US 12,216,240 B2
Method and apparatus for obtaining real-time formation gas saturation
Sheng Zhan, Houston, TX (US); Jeremy Zhang, Houston, TX (US); Zongqi Chen, Houston, TX (US); and Xianghua Liu, Houston, TX (US)
Assigned to CHINA PETROLEUM & CHEMICAL CORPORATION, Beijing (CN)
Filed by CHINA PETROLEUM & CHEMICAL CORPORATION, Beijing (CN)
Filed on Dec. 16, 2022, as Appl. No. 18/067,346.
Application 18/067,346 is a continuation in part of application No. 17/653,561, filed on Mar. 4, 2022, granted, now 12,092,787.
Application 17/653,561 is a continuation in part of application No. 17/333,834, filed on May 28, 2021, granted, now 11,906,692.
Claims priority of provisional application 63/148,571, filed on Feb. 11, 2021.
Claims priority of provisional application 63/148,573, filed on Feb. 11, 2021.
Prior Publication US 2023/0123713 A1, Apr. 20, 2023
Int. Cl. G01V 5/10 (2006.01); G01V 5/04 (2006.01)
CPC G01V 5/102 (2013.01) [G01V 5/045 (2013.01); G01V 5/105 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for evaluating a formation gas saturation of a subterranean formation, comprising:
S1: deploying a nuclear logging tool into the subterranean formation, wherein the nuclear logging tool comprises one or more neutron source and three or more dual-function detectors configured to simultaneously detect neutrons and gamma rays
S2: causing the one or more neutron sources to emit neutrons into the subterranean formation;
S3: detecting neutrons and gamma rays from the subterranean formation at the three or more detectors to form electric signals;
S4: separating electric signals from neutrons and gamma rays for each of the three or more detectors;
S5: obtaining detector count rates of total neutrons, fast neutrons and thermal neutrons;
S6: obtaining the ratios of thermal neutrons and determining the formation porosity;
S7: obtaining detector count rates of capture gamma rays, and the energy spectrum from inelastic gamma rays and the energy spectrum of capture gamma rays;
S8: determining the formation type and obtaining the ratio of capture gamma rays from at least two of the detectors
S9: determining the formation gas saturation using formation type, porosity, the ratios of thermal neutrons and the ratios of capture gamma rays.