Abstract: A method of detecting a lateral boundary of a compacting or expanding region in a subsurface formation, which method comprises determining non-vertical deformation of the earth' s surface above the subsurface formation over a period of time; identifying at least on contraction area and at least one adjacent dilatation area of the earth' s surface from the non-vertical deformation over the period of time; and using the contraction area and the adjacent dilatation area as an indication of a lateral boundary of the compacting or expanding region; and a method for producing hydrocarbons.

Abstract: A method of monitoring a subsurface formation underneath a sea bed, the method comprising determining non-vertical deformation of the sea floor over a period of time and inferring a parameter related to a volume change in the subsurface formation from the non-vertical deformation of the sea. Determining the non-vertical deformation of the sea floor comprises selecting a plurality of locations on the sea floor and determining a change in distance between at least one pair of the locations over the period of time.