Development and Testing of Downhole Pump for High-Pressure Jet-Assist Drilling

Abstract

Development and Testing of Downhole Pump for High-Pressure Jet-Assist Drilling S.D. Veenhuizen, SPE, FlowDril Corp.; and D.L. Stang, SPE, FlowDril Corp.; and D.P. Kelley, FlowDril Corp.; and J.R. Duda, SPE, U.S. Dept. of Energy; and J.K. Aslakson, SPE, Amoco Corp. Abstract A second generation prototype ultra-high pressure (UHP30,000 psi) downhole pump (DHP) for jet-assist drilling has been tested in the laboratory and downhole The development and testing program has been supported by the Gas Research Institute (GRI) and the U.S. Department of Energy Federal Energy Technology Center (DOE-FETC). It is anticipated that with development of this technology, drilling penetration rates in the harder, slower drilling formations in gas and oil wells could be increased 1.5 to 2 times through jet-assist of the drill bit. As with the first generation prototype DHP, the ultra-high pressure pump is designed to be located downhole in the BHA just above the drill bit. It is rated at an output pressure of 30,000 psi at about 20 gpm. Power to drive the DHP is delivered downhole via the conventional mud stream through elevating the surface mud pump pressure 1,500 to 2,000 psi using conventional flow rates downhole The operating principle and general arrangement of the DHP pump is discussed along with the operating behavior and performance characteristics. The pump has been tested eight times downhole in three commercial gas wells in the Travis Peak Formation of East Texas and a granite test well in Norway. Rate of Penetration (ROP) enhancements observed were up to 1.5 to 1.6 times conventional penetration rates. Testing in the laboratory to evaluate design issues that have limited downhole operating hours is summarized in terms of fluid sealing, mechanical strength, and fluid erosion. Jet-assist drilling ROP enhancement is also discussed in terms of laboratory drilling test results and field drilling results utilizing the DHP in East Texas and Norway. The main technical design challenge remaining before commercialization of the DHP technology is erosion within the pump when drilling very abrasive formations. Introduction The purpose of ultra-high pressure, jet-assist drilling is to increase the ROP in the drilling of 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, more economical drilling of gas and oil wells. To accomplish ultra-high pressure, jet-assist drilling requires a jet-assisted drill bit and a source of pressure. The source of pressure is a UHP DHP. In. late 1993, FlowDril and the Gas Research Institute (GRI) began development of a DHP based on FlowDril technology previously developed in pumping and sealing high pressure drilling mud. A first engineering prototype was designed, built and tested. Results of field experimentation with the first prototype were reported in Ref. 3. To accelerate development and commercialization of the DHP technology for ultra-high pressure, jet-assist drilling, FlowDril, in coordination with GRI, contracted with the U.S. Department of Energy (DOE) in late 1994 to develop and test a second generation prototype. DOE recognizes the benefits of advanced technologies to the gas and oil industry, and as such, manages a portfolio of drilling related research, development, and demonstration (RD&D) projects. The DOE's program is implemented by the Federal Energy Technology Center through one of its field offices located in Morgantown, WV These drilling-related projects support DOE's ultimate goal of facilitating development of the Nation's large natural gas resource base and maintaining market-responsive supplies at competitive prices. The RD&D program is highly coordinated with GRI activities and resources are leveraged when beneficial to the programmatic needs of both organizations. A more comprehensive treatment of DOE's oil/gas drilling-related RD&D is provided in Ref. 1. P. 183^