The Paleogene-Neogene lacustrine source rocks in the Mangai area of the Qaidam Basin are significant exploration targets. A comprehensive evaluation of four major intervals (E$_3^2$, N$_1$, N$_2^1$, N$_2^2$) was conducted through systematic organic geochemistry, maceral identification, thermal maturity analysis, and burial-thermal history modeling. Results show TOC contents of 0.203~1.28% (avg. 0.74%), chloroform bitumen "A" of 0.0164~0.2495% (avg. 0.132%), and total hydrocarbon contents of 69.29~1637.48 $\mu$g/g (avg. 853.39 $\mu$g/g), indicating fair to good quality. Kerogen elemental analysis (H/C=0.97~1.21), maceral composition (sapropelinite+exinite=70~98%), and saturated hydrocarbon ch... More >

The ultra-deep tight sandstone gas reservoirs in the Tarim Basin, exemplified by the Keshen A gas reservoir, face escalating challenges of water invasion and pressure maintenance after years of production. Interlayers within these reservoirs serve as critical geological barriers, yet their spatial distribution remains poorly resolved due to limitations in conventional identification methods. This study integrates core, logging, 3D seismic, and production data within a sequence stratigraphic and reservoir geology framework to establish a ``core-logging-seismic'' collaborative identification system for argillaceous interlayers. Two main interlayer types—argillaceous and physical—are identi... More >