Reservoir Prediction in a Well-absent Area - A Case Study in a Marine Area

The inspiring but indeterminate scenery, that the reef extensively developed in our marine area with obvious bright-spot reflection and distinct seismic velocity drop could be filled by favorable gas, and the blurry reflections below the reef may correspond to periods of turbidity sand reservoir, needs to be more precisely and carefully appraised for further exploration. However, AVO inversion can not be efficiently applied here due to wells insufficiency. For the sake of AVO inversion in a well-absent area, the most conventional way is to construct some pseudo-wells by assuming seismic interval velocity as P-velocity at first, then compute S-velocity and density using empirical formulas, yet a rough formula for elastic parameters prediction could destroy inversion thoroughly, and the resolution of corresponding inverted result could be extremely low. Particularly, to overcome these limitations and efficiently appraise reservoir quality, an advanced well-absent AVO inversion method, which constructs pseudo-wells according to the seismic interval velocity, amplitude and known message, is put forward and applied. It is the first time to reasonably appraise the reservoir quality in our working area. The new well-absent inversion method could overcome the obstacles in the early phase of exploration, and is suitable for offshore exploration.