阅读说明：本技术 基于流体替换的井中流体因子敏感度计算方法及系统 (Well fluid factor sensitivity calculation method and system based on fluid replacement ) 是由 毕进娜 陈科 张瑶 林庆富 张杨 朱凌燕 王佳 于 2018-09-10 设计创作，主要内容包括：公开了一种基于流体替换的井中流体因子敏感度计算方法及系统。该方法包括：根据包含初始纵波速度、初始横波速度、初始密度的测井曲线,确定储层位置,建立初始模型；对初始模型进行Gassmann流体替换,获得替换模型,计算替换模型的纵波速度、横波速度、密度；根据初始纵波速度、初始横波速度、初始密度与替换模型的纵波速度、横波速度、密度,分别计算初始模型与替换模型的多个流体识别因子；根据流体因子敏感性公式,计算每个流体识别因子对应的敏感性。本发明通过Gassmann流体替换,确定流体识别因子及其敏感性,优选敏感性高的流体识别因子,有助于精确反应储层特征,寻找含油或者含气的储层,为常规油气、煤层气及页岩油气的勘探、开发服务。(A method and system for calculating fluid factor sensitivity in a well based on fluid replacement is disclosed. The method comprises the following steps: determining the position of a reservoir according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, and establishing an initial model; carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial transverse wave velocity, the initial density and the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula. The method determines the fluid identification factor and the sensitivity thereof through Gassmann fluid replacement, preferably selects the fluid identification factor with high sensitivity, is favorable for accurately reflecting the characteristics of the reservoir stratum, finds the reservoir stratum containing oil or gas and provides service for the exploration and development of conventional oil gas, coal bed gas and shale oil gas.)

1. A method for calculating fluid factor sensitivity in a well based on fluid replacement, comprising:

according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, and establishing an initial model;

carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model;

respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial shear wave velocity, the initial density and the longitudinal wave velocity, the shear wave velocity and the density of the replacement model;

and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula.

2. A method of calculating fluid factor sensitivity in a well based on fluid substitution as claimed in claim 1 wherein the compressional wave velocity of the substitution model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

3. A method of calculating fluid factor sensitivity in a well based on fluid substitution as claimed in claim 1 wherein the shear wave velocity of the substitution model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

4. A method of calculating fluid factor sensitivity in a well based on fluid substitution as claimed in claim 1 wherein the density of the substitution model is:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

5. The fluid replacement based in-well fluid factor sensitivity calculation method of claim 1 wherein the sensitivity for each fluid identification factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

6. A fluid factor sensitivity calculation system in a well based on fluid replacement, the system comprising:

a memory storing computer-executable instructions;

a processor executing computer executable instructions in the memory to perform the steps of:

according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, and establishing an initial model;

carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model;

respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial shear wave velocity, the initial density and the longitudinal wave velocity, the shear wave velocity and the density of the replacement model;

and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula.

7. The fluid replacement-based well fluid factor sensitivity calculation system of claim 6 wherein the compressional wave velocity of the replacement model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

8. The fluid replacement-based well fluid factor sensitivity calculation system of claim 6 wherein the shear wave velocity of the replacement model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

9. The fluid replacement-based in-well fluid factor sensitivity calculation system of claim 6, wherein the replacement model has a density of:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

10. The fluid replacement based in-well fluid factor sensitivity calculation system of claim 6 wherein the sensitivity for each fluid identification factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

Technical Field

The invention relates to the field of seismic exploration and development of oil gas, shale oil gas and coal bed gas, in particular to a well fluid factor sensitivity calculation method and system based on fluid replacement.

Background

The underground rock is actually a porous two-phase medium consisting of solid minerals and pore fluid, the existence of the pore fluid inevitably affects the mechanical characteristics of the porous rock, so that the medium rock shows certain elastic abnormality, and the abnormal characteristics related to the pore fluid can be characterized as fluid factors on the basis of the construction of a seismic rock physical model and the seismic wave response analysis of reservoir fluid, so that the key is how to select the sensitive fluid factors from the constructed fluid factors.

In the identification research of oil and gas reservoirs, fluid identification is mostly carried out by obtaining three basic elastic parameters (longitudinal wave velocity, transverse wave velocity and density) in reservoir AVO information or seismic data information, and in practical application, for reservoirs of different fluid types, the three parameters are limited in application, sometimes are not very sensitive and the like, and fluid identification analysis cannot be directly and effectively carried out. Therefore, in order to effectively highlight the difference in physical properties of different fluids, experts at home and abroad in recent years have variously combined the longitudinal wave velocity, the transverse wave velocity and the density, such as the longitudinal wave impedance, the transverse wave impedance, the poisson ratio and the like, and the fluid factor of the combination improves the sensitivity of fluid identification to a certain extent. However, in the face of an increasing number of fluid identification factors, in practical applications, how to select the most sensitive fluid identification factor is an important problem to be solved urgently. Therefore, there is a need to develop a method and system for calculating fluid factor sensitivity in a well based on fluid replacement.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention provides a method and a system for calculating the sensitivity of a fluid factor in a well based on fluid replacement, which can determine the fluid identification factor and the sensitivity thereof through Gassmann fluid replacement, preferably select the fluid identification factor with high sensitivity, are beneficial to accurately reflecting the characteristics of a reservoir stratum, search the reservoir stratum containing oil or gas and serve the exploration and development of conventional oil gas, coal bed gas and shale oil gas.

According to one aspect of the invention, a method for calculating fluid factor sensitivity in a well based on fluid substitution is provided. The method may include: according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, and establishing an initial model; carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial shear wave velocity, the initial density and the longitudinal wave velocity, the shear wave velocity and the density of the replacement model; and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula.

Preferably, the longitudinal wave velocity of the replacement model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

Preferably, the shear wave velocity of the replacement model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

Preferably, the density of the replacement model is:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

Preferably, the sensitivity corresponding to each fluid recognition factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

According to another aspect of the present invention, there is provided a fluid factor sensitivity calculation system in a well based on fluid replacement, the system comprising: a memory storing computer-executable instructions; a processor executing computer executable instructions in the memory to perform the steps of: according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, and establishing an initial model; carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial shear wave velocity, the initial density and the longitudinal wave velocity, the shear wave velocity and the density of the replacement model; and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula.

Preferably, the longitudinal wave velocity of the replacement model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

Preferably, the shear wave velocity of the replacement model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

Preferably, the density of the replacement model is:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

Preferably, the sensitivity corresponding to each fluid recognition factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

The method and apparatus of the present invention have other features and advantages which will be apparent from or are set forth in detail in the accompanying drawings and the following detailed description, which are incorporated herein, and which together serve to explain certain principles of the invention.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts.

FIG. 1 shows a flow chart of the steps of a fluid factor sensitivity calculation method in a well based on fluid substitution according to the present invention.

FIG. 2 shows a histogram of the sensitivity of 18 fluid identification factors according to one embodiment of the invention.

Detailed Description

The invention will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention 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 invention to those skilled in the art.

FIG. 1 shows a flow chart of the steps of a fluid factor sensitivity calculation method in a well based on fluid substitution according to the present invention.

In this embodiment, the fluid factor sensitivity calculation method in a well based on fluid replacement according to the present invention may include: step 101, deleting abnormal values in data in a logging curve according to the logging curve comprising initial longitudinal wave velocity, initial transverse wave velocity and initial density, determining a reservoir position and establishing an initial model; 102, performing Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; 103, respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial transverse wave velocity, the initial density and the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; and step 104, calculating the sensitivity corresponding to each fluid identification factor according to the fluid factor sensitivity formula.

In one example, the compressional wave velocity of the surrogate model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

In one example, the shear wave velocity of the replacement model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

In one example, the density of the replacement model is:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

In one example, the sensitivity for each fluid identification factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

Specifically, the fluid factor sensitivity calculation method in the well based on fluid replacement can comprise the following steps:

according to a logging curve containing initial longitudinal wave velocity, initial transverse wave velocity and initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, inputting the oil, gas and water content of the reservoir, setting the total content of the three to be 100%, setting the elastic parameters and modulus parameters (volume modulus and shear modulus) of oil, gas and water, setting the skeleton and the argillaceous characteristics of the rock, namely the elastic parameters (longitudinal wave velocity, transverse wave velocity and density) and the modulus parameters (volume modulus and shear modulus) of the rock, and obtaining an initial model.

Setting the content of oil, gas and water in the pores of the reservoir after the Gassmann fluid replacement, wherein the sum of the content of the oil, the gas and the water is 100%, performing Gassmann fluid replacement on the initial model according to a Gassmann fluid replacement formula and a Wood model to obtain a replacement model, calculating the longitudinal wave velocity of the replacement model through a formula (1), calculating the transverse wave velocity of the replacement model through a formula (2), and calculating the density of the replacement model through a formula (3).

And respectively calculating a plurality of fluid identification factors of the initial model and the replacement model according to the initial longitudinal wave velocity, the initial transverse wave velocity, the initial density and the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model and a fluid identification factor calculation formula.

According to a fluid factor sensitivity formula, calculating the sensitivity corresponding to each fluid identification factor through a formula (4), wherein the larger the value of the sensitivity is, the better the sensitivity of the fluid identification factor is, the stronger the capacity of distinguishing the two fluids is, and the fluid identification factor can be preferably selected and applied to other unknown logging in the same work area.

The method determines the fluid identification factor and the sensitivity thereof through Gassmann fluid replacement, preferably selects the fluid identification factor with high sensitivity, is favorable for accurately reflecting the characteristics of a reservoir stratum, finds the reservoir stratum containing oil or gas and provides service for the exploration and development of conventional oil gas, coal bed gas and shale oil gas.

Application example

To facilitate understanding of the solution of the embodiments of the present invention and the effects thereof, a specific application example is given below. It will be understood by those skilled in the art that this example is merely for the purpose of facilitating an understanding of the present invention and that any specific details thereof are not intended to limit the invention in any way.

The fluid factor sensitivity calculation method in the well based on fluid replacement can comprise the following steps:

according to a logging curve containing initial longitudinal wave velocity, initial transverse wave velocity and initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, inputting the oil, gas and water content of the reservoir, setting the total content of the three to be 100%, setting the elastic parameters and modulus parameters (volume modulus and shear modulus) of oil, gas and water, setting the skeleton and the argillaceous characteristics of the rock, namely the elastic parameters (longitudinal wave velocity, transverse wave velocity and density) and the modulus parameters (volume modulus and shear modulus) of the rock, and obtaining an initial model.

Setting the content of oil, gas and water in the pores of the reservoir after the Gassmann fluid replacement, wherein the sum of the content of the oil, the gas and the water is 100%, performing Gassmann fluid replacement on the initial model according to a Gassmann fluid replacement formula and a Wood model to obtain a replacement model, calculating the longitudinal wave velocity of the replacement model through a formula (1), calculating the transverse wave velocity of the replacement model through a formula (2), and calculating the density of the replacement model through a formula (3).

According to the initial longitudinal wave velocity, the initial shear wave velocity, the initial density and the longitudinal wave velocity, the shear wave velocity and the density of the replacement model, 18 fluid identification factors of the initial model and the replacement model are respectively calculated through a fluid identification factor calculation formula, as shown in table 1.

TABLE 1

Serial number	Fluid factor	Serial number	Fluid factor
					1	Velocity of longitudinal wave	10	Poisson's ratio of Lam's coefficient
2	Impedance of longitudinal wave	11	Gassman fluid term Poisson's ratio
				3	Lame coefficient density	12	Impedance ratio
4	Shear modulus density	13	Porosity of Gassman fluid phase
				5	Gassmann fluid items	14	Density of
6	Poisson ratio	15	Difference in impedance
				7	Transverse wave impedance	16	Russell factor
8	Velocity of transverse wave	17	HSFIF fluid factor
				9	Coefficient of compression of fluid	18	Poisson impedance

Wherein, the longitudinal wave velocity: v_p(ii) a Longitudinal wave impedance: i is_p＝ρ×V_p(ii) a First ramel coefficient density λ ρ:

second ramei coefficient density μ ρ:

gassman fluid item:

c is the square ratio of the longitudinal wave velocity and the transverse wave velocity of the dry rock; poisson ratio:transverse wave impedance: i is_s＝ρ×V_s(ii) a Transverse wave velocity: v_s(ii) a Coefficient of compression of fluid:first ramet coefficient poisson ratio λ σ:gassman fluid term poisson ratio f σ:

the square ratio of the longitudinal wave velocity and the transverse wave velocity of the dry rock; impedance ratio (longitudinal-transverse wave velocity ratio):

gassman fluid phase porosity K_f：

φ_cA critical porosity; density: rho; impedance difference: i is_p-I_s(ii) a Russell factor ρ f:

c is an adjustment parameter; HSFIF fluid factor σ_HSFIF：

To adjust the parameters; poisson impedance: PI ═ ρ (V)_p-cV_s)。

FIG. 2 shows a histogram of the sensitivity of 18 fluid identification factors according to one embodiment of the invention.

According to the fluid factor sensitivity formula, the sensitivity corresponding to each fluid identification factor is calculated through the formula (4), as shown in fig. 2, the larger the value of the sensitivity is, the better the sensitivity of the fluid identification factor is, the stronger the ability of distinguishing the two fluids is, the fluid identification factor can be preferably selected and applied to other unknown logging in the same work area.

In conclusion, the fluid identification factor and the sensitivity thereof are determined through Gassmann fluid replacement, and the fluid identification factor with high sensitivity is preferably selected, so that the reservoir characteristics can be accurately reflected, the reservoir containing oil or gas can be searched, and the exploration and development service of conventional oil gas, coal bed gas and shale oil gas can be realized.

It will be appreciated by persons skilled in the art that the above description of embodiments of the invention is intended only to illustrate the benefits of embodiments of the invention and is not intended to limit embodiments of the invention to any examples given.

According to an embodiment of the present invention, there is provided a fluid factor sensitivity calculation system in a well based on fluid replacement, the system comprising: a memory storing computer-executable instructions; a processor executing computer executable instructions in the memory to perform the steps of: according to a logging curve comprising an initial longitudinal wave velocity, an initial transverse wave velocity and an initial density, deleting abnormal values in data in the logging curve, determining a reservoir position, and establishing an initial model; carrying out Gassmann fluid replacement on the initial model to obtain a replacement model, and calculating the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; calculating a plurality of fluid identification factors according to the initial longitudinal wave velocity, the initial transverse wave velocity, the initial density and the longitudinal wave velocity, the transverse wave velocity and the density of the replacement model; and calculating the sensitivity corresponding to each fluid identification factor according to a fluid factor sensitivity formula.

In one example, the compressional wave velocity of the surrogate model is:

wherein, V_pFor replacing the longitudinal wave velocity of the model, K_satTo replace the bulk modulus of the model, μ_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

In one example, the shear wave velocity of the replacement model is:

wherein, V_sTo replace the shear wave velocity, μ, of the model_satTo replace the shear modulus of the model, ρ_satTo replace the density of the model.

In one example, the density of the replacement model is:

ρ_sat＝(1-φ)ρ_ma+φρ_fl(3)

where ρ is_satTo replace the density of the model, p_flIs the fluid density, p_maIs the skeleton density and phi is the porosity.

In one example, the sensitivity for each fluid identification factor is calculated by equation (4):

wherein mean is_waterMean being the mean of the flow factor of the water layer_gasoilMean value of fluid factor, std, of hydrocarbon reservoir_gasoilIs the variance of the reservoir fluid factor.

The system determines the fluid identification factor and the sensitivity thereof through Gassmann fluid replacement, preferably selects the fluid identification factor with high sensitivity, is favorable for accurately reflecting the characteristics of a reservoir stratum, finds the reservoir stratum containing oil or gas and provides service for the exploration and development of conventional oil gas, coal bed gas and shale oil gas.

It will be appreciated by persons skilled in the art that the above description of embodiments of the invention is intended only to illustrate the benefits of embodiments of the invention and is not intended to limit embodiments of the invention to any examples given.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. 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.