Identification of Thin Reservoirs, Missing Zones and Suitable Targets for Perforation: A Case History
Trilok Chand, Sapana Sethi, Sanjeev Kaushal, Harvir Singh, Prasad Inupakutika, and Ramraj Singh
Geochemistry, KDMIPE,ONGC, Dehradun, India
Geochemistry is playing a critical role in finding the remaining resources that are becoming more difficult to locate and produce. However, petroleum geochemistry is not a completely mature predictive science but could yield tremendous competitive advantages in exploration and production. Thermo Vaporized free hydrocarbons, total organic contents and GC fingerprints of residual oils (core extracts) have been utilized to identify missed zones of hydrocarbon accumulation in wells, which have been missed by conventional techniques. The results indicate the effectiveness of the technique, which can be used to identify the thin reservoirs/ missing zones for perforation before testing the exploratory well as supporting geochemical tool along with other conventional tools to further reduce the risk.
The migratory index (S1/TOC) computed for the studied 64 sidewall core samples and plotted against their respective depths. Based upon the migratory index profile and GC fingerprints three suitable perforation intervals (3977-3981.2m, 4039.8-4055.8m and 4085.5-4090.5m) were identified and recommended for testing in DSAB well. But In the well DSAA the depth intervals (3752.2-3755m 3605.5 -3620.2m) recommended for perforation. The tested zone proved to be gas and oil bearing and proved the effectiveness of the technique.
Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery