Development characteristics and orientation of tight oil and gas in China

SUN Longde,ZOU Caineng,JIA Ailin,WEI Yunsheng,ZHU Rukai,WU Songtao,GUO Zhi

Table 8 Comparison of tight oil geological conditions between North America and China.

Region Sedimentary basin Source rock characteristics Reservoir characteristics Geological background Sedimentation background Distribution area/km2 Litho- logy TOC/% Ro/% Main Lithology Physical properties Distribution America Stable structure Dominated by marine sediments (1-7)× 104 Mainly marine shale 2-20, TOC is high 0.6-1.7, high maturity Carbonate rock, sandstone, mixed rock Relatively good in physical properties and connectivity, high in porosity Stable distribution and good continuity China Late tectonic activity Dominated by terrestrial deposit Hundreds to tens of thousands Lake facies mud shale 0.4-16.0, wide variation in TOC 0.4-1.4, low maturity Carbonate rock, tight sandstone, mixed rock and tuff Poor physical properties, low porosity, strong heterogeneity and thin reservoir layer Strong heterogeneity Region Reservoir characteristics Fluid characteristics Economy Concentrated section thickness/m Porosity/ % Formation pressure Pressure coefficient Oil density/ (g?cm-3) Gas to oil ratio Single-well cumulative production/104 t Burial depth and reserves abundance America 5-20 5-13 Mainly overpressure 1.35-1.78 0.75-0.85 Dozens 2-10 Moderate, high reserves abundance China 10-80 3-12 Low pressure coefficient 0.70-1.80 0.75-0.92 Hundreds to thousands 1-4 Large difference in burial depth and reserves abundance