Thoughts on detecting wormholes in cold production of heavy oil using time-lapse seismology

Qiaozhi (Sandy) Chen and Larry Lines

ABSTRACT

During the heavy-oil cold production process, producing sand and oil simultaneously causes a dramatic increase in oil recovery. The reason for the higher oil recovery is due to the wormhole development during production, where wormholes create interconnections between the boreholes in the reservoirs. Therefore, detecting the distribution of the wormholes is very significant for designing the well spacing and infill drilling locations. Time-lapse seismology could be a useful new technique to monitor wormholes based on the physical characteristics of wormholes, such as high porosity, unconsolidated sand-free channels, and foamy oil with gas saturation. This paper will discuss some ideas on how to detect wormhole distribution by employing the Vp/Vs ratio and AVO anomalies in time-lapse seismology techniques.

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