Large array 3D VSP and Full three-dimensional surface seismic Joint acquisition,processing and interpretation of the volcanic gas reservoir——A Case Study of XS21-1 Well

Because of low-resolution and lack of detailed velocity information,the conventional surface seismic has not meet the needs of Fine exploration and development.for this reason,Attempt to apply high-resolution 3D seismic is even more necessary for Volcanic reservoir,which geological conditions extremely complex.This article based on Zero-well spacing VSP,8 direction Walkaway VSP,3D VSP and Full three-dimensional surface seismic Joint acquisition,processing and interpretation,Discussed rationality of Acquisition Observations design and reasonable efficiency of processing Program,and carried out Structural interpretation,Identification of Volcanic organization, fracture prediction and gas detection of volcanic reservoir on the basis of this.Obtained a five-point understanding by this study:First,Developed and improved Joint processing technology of the Zero-well spacing VSP,3D VSP and 8 direction Walkaway VSP,and Prestack compensation and Deconvolution method of Zero-well spacing VSP and surface seismic,and complete Quality control methods;Second,Horizon calibration used Joint calibration of VSP and Synthetic Seismic records,and from the point to line,from line to a plane,Three-dimensional space Fine structural interpretation,improved the precision of structural interpretation;Third,it was effective to identificate volcanic cone by plane amplitude,frequency,phase,coherence,and Wave Cluster etc,a variety of seismic attributes;Fourth, analysised that Fracture zone and the distribution of volcanic cones and faults is closely related in this area,fracture density is the highest at volcanic cones,followed by the fault zone;Fifth,determining gas by the changes of AVO intercept attribute with the offset is not absolute,it was feasible to predict distribution of the volcanic favorable gas reservoir Joint Poisson's ratio attribute.