US 11,940,590 B1
Fast forward method and system for gamma-ray logging of highly-deviated and horizontal wells preliminary class
Cairui Shao, Qingdao (CN); Miantao Yu, Qingdao (CN); and Fuming Zhang, Qingdao (CN)
Assigned to CHINA UNIVERSITY OF PETROLEUM(EAST CHINA), Qingdao (CN)
Filed by CHINA UNIVERSITY OF PETROLEUM(EAST CHINA), Qingdao (CN)
Filed on Sep. 20, 2023, as Appl. No. 18/470,946.
Claims priority of application No. 202211214456.9 (CN), filed on Sep. 30, 2022.
Int. Cl. G01V 5/06 (2006.01); E21B 49/00 (2006.01)
CPC G01V 5/06 (2013.01) [E21B 49/00 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A fast forward method for gamma-ray logging of highly-deviated and horizontal wells, comprising the following steps:
step S1: based on an effective detection space of a gamma detector, in the effective detection space, obtaining a one-dimensional equivalent longitudinal contribution coefficient (varying with a distance between a formation and the center of the detector) of a gamma-ray flux received by the gamma detector under the condition of a straight well;
step S2: converting an integral of a gamma-ray flux received by the detector under the condition of a deviated well into an equivalent integral of the gamma-ray flux of a same space under the condition of the straight well; and
step S3: performing fast forward for gamma-ray logging of highly-deviated and horizontal wells under the condition of parallel sedimentary formations by using the obtained equivalent integral under the condition of the straight well, and then obtaining a forward value of a measurement point according to the one-dimensional equivalent longitudinal contribution coefficient, where the deviated well refers to a well whose wellbore is non-orthogonal to the formation, and the straight well refers to a well whose wellbore is orthogonal to the formation.