1st Eocene New Challenge Areas Integrating Geological, Petrophysical and Production Data in Wafra Field, PNZ, Kuwait

Eloutefi, Nader M.; Fawzi, Nasser; Al-Khaldi, Fahad
KGOC, Kuwait, Kuwait.

Wafra field lies in the northwest part of Kuwait/ Saudi Arabia partitioned Neutral Zone (PNZ). 1st Eocene is the shallowest reservoir in the field and ranges in time from Paleocene to Eocene. This reservoir is complicated due to multiple conditions such as heavy oil behavior, variation in both oil gravity and connate water salinity, heterogeneous lithology, varying scale of fractures and provisional NE-SE elements.

The structure of 1st Eocene consists of two parallel anticlines, trending NW-SE. It is proposed that these anticlines are cut by NE-SW elements (strike slip faults). Accordingly, Structural compartmentalization has been created due to horizontal and vertical displacements, with some rotation especially in the southern area of the field. These elements are believed to play an important role in the development of structures in PNZ.

The deposition environment of 1st Eocene in Wafra field area appears to have been a relatively stable shelf area during the period of 1st Eocene deposition. There are several evidences to show that there were numerous and frequent relative changes in sea level during this period of time. These changes resulted in digenetic changes in the carbonate reservoir and the presence of anhydrite layers. Also, they control to a large extent the present day limits of the hydrocarbon accumulations in the area.

The integrated structure and HPV maps with the production data of 1st Eocene wells show that the hydrocarbon accumulations in this reservoir cannot be explained by structure alone because the highest structure area of the field has the lowest production figure. Accordingly, the various potential areas in the field are controlled by combinations of structure and stratigraphy.

New challenge areas have been identified outside the known reservoir boundaries especially in the northern and southern areas of the field. This has been proven by integrating all available data. These new areas have a direct positive response on the daily oil production and the expected reserve of the reservoir.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012