Abstract In directional drilling, MWD technology is applied to transmit directional and petrophysical data from downhole. In combination with modern directional drilling tools such as rotary steerable systems, MWD technology has enabled the drilling of complex 3D well profiles precisely placed in the reservoir. However, even on these high-tech wells the drilling process itself is still controlled mainly using traditional surface acquired data such as hook load, ROP, RPM etc.
The transmission and utilization of downhole drilling process data in addition to the surface logging data offer a not yet fully explored potential for drilling process optimization, since modern data acquisition technology close to the bit can provide not only more accurate data but also important additional parameters not available at the surface. Examples of value-adding downhole drilling process data are annulus pressure, weight-on-bit, drillstring bending, RPM, bit torque and dynamics diagnostics. Additional drilling process information on drilling hydraulics or drillstring friction can be obtained by feeding drilling engineering algorithms with downhole and surface acquired data.
The paper provides an overview of the available downhole drilling process data and demonstrates with numerous case studies the value that these parameters add. Furthermore, the paper discusses factors constraining the use of the technology and gives an outlook on future developments in drilling process optimization utilizing real-time downhole data.
Introduction Drilling optimization remains a key issue in the drilling industry due to the high drilling costs in today's challenging applications such as Extended Reach Drilling (ERD), designer profile wells, deepwater wells, drilling in depleted reservoirs etc.
Over the past years, the drilling rig industry has made significant progress in introducing computer-based instrumentation, power-handling tools and automated equipment on the rigs to improve rigsite safety and to optimize the drilling process. The introduction of Local area networks (LAN) on the rig has improved the acquisition of data from surface sensors and information sharing on the rig.
In parallel, downhole MWD technology has made progress in miniaturization of electronics, quality, range, and reliability of sensors, and the development of specific diagnostic techniques to describe the downhole environment. These sensors provide new sources of downhole information for the driller, previously trained on controlling the drilling process using only his rig dials.
The purpose of this paper is to demonstrate how real-time downhole drilling process data, along with surface acquired data, can support the decision making progress on the rig to optimize the drilling process.
Downhole Drilling Process Measurements and Applications The following provides a comprehensive overview of the drilling process measurements available in today's downhole Measurement-While-Drilling (MWD) systems. Case studies describe how the data are utilized at surface to overcome drilling related problems.