A Review of Downhole Wireless Technologies and Improvements

Abstract

Downhole wireless communication in the form of mud pulse telemetry enabled directional drilling over the past 60 years and has been hugely successful. Technologies like Measurement While Drilling (MWD), Logging While Drilling (LWD), and Geosteering would simply not exist without it. But in the Production and Producing end of the business, applications for downhole wireless communication have been less clear, especially where long distances and long-term monitoring are concerned. Several wireless technologies are in use today for long-term production applications. Electromagnetic (EM), acoustic, and pressure pulse telemetries are finding application as wireless production gauges, drill stem test tools, and drilling alternatives to pressure pulse. But the large-scale vision of, "Breaking the Wire!" in production wells has not yet occurred. Permanent Downhole Gauges (PDG) with an umbilical to surface are still the product of choice for long-term production monitoring. A history of wireless approaches in production applications will be given and the different methods used in the industry will be explained. A comparison and contrast of wireless telemetry methods will be explored, explained, and evaluated. Advantages and disadvantages will be listed for each approach. A ranking system will be employed to illustrate the evaluation results of the different wireless telemetry methods. New variants for wireless telemetry, power supplies, and measurement methods will be proposed. Preferred applications for each gauge type will be given. Downhole gauges can be improved by integrating pressure pulse, a downhole power generator, and downhole flow rate measurement into a single unit. The overall size can be ten times shorter than existing systems while still generating a larger wireless signal. Such a system would make wireless downhole gauges much more practical and should significantly increase their uptake in the industry. Real-time measurement of downhole pressure and downhole flow rate transforms the accuracy and effectiveness of Pressure Transient Analysis (PTA). Better reservoir understanding can be gained by using only drawdown tests, without shutting in the well. Smaller tools are generally more cost effective.