US 12,248,115 B2
Method and apparatus for using pulsed neutron generators and dual-function detectors to obtain formation mineralogy
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 Feb. 21, 2023, as Appl. No. 18/172,302.
Application 18/172,302 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 2023/0204813 A1, Jun. 29, 2023
Int. Cl. G01V 5/10 (2006.01); E21B 49/00 (2006.01)
CPC G01V 5/104 (2013.01) [E21B 49/00 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for evaluating a formation mineralogy 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 generators and two or more dual-function detectors configured to simultaneously detect neutrons and gamma rays
S2: causing the one or more neutron generators 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; obtaining space, time and energy dependent neutron fluence rates of fast neutrons and thermal neutrons;
S6: obtaining detector count rates of inelastic gamma rays and capture gamma rays, and the energy spectrum of inelastic gamma rays and the energy spectrum of capture gamma rays;
S7: calculating elemental concentrations of a plurality of elements in the formation using the energy spectrum of inelastic gamma rays and/or the energy spectrum of capture gamma rays, and the space, time and energy dependent neutron fluence rate of fast neutrons and/or the space, time and energy dependent neutron fluence rate of thermal neutrons; and
S8: determining the formation mineralogy based on the elemental concentration of the plurality of elements in the formation.