Methods, apparatus and products for production of fluids from subterranean formations

Abstract

Methods, apparatus and products for separating oil and mud filtrate down hole and production of each to the surface via separate tubing, that includes custom engineered drill pipe for which two types of openings called ports have been cut or drilled: production ports and isolation ports. The production port produces formation fluid (normally hydrocarbons) from a perforation. In one non-limiting embodiment, a tube is welded to the inside of the casing at each production port to transmit the formation fluid to the top of the drill pipe section where it is attached to a custom engineered casing collar (described below) designed to allow flow to the next drill pipe section of the device. The isolation port produces mud filtrate from the adjacent borehole wall exterior to the casing, and these isolation ports are arranged in a pattern around each production port to keep mud filtrate in the invaded zone from reaching the production port. The number and placement of the production ports as well as the number, placement and shape of the isolation ports are determined using the information regarding the perforating design and other information such as the filtrate type and estimates of invasion depth as determined by well logs. Packers are set above and below the apparatus to provide an 'isolation' chamber to contain the produced filtrate. Tubing through the upper packer will produce the filtrate to the surface via differential pressure or pumping. After the casing has been cemented, the perforating guns in the production ports are fired to begin production of formation fluid.