致密油聚集特征及潜力盆地选择标准

Tight Oil Accumulation Characteristics and Selection Criteria for Potential Basins

根据北美成熟页岩区块勘探开发总结的8大参数，提出了致密油10大聚集特征：特定页岩类型；有机质丰度达到一定指标；有机质热成熟度在生油窗之内；有机质类型以I型和Ⅱ型为主；富有机质页岩厚度达到一定规模；页岩间存在孔渗较好夹层；存在超高压条件；页岩具有高杨氏模量和低泊松比；脆性矿物含量高；原油为轻质油。在此基础上，揭示致密油和页岩气在烃源岩品质和储集层经济开发特征方面的差异。分析了北美致密油富集石油地质条件，给出致密油盆地页岩潜力评价标准：有机碳含量大于2％，镜质体反射率为0．5％-1.3％，致密油相对密度小于0．87g/cm3，黏度小于10mPa·S，参照此标准筛选出全球98个具有致密油勘探潜力的盆地，致密油集中分布在中生界和古生界。

Based on statistic and compared all available definitions of tight oil given by oil exploration scholars across the world, it can be defined that tight oil, which can be economically recovered only by large fracturing, is continuously accumulated within the source rock as well as its top and bottom, with tight clastic rock and carbonate rock as the reservoir rock, permeability less than 1 mD and porosity less than 12%. According to 8 parameters summarized after successful exploration and development of mature shale blocks in North America, the tight oil is of 10 accumulation characteristics： （a） special shale type is required; （b） organic matter abundance reaches a given level; （c） organic matter thermal maturity lies in the oil window; （d） organic matter type is mainly Type I and Type II; （e） organic-rich shale thickness reaches a given scale; （f） interbeds with good porosity and permeability exist between shale rocks; （g） overpressure conditions exist; （h） shale has high Young＇s modulus and low Poisson＇s ratio; （i） brittle minerals content is high; （j） crude oil is light. On these bases, this paper points out the differences between tight oil and shale gas in source rock quality and reservoir characteristics for economic development, and presents the assessment criteria for potential shale in tight oil basins from analyzing the geological conditions of tight oil accumulation in North America： TOC〉2% Ro： 0.5%-1.3%, pr〈0.87 g/cm3,/Xo〈10 mPa· s. According to this criteria, 98 basins with tight oil exploiation po- tential have been screened out across the world, their tight oils are mainly distributed in Mesozoic and Paleozoic.