Abstract
The duty of a newly arrived service company person in an oil-producing country is to familiarize themselves with the conditions. As a log analyst, their preoccupations will concern the borehole logging, both open and cased, geology, log, and reservoir evaluation. When I first arrived in Libya in 1961, we were in the middle of the exploration phase. Later in 1968-70, I witnessed some of the large oil discoveries. During this period, a review of logging and interpretation problems in Libya was presented in the Well Evaluation Conference (W.E.C) held in 1970. It was interesting to note that in Libya we faced a large inventory of reservoirs with very different petrophysical properties, from low porous fractured quartzites to traditional shaly sands or highly porous carbonates, not forgetting some oil production from granite.
Over the past 30 years, the geology and the reservoir geometry have not changed. Most of the problems experienced in the 60s and 70s are still persisting, such as OBM log evaluation, fractured reservoirs, or thin layers. However, other conditions have drastically evolved for three main reasons:
- In 2000, Libya is a mature oil-producing country
- Drilling and oil production concepts have changed
- Logging and log/reservoir evaluation have improved dramatically