Oil and Gas Office How can geology geophysics

Oil and Gas Office How can geology & geophysics improve brownfield recovery? Malcolm Pye, DTI Oil & Gas Office, Aberdeen

Oil and Gas Office Are the existing wells draining the field? Where are the barriers in the field behind which oil could be trapped?

Oil and Gas Office Horizontal barriers within the reservoir. The reservoir subdivision will have been drawn up from the static appraisal data. Review it against the dynamic data.

Oil and Gas Office Massive Sands Do post-production logs and pressures show that the massive sands behave as a single flow unit?

Oil and Gas Office Channel Sands Do the sands communicate between wells? What is the channel orientation?

Oil and Gas Office Review the reservoir succession using sequence stratigraphy Gamma ray spikes Prograding sands Incised channels

Oil and Gas Office Gamma ray spikes – are they flooding surfaces? – could they be horizontal barriers?

Oil and Gas Office Prograding sands - not a layer cake stratigraphy - can the prograding surfaces be recognised?

Oil and Gas Office Incised channels - can occur at sequence boundaries - at a scale less than the well spacing Downcutting Ness channels into the Etive are seen in Tern and NW Hutton

Oil and Gas Office Vertical barriers in the reservoir Faults Unrecognised faults in wells may result in undrained sands.

Oil and Gas Office The mapping of faults from seismic has improved - Higher frequency content seismic - Coherency - Pre-stack depth migration

Oil and Gas Office Mapping sand bodies from seismic - using seismic attributes - using seismic inversion

Oil and Gas Office Mapping hydrocarbons from seismic - direct hydrocarbon indicators (DHIs) - 4 D seismic

Oil and Gas Office Combining all this G&G data to build static 3 D geological models which can be upscaled to 3 D reservoir models

Oil and Gas Office However, even if data is sparse geological intuition can still locate infill locations.

Oil and Gas Office Possible infill locations - attics - fault shadows - undrained compartments

Oil and Gas Office So hopefully…. this talk has demonstrated how geology & geophysics can improve brownfield recovery. Now go and design some exciting new wells to recover this oil ! Thank you for listening.