Abstract:

The carbonate reservoir spaces in the upper Ordovician Lianglitage Group carbonate formation within Tazhong No.I slope break zone include pores, caves and fractures, and micro pores. The micro ones contain intragranular pores, moldic pores, intergranular, pores intercrystal pores and micro fractures. The above results are based on the study of carbonate reservoir diagenesis of 16 wells in the region. It reveals that the micro-pores in limestone were developed in a burial environment. It is indicated that burial corrosion should contribute to the reservoir spaces. The evidences are as follows. 1)The carbonate cements contained abundant high temperature inclusions. 2)The character of oxygen and carbon isotope abundance in carbonate cements indicated cements and pores developed in burial environment. 3)Abundant dolomite in carbonate rock formed due to burial diagenesis, which indirectly demonstrated the pores formed due to burial corrosion. 4)Massive H₂S distributed in the Lianglitage Group carbonate rocks. In addition, laser Raman spectroscopy analysis indicates the components of corrosion fluid inclusions include CO₂,H₂S and organic acid.

Key words: Tarim basin, Tazhong No.I slope break zone, Ordovician, limestone, micro-pores, diagenetic sequence, carbonates, burial corrosion