Well completion device with acid soluble plug

Claim 1

IN WELL COMPLETION APPARATUS OF THE KIND WHEREIN A BORE HOLE CASING IS ADAPTED TO BE POSITIONED IN A BORE HOLE AND DUCT-FORMING DEVICES OF ACID-RESISTANT METAL ARE SECURED TO THE CASING IN ALIGNMENT WITH HOLES MACHINED IN THE CASING WALL, EACH DUCT-FORMING DEVICE BEING CAPABLE OF BEING LATERALLY EXTENDED FROM THE CASING FOR MAKING CONTACT WITH A PRODUCING FORMATION AND WHEREIN EACH DUCT-FORMING DEVICE INCLUDES A TERMINAL SLEEVE WHOSE OUTER END IS BLOCKED AND CLOSED BY AN ACID-SOLUBLE METAL PLUG WHICH UPON INTRODUCTION OF ACID INTO THE SLEEVE IS AT LEAST PARTIALLY DISSOLVED TO BECOME DISLODGED FROM ITS ASSOCIATED SLEEVE, THE IMPROVEMENT WHICH COMPRISES THAT THE ACID-SOLUBLE METAL PLUG IS IN THE FORM OF A GENERALLY CYLINDRICAL, EXTERNALLY THREADED BODY HAVING A FRONT END AND A REAR END AND BEING FORMED WITH AN AXIAL BORE EXTENDING FRONTWARDLY FROM ITS REAR END BUT TERMINATING SHORT OF ITS FRONT END TO DEFINE AN OPEN REAR END AND A CLOSED FRONT END, THE PERIPHERAL WALL DEFINING SAID BORE HAVING AN ANNULAR ZONE OF SUBSTANTIALLY REDUCED RADIAL THICKNESS BETWEEN SAID REAR AND FRONT ENDS; WHEREBY UPON INTRODUCTION OF ACID INTO SAID CASING AND SAID BORE, THE ACID WILL RAPIDLY EAT AWAY SAID ANNULAR ZONE FOR PENETRATION OF THE ACID EXTERNALLY OF THE PLUG TO EAT AWAY THE THREADS OF SAID PLUGS.