Patent ID: 7117946

Claim:
A method for the exploitation of desirable geoproductive resources from boreholes having therein a casing and a pressure barrier which provides a pressure-tight separation of an external chamber around the casing from a lower borehole chamber, the method comprising: a) fitting a pressure seal within the casing to provide pressure separation between the lower borehole chamber and a flow chamber above the seal within the casing; b) introducing a working pressure at least into parts of the flow chamber; and c) abruptly disabling the pressure seal to introduce the working pressure into the lower borehole chamber, the working pressure being sufficiently lower than the pressure previously present in the lower borehole chamber due to the prevailing rock strata pressure that the resulting difference in pressure induces physical and/or chemical processes in the lower borehole chamber and/or in the rock strata surrounding the latter which render the desirable geoproductive resources exploitable and further comprising the steps of: d) fitting an internal seal into the lower end of a production pipe adapted to be inserted in the casing; e) fitting an external pressure seal in the form of a screwable sealing device around the production pipe, the external pressure seal being so located and configured that, when the production pipe is inserted into the casing, the seal provides pressure-tight separation of the external chamber around the production pipe from the lower borehole chamber; f) introducing the production pipe, with the internal and external seals pre-installed, into the borehole chamber; g) activating the external pressure seal; h) opening the internal seal of the production pipe; and i) using the interior of the production pipe as the flow chamber wherein the screwable sealing device includes a threaded member connected to the casing, and a matching threaded member having a sealing surface pointing radially inward, which is adapted to make sealing contact with a further pipe section; and wherein the further pipe section is a valve pipe connected to the production pipe, wherein the valve pipe has a plurality of openings of predetermined size and shape at predetermined places, and which can reversibly be brought by corresponding control movements into different positions, which distinguish at least “open” and “closed” and connect the flow chamber and the lower borehole chamber or separate them from each other in a pressure-tight way.