Kuwait Oil Company (KOC) needed to add remote monitoring systems on 357 wellheads to improve upon existing data gathering procedures. These procedures required frequent trips to each wellhead to record data, and manual data entry to get this information into production optimization systems.
At KOC, remote monitoring of wellheads is called real-time surveillance, and they expect it to provide four main benefits:
- Enable faster and lower-cost first production
- Reduce operating, maintenance and compliance costs
- Sustain optimal production and maximize yield
- Ensure health, safety and environmental (HSE) compliance
To realize these benefits, KOC first needed to build a foundation for analysis and optimization, which requires access to the real-time data needed to improve day-to-day asset management. This required installing instrumentation at each wellhead, and then exploiting the breadth of available technologies to monitor key process variables in real-time.
Wired and wireless solutions were both considered, with wireless instruments selected due to lower costs, faster implementation, and reduced HSE risks.
Initial Implementation of Real-Time Surveillance
For the first few decades of oil production, KOC relied on the pressure in underground formations to extract oil. But by late 2010, KOC started depending on artificial lift stations to produce the required pressure, with the number of lift units increasing dramatically each year thereafter to the present total of 357 (Figure 1).
Manual operation and monitoring of such a high number of wells began to be very tedious and time-consuming, and it presented hazards to field personnel. Optimizing production was almost impossible due to insufficient instrumentation at many sites and lags in data collection and subsequent data entry. Both of these delayed real-time surveillance.
Real-time automation was first introduced as a solution in early 2012. KOC started with a few wells, and used the information from these wells in very basic optimization applications to demonstrate value. A typical wellhead with a lift station was equipped with the following instrumentation, data gathering and control components:
- Wellhead/Flowline/Casing pressure and temperature (Figure 2)
- H2S and CH4 gas detection
- RTU/PLC for local monitoring and control
- Remote shutdown
- Interface to downhole gauges
- Tank level measurement
Although these measurements provided tremendous value, early implementations indicated the average time needed to install the necessary wired instrumentation was one to two weeks per well, much too long given the hundreds of wells requiring upgrades. They were also operational constraints with wired instrument installation including required excavation procedures and costs, and HSE risks.
These issues led KOC to consider a wireless solution as it met their two main criteria:
- Standardization, improvement and integration of systems and work practices to improve capital efficiency, lower project cost and meet challenging deadlines
- Measurement devices designed to work together with simple means of integration, and possessing diagnostic capability to enable data validation and analysis.
KOC decided to adapt wireless technologies and preconfigured software because they felt it would increase standardization and facilitate getting production online faster. WirelessHART instruments and related components from Emerson Process Management were selected because of KOC’s prior positive experience with other Emerson products and services, and because of the investments Emerson made to work as a partner on projects.
All the instruments at each wellhead are connected to an Emerson wireless gateway, and the gateway is connected back to the central control and monitoring room via Wi-Fi and WiMAX networks. An Emerson RTU is installed at each site to provide the required local monitoring and control, and this unit is also networked back to the central control room via the gateway.
Benefits of Wireless Monitoring
With wireless technology, instrument installation requires no signal wiring, and only some of the wireless instruments require power wiring. Each wireless instrument is connected back to the gateway through the WirelessHART mesh network. This is in contrast to a traditional wired installation, where each instrument requires power wiring, and signal wiring must be run from each instrument to an RTU gateway.
By eliminating most of the required wiring and corresponding infrastructure, installation time was reduced from one week per wellhead to two wells per day, a tenfold improvement. Installations costs were cut in half, saving $3,000 USD per well. HSE risks were also reduced, as much less excavation and wiring work is required in these potentially hazardous areas. Data accuracy is in the range of 99.9%, more than sufficient for the application, and data availability is also high.
The existing SCADA system has been expanded to accommodate all of the new wireless points of measurement. SCADA data management software tools provide easy visualization, trending and analysis—turning raw data from wireless instruments into actionable information—which KOC uses to improve production planning. Now that the surveillance foundation is in place, consideration is being given to utilizing diagnostic tools to confirm instrument health and data validation.
One benefit quickly realized is a reduction in troubleshooting time as technicians have remote access to a wealth of information regarding the operation of each well. This allows them to diagnose problems quickly, and to arrive at the site with all the tools needed to address any issues.
With the expansion in artificial lift units and corresponding instrumentation, the variety and real-time availability of data is dramatically increasing in quantity and complexity. Finding the expertise to filter and interpret data in a timely manner is a challenge, but one well worth the effort as it promises to deliver even more benefits through optimization of wellhead operation, and ultimately the entire oil production system. Optimization will allow KOC to fine tune well production, and maintain oil reservoir recovery to meet production targets.
Enhancing oil production by installing a monitoring system has many challenges, including start-up delays, excavation, costs and HSE risks. Wireless instrumentation allowed KOC to meet these challenges and implement an automation strategy based on real-time surveillance, analysis and optimization. This achievement has lowered operating and maintenance costs, improved HSE performance, and increased production.
A wireless mesh network infrastructure is now in place at each wellhead, making installation of additional WirelessHART instruments a quick and inexpensive proposition should the need arise to install additional points of measurement.
Reprinted from Oilfield Technology, July 2016