Erosion corrosion is believed to occur as a surprise. While other reasons of corrosion can be anticipated depending on presence corrosion causing factors such as H2S, water injection and oxygen in dry pipelines, erosion caused as a result of sand or solids cannot be directly identified. The sudden pipeline leaks and failures can be attributed to this phenomenon. This is a hidden threat to the well and to the Asset integrity.
While the corrosion stops after passive layer formation, solids especially sand particles getting produced with crude, often erode this layer, enhancing the corrosion rates. The produced sand can travel up to the terminals even with the best downhole completions or sand filters. The effect gets accelerated with high velocity of fluid for the wells with high production rates. By detecting the sand at the wellheads, the flow rates can be altered in real-time, to achieve fluid velocity below critical velocity.
This is proven to avoid production of sand at the wellhead. While the world reservoirs are declining, sand production is known to be a worldwide issue. It can also reduce production from time to time plugged pumps and wellhead components. This calls for frequent well interventions for cleaning and flushing.
While the problem is dual fold, combining sand detection with the real time corrosion monitoring downstream of the choke provides a complete integrity solution. The areas with altered cross section areas are subjected to increased velocity of the fluids with accelerated erosion corrosion. Devices measuring the change in the cross-section of the flowline provide real time corrosion monitoring. It is also possible to estimate the life of the flowline with the current corrosion rates.
Emerson’s Sand Monitors along with Permasense-corrosion monitoring, together can be used to detect the erosion corrosion. Both devices are non-intrusive and easy to install and belong to the family of Pervasive sensing devices. The combined solution is available in wireless configuration. This provides seamless data transfer of sand and resulting corrosion to the control room. The production engineers may view this data when transmitted to the control room for analysis and decision making. This facilitates real time production optimisation.
The solution is believed to fetch 66% return on investment for a field with around 500-1000 wells. A software, called Fieldwatch can provide the sand detection and erosion data for the field with report by exception capability. This proves very beneficial for the production team to plan the well interventions and other actions in advance, leading to predictive maintenance.
This wireless solution can help avoid the manual inspections, which at times can be misleading due to human errors in observing and interpretation. It further helps in seamless data connectivity to the control room leveraging predictive maintenance, a step towards Digital Transformation.
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