Using Autonomous Control to Stabilize Well Performance without the Downhole Pressure Gauge

Abstract

Optimizing a gas lift well can be challenging. Essentially, it needs to optimize a complex system, where gas is compressed and injected to the bottom of the well to lift oil/water/gas to the surface. It contains numerous facilities and equipment, from compressor, injection valves, downhole gas lift mandrel, valves, well head, surface separator to the sales lines. Flowing bottom hole pressure plays a critical role in the system. In a lot of cases, stabilizing the flowing bottom hole pressure within a desired range means the system is optimized. However, downhole pressure gauges are expensive, and it isn't realistic to install one on every well, which brings more challenges to optimize gas lift well performance against target flowing bottom hole pressure.

Edge IoT platform provides customized autonomous control logic to accommodate the customer's optimization challenge at the well level. Weatherford deployed the customized autonomous control logic which includes two distinct logics – pressure control logic and injection rate logic. The pressure control logic updates the well head choke diameter based on the calculated FBHP. The injection rate is optimized based on well daily performance.

In the 60 days trial, the field results are proved to be able to utilize the next generation autonomation device to stabilize well head pressure, and casing head pressure, and to minimize buy back gas and reduce the manual intervention.

The autonomous control logic and its corresponding workflow, embedded in the next generation automation device, not only incorporates the industry 4.0 technology, but also leverages both system analysis methods and high frequency real time data to improve the optimization granularity, deliver the values to the customer at the well site.