Experimental Injection Set-Ups for Downhole Chemical Dosing

Abstract

Hollow sucker rods have been substituted for the conventional capillary tubing as the means for conveyance of calcite inhibitor solution in APO-1D, a production well in Mindanao Geothermal Production Field (MGPF), Philippines. Flow control and prevention of chemical flashing inside the 24-mm rod are accomplished with the use of an integrated check valve-and-dispersion-ports mechanism at the end of the rod. Despite the calculated feasibility of the set-up, actual injection ran through technical difficulties. Despite controls over unwanted boiling of the polyacrylate inhibitor chemical in the injection string, it appears that this tandem will never achieve success due to many more mismatches between them, and modifications would be very expensive. Testing a different chemical such as a polymalaete acid is recommended for future testing. Another injection set-up using the conventional ºî OD stainless steel capillary tubing and the same polyacrylate inhibitor solution has been successfully tested in an adjacent production well, SP-4D. Problems earlier encountered and raised by other geothermal field operators have been addressed and modifications on the older systems applied.