Directional wells through the 6-in. production-hole sections in the Marrat Reservoir of the Jurassic formations have traditionally required several wireline-logging and hole-conditioning runs for comprehensive petrophysical interpretation and completion design.
As the planned well inclinations increase to maximize reservoir exposure and sweep efficiency, wireline deployment poses significant challenges due to the increased risk of losing the bottomhole assembly (BHA) in the hole. Over time, logging-while-drilling (LWD) tools have become preferable for the asset team, where the tools are run either in the drilling BHA or during a dedicated wiper trip after the section has been drilled to total depth (TD). Using LWD tools in this application also reduces well delivery times and costs.
A comprehensive logging solution was required to drill the 6-in. reservoir section of a study well. The complex LWD string, consisting of gamma ray, resistivity, neutron porosity, azimuthal density, azimuthal sonic, and nuclear magnetic resonance (NMR) tools, was deployed on a motorized rotary steerable system (MRSS) BHA. In addition, a prototype high-resolution acoustic imaging and caliper tool, designed to be run in both water-based mud (WBM) and oil-based mud (OBM), was also included. The acquired logging data were used for enhanced formation evaluation. Fracture and borehole breakout interpretation from the image data played a key role in the successful completion design.
This ultimately led to Kuwait’s first successful “hexa-combo” LWD drilling run and the country’s first LWD ultrasonic imaging tool run in OBM in this hole size, with 13.3 ppg OBM with a maximum downhole temperature of 275°F.