Abstract: Three types of volcanic rocks,i.e.basalt,trachyte,and tuff,are developed in the Shahejie Formation of Ou-Huang area in Liaohe depression.The trachyte that had gone through structural fracturing in la-ter stage forms high-grade reservoir in the area.To acquire accurate parameters that honestly reflect the reservoir space types and features,techniques such as SEM,cast lamella,and X-CT scanning,are integrated for fine description of the primary pores and fractures and secondary dissolution pores and fractures in the reservoir space of trachyte,and for obtaining reservoir physical properties in combination with RLT.The result indicates that the dissolved vuggy-fractured reservoir has the best poroperm properties,and the second best are the dissolved pore-micropore reservoirs.It also suggests that by adopting technologies like log response and multi-well constrained impedance inversion,together with proper choice of methods and parameters,the re-cognition and prediction of high-grade reservoirs in the study area(where conventional techniques are inefficient)is not only possible but consists well with the real drilling/well-logging data(with thickness error at 3% only).

Key words: trachyte, reservoir space, reservoir type, eastern sag, Liaohe depression