Case History 4 3-D Seismic Interpretation of an Upper Permian Gas Field in Northwest Germany
H. E. C. Swanenberg, F. X. Fuehrer, 2011. "Case History 4 3-D Seismic Interpretation of an Upper Permian Gas Field in Northwest Germany", Interpretation of Three-Dimensional Seismic Data, Alistair R. Brown
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In northwest Germany, sour gas is produced from Zechstein (Upper Permian) carbonates in a number of mainly medium-sized fields. A 3-D survey was acquired in 1985 to optimize drilling in the Goldenstedt field and some smaller adjacent fields (Figure 14-4-1). Recent appraisal drilling has proved significantly more potential than originally assumed in this area of complex structure and facies. Total reserves are currently estimated at 0.5 tcf of sour gas with an H2S content varying between 7 and 26%.
Structural definition and resolution of the target horizon at 3500 to 4000 m depth (corresponding to 2.2 to 2.4 sec two-way traveltime) is severely influenced by lateral velocity variations in the overburden, which complicated processing and interpretation of the survey. Despite nominally lower coverage than regular 2-D, the superiority of 3-D data significantly enhanced structural control. Some information on the reservoir was also obtained from reflection amplitudes. The 3-D data set thus revealed details of the tectono-depositional framework not observed on previous 2-D data.