Abstract:

The geology feature of EBANO oilfield in Mexico is complex, leading to difficulty in predicting hydrocarbon distribution, and poor development results.Based on the core description, well logging and seismic data, and well production performance data, we studied the reservoir characteristics and the main factors controlling hydrocarbon accumulation in a systematic way.The results show that the limestone KSF and Kan strata of the Upper Cretaceous are the major pay zones of EBANO oilfield.Due to regional tectonic movement, the fault system shows large difference between the northern and southern parts, with of smaller rank in the north:shorter fault displacement, fewer horizons getting incised and shorter extension distance in the north, and larger rank ones to the south.The reservoir space is dominated by both matrix pores and fractures:the oil-bearing matrix is strong in heterogeneity, and the oil content surrounding faults is high.The hydrocarbon enrichment in EBANO oilfield is controlled mainly by fault, structure, fracture and effective thickness of matrix.Given the above-mentioned new understandings, we implemented a strategic transfer of well emplacement from the higher structures in the north to the lower structures in the south.The development results is obviously improved with the average initial production of new wells 2.1 times that of the old ones, laying a foundation for the successful development of the oilfield.

Key words: reservoir characteristics, hydrocarbon accumulation pattern, limestone of fracture type, limestone of pore type, heavy oil, Upper Cretaceous, EBANO oilfield, Mexico