A Case Study of Geosteering in the one of the Middle East Under Saturated Heterogeneous Carbonate Reservoir

Drilling horizontal wells in the heterogeneous carbonate reservoirs are always challenging to keep the wellbore in the right spot of the reservoir. Indeed, the only indication for the reservoir heterogeneity is the seismic interpretation which is very uncertain and shows the accuracy of the right horizon needed for precise geosteering. Also drilling horizontal wells are a costly service that will be lead to time and money consuming if the operators could not adjust the well in the target zone. Geosteering is the skill of keeping the well trajectory in the best interval, named sweet spot. In this study geosteering process was applied in a well of a heterogeneous carbonate reservoir in the west of Iran using LWD data (Gamma-ray) by using both strata-based and model-based methods that led to increase ROP and kept 85.88% of the total horizontal depth (THL) in the sweet spot and also showed GR data is completely enough to steer a well path and there is no need to expend more money for more LWD log data.Post-processing analysis (resteering model) after the end of drilling by using porosity logs (neutron, density and sonic) revealed that obtained correlations and stratigraphic model from the geosteering process by LWD-GR data are accurate.

کلیدواژه ها:

Horizontal well ، Heterogeneous carbonate ، Geosteering ، Sweet spot