Integrated Approach Schedules, Validates Steady-State Production-Well Tests

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 230051, “An Integrated Approach for Scheduling and Validation of Steady-State Production-Well Tests in Unconventional Wells,” by Emmanouil Karantinos, XTO Energy, and Akshith Yalala and Craig Ellis Newlin, ExxonMobil, et al. The paper has not been peer-reviewed. _ Steady-state production-well tests are a key component of day-to-day operations, providing critical data for regulatory reporting, volume allocation, and identification of well-work opportunities. This paper presents an automated workflow deployed for scheduling and validating steady-state production-well tests across more than 2,300 of the operator’s wells in the Permian Basin. Field Instrumentation and Well-Testing Procedure Permian Basin wells typically produce fluids containing vapor and liquid hydrocarbon phases and water. Produced fluids are routed by a well header, either a three-phase production (bulk) separator or a three-phase test separator where a single well is tested. A standard three-phase separator is configured such that the produced fluid is separated into gas, water, and liquid hydrocarbons using gravity separation. A steady-state production-well test is initiated by physically routing a well into a test separator through the manual well-header valve or through an automated actuating valve. Permian Basin operations have elected to install human/machine interfaces (HMI) at the separators to streamline the capture of well-test information, enabling the operator to enter the well on test directly using the HMI with predetermined test durations, typically 8, 12, or 24 hours. At the end of the test, field-automation equipment captures the accumulated volumes over the test period. For each well test, oil, water, and gas volumes are reported by the field-automation equipment and published to cloud databases. Upon the completion of a well test, the produced oil, water, gas, and gas-injection volumes are made available to a mobile application so that field operators can review and approve or reject a production-well test by comparing the current well performance with previous well tests while considering any facility or well events that occurred during the well test. Field-Data Collection The automated well-test validation (WTV) process consists of loosely coupled operational-technology (OT) as well as information-technology processes and systems. The data originates on the edge of the network, typically in a controller such as a programmable logic controller (PLC) or remote terminal unit that communicates with field devices, sensors, and electronic-flow-measurement (EFM) equipment. This data is collected into the controller and runs through either standard third-party well-test programs or internal well-test logic developed by field personnel. A typical well-test data-gathering program features a set of registers to store ongoing and completed well tests and notify other systems that a well test has been completed. Edge-computing resources also run at these locations; these resources connect to and monitor the PLC controller over various OT protocols. Processes on these edge devices then capture the current well-test results and send them to middleware using the message-queuing telemetry transport (MQTT) protocol. Subscribing nodes within the supervisory control and data acquisition (SCADA) system then monitor the data feeding into the MQTT brokers, capture any well-test records, and store this information to a centralized database. The local edge-computing devices publish high-resolution, real-time EFM volumes and associated test-vessel data continually during each well test over MQTT. The subscribing SCADA system historizes this data in both on-premises databases and the cloud, where it is housed as time-series data and used in WTV analytics.