Abstract: A method of creating a zonal isolation above a target zone in an underground wellbore comprises: inserting a slurry injection tubing into the wellbore; arranging within an annular space surrounding said tubing an particle accumulation means, such as an expandable screen or an area where the slurry velocity is reduced; and pumping a slurry comprising a carrier fluid and granular material down via the slurry injection tubing and the target zone and then up into the annular space, such that at least some granular material accumulates and forms an elongate zonal isolation in the annular space between the target zone and the particle accumulation means, which zonal isolation is removable and exerts a limited radial force to the surrounding formation, thereby reducing the risk of formation damage.

Abstract: A method of investigating a reservoir region in a subsurface formation by a time-lapse seismic survey, which subsurface formation comprises a further formation region adjacent to the reservoir region, which method comprises the steps of obtaining data from a time-lapse seismic survey including seismic data of the subsurface formation at a first point in time and a later point in time, processing the seismic data to obtain a seismic representation of change in a predetermined seismic parameter in the further formation region, which seismic parameter is dependent on stress; interpreting the seismic representation of change in the seismic parameter in the further formation region for an indication of changes of stress distribution in the further formation region; and deriving a property of the reservoir region using the indication of change of stress distribution in the further formation region.