US 12,436,141 B1
Method for quantitative evaluation of self-sealing property of organic-rich shale
Kun Zhang, Chengdu (CN); Xinyang He, Chengdu (CN); Shu Jiang, Wuhan (CN); Yan Song, Beijing (CN); Hulin Niu, Chengdu (CN); Chengzao Jia, Beijing (CN); Zhenxue Jiang, Beijing (CN); Lin Jiang, Beijing (CN); Xueying Wang, Chengdu (CN); Xiong Ding, Chengdu (CN); Yi Shu, Wuhan (CN); Yi Zhang, Chengdu (CN); Yiting Qiao, Chengdu (CN); Jiayi Liu, Chengdu (CN); Jun Peng, Chengdu (CN); Bin Li, Chengdu (CN); Jinhua Liu, Chengdu (CN); Binsong Zheng, Chengdu (CN); Lei Chen, Chengdu (CN); Xuefei Yang, Chengdu (CN); Fengli Han, Chengdu (CN); Weishi Tang, Chengdu (CN); Jingru Ruan, Chengdu (CN); Hengfeng Gou, Chengdu (CN); Yi Xiao, Chengdu (CN); Lintao Li, Chengdu (CN); Yipeng Liu, Chengdu (CN); Ping Liu, Chengdu (CN); Meijia Wu, Chengdu (CN); Lu Lu, Chengdu (CN); Zeyun Wang, Chengdu (CN); and Laiting Ye, Chengdu (CN)
Assigned to Southwest Petroleum University, Chengdu (CN); China University of Geosciences (Wuhan), Wuhan (CN); and China University of Petroleum (Beijing), Beijing (CN)
Filed by Southwest Petroleum University, Chengdu (CN); China University of Geosciences (Wuhan), Wuhan (CN); and China University of Petroleum (Beijing), Beijing (CN)
Filed on Feb. 17, 2025, as Appl. No. 19/054,931.
Claims priority of application No. 202410696142.X (CN), filed on May 31, 2024.
Int. Cl. G01N 33/24 (2006.01); G01N 15/08 (2006.01); G01N 24/08 (2006.01)
CPC G01N 33/246 (2013.01) [G01N 15/08 (2013.01); G01N 24/081 (2013.01); G01N 2015/0866 (2013.01)] 6 Claims
 
1. A method for quantitative evaluation of self-sealing property of organic-rich shale, comprising:
S1, selecting geological parameters for evaluating the self-sealing property of the organic-rich shale, wherein the geological parameters comprise five geological parameters of adsorption gas content, overlying pressure, connectivity difference A, connectivity difference B and bound water content;
wherein the connectivity difference A is a difference between connectivity of shale itself and connectivity of roof strata;
wherein the connectivity difference B is a difference between the connectivity of the shale itself and connectivity of floor strata;
S2, taking a plurality of organic-rich shale samples, measuring the adsorption gas content, the overlying pressure, the connectivity difference A, the connectivity difference B and the bound water content of each of the plurality of organic-rich shale samples, and then carrying out standardization processing on each of the five geological parameters to obtain standardized geological parameters Zxij, wherein the standardized geological parameter for the j-th geological parameter is denoted as Pj, and a formula of the standardization processing is as follows:

OG Complex Work Unit Math
where xij is a value of an i-th sample of a j-th geological parameter before the standardization processing; Zxij is a value of the i-th sample of the j-th geological parameter after the standardization processing; min {x1j, x2j, . . . , xnj} is a minimum value of all sample data of the j-th geological parameter, max {x1j, x2j, . . . , xnj} is a maximum value in all sample data of the j-th geological parameter; and j=1, 2, 3, 4, 5;
S3, calculating a weight coefficient ωj′ of each of the five geological parameters to obtain five weight coefficients respectively corresponding to the five geological parameters, where ωj′=tj;
S4, sorting the five weight coefficients in descending order to obtain an ordered sequence: t1>t2>t3>t4>t5, wherein a standardized geological parameter corresponding to the weight coefficient t1 is P1, a standardized geological parameter corresponding to the weight coefficient t2 is P2, a standardized geological parameter corresponding to the weight coefficient t3 is P3, a standardized geological parameter corresponding to the weight coefficient t4 is P4, and a standardized geological parameter corresponding to the weight coefficient t5 is P5;
S5, calculating a self-sealing evaluation coefficient S, wherein a formula of the self-sealing evaluation coefficient S is as follows:

OG Complex Work Unit Math
S6, correcting the self-sealing evaluation coefficient S by taking a measured total gas content Q corresponding to different samples as a constraint, and establishing a functional relation between the self-sealing evaluation coefficient S and the measured total gas content Q by taking the self-sealing evaluation coefficient S as a dependent variable and the measured total gas content Q as an independent variable using a least square method, namely, a correction formula of the self-sealing evaluation coefficient S as follows:
S′=aQ+b,
where S′ is a corrected self-sealing evaluation coefficient, a is a slope, and b is an intercept; and calculation formulas of the a and the b are as follows:

OG Complex Work Unit Math
where Qi is a measured total gas content corresponding to the i-th sample, Q is an average value of the measured total gas content of all samples, Si is a self-sealing evaluation coefficient of the i-th sample before correction, and S is an average value of the self-sealing evaluation coefficients of all samples before correction;
S7, substituting the measured total gas content Q corresponding to the different samples into the correction formula established in the step S6 to obtain the corrected self-sealing evaluation coefficient S′, and establishing, according to the corrected self-sealing evaluation coefficient S′, a self-sealing evaluation standard of the organic-rich shale comprising four grades as follows:
an excellent self-sealing grade in response to the corrected self-sealing evaluation coefficient S′ greater than or equal to 0.6;
a good self-sealing grade in response to the corrected self-sealing evaluation coefficient S′ greater than or equal to 0.45 and less than 0.6;
a medium self-sealing grade in response to the corrected self-sealing evaluation coefficient S′ greater than or equal to 0.3 and less than 0.45;
a poor self-sealing grade in response to the corrected self-sealing evaluation coefficient S′ less than 0.3.