CN-121995504-A - Stratum true resistivity solving method, system, electronic equipment and storage medium

CN121995504ACN 121995504 ACN121995504 ACN 121995504ACN-121995504-A

Abstract

The invention relates to the technical field of geophysical well logging, and particularly discloses a method, a system, electronic equipment and a storage medium for solving true formation resistivity, wherein the method comprises the steps of calculating a pressure value of a target formation by using a formation fluid quality continuity equation, and obtaining three-phase saturation of the target formation according to the pressure value; substituting the three-phase saturation into an expression representing the association relation between the saturation and the resistivity to calculate so as to obtain the first formation resistivity of the target formation; and acquiring the target formation conductivity of the target formation, and determining the true formation resistivity of the target formation based on the first formation resistivity and the target formation conductivity. The method can reduce the calculation error of the formation resistivity, thereby obtaining the real formation resistivity and having extremely important effect on accurately evaluating the formation oil-gas property.

Inventors

HE ZHIMING
ZHAO YIDI
XIAO CHENGWEN
LIU YUE
CHEN WENHUI
LI XIAOFENG
GUO YUQING
WANG GUIQING
LI XINCHENG
WU YAN

Assignees

中国石油天然气集团有限公司
中国石油集团测井有限公司

Dates

Publication Date: 20260508
Application Date: 20241107

Claims (10)

1. The method for obtaining the true resistivity of the stratum is characterized by comprising the following steps of: calculating a pressure value of a target stratum by using a stratum fluid mass continuity equation, and obtaining the three-phase saturation of the target stratum according to the pressure value; substituting the three-phase saturation into an expression representing the association relation between the saturation and the resistivity to calculate so as to obtain the first formation resistivity of the target formation; And acquiring the target formation conductivity of the target formation, and determining the true formation resistivity of the target formation based on the first formation resistivity and the target formation conductivity.
2. The method for determining the true formation resistivity according to claim 1, further comprising: Constructing a stratum volume model of the well bore and stratum in a one-dimensional cylindrical coordinate system in the radial direction; and constructing a stratum fluid mass continuity equation by utilizing Darcy's law and a mass continuity-based seepage equation and combining the stratum volume model.
3. The method of claim 1, wherein the step of calculating the pressure value of the target formation using the formation fluid mass continuity equation comprises: the pressure value of the target formation is calculated using a chase method in combination with the formation fluid mass continuity equation.
4. The method of claim 1, wherein determining the true formation resistivity of the target formation based on the first formation resistivity and the target formation conductivity comprises: acquiring resistivity profile information of the first stratum resistivity and a differential geometry factor of the target stratum, and calculating first stratum conductivity according to the resistivity profile information and the differential geometry factor; and if not, adjusting the value of the first formation resistivity within a preset range, and returning to execute the step of acquiring the resistivity profile information of the first formation resistivity until the true formation resistivity is determined.
5. The stratum true resistivity solving system is characterized by comprising a first operation module, a second operation module and a third operation module; The first operation module is used for calculating a pressure value of a target stratum by using a stratum fluid mass continuity equation and obtaining the three-phase saturation of the target stratum according to the pressure value; The second operation module is used for substituting the three-phase saturation into an expression representing the association relation between the saturation and the resistivity to calculate so as to obtain the first formation resistivity of the target formation; the third operation module is used for acquiring target stratum conductivity of the target stratum and determining stratum true resistivity of the target stratum based on the first stratum resistivity and the target stratum conductivity.
6. The system for determining true formation resistivity according to claim 5, further comprising a building block configured to: Constructing a stratum volume model of the well bore and stratum in a one-dimensional cylindrical coordinate system in the radial direction; and constructing a stratum fluid mass continuity equation by utilizing Darcy's law and a mass continuity-based seepage equation and combining the stratum volume model.
7. The system for determining true formation resistivity according to claim 5, wherein the step of calculating a pressure value for the target formation using a formation fluid mass continuity equation in the first operational module includes: the pressure value of the target formation is calculated using a chase method in combination with the formation fluid mass continuity equation.
8. The formation true resistivity system of claim 5, wherein the step of determining the formation true resistivity of the target formation based on the first formation resistivity and the target formation conductivity in the third operational module includes: acquiring resistivity profile information of the first stratum resistivity and a differential geometry factor of the target stratum, and calculating first stratum conductivity according to the resistivity profile information and the differential geometry factor; and if not, adjusting the value of the first formation resistivity within a preset range, and returning to execute the step of acquiring the resistivity profile information of the first formation resistivity until the true formation resistivity is determined.
9. An electronic device comprising a processor coupled to a memory, the memory having stored therein at least one computer program loaded and executed by the processor to cause the electronic device to implement the stratigraphic true resistivity determination method of any one of claims 1 to 4.
10. A computer readable storage medium, wherein at least one computer program is stored in the computer readable storage medium, and the at least one computer program is loaded and executed by a processor, so that the computer readable storage medium implements the method for determining the true formation resistivity according to any one of claims 1 to 4.

Description

Stratum true resistivity solving method, system, electronic equipment and storage medium Technical Field The invention relates to the technical field of geophysical well logging, in particular to a method, a system, electronic equipment and a storage medium for solving true formation resistivity. Background In the petroleum drilling process, the well logging cannot be completed on time after the well is drilled due to special reasons, and the drilling fluid pressure is larger than the stratum pressure, so that drilling fluid mud invades into the stratum. The longer the drilling fluid mud is immersed in the well bore, the deeper the drilling fluid mud is immersed into the deep part of the stratum, the larger the drilling fluid mud is immersed, the larger the stratum fluid property is changed, and the larger the stratum resistivity is changed. Even if timely logging is completed on time after drilling is completed, drilling fluid mud can invade the stratum, and the stratum properties can be changed. If the drilling fluid slurry mineralization is greater than the formation water mineralization, the slurry invasion is drag-reducing invasion, whereas if the drilling fluid slurry mineralization is less than the formation water mineralization, the slurry invasion is drag-increasing invasion. Whether drag reduction invaded or drag increase invaded, oil, gas and water in formation pores can be completely or partially replaced by slurry filtrate, so that formation resistivity is changed, difficulty is brought to measurement of the true resistivity of the formation, and further, great errors are caused in evaluation of the formation oil-gas properties. The well logging is conducted in time after the well drilling is completed, the influence of mud invasion on the measurement of the true resistivity of the stratum can be greatly reduced, the radius of a flushing zone and the radius of an invasion zone are smaller, and the invasion depth is smaller. Depending on the formation characteristics, the flush zone radius and invaded depth will also vary. In modern drilling work, the requirements on drilling safety are stricter than before, especially the countermeasures for blowout and other extreme safety events are perfected, the timeliness is emphasized in the past, the safety of well control is protected, the proportion of used drilling fluid slurry is larger and larger, the drilling fluid pressure is larger than the formation pressure, and therefore the damage to undisturbed formations is larger and larger. The specific gravity of drilling fluid slurry is increased, the specificity of the superimposed stratum is increased, well logging is not performed in time due to a special reason sometimes, so that deep invasion of balanced drilling, invasion of high-mineralization brine slurry, long-time invasion of target layer slurry and leakage of target layer slurry are caused, the situation can further destroy the undisturbed stratum, the formation resistivity and the true formation resistivity measured by an electrical well logging method and an induction well logging method are greatly different, and the conclusion that the evaluation of the oil-gas content of the stratum is wrong is caused. Under the condition that an undisturbed stratum is damaged by the invasion of drilling fluid slurry, the stratum invasion profile and the stratum true resistivity are accurately calculated, and in particular, the radius of a quasi-flushing zone and the radius of an invasion zone are calculated, and then the quasi-flushing zone true resistivity and the invasion zone true resistivity are calculated, so that the method has an extremely important role in accurately evaluating the oil-gas properties of the stratum. In actual production, as mud filtrate in a well bore invades a stratum to damage a reservoir, particularly some reservoirs soaked by the mud filtrate for a long time, the characteristics of an oil-water reservoir on an array induction logging curve are not obvious, and an interpreter cannot effectively identify the reservoir by utilizing an array induction logging response. In order to eliminate the influence of mud invasion, in-situ personnel in oil fields generally adopt correction patterns, resistivity inversion and other methods to correct the array induction apparent resistivity. Mud invasion is a time-varying dynamic seepage process, and due to the complexity of the subsurface reservoirs, the effect of mud invasion on the well medium is very complex, making mud invasion correction plates more limited. After array induction logging appears, in order to determine the true resistivity of the stratum after the stratum is invaded by mud, under the drive of the Schlembeset, the logging world carries out extensive and intensive research on mud invasion: 1) Cui Likai in the numerical simulation and microcosmic mechanism of mud invasion based on a digital core, a digital core model obtained by core CT scanning is used as a basis, a latt