Patent EA-000922-B1 (EA)
Title: Method for using equipment in a well system, well system and method for a phased development
Inventor: DEN BOER JOHANNIS JOSEPHUS
IPC: E21B23/00
Filed: 1998-04-27
Abstract: 1. A method for moving equipment into, through and/or from a well system for the production of hydrocarbon fluids, which well system comprises a plurality of entrance points at or near the earth surface and a system of one or more underground wellbores which provide a subsurface connection between said entrance points, wherein that the method comprising moving equipment into, through and/or from the well system via a first of said entrance points whilst production of hydrocarbon fluids takes place via another entrance point during at least part of the period that the equipment is moved and/or actuated to perform downhole drilling, service, maintenance monitoring operations in the well system. 2. The method of claim 1, wherein said first and any other entrance points are wellheads of hydrocarbon fluid production wells and the production of hydrocarbon fluids via the wellhead that forms the first of said entrance points is interrupted or minimized by arranging the equipment between the first of said entrance points and a downhole seal which prevents or reduced flow of hydrocarbon fliids from the well system towards the first of said wellheads during at least part of the period that the equipment ia actuated within and/or moved into, through and/or from the well system. 3. The method of claim 1 or 2, wherein the equipment is moved through the well system by carrier means which are connected to surface power supply and/or control facilities via an electrical, fibre optical hydraulic, or other umbilical conduit which passes through the first of said entrance points. 4. The method of claim 3, wherein the carrier means are provided with plugging equipment which temporarily provides a plug which blocks or reduces flow of fluids from the well system towards the first of said entrance points during at least part of the period that the carrier means and/or other equipment are actuated or moved into, through or from the well system. 5. A well system for production of hydrocarbon fluids which comprises a plurality of entrance points at the earth surface and a system of underground wellbores which provides a subsurface connection between said entrance points, wherein equipment is movably arranged in the well system, characterized in that the equipment consists of drilling,  service, maintenance monitoring equipment which can be actuated downhole and/or which can be inserted and/or removed from the well system via a first of said entrance points whist production of hydrocarbon fluids takes place via another entrance point. 6. The well system of claim 5, wherein the entrance points are mutually spaced and the system of underground wellbores comprises at least one central wellbore which provides a subsurface connection between at least two entrance points through which equipment can be moved and optionally a number of wellbranches which are directly or indirectly connected to a central wellbore. 7. The well system of claim 5, wherein the system comprises a number of downhole base points in which equipment and/or carrier means can be docked while production of hydrocarbon fluids via the well system takes place and in which battery packs of the equipment and/or carrier means can be reloaded and data gathered by the equipment and/or carrier means can be unloaded and transmitted to data processing equipment at the earth surface. 8. The well system of claim 5, wherein the equipment is arranged between the first of said entrance points and a downhole seal which prevents or reduced flow of hydrocarbon fliids towards the first of said wellheads. 9. A method for the phased development of a well system the method comprising drilling and completing a hydrocarbon fluid production well via a well entrance point at or near the earth surface and initiating the production of hydrocarbon fluids via that entrance point; and subsequently drilling another well via another entrance point at or near the earth surface such that the wellbores of  the wells intersect and form a subsurface corridor via which equipment can be moved, wherein production of hydrocarbon fluids via the already completed well continues during at least part of the period that the other well is being drilled and/or completed.  10. The method of claim 8, wherein one or a plurality of said wellbranches are drilled from the well system using the drilling equipment which is inserted into the well system, providing its operation there and/or which is removed from the system via the first entrance point, whilst production of hydrocarbon fluids takes place via another entrance point.