Online monitoring in action
Online underwater cameras and sensors deployed during drilling in the Statoil-operated Hyme oilfield and Morvin subsea field documented in real-time what was happening in a sensitive area near cold-water corals, for example.
Statoil encourages supply chain companies, academia and other oil companies to work jointly with them on research and development (R&D) projects such as the LOVE ocean observatory programme, helping to push development of online EMM technology and models in Norway.
“There is debate in Norway about opening up sensitive areas for oil and gas developments. The sensors being deployed will enable fact-based discussion of risk and its mitigation,” Austrheim explained.
A guideline for EMM design
While the environmental performance benefits of EMM are clear, the industry lacks standards for designing and implementing such activities. Statoil and DNV GL have collaborated therefore to develop a guideline, proposing an approach for conceptual design of robust EMM systems that, importantly, is also cost-efficient.
The module-based guideline (refer to infographic) uses evaluation criteria established by defining the challenge; which decisions need support, and the data required; the area for monitoring, for how long and how often; data analysis needs; and the acceptable level of uncertainty for data accuracy.
The selection process for three system designs for an EMM programme related to the discharge and environmental fate of drill cuttings is illustrated.
This approach involves steps that translate into hardware and software requirements. Austrheim hopes that the industry’s familiarity with these steps from other technology evaluations will lead to wide and easy implementation of the EMM guideline. “It is offered as an industrywide approach that would allow us all to evaluate EMM hardware and software in the same way. This would broaden and compare experience with these systems.”
Normally, several EMM system designs will meet the requirements specified. Cost efficiency is included therefore as a key criterion for making the final selection.
Operational expenditure (opex) is high for traditional, offline EMM programmes because of vessel rates and labour costs offshore and in the laboratory.
Capital expenditure is higher for online EMM, with hardware for a greenfield development typically costing around USD1 million, Austrheim said. “However, you can potentially get payback on hardware by saving on vessel time,” he added.
Currently, maintenance constitutes the highest opex element of environmental monitoring and modelling systems. Furthermore, reliable data transfer from subsea hardware is among the challenges for online implementations of EMM.
Transfer quality can vary, particularly so during oil and gas exploration activity in remote and deepwater locations, in harsh climates, and where there is no existing infrastructure.
However, opex remains low compared with offline EMM systems that require vessel time and large numbers of personnel for baseline and follow-up environmental surveys.
Online data collection
Where consistent online data transfer is difficult, operators could reduce cost by using a rig-based, remotely operated underwater vehicle, or a standby vessel’s spare time, to achieve data transfer on demand.
“Online, sensor-based approaches can also improve decisions on whether or when inspections and/ or interventions are needed, which increases cost efficiency as it helps to avoid downtime,” Austrheim added.
He concluded with a call for action to refine the use of EMM: “Reliable monitoring systems such as LOVE already provide volume, quality and reliability of real-time data streams. Some environmental data analysis tools are sufficiently developed, but more R&D is needed to generate better models for improved decision support.”
 ‘Guideline for design of cost-efficient and robust sensor based environmental monitoring systems’, A Ulfsnes et al, SPE International Conference and Exhibition on HSSE and Social Responsibility, Stavanger, Norway, April 2016