; the vertical depth spacing, number and layout depth range of well detectors; and the number and interval of active seismic acquisition.

[0018] Furthermore, the ground detectors are laid out once without rolling reception; the in-well detectors use three components and are laid out in a string at intervals along the well wall, close to the well wall.

[0019] Furthermore, continuous passive seismic data acquisition means that all ground and well detectors remain in position and receive data uninterruptedly during the entire monitoring process.

[0020] Furthermore, when active seismic data are collected in stages, the locations of the detection points and source points in each stage remain unchanged.

[0021] Furthermore, active seismic data processing includes but is not limited to the following processing: calculating the difference between active seismic attributes of the previous and next two periods and near-surface correction, energy compensation, space correction, matched filtering, amplitude equalization and velocity correction of the two periods of data.

[0022] Furthermore, the processing of passive seismic data includes but is not limited to the following: positioning of microseismic events generated during reservoir development, near-surface correction, denoising, energy enhancement, effective event identification, velocity modeling; passive seismic data interferometric imaging and denoising, energy enhancement, effective event identification, velocity modeling and a series of preprocessing methods.

[0023] Furthermore, the active seismic processing results constrain the passive processing in one of the following ways:

[0024] 1) Use the seismic velocity and near-surface correction obtained from active seismic data for microseismic event location and interferometric imaging of passive data;

[0025] 2) Using the target reflection layer obtained by active seismic as a standard to constrain the passive seismic interferometric imaging processing;

[0026] 3) The spatial range of oil and gas reservoir transformation obtained by active seismic time-lapse processing is used as a solution space constraint for microseismic event positioning.

[0027] Furthermore, the dynamic monitoring interpretation method of oil and gas reservoirs includes one of the following methods:

[0028] 1) Dynamically display the location of microseismic events obtained from passive seismic data during the entire monitoring period at certain time intervals;

[0029] 2) Dynamically display the attributes of passive seismic data during the entire monitoring period at certain time intervals.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The method of the present invention jointly collects active and passive seismic data, utilizes the high precision and high certainty of active seismic to constrain the processing of passive seismic, reduces the uncertainty of passive seismic results, and realizes high-frequency time-lapse seismic dynamic monitoring of oil and gas reservoirs throughout the entire development cycle of oil and gas reservoirs, takes into account both economy and monitoring effect, and is easier to realize industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0033] Figure 1 This is a flow chart of the method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic methods as described in Example 1 of the present invention.

[0034] Figure 2 A diagram showing the locations of ground seismic sources and geophones in Embodiment 2 of the present invention;

[0035] Figure 3 This is a diagram showing the position of the geophone in the well in Example 2 of the present invention;

[0036] Figure 4 The active seismic raw data in Example 2 of the present invention;

[0037] Figure 5 The passive seismic raw data in Example 2 of the present invention;

[0038] Figure 6 It is a correlation coefficient attribute diagram of the second-period active earthquake and the first-period active earthquake waveforms in Example 2 of the present invention;

[0039] Figure 7 It is a passive seismic stacking section after the active seismic reflection layer constraint processing in Example 2 of the present invention;

[0040] Figure 8 Seismic velocity field obtained for active earthquakes;

[0041] Fig. 9 The passive microseismic event location results under active earthquake constraints;

[0042] Fig.10 Passive seismic energy profile obtained 20 minutes after steam injection into the reservoir;

[0043] Fig.11 Passive seismic energy profile obtained after 40 minutes of steam injection into the reservoir;

[0044] Fig.12 Passive seismic energy profile obtained 60 minutes after steam injection into the reservoir. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0047] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0048] Example 1

[0049] like Figure 1 As shown, the method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic operations includes the following steps:

[0050] 1) Design active and passive seismic combined oil and gas reservoir monitoring acquisition parameters according to the target area of ​​oil and gas reservoir monitoring.

[0051] Design the vertical and horizontal spacing and number of ground geophones; the vertical and horizontal spacing and number of ground seismic sources; the vertical depth spacing, number and depth range of well geophones; the number and intervals of active seismic acquisition.

[0052] The ground detectors are laid out once without rolling reception; the in-well detectors use three components and are laid out in a string at certain intervals along the well wall, close to the well wall.

[0053] 2) Continuous acquisition of passive seismic data and phased acquisition of active seismic data.

[0054] Passive seismic data continuous acquisition means that all ground and well detectors remain in the same position and receive data uninterruptedly during the entire monitoring process.

[0055] When active seismic acquisition is carried out in stages, the locations of the detection points and source points in each stage remain unchanged.

[0056] 3) Process each period of active seismic data.

[0057] 4) The passive seismic data are processed using the active seismic processing results of each period as constraints.

[0058] 5) Dynamic monitoring and interpretation of oil and gas reservoirs based on active and passive seismic processing results.

[0059] 6) Adjust the development plan based on the results of dynamic monitoring and interpretation of oil and gas reservoirs.

[0060] Example 2

[0061] Taking a domestic oil field as an example, the method of using active and passive seismic combined to monitor heavy oil steam huff and puff thermal recovery includes the following steps:

[0062] (1) Obtain the area of ​​the monitored reservoir and design Figure 2 and Figure 3 The active and passive seismic combined oil and gas reservoir monitoring observation system shown.

[0063] (2) Carry out continuous passive seismic data acquisition and phased active seismic data acquisition, Figure 4 In order to collect the raw data of active seismic data, two phases of active seismic data were designed, one before steam injection and one after steam injection; Figure 5 It is the passive seismic raw data collected continuously.

[0064] (3) Calculate the similarity coefficient of the two periods of active seismic data collected before and after, Figure 6 is the plane graph of similarity coefficients, Figure 6 The area within the middle dotted line is an area with a smaller similarity coefficient, which is the steam wave range.

[0065] (4) The steam wave range and seismic velocity field (such as Figure 8 As shown in Figure 3), the standard reflection layer is used as a constraint to process passive seismic.

[0066] (5) Figure 7 The passive seismic profile obtained after active seismic constraint processing shows that the standard reflection layers are basically consistent, which reduces the uncertainty of passive seismic.

[0067] (6) Fig. 9 The passive microseismic event location results obtained by post-processing active earthquake constraints. The event distribution range is Figure 6 The dotted line range is roughly the same.

[0068] (7) Fig.10 -Attached Fig.12 The passive seismic energy profiles are obtained after 20 minutes, 40 minutes and 60 minutes of steam injection into the reservoir. It can be seen that the range of the steam chamber gradually increases with time. The morphology and spatial distribution of the steam chamber are dynamically described, and the favorable area for the distribution of remaining oil is predicted.

[0069] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for dynamic monitoring of oil and gas reservoirs by combining active and passive seismic methods, characterized in that: The following steps are involved: Design active and passive seismic combined oil and gas reservoir monitoring acquisition parameters according to the target area of ​​oil and gas reservoir monitoring; Continuous acquisition of passive seismic data and phased acquisition of active seismic data; Process each period of active seismic data; The passive seismic data are processed using the active seismic processing results of each period as constraints; Conduct dynamic monitoring and interpretation of oil and gas reservoirs; Adjust the development plan based on the interpretation results; The active and passive seismic combined oil and gas reservoir monitoring acquisition parameters include: the vertical and horizontal intervals and numbers of ground geophones; the vertical and horizontal intervals and numbers of ground seismic sources; the vertical depth intervals, numbers and layout depth ranges of geophones in the well; the number and intervals of active seismic acquisition; When active earthquakes are collected in stages, the locations of the receiver points and source points in each stage remain unchanged; Active seismic data processing includes: calculating the difference between active seismic attributes before and after the two periods, as well as near-surface correction, energy compensation, space correction, matched filtering, amplitude equalization and velocity correction of the two periods of data; Passive seismic data continuous acquisition means that all ground and well detectors remain in the same position and receive data uninterruptedly during the entire monitoring process; The processing of passive seismic data includes: positioning of microseismic events generated during reservoir development, near-surface correction, denoising, energy enhancement, effective event identification, and velocity modeling; passive seismic data interferometric imaging and denoising, energy enhancement, effective event identification, and velocity modeling; The active seismic processing results can be used to constrain the passive processing in one of the following ways: 1) Use the seismic velocity and near-surface correction obtained from active seismic data for microseismic event location and interferometric imaging of passive data; 2) Using the target reflection layer obtained by active seismic as a standard to constrain the passive seismic interferometric imaging processing; 3) The spatial range of oil and gas reservoir transformation obtained by active seismic time-lapse processing is used as the solution space constraint for microseismic event location; The dynamic monitoring interpretation methods of oil and gas reservoirs include one of the following methods: 1) Dynamically display the location of microseismic events obtained from passive seismic data during the entire monitoring period at certain time intervals; 2) Dynamically display the attributes of passive seismic data during the entire monitoring period at certain time intervals.

2. The method according to claim 1, characterized in that The ground detectors are laid out once without rolling reception; the in-well detectors use three components and are laid out in a string at intervals along the well wall, close to the well wall.

Images