New Opportunities in Lower B Sands VLC-100/949 Reservoirs, Block III, Lake Maracaibo

Gedi Gonzalez, Carolina Coll, Jose L. Mora, Miguel Araujo, Elvira Meza, and Luis Rondon

The Lower B Misoa Formation of Middle Eocene age is characterized by massive sand bodies. These sands were successfully tested in the northern part of Block III in Lake Maracaibo in 1956. Subsequent drilling during the next 27 years has failed to locate any productive pay zones. Only during the past 8 years, new seismic and well data have delineated a number of minor oil reservoirs resulting in extensive production from Misoa Lower B sands.

The oil production came primarily from small structural traps located on the hanging walls of normal listric faults. Fault diagnosis and locations were more accurately mapped with the availability of 3-D seismic data. Consequently, VLC-100 and VLC-949 reservoirs are now considered to be part of the same trap instead of being separated. A careful review of the fluid distribution and material balance calculations has confirmed that the wells from these reservoirs have, in fact, been producing from the same accumulation thereby validating the new geological model.

The new model has defined new opportunities of oil exploitation. Firstly, it has led to the drilling of 4 new wells and increased production by 4,500 STB/D. Secondly, it has indicated additional recovery opportunities in the form of drilling horizontal wells in the updip area. Finally, the new model indicates the existence of an aquifer of much lower strength than was previously thought. This has caused a revision in our reservoir management strategy and we now recommend water injection to supplement the aquifer support and enhance oil recovery.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California