The Phillips operated Alison field in the UK North Sea produces gas from a low permeability layered Rotliegendes sand reservoir. The field was developed with a single subsea well producing out of three horizontal laterals. Four laterals were drilled. The first lateral encountered a fracture system and was abandoned to eliminate any risk of producing water through the fractures. The second lateral was completed with a slotted liner in layer C, the tightest but thickest layer in the reservoir. Following a production test of this lateral, the third and fourth laterals were drilled in layers B and D respectively and completed open hole.

Phis paper will discuss various aspects of the project, including drilling the horizontal section for each of the laterals, the tools and techniques used to abandon the first lateral, and the different methods used in establishing the junctions concentrating on the open hole junction used to establish the fourth lateral. The success of the open hole junction in this well has resulted in the use of this technique for wells in other developments, including one example where a lateral was drilled to TD, the junction established and drilling continued in the second lateral without a trip.

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