CN-116068617-B - Elastic parameter prediction method and device considering boundary conditions of low-frequency experiment

CN116068617BCN 116068617 BCN116068617 BCN 116068617BCN-116068617-B

Abstract

The application relates to an elasticity parameter prediction method and device considering boundary conditions of a low-frequency experiment, wherein the method comprises the steps of obtaining pipeline fluid volume information for the low-frequency equipment, obtaining corresponding elasticity parameters through the pipeline fluid volume information based on a preset elasticity parameter model, wherein the preset elasticity parameter model is constructed based on the boundary conditions of the low-frequency experiment, and in the low-frequency experiment, the elasticity parameters influenced by the boundary conditions can be predicted effectively by fully considering the boundary conditions through inputting the pipeline fluid volume information into the preset elasticity parameter model constructed based on the boundary conditions, so that more accurate and powerful support is provided for distinguishing lithology and detecting oil gas by utilizing seismic information afterwards.

Inventors

TAN WENHUI
LIU WEIHUA
SHEN HUI
BAI JUN
ZHANG FANGNAN

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司石油物探技术研究院

Dates

Publication Date: 20260512
Application Date: 20211029

Claims (9)

1. A method for predicting elastic parameters in consideration of boundary conditions of a low-frequency experiment, the method comprising: acquiring fluid volume information of a pipeline for low-frequency equipment; Based on a preset elastic parameter model, acquiring corresponding elastic parameters through the pipeline fluid volume information, wherein the preset elastic parameter model is constructed based on low-frequency experiment boundary conditions; the construction of the preset elastic parameter model comprises the following steps: Acquiring the relative change of the volume of a sample under the boundary condition of a low-frequency experiment, wherein the boundary condition comprises the conditions that the sample is in boundary seal and the sample is in open, and the relative change of the volume of the sample is characterized by the change proportion of the volume change of fluid and the volume change of an experimental rock sample skeleton in the low-frequency experiment process; the preset elastic parameter model is constructed through the relative change of the volume of the sample based on the total pressure to which the sample is subjected and the volume change modulus of the saturated fluid.
2. The method of claim 1, wherein obtaining the relative change in sample volume at the boundary condition while the sample is in the boundary seal comprises: And acquiring the volume change of the fluid and the volume change of the experimental rock sample skeleton in the low-frequency experimental process, and obtaining the relative volume change of the sample when the sample is in boundary sealing based on the volume change and the volume change.
3. The method of claim 2, wherein the change in volume of the fluid is a sum of a pore fluid volume and a conduit fluid volume change, and wherein the change in volume of the fluid is characterized by: variation of experimental rock sample skeleton volume: Wherein, the And Is the change in the total fluid volume, Is the volume of the sample that is to be measured, Is the porosity of the rock, which is referred to as the porosity, Is the volume of the fluid conduit and, Is the pore volume of the sample and, Is the change of solid skeleton volume, which is equal to fluid pressure ) And skeleton stress The resulting change in volume is referred to as a change in volume, Is the bulk modulus of the fluid and, Is the bulk modulus of the solid framework, Is the stress to which the sample skeleton is subjected, Is the fluid pressure.
4. A method according to claim 3, wherein the relative change in sample volume when the sample is in the boundary seal is characterized by: 。
5. The method of claim 4, wherein the relative change in sample volume while the sample is in an open state comprises: Wherein, the Is the bulk modulus of the sample in terms of drainage, Is the rate of change of the sample volume caused by the framework stress, Is the rate of change of the volume of the solid framework caused by the fluid pressure.
6. The method of claim 5, wherein the predetermined elastic parameter model is characterized by: 。
7. an elastic parameter prediction apparatus taking into account boundary conditions of a low frequency experiment, the apparatus comprising: The fluid pipeline volume acquisition module is used for acquiring pipeline fluid volume information for the low-frequency equipment; The elastic parameter module is used for obtaining corresponding elastic parameters through the pipeline fluid volume information based on a preset elastic parameter model, wherein the preset elastic parameter model is constructed based on low-frequency experiment boundary conditions; the construction of the preset elastic parameter model comprises the following steps: Acquiring the relative change of the volume of a sample under the boundary condition of a low-frequency experiment, wherein the boundary condition comprises the conditions that the sample is in boundary seal and the sample is in open, and the relative change of the volume of the sample is characterized by the change proportion of the volume change of fluid and the volume change of an experimental rock sample skeleton in the low-frequency experiment process; the preset elastic parameter model is constructed through the relative change of the volume of the sample based on the total pressure to which the sample is subjected and the volume change modulus of the saturated fluid.
8. A terminal device comprising a processor and a memory; the memory is configured to store computer instructions and the processor is configured to execute the computer instructions stored by the memory to implement the method of predicting an elastic parameter taking into account boundary conditions of a low frequency experiment as claimed in any one of claims 1 to 6.
9. A computer readable storage medium storing one or more programs executable by one or more processors to implement the method of elasticity parameter prediction taking into account low frequency experimental boundary conditions of any one of claims 1 to 6.

Description

Elastic parameter prediction method and device considering boundary conditions of low-frequency experiment Technical Field The invention belongs to the field of applied geophysical seismic exploration, and particularly relates to an elastic parameter prediction method and device considering low-frequency experimental boundary conditions. Background Since the low frequency experimental method has many advantages in measuring the mechanical properties of rock (MIKHALTSEVITCH et al, 2014), the measurement method is mainly based on forced vibration, and in recent years, the low frequency equipment has been widely used in laboratories (Subramaniyan et al, 2014). The method is used for measuring the stress-strain relation of a sample under confining pressure oscillation and calculating elastic parameters according to the relation. One of the key techniques in low frequency experiments is how to interpret the data correctly, where the boundary conditions of the saturated sample being measured have a crucial influence on the measurement results. Dunn (1986) and White (1986) studies have shown that the use of forced vibration on rock samples, open boundary conditions, can result in radial fluid movement, thereby causing dispersion and attenuation of the elastic modulus. Pimienta et al (2016) show that the connection of the fluid conduit to the sample has a significant effect on the modulus parameter obtained from the saturated fluid sample, because the location of the conduit portion is not separated by the sample between the sample and the nearest valve, creating a fluid reservoir space, also known as the "residual volume", that is in direct communication with the void space of the sample. Consider the Gassmann theory (Gassmann, 1951) as being primarily used to verify the validity of experimental data measured on saturated fluid samples. Taken together, the above studies have found the effect of the existence of boundary conditions in low frequency experiments, but have not been quantified accurately using mathematical formulas. Therefore, it is necessary to directly and effectively quantify the relationship between the "remaining fluid capacity volume" and the elasticity parameter of the saturated fluid sample with respect to the influence of the "remaining fluid capacity volume" on the elasticity parameter acquired by the saturated fluid sample. Disclosure of Invention Based on the above, it is necessary to provide an elasticity parameter prediction method and device considering the boundary conditions of low-frequency experiments, which can fully consider the boundary conditions, effectively quantitatively analyze the relationship between the residual fluid volume and the elasticity parameters of the saturated fluid sample, namely, effectively predict the elasticity parameters affected by the boundary conditions, and provide more accurate and powerful support for distinguishing lithology and detecting oil gas by using the seismic information. The first aspect of the invention provides an elasticity parameter prediction method considering low-frequency experiment boundary conditions, which comprises the following steps: acquiring fluid volume information of a pipeline for low-frequency equipment; and obtaining corresponding elastic parameters through the pipeline fluid volume information based on a preset elastic parameter model, wherein the preset elastic parameter model is constructed based on low-frequency experimental boundary conditions. Optionally, the constructing of the preset elastic parameter model includes: Acquiring the relative change of the volume of a sample under the boundary condition, wherein the boundary condition comprises the conditions that the sample is in boundary sealing and the sample is in opening, and the relative change of the volume of the sample is characterized by the ratio between the change of the volume of fluid and the change of the volume of an experimental rock sample skeleton in the low-frequency experimental process; the preset elastic parameter model is constructed through the relative change of the volume of the sample based on the total pressure to which the sample is subjected and the volume change modulus of the saturated fluid. Optionally, acquiring the relative change in sample volume under boundary conditions while the sample is in the boundary seal comprises: And acquiring the volume change of the fluid and the volume change of the experimental rock sample skeleton in the low-frequency experimental process, and obtaining the relative volume change of the sample when the sample is in boundary sealing based on the volume change and the volume change. Optionally, the volume change of the fluid is a sum of a pore fluid volume and a tube fluid volume change, and in particular, the volume change of the fluid is characterized by: variation of experimental rock sample skeleton volume: ΔVs＝ΔVs1+ΔVs2 Wherein, the ΔVs2＝-VΔPs/Ks Further, deltaV f is the change in total fluid v