CN-117709043-B - Ground stress calculation method based on directional well overall process stratum floor drain test

CN117709043BCN 117709043 BCN117709043 BCN 117709043BCN-117709043-B

Abstract

The application provides a ground stress calculation method based on a whole-process stratum floor drain test of a directional well, which comprises the following steps of carrying out a whole-process floor drain test on a target directional well, recording test data, calculating horizontal minimum ground stress and overburden pressure according to the test data of the whole-process stratum floor drain and rock mechanical characteristic parameters of the target directional well, calculating fracture pressure values under all possible arrangement and combination conditions of horizontal maximum ground stress and horizontal minimum ground stress in a well oblique direction of the target directional well according to well Zhou Yingli distribution and tensile failure criteria of a stratum floor drain test well section, drawing a contour map of the fracture pressure, thereby establishing a ground stress query plate of the target directional well, and querying horizontal maximum ground stress corresponding to the calculated horizontal minimum ground stress in the ground stress query plate. The method calculates the ground stress based on the test data of the whole-process floor drain test of the target directional well, and effectively improves the accuracy of the ground stress calculation result.

Inventors

XIONG ZHENYU
QIU KANG
LI JIWEI
WANG KEXIN
LI QIAN
HE YANGZI

Assignees

中石化石油工程技术服务有限公司
中石化海洋石油工程有限公司石油工程技术研究院

Dates

Publication Date: 20260508
Application Date: 20220906

Claims (7)

1. Ground stress calculation method based on directional well overall process stratum floor drain test, wherein the ground stress comprises horizontal minimum ground stress Horizontal maximum ground stress And overburden ground stress The method is characterized by comprising the following steps of: s1, performing a whole-process floor drain test on a target directional well, and recording test data of a whole-process stratum floor drain of the target directional well; s2, acquiring a leakage test curve of the target directional well according to the test data, and calculating leakage pressure according to the leakage test curve Formation fracture pressure Crack extension pressure Crack closure pressure And fracture stress ; S3, calculating horizontal minimum ground stress And rock tensile strength : , ; S4, acquiring rock mechanical characteristic parameters of the target directional well, and calculating cohesion CS and internal friction angle of the current stratum rock : , ; In the formula, The current stratum acoustic wave speed is represented by m, which is a regional correction coefficient; s5, calculating overburden pressure OBG: ; in the formula, For the formation layer velocity or the inversion velocity, Is the density of the seawater, and the seawater is the density of the seawater, The gravity acceleration is g, a and b are constants, h1 is water depth, h2 is initial vertical depth of the density logging data, and h3 is measuring point vertical depth; Overburden formation stress Overburden pressure OBG; s6, according to the well Zhou Yingli distribution and the tensile failure criterion of the stratum floor drain test well section, minimum ground stress is based on the level Tensile strength of rock Cohesion CS and internal friction angle of the rock of the current stratum And overburden ground stress Calculating the horizontal maximum ground stress of the target directional well in the well deviation direction Horizontal minimum ground stress Burst pressure values for all possible permutations ; S7, drawing horizontal maximum ground stress of the target directional well in a well deviation direction Horizontal minimum ground stress A contour map of fracture pressure for all possible permutations and combinations, thereby creating a geostress query template for the target directional well; s8, according to the horizontal minimum ground stress calculated in the step S3 Querying the ground stress query pattern plate for the minimum ground stress of the level Corresponding horizontal maximum ground stress 。
2. The method for calculating the ground stress according to claim 1, wherein the step S1 comprises the following sub-steps: S11, in the whole floor drain test process, the pumping quantity is recorded once at intervals of 20-50L, or the pumping quantity and the injection quantity are recorded once at intervals of 10S; S12, continuing pumping after stratum fracturing until a pressure stable section is recorded, stopping pumping, and recording pumping pressure once every 10 seconds of stopping pumping until the pumping pressure stable section is recorded; after the pumping pressure is relatively stable, restarting pumping the stratum, continuing pumping the drilling fluid until stopping the pumping at the pressure plateau section again, and recording the re-tensioning pressure every 10 seconds; S13, recording pressure and displacement change conditions in the whole-process floor drain test process, wherein test data of the whole-process stratum floor drain of the target directional well comprise a fracture pressure value, a fracture extension pressure, an instantaneous pump stopping starting pressure, an inflection point of pressure drop after pump stopping, a fracture re-tensioning pressure after restarting and a fracture extension pressure.
3. The method for calculating the ground stress according to claim 1, wherein the step S2 comprises the following sub-steps: S21, reading leakage apparent pressure on a leakage test curve Apparent pressure of formation fracture Crack extension gauge pressure Apparent pressure of crack closure And fracture re-tensioning gauge pressure ; S22, the leakage pressure The method comprises the following steps: ; The formation fracture pressure The method comprises the following steps: ; The crack extension pressure The method comprises the following steps: ; the crack closing pressure The method comprises the following steps: ; Crack stress The method comprises the following steps: ; In the above-mentioned description of the invention, And H is the sagging depth of the leak testing layer for the density of drilling fluid.
4. The method of claim 1, wherein in step S4, the current formation acoustic velocity is calculated The acquisition mode is that the rock core near the stratum floor drain test well section of the target directional well is collected and directly measured through an indoor triaxial test.
5. The method of claim 1, wherein in step S4, the current formation acoustic velocity is calculated The acquisition mode is that the acoustic logging data of the target directional well is collected and is used for obtaining.
6. The method of claim 1, wherein in step S4, the current formation acoustic velocity is calculated The acquisition mode is that the acoustic logging data of the adjacent well closest to the target directional well is collected and is obtained by using the acoustic logging data.
7. The method for calculating the ground stress according to claim 1, wherein the step S6 comprises the following sub-steps: s61, making: ; in the formula, In order to achieve a well inclination angle, Is the well circumference angle, takes the value of , For a well inclination azimuth relative to a horizontal maximum ground stress azimuth, Is poisson's ratio; The three-way main stress on the inclined shaft wall is expressed as: ; in the formula, For the pressure of the liquid column of drilling fluid, K is the well wall permeability coefficient and the value is 0-1; And (3) making: ; S62, shearing a directional well wall, and stretching a failure criterion: rock shear failure criteria: ; Tensile failure criteria for rock: ; S63, drilling fluid density meeting shear failure criterion in step S62 The method comprises the following steps: ; drilling fluid Density meeting the tensile failure criterion in step S62 The method comprises the following steps: ; in the formula, Is the effective stress coefficient; S64, calculating horizontal maximum ground stress of the target directional well in a well deviation direction Horizontal minimum ground stress Burst pressure in all possible permutations : (1) When (when) When the value of the well periphery angle is satisfied In the time-course of which the first and second contact surfaces, From the following components Calculating the minimum well circumference The value is recorded as ; (2) When (when) When the value of the well periphery angle is satisfied In the time-course of which the first and second contact surfaces, From the following components Calculating the minimum well circumference The value is recorded as ; (3) When the value of the well circumference angle is satisfied In the time-course of which the first and second contact surfaces, From the following components Calculating the minimum well circumference The value is recorded as ; (4) Fracture pressure The method comprises the following steps: 。

Description

Ground stress calculation method based on directional well overall process stratum floor drain test Technical Field The invention relates to the technical field of research on wall stability in petroleum engineering rock mechanics and oil and gas well engineering, in particular to a ground stress calculation method based on a directional well overall process stratum floor drain test. Background The traditional ground stress calculation method is generally based on the interpretation of geophysical well logging, and the change trend of well logging data can better represent parameters such as formation pressure, formation fluid properties and the like, but larger errors exist in the representation of ground stress. Particularly, the middle ground stress is the average value of the maximum ground stress and the minimum ground stress, but the average value is often different from the actual situation, and the error is larger. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a method for calculating a ground stress based on a directional well overall process floor drain test, which can accurately obtain the ground stress. In order to achieve the above object, the present invention provides a method for calculating a ground stress based on a directional well overall process formation floor drain test, the ground stress including a horizontal minimum ground stress σ h, a horizontal maximum ground stress σ H, and an overburden ground stress σ v, the method for calculating a ground stress comprising the steps of: s1, performing a whole-process floor drain test on a target directional well, and recording test data of a whole-process stratum floor drain of the target directional well; S2, acquiring a leakage test curve of a target directional well according to the test data, and calculating leakage pressure P L, stratum fracture pressure P F, fracture extension pressure P E, fracture closure pressure P C and fracture re-tensioning pressure P R according to the leakage test curve; S3, calculating horizontal minimum ground stress sigma h and rock tensile strength S t：σh＝PC,St＝PF-PR; S4, acquiring rock mechanical characteristic parameters of the target directional well, and calculating cohesion CS and internal friction angle phi of the current stratum rock: Wherein V p1 is the current stratum acoustic velocity, and m is the region correction coefficient; s5, calculating overburden pressure OBG: Wherein V p2 is stratum velocity or inversion velocity, ρ w is sea water density, ρ i is stratum density, g is gravity acceleration, a and b are constants, h1 is water depth, h2 is initial vertical depth of density logging data, and h3 is measuring point vertical depth; Overburden earth stress σ v = overburden pressure OBG; S6, calculating a fracture pressure value P f under all possible arrangement and combination conditions of horizontal maximum ground stress sigma H and horizontal minimum ground stress sigma h of the target directional well in a well inclination direction according to well Zhou Yingli distribution and tensile failure criteria of a stratum floor drain test well section based on the horizontal minimum ground stress sigma h, the rock tensile strength S t, the cohesion CS and internal friction angle phi of the current stratum rock and the overlying stratum ground stress sigma v; S7, drawing a contour map of the fracture pressure under all possible arrangement and combination conditions of horizontal maximum ground stress sigma H and horizontal minimum ground stress sigma h under the well inclination direction of the target directional well, so as to establish a ground stress query plate of the target directional well; And S8, inquiring the horizontal maximum ground stress sigma H corresponding to the horizontal minimum ground stress sigma h in the ground stress inquiry chart according to the horizontal minimum ground stress sigma h calculated in the step S3. The application calculates the ground stress based on the test data of the whole-process floor drain test of the target directional well, the test data of the whole-process floor drain test has strong correlation with the mechanical strength characteristics of stratum rock and the ground stress state, the stratum rock condition can be truly reflected, the ground stress is more direct and reliable compared with the explanation of logging data, and the accuracy of the ground stress calculation result is finally improved. In the technical scheme, the optimized step of the whole-process floor drain test of the target directional well is as follows, wherein the step S1 comprises the following sub-steps: S11, in the whole floor drain test process, the pumping quantity is recorded once at intervals of 20-50L, or the pumping quantity and the injection quantity are recorded once at intervals of 10S; S12, continuing pumping after stratum fracturing until a pressure stable section is recor