NOVELTY - The method involves establishing secondary bore holes extending from a primary bore hole, where each secondary bore hole is established using a boring apparatus. The boring apparatus comprises a down-hole boring unit (12) that is arranged to deploy a conduit (14, 15) in the secondary bore holes during establishment of the secondary bore holes. The conduit is utilized as a part of a conduit system to make fluid down and/or up the secondary bore holes for each secondary bore hole when establishment of the secondary bore holes are completed.    USE - Method for establishing a well such as geothermal well for exploitation of geothermal energy in a geothermal energy plant or hydrocarbon well for production of hydrocarbons, in a boring initiation arrangement (all claimed).    ADVANTAGE - The method enables partially or completely blocking heat exchange bore holes once bored, where the heat exchange bore holes can hinder and even prohibit deployment of insulated conduits in worse case. The method enables improving efficient deployment of conduits in the secondary bore holes extending from the main or primary bore hole in a simple manner. The method ensures non-continuous circulation regime so as to reduce heat loss from upwardly flowing fluid during return leg of the fluid and time available for heat to be transferred to colder downwardly flowing fluid. The method enables increasing recovery of hydrocarbons in a hydrocarbon well by establishing the secondary bore holes extending from already established the primary bore hole, so that a blowout preventing element is fixed into a place in the primary bore hole upstream of the secondary bore holes, thus allowing safe and efficient collection of hydrocarbons originating from the different secondary bore holes.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a well.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of fluid circulation in the secondary bore holes.    Down-hole boring unit (12)    Conduit (14, 15)    Hole conduit (24)    Annular space (27)    Valve system (31)