CN-122017969-A - Method for synchronously inverting five reservoir parameters of submarine gas reservoir based on longitudinal wave speed and density

CN122017969ACN 122017969 ACN122017969 ACN 122017969ACN-122017969-A

Abstract

The application relates to the technical field of submarine gas reservoir exploration and discloses a method for synchronously inverting submarine gas reservoir five reservoir parameters based on longitudinal wave speed and density, which comprises the steps of obtaining the actual measured longitudinal wave speed, density data, reservoir distribution range and reservoir parameters of a submarine gas reservoir, and constructing a longitudinal wave speed model and a volume density model of a gas reservoir rock; the method comprises the steps of obtaining reservoir parameter constraint boundary data, setting five reservoir parameters as unknowns to be inverted, constructing a multidimensional nonlinear optimization problem of minimized sum of squares by a correlation model and measured data, setting a value range, adopting an interior point method to carry out iterative solution, outputting five reservoir parameter inversion values and optimal consolidation coefficients, obtaining a two-dimensional/three-dimensional longitudinal wave speed and density profile obtained by inversion of seismic data, calling the optimal consolidation coefficients to carry out repeated inversion, and outputting a two-dimensional/three-dimensional reservoir parameter distribution profile for gas reservoir reserve evaluation and development optimization. The application can meet the actual requirements of deep water natural gas exploration and development.

Inventors

YAN YUNING
ZHAO ZHONGXIAN
HAO GANG
WEI LELE

Assignees

中国科学院南海海洋研究所

Dates

Publication Date: 20260512
Application Date: 20260112
Priority Date: 20251014

Claims (10)

1. A method for synchronously inverting five reservoir parameters of a submarine gas reservoir based on longitudinal wave speed and density, which is characterized by comprising the following steps: acquiring actual measured longitudinal wave speed, actual measured density data and reservoir distribution range of a submarine gas reservoir through logging equipment, and measuring actual free gas saturation, porosity and mineral component proportion data of a rock skeleton to verify inversion accuracy; Setting free gas saturation, porosity, clay content, carbonate content and gas-water mixing coordination factors in the longitudinal wave velocity model and the volume density model as unknowns needing inversion, associating the longitudinal wave velocity model with actual measured longitudinal wave velocity, associating the volume density model with actual measured density data, constructing an optimization problem corresponding to multidimensional nonlinearity with the aim of minimizing the sum of squares of calculated values and actual measured values of the model, and setting the value range of each inversion unknowns by combining the longitudinal wave velocity model and the volume density model; After the optimization problem is built, simultaneously acquiring reservoir parameters and iteration initial values in logging data, wherein the iteration initial values are randomly selected in a value range corresponding to reservoir parameter constraint boundary data; the optimal inversion value and the optimal consolidation coefficient of five reservoir parameters are output, the five reservoir parameter inversion value is used for verifying the inversion precision, and the optimal consolidation coefficient is used for two-dimensional/three-dimensional reservoir parameter prediction; In the two-dimensional/three-dimensional reservoir parameter prediction process, acquiring submarine gas reservoir seismic data acquired by seismic equipment, carrying out inversion processing on the submarine gas reservoir seismic data to obtain a two-dimensional or three-dimensional longitudinal wave velocity profile and a two-dimensional or three-dimensional density profile, calling the optimal consolidation coefficient, substituting the two-dimensional or three-dimensional longitudinal wave velocity profile, the two-dimensional density profile or the three-dimensional density profile into an optimization problem of longitudinal wave velocity model and volume density model construction, repeating the inversion processing process, inverting five reservoir parameters of each depth point in each seismic CDP (seismic common depth point, common depth point) channel, and outputting a two-dimensional reservoir parameter distribution profile or a three-dimensional reservoir parameter distribution profile of the submarine gas reservoir, wherein the two-dimensional reservoir parameter distribution profile or the three-dimensional reservoir parameter distribution profile is used for gas reservoir storage assessment and development optimization.
2. The method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density of claim 1, further comprising: The mineral component proportion data includes bulk modulus of clay Modulus of shear Bulk modulus of quartz Modulus of shear And bulk modulus of carbonate Modulus of shear ; The expression of the simplified two-phase Biot equation is: (1) In the formula 1, the components are mixed, Is the overall bulk modulus of the rock, Is the bulk modulus of the rock framework mineral matrix, Is the shear modulus of the mineral matrix of the rock framework, The Biot coefficient was approximated for the bulk modulus, For the equivalent bulk modulus of the material, In order to achieve a degree of porosity, the porous material, Is the bulk modulus of the gas-water mixed fluid, For the overall shear modulus of the rock, Is the shear modulus of the mineral matrix of the rock framework, Approximating the Biot coefficient for the shear modulus; Bulk modulus of the rock matrix mineral matrix And shear modulus Calculated by a Hill formula, the Hill formula has the expression: ; (2) In the formula 2, the components are mixed, 、 The volume fractions of clay and carbonate in the rock framework are respectively.
3. The method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density of claim 2, further comprising: the bulk modulus approximates the Biot coefficient Approximation of the Biot coefficient to the shear modulus The expression of (2) is: (3) In the formula 2, the components are mixed, Is the consolidation coefficient of the target point, Consolidation coefficients at points of the reservoir distribution range, For a range of reservoir distribution, Is the depth of the target point, Is porosity; The bulk modulus of the mixed fluid is expressed as: (4) In the formula 4, the components are mixed, Is the bulk modulus of the gas-water mixed fluid, In order to achieve the saturation of the free gas, Is the bulk modulus of liquid water, Is the bulk modulus of free gas, (-) ; The expression of the density formula is: (5-1) In the formula 5-1, the components, In order to achieve a reservoir volume density, In the form of the volume fraction of the clay, In order to achieve a density of the clay, Is the density of the quartz and is used for the treatment of the surface, For the density of the carbonate salt, Is the density of the liquid water and is equal to the density of the liquid water, Is the density of the free gas.
4. A method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density according to claim 3, the method further comprising: The calculation expression of the longitudinal wave speed in the longitudinal wave speed model is as follows: (5-2) In the case of 5-2, For the reservoir longitudinal wave velocity, Is the overall bulk modulus of the rock, Is the overall shear modulus of the rock; the objective function expression of the multidimensional nonlinear optimization problem is that (6) In the formula 6, the components are, As a function of the object to be processed, In order to actually measure the velocity of the longitudinal wave, As the calculated value of the longitudinal wave velocity model, In order to measure the density data of the object, Calculated values for the bulk density model; The value range of each inversion unknown number is 0 , , , In the formula (I), in the formula (II), The upper limit of free gas saturation in the boundary data is constrained for the reservoir parameters.
5. A method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density according to claim 3, the method further comprising: Consolidation coefficient of the reservoir distribution range point The value range of (2) is 3-less ≤11; The reservoir parameters comprise the measured free gas saturation, porosity, volume fraction of clay and volume fraction of carbonate in the logging data; And the error minimization is realized by calculating the error between the inversion result and the reservoir parameter, and when the error is not reduced along with the iteration number and is stable within a preset range, the convergence state is judged, and the error is calculated based on the deviation between the inversion result and the reservoir parameter.
6. The method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density of claim 1, further comprising: When the interior point method is adopted to carry out iterative solution on the optimization problem, a plurality of groups of iteration initial values are randomly selected in a value range corresponding to the reservoir parameter constraint boundary data, and after the solution is carried out, the result with the minimum objective function value is selected as an optimal solution; Inversion processing of the submarine gas reservoir seismic data comprises obtaining a two-dimensional or three-dimensional longitudinal wave velocity profile and a two-dimensional or three-dimensional density profile by adopting a post-stack seismic inversion method if the submarine gas reservoir seismic data are post-stack seismic data; And if the seismic data are pre-stack seismic data, obtaining a two-dimensional or three-dimensional longitudinal wave velocity profile and a two-dimensional or three-dimensional density profile by adopting an inversion method of amplitude along with offset.
7. The method of synchronously inverting five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity and density according to claim 1, wherein during the repeating inversion process, the method further comprises: Repeatedly executing the following steps of constructing a longitudinal wave speed model and a volume density model based on the mineral physical property parameter data; setting free gas saturation, porosity, clay content, carbonate content and gas-water mixing coordination factors as unknowns needing inversion, constructing a multidimensional nonlinear optimization problem aiming at minimizing a model calculation value and a section data square sum; The two-dimensional reservoir parameter distribution profile or the three-dimensional reservoir parameter distribution profile comprises spatial distribution information of free gas saturation, porosity, clay content, carbonate content and gas-water mixing coordination factors in a submarine gas reservoir area, wherein the spatial distribution information corresponds to earthquake CDP channels and depth points one by one.
8. Device of five reservoir parameters of submarine gas reservoir synchronous inversion based on longitudinal wave speed, density, its characterized in that includes: The data acquisition and physical model construction module acquires the actual measured longitudinal wave speed, the actual measured density data and the reservoir distribution range of the submarine gas reservoir through logging equipment, and measures the actual free gas saturation, the actual porosity and the mineral component proportion data of the rock framework to verify inversion accuracy; The system comprises a constraint data acquisition and optimization problem construction module, a longitudinal wave velocity model and a volume density model, wherein the constraint data acquisition and optimization problem construction module acquires reservoir parameter constraint boundary data of a submarine gas reservoir, the reservoir parameter constraint boundary data comprises a free gas saturation upper limit, a porosity value range and a mineral component proportion value range, the free gas saturation, the porosity, clay content, carbonate content and gas-water mixing coordination factors are set as unknowns needing inversion in the longitudinal wave velocity model and the volume density model, the longitudinal wave velocity model is associated with actual measured longitudinal wave velocity, the volume density model is associated with actual measured density data, an optimization problem corresponding to multidimensional nonlinearity with a minimum model calculation value and an actual measurement value square sum as targets is constructed, and the value range of each inversion unknowns is set by combining the reservoir parameter constraint boundary data; The optimization solving and core parameter outputting module is used for simultaneously acquiring reservoir parameters and iteration initial values in the logging data after the optimization problem is built, wherein the iteration initial values are randomly selected in a value range corresponding to the reservoir parameter constraint boundary data; the optimal inversion value and the optimal consolidation coefficient of five reservoir parameters are output, the five reservoir parameter inversion value is used for verifying the inversion precision, and the optimal consolidation coefficient is used for two-dimensional/three-dimensional reservoir parameter prediction; The method comprises the steps of obtaining submarine gas reservoir seismic data acquired by seismic equipment in a two-dimensional/three-dimensional reservoir parameter prediction process, carrying out inversion processing on the submarine gas reservoir seismic data to obtain a two-dimensional or three-dimensional longitudinal wave velocity profile and a two-dimensional or three-dimensional density profile, calling the optimal consolidation coefficient, substituting the two-dimensional or three-dimensional longitudinal wave velocity profile, the two-dimensional density profile or the three-dimensional density profile into an optimization problem of longitudinal wave velocity model and volume density model construction, repeating the inversion processing process, inverting five reservoir parameters of each depth point in each seismic CDP channel, and outputting a two-dimensional reservoir parameter distribution profile or a three-dimensional reservoir parameter distribution profile of the submarine gas reservoir, wherein the two-dimensional reservoir parameter distribution profile or the three-dimensional reservoir parameter distribution profile is used for gas reservoir assessment and development optimization.
9. A system for synchronized inversion of five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity, density, comprising a memory, a processor, and a program stored on the memory for synchronized inversion of five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity, density, which program when run by the processor implements the steps of the method of any of claims 1-7.
10. A computer storage medium, characterized in that it has stored thereon a program for simultaneous inversion of five reservoir parameters of a subsea gas reservoir based on longitudinal wave velocity, density, which program, when being executed by a processor, implements the steps of the method according to any of claims 1-7.

Description

Method for synchronously inverting five reservoir parameters of submarine gas reservoir based on longitudinal wave speed and density Technical Field The application relates to the technical field of submarine gas reservoir exploration, in particular to a method for synchronously inverting submarine gas reservoir five-reservoir parameters based on longitudinal wave speed and density. Background Natural gas is of great interest as a low-pollution high-heating-value energy source, and submarine gas reservoirs are huge in reserves, and free gas saturation and porosity are key parameters for evaluating reserves and development potential. The current technology mainly depends on logging and seismic exploration, namely, logging precision is high, cost is high, coverage is limited, seismic exploration range is wide, cost is low, and accurate quantification of reservoir parameters is difficult, so that a method for constructing quantitative inversion key parameters based on longitudinal wave speed and density data is needed. The conventional prediction method based on earthquake petrophysical has obvious defects that the practical applicability is limited due to the fact that the empirical coefficient without explicit physical meaning is relied on, stratum mineral components or porosity data which are difficult to master comprehensively are required to be acquired in advance, or complex elastic impedance profile data is relied on, and in addition, the reservoir parameters are generally high in heterogeneity, so that the key reservoir parameters are difficult to invert synchronously with high precision and high efficiency, and the practical requirements of deep water natural gas exploration and development cannot be met. From the above, how to realize meeting the practical requirements of deep water natural gas exploration and development remains to be solved. Disclosure of Invention In order to meet the actual requirements of deep water natural gas exploration and development, the application provides a method for synchronously inverting five reservoir parameters of a submarine gas reservoir based on longitudinal wave speed and density. In a first aspect, the application provides a method for synchronously inverting parameters of five reservoirs of a submarine gas reservoir based on longitudinal wave speed and density, which adopts the following technical scheme: A method for synchronously inverting five reservoir parameters of a submarine gas reservoir based on longitudinal wave speed and density, comprising the following steps: acquiring actual measured longitudinal wave speed, actual measured density data and reservoir distribution range of a submarine gas reservoir through logging equipment, and measuring actual free gas saturation, porosity and mineral component proportion data of a rock skeleton to verify inversion accuracy; Setting free gas saturation, porosity, clay content, carbonate content and gas-water mixing coordination factors in the longitudinal wave velocity model and the volume density model as unknowns needing inversion, associating the longitudinal wave velocity model with actual measured longitudinal wave velocity, associating the volume density model with actual measured density data, constructing an optimization problem corresponding to multidimensional nonlinearity with the aim of minimizing the sum of squares of calculated values and actual measured values of the model, and setting the value range of each inversion unknowns by combining the longitudinal wave velocity model and the volume density model; After the optimization problem is built, simultaneously acquiring reservoir parameters and iteration initial values in logging data, wherein the iteration initial values are randomly selected in a value range corresponding to reservoir parameter constraint boundary data; the optimal inversion value and the optimal consolidation coefficient of five reservoir parameters are output, the five reservoir parameter inversion value is used for verifying the inversion precision, and the optimal consolidation coefficient is used for two-dimensional/three-dimensional reservoir parameter prediction; In the two-dimensional/three-dimensional reservoir parameter prediction process, acquiring submarine gas reservoir seismic data acquired by seismic equipment, carrying out inversion processing on the submarine gas reservoir seismic data to obtain a two-dimensional or three-dimensional longitudinal wave velocity profile and a two-dimensional or three-dimensional density profile, calling the optimal consolidation coefficient, substituting the two-dimensional or three-dimensional longitudinal wave velocity profile, the two-dimensional density profile or the three-dimensional density profile into an optimization problem of longitudinal wave velocity model and volume density model construction, repeating the inversion processing process, inverting five reservoir parameters of each depth point in each seismic CDP (s