Development and testing of a high-pressure downhole pump for jet-assist drilling. Topical report, Phase II

摘要

The goal of jet-assisted drilling is to increase the rate of penetration (ROP) in deeper gas and oil wells, where the rocks become harder and more difficult to drill. Increasing the ROP can result in fewer drilling days, and therefore, lower drilling cost. In late 1993, FlowDril and the Gas Research Institute (GRI) began a three-year development of a down hole pump (DHP(reg sign)) capable of producing 30,000 psi out pressure to provide the high-pressure flow for high-pressure jet-assist of the drill bit. The U.S. Department of Energy (DOE) through its Morgantown, WV (DOE-Morgantown) field office, joined with GRI and FlowDril to develop and test a second prototype designed for drilling in 7-7/8 inch holes. This project, (open quotes)Development and Testing of a High-Pressure Down Hole Pump for Jet-Assist Drilling,(close quotes) is for the development and testing of the second prototype. It was planned in two phases. Phase I included an update of a market analysis, a design, fabrication, and an initial laboratory test of the second prototype. Phase II is continued iterative laboratory and field developmental testing. This report summarizes the results of Phase II. In the downhole pump approach shown in the following figure, conventional drill pipe and drill collars are used, with the DHP as the last component of the bottom hole assembly next to the bit. The DHP is a reciprocating double ended, intensifier style positive displacement, high-pressure pump. The drive fluid and the high-pressure output fluid are both derived from the same source, the abrasive drilling mud pumped downhole through the drill string. Approximately seven percent of the stream is pressurized to 30,000 psi and directed through a high-pressure nozzle on the drill bit to produce the high speed jet and assist the mechanical action of the bit to make it drill faster.