Abstract:

Algal limestone is widely distributed in Tertiary lacustrine strata in the west part of Qaidam Basin，and is one of the most important carbonate reservoir types.Reservoir property of the types is excellent，and single well productivity is high，so it is a new exploration field in Yuexi area.But algal limestone is thin in thickness，interbedded sedimentary rocks，and diversity in lithologies，so it is rather difficult to identify and evaluate.In this paper，starting from logging response characteristics of algal limestone，based upon identifying reservoir with lithologic logging overlapping with acoustic logging curve，algal limestone is identified by using 3-porosity curves overlapping each other.This method has good effect and provide a new thought and method for identifying the kind of complicated reservoir.

Key words: Algal-limestone reservoir, logging identification, curve overlapping, Yuexi area, Qaidam Basin