METHOD FOR EXTRACTION AND USE OF CONCENTRATED GEOTHERMAL BRINES Russian patent published in 2014 - IPC E21B43/00 F24J3/08 

FIELD: mining.

SUBSTANCE: as per proposed method, a pressure brine-carrying formation is developed by means of a well; high-mineralised geothermal brine is removed from it along a production casing string. After that, along an annular space between production and intermediate casing strings, which is interconnected via the wellhead with ground reservoirs and delivery equipment, as well as with an absorption zone formed before development of the brine-carrying formation at the interval of a geological cross-section of the well below the unit of a regional water-tight stratum. Brine is removed during opening, development and further operation of the formation to the absorption zone and the ground reservoirs with a possibility of using a hydraulic mineral potential of the brine from the reservoirs. Protection of the production string against deposition of hard formations on its walls from the produced brine during its movement from the formation to the well mouth is performed by temperature control of the upper part of the string at the interval of probable temperature phase transition due to continuous or periodic pumping along the brine flow in the string with a possibility of heat transfer to it of a heat carrier with initial temperature exceeding expected brine temperatures without any temperature control at the interval of probable temperature phase transition. According to the invention, heat carrier pumping is performed inside the brine lifted along the production string by arranging in the same string of a closed circulation circuit with the heat carrier in the form of service water. This circuit is made in the form of a coaxial heat exchanger drawn in the string to the depth that is not less than the value of phase transition interval. It consists of a heat-conducting vertical cylindrical housing coaxial to the string, closed in the base and provided from above with holes for water supply to the housing. Inside the housing there is a central pipeline with an open lower end that does not touch the base and an upper end opened for water discharge above the well mouth. With that, water is pumped first via an annular space of the heat exchanger, which is formed with the housing and the pipeline, in the direction opposite to the direction of brine lifting via the production string; then, it is supplied via the central pipeline to the heat exchanger outlet. Use of hydraulic mineral potential of the brine is performed with discharge of a less concentrated fluid formed at use together with discharged excess brine from the formation and reservoirs to the absorption zone. Before the fluid is supplied to a common discharge line, it is filtered from mechanical impurities.

EFFECT: enhanced method's efficiency.

5 cl, 3 dwg