Chałupki Dębniańskie Field: Improving drilling success in shallow gas reservoirs with VectorSeis

Edward Gruszczyk, Zygmunt Trzesnioswki and Piotr Misiaczek of Geofizyka Krakow, Poland with Paul Brettwood (UK) and Jon Tessman (USA) of Input/Output provide a case study comparing the performance in the field of I/O VectorSeis sensor technology with conventional analogue geophone systems. In the spring of 2002, a field experiment was conducted over a gas field in southeast Poland. The primary objective was to characterize the response of the I/O VectorSeis sensor in a direct comparison with conventional analogue geophone systems. Both dynamite and Vibroseis sources were tested during the course of the experiment. Analysis of the acquired datasets demonstrated clearly that, in this relatively shallow (160 m - 800 m depth range) clastic depositional environment, VectorSeis sensors not only matched the results of the analogue geophones but also produced datasets with superior vertical resolution. In addition to the conventional compressional datasets, converted wave data were also acquired. These demonstrated that high quality converted wave data could be acquired in a cost-effective manner and that they could solve a number of imaging problems directly related to the presence of multiple stacked gar reservoirs. Mapping of the PS data into PP time also demonstrated that the PS data had similar apparent frequency response when compared to analogue geophone compressional data.