WRIGHT, IAIN P., MALCOLM F. FRANCIS, GEORGE ZEITO JR., Brass Exploration Ultd. London, UK

Abstract: The Abana Field, Nigeria, from Discovery to Recovery: A Case Study

The Abana field, located in block OPL230, Nigeria, was discovered only six months from the start of the block exploration programme. It was developed and brought on stream via nine horizontal production wells with pressure support from two water injection wells, within two years of the discovery.

The Abana structure was defined from the interpretation of exploration phase 3D seismic data, as an elongate, four way dip closed, rollover anticline containing two structural culminations.

The discovery wells encountered a relatively thin oil column beneath a gas cap in excellent quality Agbada formation sands interpreted to be a shoreface beach/barrier bar complex. Each well tested at over 3000 bopd Analysis of RFT and PVT data, supported by the 3D seismic data indicated that the two wells defined a single accumulation.The reservoired oil was at bubble point.

With this information it was determined that sufficient subsurface technical risk had been defined to rapidly move forward to the economic recovery of the insitu oil.

Pilot hole appraisal drilling gave a clearer picture of the reservoir. Core verified the geological setting. A saddle between the west and east culminations, each having a slightly different OWC was defined.The water injection wells indicated that the saddle was further south than originally mapped.

Oil in place was close to predrill predictions while reservoir quality was better than anticipated.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England