The Origin of Micro Pores in the Upper Ordovician Lianglitage Group Carbonate Reservoir within Tazhong No.I Slope Break Zone,Tarim Basin,China

Bo, Zhou

The carbonate reservoir storage space in the upper Ordovician Lianglitage Group carbonate formation within Tazhong No.I slope break zone (central Tarim basin in China) covers pores, caves and fractures, and micro pores in carbonate reservoirs include the intragranular pores, moldic pores, intergranular, pores intercrystal pores and micro fractures.To demonstrate the development mechanism of the pores, we studied the carbonate reservoirs diagenesis of 16 wells in the region. Rock slices examination; cements geochemical analysis and diagenetic evolution sequence research all reveal that the micro-pores in limestone developed in burial environment. The thesis emphasizes the burial corrosion contributed to the reservoirs and also puts forward a series of evidences accordingly. These evidences including:(1) The carbonate cements contained abundant high temperature inclusions; (2) The characteristics of oxygen and carbon isotope abundance in carbonate cements indicated cement and pore developed in burial environment ;(3) Abundant dolomite in carbonate rock formed due to burial diagenesis, which indirectly demonstrated the pores formed because of 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. Finally the regional difference of burial corrosion within No.I slope break zone was recognized according to the contents of burial cement.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013