Petroleum Development of Oman (PDO) is undertaking a waterflood development of one of their fields. This project requires drilling horizontal wells in heterogeneous carbonate formations. The water injection wells are planned to be drilled in the lower part of the reservoir which has high porosity and water saturation of minimum 40%.
Azimuthal density images have always been the approach for real time formation evaluation and steering. However, for this project, the operator has selected the high resolution LWD resistivity images due to their closer position to the bit, as well as their better stratigraphical resolution.
This shift in technology was due to the need for making proactive decisions and to address structural complexity of the targeted layers.
The resistivity images allowed readjusting the well path during geosteering. It helped precisely evaluate the dip of the formation, when even one degree can affect drastically the length of the reservoir exposed for production.
On a geological level, the resistivity images permitted the interpretation of features that could not be easily detected with other technologies. Different categories of faults, fractures and bed boundaries were detected, first time in this particular layer with an LWD technology.
The use of high-resolution resistivity images, allowed optimal placement of the well in a more focused target (thinner zone for the entire drain section) and a better understanding of the geological environment. This not only helps in updating the overall field model of the client but also means improved strategic planning for better results in future wells.