A New Generation, Multi-Sensor MLWD Device for Optimized Drilling Performance and Reservoir Insight: A Case Study, Offshore Abu Dhabi

Abstract

Acquisition of reservoir properties measurements, high-resolution borehole images, and continuous directional surveys has historically required the deployment of multiple discrete tools. This paper details the first-time deployment of a new, integrated, multi-sensor tool, in one of the largest oil-producing reservoirs in Abu Dhabi. Deployment of the new technology helped to achieve a new record for the longest bit run with the new system. The new measurement-and-logging-while-drilling (MLWD) platform incorporates multiple sensors with significantly reduced footprint, delivering critical, high-definition measurements closer to the bit than previous technologies with modular designs. In this case study, the existing MLWD technologies were included in the drilling assembly for measurement validation and benchmarking. The new tool provided borehole size and shape measurements, and high-resolution radius and acoustic reflection-amplitude images with an axial resolution of 0.1 inches. In addition, the tool provided vibration, weight, torque, and pressure-while-drilling measurements, to help optimize the drilling parameters, and an azimuthal gamma ray sensor for formation evaluation. The new design also includes a compact directional module to provide static surveys and high-resolution continuous inclination and azimuth while drilling, facilitating wellbore placement and safe and efficient drilling by minimizing the tortuosity. The bottomhole assembly included LWD gamma ray, propagation resistivity, formation density, and neutron porosity sensors from the legacy system, along with a point-the-bit rotary steerable system and a new-generation resistivity sensor. The new system was deployed in an 8½-in. horizontal section of 14,318 ft, reaching a total depth of 25,500 ft. MD. It was the longest run of the new MLWD system globally to date. The real-time MLWD data included gamma ray and ultrasonic borehole size. Furthermore, the high-resolution radius and reflection-amplitude images captured geological features that often control the reservoir properties such as vugs, fractures, and minor faults. The radius measurements provided details of the borehole size and shape, with a three-dimensional (3D) visualization of the wellbore helping to identify borehole enlargement and breakout. In addition, the new and legacy propagation resistivity measurements matched closely. The continuous, high-definition surveys helped the drilling team to ensure smooth hole and avoid any collision risk with nearby wells. The forward plan is to continue to deploy the new generation of tools in a wider range of conditions and locations, and to add additional next-generation sensors, including higher resolution density, neutron porosity, and deep multilayer reservoir mapping sensors.