I have heard the term “digital oilfield” for some time. The definition seems to change quite often, especially when listening to a vendors pitch for their vision of the digital oilfield. Here’s what the digital oilfield means to me in the E&P segment.
In the E&P segment, technology on the production side seems to be adapted slowly. Many producers were weary of electronic measurement not that long ago. Many just could not justify the cost for their legacy assets. Many just seemed plain skeptical. Electronic measurement has existed in the E&P sector for a good while. With many corporations, most installations were at custody transfer meters, and segment meters to measure a group of wells, or the total of an assets production.
Unconventional plays have changed all this. Electronic measurement has become ubiquitous in unconventional fields. Instantaneous data has become important, but more than that, RTU’s are performing many jobs nowadays.
Over the last decade the RTU and the PLC have really started to become indistinguishable. Many RTU’s perform quite a few functions that just a short while ago were relegated to the realm of the PLC.
Not only is the RTU measuring the production on a pad, in many instances it is controlling the pad, whether it be meter run sequencing, controlling the choke in the production unit, or controlling safety processes such as well pad and gathering compressor ESD schemes and liquid level shut down.
Some manufacturers have adopted the IEC-61131 standard, or at least parts of it, to make simple logic programming pretty painless.
With the Emerson Process Management Fisher ROC series of RTU’s simple logic can be implemented pretty quickly and quite easily via the FST Registers.
For more complex control schemes, user C binary files can be obtained from 3rd party vendors, such as Vinson process controls for artificial lift, and Spartan controls for ESD sequencing.
The ABB TotalFlow G4 series also has provisions for quick and easy math and logic implementation, and using their EZ Blocks application those with prior PLC experience will have no problem. The TotalFlow G4 series is easily expandable and expansion cards for valve control, plunger control, and motor control are readily available and quick to implement.
Pad monitoring such as tank monitoring, liquid separator monitoring and water impoundment monitoring has also changed, and the cost of ownership has much improved with technologies such as Oleumtech wireless sensor solutions. Bringing in IO point wirelessly via IO integrated with 900 MHz spread spectrum technology has eliminated the need for long expensive conduit runs, and 4-20 transmitters. Now low power 1-5 volt transducers and magnetostrictive level indicators can be brought wirelessly into a radio gateway, which communicates with the RTU via Modbus. Now changes to a pad, or changes and future upgrades to your process control schemes can be made quickly and cost-effectively.
Another change is in the realms of communications. Industrial Ethernet is starting to be more widely used, supplanting rs-232. And never have there been so many options to get the data back to the SCADA system. License free radio systems in the ISM bands from MDS, Freewave, Maxstream and others are enjoying wide use. Cellular modems can be deployed quickly. Satellite options, such as VSAT for data back-haul, LEO for very remote monitoring, BGAN for mobile equipment are all readily available. Licensed radio offerings have much improved over the last decade, with embedded web servers, and the option to monitor the health and diagnostics of your radio network remotely. And spectrum for 220 MHz equipment has become available that will serve terrain as such that can be found in the Appalachian basin very well.
This is what I think of when I hear the term digital oilfield.
Some things I would like to see change in the future is standardization. I would like to see multiple RTU and peripheral vendors support a communications protocol that is more secure than Modbus. A standard secure communications protocol that is adopted by all would serve this industry well.