储层中固体沥青研究现状、地质意义及其发展趋势

Research Status,Geological Significance and Development Trend of Solid Bitumen in Reservoirs

固体沥青包含了油气形成与演化等重要信息,其研究对油气勘探与开发具有重要的指导作用。综合国内外众多学者的研究,阐述了固体沥青的定义、成因与分类、反射率、对储层物性的影响及测井识别。固体沥青成因类型多样,归纳起来主要包括热成因和冷变质成因两大类。固体沥青反射率可以作为成熟度评价的有效参数,但需结合实际地质情况合理选择转换关系式。固体沥青充填在储集层孔隙空间中,堵塞孔隙喉道:一方面造成储集层的严重损害,导致油藏分布不均;另一方面作为封堵带,有利于油气的保存,形成隐蔽油气藏。固体沥青在核磁共振上具有独特的响应特征,利用核磁共振T1/T2值、中子-密度交会、密度孔隙度与气测孔隙度差值以及纵波时差-电阻率交会可以有效识别固体沥青。对于固体沥青后续研究,固体沥青结构、性质与固体沥青反射率的关系,以及如何使用测井参数定量标定固体沥青体积分数,是未来固体沥青在储层评价和油气开发研究的热点和难点。

The research of solid bitumen can provide the information about hydrocarbon formation and evolution,which can guide for hydrocarbon exploration and development.Based on the analyses at home and abroad,the definition,origin and classification of solid bitumen,influence of solid bitumen on reservoir properties,and identification of solid bitumen logging are comprehensively expounded.There are various genetic types of solid asphalt,which can be divided into two categories:thermal and cold metamorphism.Solid bitumen reflectance can be used as an index to judge maturity,but transformation relationship should be determined based on the actual geological situation.Solid bitumen can fill up reservoir pores,and pore throats can be blocked.This can result in reservoirs destructed and uneven distributed,however,solid bitumen can be favorable sealing belts for preservation and formation of subtle reservoirs.Solid bitumen has special response characters in nuclear magnetic resonance,and can be identified by NMR T1/T2index,neutron-density cross plot,difference between density porosity and gas porosity,and longitudinal wave slowness-resistivity cross plot.Further analyses on solid bitumen should concentrate on the relationship between its structure and reflectance.The way to calibrate solid bitumen with logging parameters quantitatively will be the difficult and hot spot in the future solid bitumen analyses.