Historical Well Control for Salt Dome Structural Mapping
Geospatial well control for salt dome structural contour mapping.
A cavern storage client needed to define the geometry of a salt dome in Louisiana to meet regulatory cavern setback requirements. Setback is the proximity of a storage cavern to the edge of the host salt dome. To produce an accurate salt dome structure map, an accurate well-location base map was required. Historical well placement records are often approximate at best and often only located to the nearest quarter-quarter section; however, accurate well placement is crucial for defining domal geometry. To meet this challenge and locate the wells more accurately than state records, RESPEC obtained and reviewed well files, historical aerial photographs, and published technical literature. Final coordinates were established for several hundred wells after a quality control check was performed on state-reported coordinates using supporting documentation, such as well records along with georectified historic aerial imagery. RESPEC also reviewed geophysical logs for many of these wells and created a database of depth to caprock and salt. The data were ultimately combined with seismic data to produce a more accurate salt dome structure map than was previously published.