Cambrian strata of well TS1 are composed of Awatage Formation (middle Cambrian) and the lower Qiulitage Group (upper Cambrian). A detail investigation of cores and analysis of thin sections shows that Awatage Formation is mainly composed of dark gray to gray algal dolomite (micritic to fine-crystal), and Qiulitage Group is mainly composed of gray to light gray crystalline dolomite and ghost structure dolomite. Algal dolomites are present in moderate strength with brick-red to orange colors as the main features under cathodoluminescence together with δ¹⁸O value from -6.3‰ to -4.5‰ (average value is -5.3‰, VPDB), and contain a relatively high total rare earth elements (REE) with REE patterns similar to those of normal marine carbonate rocks. Crystalline dolomites and ghost dolomites show purple to red-brick color in dimly moderate strength under cathodoluminescene with lighter δ¹⁸O value from -9.2‰ to -5.7‰ (average value is -7.5‰, VPDB), together with relatively low total rare earth element/positive Eu anomaly and obvious loss of HREE. The difference between Awatage Formation and Lower Qiulitage Group indicates that the diagenesis-alteration process of dolomite reservoirs is different. This study suggests that the high quality reservoir of Awatage Formation in great depth might be controlled by several factors. Among them, dissolution of gypsum nodules and other unstable minerals by meteoric water or sea water in penecontemporaneous period established the foundation, followed by diagenesis-alteration strengthening constructively with fluid action, which even damaged the space by local filling and recrystallization.