Maximizing Drilling Sensor Value through Optimized Frequency Selection and Data Processing

Abstract

Downhole high frequency sensors are heralding the era of big data in drilling and have already shown potential to significantly push the limits of drilling performance. Downhole data transmitted in real time can be used to optimally select parameters during drilling and optimize off-bottom operations. The wealth of information from retrieved memory data gives immediate insights in well specific performance limiters. Nevertheless, downhole data is not yet used to its full potential, as the industry is only just beginning to make sense out of the many gigabytes of recorded data. Often, measurements cannot be unambiguously linked to specific downhole dynamics and their respective dysfunction. Most valuable information is lost directly at the sensor when processing (e.g. averaging) is not done appropriately. In other cases, huge amounts of high frequency data are transmitted and stored without providing much useful information. Large data volumes quickly reach the limits of transmission broadband and memory capacities of downhole tools and pose huge challenges to drilling data analysis and data integration. As a solution to handling the rapidly increasing amounts of drilling data, this paper proposes a value of information based approach to downhole sensors, data processing and analysis. An extensive set of field data from multiple operations is used to demonstrate the interrelation of dynamic effects and their impact on downhole sensor measurements. Different requirements on sensor type and collection frequency apply to identify different types of drilling performance limiting dysfunction, such as vibrations, well tortuosity or cutting accumulations due to poor hole cleaning. It is shown that the analysis of frequencies is key to separate multiple downhole effects wrapped into one measurement. For each prominent type of dysfunction, minimum data collection frequencies are specified which allows for the differentiation of unimportant noise from valuable drilling performance limiters. These insights are used to describe more effective methods of data processing, by cross-linking information from multiple sensors.

The Application of Downhole Vibration Factor in Drilling Tool Reliability Big Data Analytics—A Review

“…Lateral vibration is related to the bending of the drilling axis and the resonant behaviors at some critical rotary speed as well [9]. Lateral vibration is typically responsible for the highest frequency dynamics (normally 50 Hz and above, or below 0.02 s period) [23]. The influencing factors of drilling lateral vibration include the fossa dynamics, the axial alternating force, the drill bit displacement, the shaft lining, and the drill string construction [20].…”

“…Axial vibration is more prevalent when tricone bits are applied for drilling [9]. Axial vibrational can be discovered in the order of 3-20 HZ frequency [23]. Low-frequency (3-7 HZ) axial vibration is generally associated with bouncing motions, and higher frequencies (greater than 15 HZ) are relevant to the BHA resonances or the interaction of the teeth or the cutters with the formation [26].…”

“…Axial vibration can result in drill bits damage, buckling fatigue, low ROP, accelerated bearing, seal, stabilizers and top-drive wear, broken tooth cutters, and LWD/MWD tool failures [9,27]. Axial vibration commonly exists in vertical wells when drilling hard formations, which can manifest as WOB fluctuations with relatively stable downhole torque values and be detected at surface [10,23]. Axial vibration becomes more crucial to implement downhole axial generator tools or drill hard formations.…”

“…Torsional vibration also commonly appears when polycrystalline diamond compact bits are used without depth of cut control, and it is often formationdependent due to lithology changes [9]. During the "stick" phase, the drill bit and/or drill string rotation ceases, both radial and axial accelerations are significantly reduced, close to zero or even negative, sufficient torque builds up and WOB gets lowered slightly, which causes the drill string rotation to resume in the "slip" phase [9,23]. Another possible reason for torsional vibration is that the motor continues to run the drill string while the bit is stuck downhole [4].…”

“…Consequently, the torsional energy accumulated in the drill string will be released once the drill bit is free, causing the BHA to rotate in the undesired opposite direction [4]. Torsional vibration has a remarkable effect on all downhole measurements [23]. Torsional vibration causes irregular downhole rotation, material fatigue, physical damage of the drilling tool and electronics, and slows down the drilling process [4,29].…”