Patent EA-004323-B1 (EA)
Title: Multilateral well and electrical transmission system
Inventor: BOER JOHANNIS JOSEPHUS DEN
IPC: E21B47/12
Filed: 2000-01-31
Abstract: 1. A multilateral well and electric transmission system, comprising: - a primary wellbore (2) in which a primary well tubular is arranged; - a branch wellbore (3) in which a electrically conductive branch well tubular (12, 13) is arranged; and - wherein the branch well tubular (12, 13) is connected to the primary well tubular (11), characterized in that the primary and branch well tubulars (11, 12, 13) are interconnected to provide an electrical conductivity and form a link for transmission of electrical power and/or signals between the primary and branch wellbore (2, 3), the primary and branch well tubulars forming a link for transmitting low voltage power from a first pole of an electrical power source (10) which is electrically connected to the primary well tubular (11) to electrically powered equipment (68, 70, 75) within the branch wellbore which is electrically connected to the branch well tubular, and wherein a second pole (10B, 21) of the electrical power source (10) and the branch well tubulars (12, 13) are electrically connected to the earth (5), wherein the electrically powered equipment comprises a re-chargeable battery (71), which is trickle-charged by the low voltage electrical power transmitted via the well tubulars (11, 12, 13). 2. The multilateral well and electric transmission system of claim 1, wherein the branch well tubular (12, 13) is a radially expandable tubular which is made of an electrically conductive material and which is radially expanded within the branch well (3) during installation and wherein an electrically conductive receptacle (43) is arranged at or near the branch point such that the expanded branch well tubular is pressed into electrical contact with the receptacle (43) as a result of the expansion process. 3. The multilateral well and electric transmission system of claim 2, wherein the receptacle (43) is formed by the primary well tubular (43) itself and the branch tubular (45) has a downstream end which is radially expanded against the inner wall of the primary well tubular (43) and extends through a window (42) in the primary well tubular (43) into the branch wellbore (40). 4. The multilateral well and electric transmission system of claim 2, wherein the receptacle (43) is formed by a tubular branch section of a bifurcation element (50) which bifurcation element has a primary section which is electrically connected to the primary well tubular (51) and the branch section extends from the primary wellbore into the branch wellbore. 5. The multilateral well and electric transmission system of claim 2, wherein the primary and branch well tubulars (11, 12, 13) are made of a formable steel grade and the branch well tubular is expanded during installation such that the expanded branch well tubular (12, 13) has an inner diameter which is at least 0.9 times the inner diameter of the primary well tubular (11). 6. The multilateral well and electric transmission system of claim 1, wherein the electrically powered equipment (68, 70, 75) comprises measuring and/or control equipment which is powered by a rechargeable lithium-ion high temperature battery (71) and is mounted on an equipment carrier module (65) which is removably secured within the branch well tubular (61) such that one electrode (73) of the battery is electrically connected to the branch well tubular and another electrode (72) of the battery is electrically connected to the subsurface (63) earth formation surrounding the branch wellbore (60). 7. The multilateral well and electric transmission system of claim 6, wherein the equipment carrier module formed by a sleeve (65) which is removably connected within the branch well tubular (61) by means of a number of expandable clamps (66). 8. The multilateral well and electric transmission system of claim 7, wherein the sleeve (65) spans an inflow area of the branch wellbore (65) where the branch well tubular (61) is perforated, the expandable clamps consist of a pair of expandable packers (66) which seal off an annular space between the branch well tubular (61) and sleeve (65) near each end of the sleeve (65) and wherein the sleeve is provided with one or more fluid inlet ports (67) which can be opened and closed by one or more valves (68) which are powered by the rechargeable battery (71). 9. The multilateral well and electric transmission system of claim 1, wherein at least one of the primary and branch well tubulars (11, 12, 13) is equipped with at least one electrical booster station (17) which station spans an electrically non-conductive section of the well tubular (11, 12, 13) and which station is electrically connected to the electrically conductive parts of the well tubular at both sides (18, 19) of the electrically non-conductive section thereof. 10. The multilateral well and electric transmission system of claim 9, wherein the electrically nonconductive section of the well tubular (11, 12, 13) is formed by an electrically non-conductive annular seal (22) which is arranged between overlapping co-axial sections of the well tubular and wherein the electrical booster station (17) is arranged within the outermost section (12) of the well tubular near the end of the innermost section of the well tubular such that one electrode (18) of the electrical booster station (17) is connected to said outermost section and another electrode (19) of said station (17) is electrically connected to said innermost section. 11. The multilateral well and electrical transmission system of claim 10, which comprises a plurality of branch wellbores (3, 4) and a plurality of electrical booster stations (17). 12. A sleeve-type equipment carrier module (65) for use in a multilateral well and electric transmission system according to claim 1, which module is sealingly securable in an inflow region of the well and comprises one or more fluid inlet ports (67) which can be opened and closed by one or more valves (68) which are powered by a rechargeable battery which is in use trickle charged by transmitting low voltage electrical power through tubulars (11, 12, 13, 61) in the primary and branch wellbore (2, 3, 4).