Relief Well Killing In Shallow Reservoirs
MetadataShow full item record
After the "Wisting"-discovery was made in the Barents sea, operators are likely to be more aware of the potential in shallower formations when planning exploration wells. With the possible development of more shallow reservoirs, there is one issue that needs to be addressed; blowout contingency plans, including relief well drilling. Modern electromagnetic tools used in standard relief well drilling would not work properly for a blowout in a shallow reservoir. A contender to solve this issue is surface seismic while drilling technology. The effect of the relief well intersection point and other parameters is investigated using a software code. The code is made from scratch, but is inspired by the work done by Evensen (2013). Several features is included in the code, like reservoir inflow performance and the ability to simulate any well trajectory. The blowout scenario investigated is similar to the "Wisting"-discovery, with a horizontal reservoir section. Simulations indicate that the potential blowout rates can be just as high for shallow low-pressure reservoirs as for deep, high-pressure reservoirs. With respect to the kill operation, the injection rate needed to kill the well is independent of the intersection point along the horizontal reservoir section. If the intersection is made towards the bottom of the well, a higher pressure will be exerted on the formation than if intersecting at the heel. This could arguably mean that it is beneficial to intersect off-bottom, favorably at the heel of the well. This contradicts the results that Evensen found for a vertical well. The pump power required to kill the blowout is also investigated. It shows that the kill process for a shallow reservoir well is easier to conduct compared to what Evensen found for a deeper reservoir. This is mostly due to the nature of shallow reservoirs, involving shorter wells. This decreases the total friction pressure loss of the system, and results in a lower pump power demand. Calculations indicate that the blowout scenario investigated here could be killed using a standard drilling rig.