No abstract

Fracturing and refreezing of sea ice in the Kara sea are investigated using complex network analysis. By going to the dual network, where the fractures are nodes and their intersections links, we gain access to topological features which are easy to measure and hence compare with modeled networks. Resulting network reveal statistical properties of the fracturing process. The dual networks have a broad degree distribution, with a scale-free tail, high clustering and efficiency. The degree-degree correlation profile shows disassortative behavior, indicating preferential growth. This implies that long, dominating fractures appear earlier than shorter fractures, and that the short fractures which are created later tend to connect to the long fractures. The knowledge of the fracturing process is used to construct growing fracture network (GFN) model which provides insight into the generation of fracture networks. The GFN model is primarily based on the observation that fractures in sea ice are likely to end when hitting existing fractures. Based on an investigation of which fractures survive over time, a simple model for refreezing is also added to the GFN model, and the model is analyzed and compared to the real networks.

Sleipner Vest is a large gas-condensate field which is produced by pressure depletion. Currently (January 2018) the best production well is B-1. B-1 is placed in a segment with very strong pressure support from aquifer. In summer 2016, it was about to water out. A straddle operation was planned and executed. The straddle operation was very successful. More than a year later, B-1 still produced more than twice as much as any other Sleipner well. However, the water is eventually expected to come back in the remaining perforations. Concepts for crossflowing the gas and water production from the well into another reservoir has been investigated.