Increasing oil field yields with seismic sensors Improving reservoir knowledge and management in oil fields is recognised as being an important factor to increasing total yield. Borehole seismic monitoring technology can help increase these desired yields, but until now, flow induced acoustic noise had prevented the permanent deployment of these seismic sensors. Energy © PhotoDisc In order to remove the seismic monitoring deployment barrier, this project concentrated on understanding fundamental physical and mechanical noise generation in flowing wells. With this knowledge the researchers knew they could move forward and enable the development of practical solutions to this deployment problem in active hydrocarbon wells. The first requirement was to separate the seismic signal from the environmental noise, whilst also ensuring good coupling to the rock-mass. Therefore the choice of materials and structures for the sensor mounting and the actual placement of the sensors became vital. Noise propagation measurement and characterisation then lead to the design and test measurements to minimise overall noise in the vicinity of the sensors. Six major achievements resulted from the research which included flow testing and noise characterisation to 30 000 barrels per day in both test block and inclined experimental test wells. The design and testing of the prototype resulted in a sensor that has 30-40 decibels increased noise rejection than any other current commercial system. Generally speaking, the results of the project are proven technologies that can be used for the permanent deployment of borehole seismic sensor systems. The specific results achieved are: The definition of key parameters affecting noise, borehole acoustic noise characterisation, predictive modelling tools for assessing ameliorative noise, definition of noise management techniques and deployment specifications for seismic sensors. This research is particularly unique, and has provided a technological advantage over non-European competitors in the oil and gas industry, which in turn could present the consortium with a distinct competitive edge. The project partners are now working with end users to identify specific implementation targets, and are eager to establish more and stronger involvement with end-users. Keywords seismic monitoring
