The goal of this project is to overcome problems encountered during deep drilling in over-pressured formations as well as increase drilling rates.

Tempress Technology, Inc.

Location:
Kent, Washington 98032

Slow penetration rates in deep, over-pressurized formations represent a critical challenge for gas drilling operations. Hydraulic pulse drilling is designed to increase overbalanced drilling rates by generating suction pulses at the bit and by fluidizing the drillstring. Theoretical and laboratory scale investigation of the mechanics of drilling with hydraulic pressure pulses will be conducted initially to determine feasibility and optimal operating parameters required to cause spalling of fluid-saturated, pressurized rock. Small-scale testing using pressure pulses generated using the water-hammer effect will be conducted to demonstrate penetration of pressurized shale on a small scale. Following completion of small-scale testing, a prototype hydraulic pulse generator subassembly will be built and tested in wells deeper than 5,000 feet to demonstrate higher rates of penetration at lower cost than conventional rotary drilling.

The potential impact of the hydropulse drill stems from its unique approach to breaking rock. At depths beyond 5000 feet, the hydrostatic head is sufficient to allow a suction pulse effect to assist in breaking the rock, especially in shale formations (which make up a significant portion of many petroleum-producing sedimentary basins). In addition to the potential application to drilling wells, the value of this tool to generate a consistent and powerful seismic signal is being explored. Seismic-while-drilling (SWD) is a critical technology needed by industry, especially in deep wells (beyond 20,000 feet) for “Look Ahead” application to detect zones of high pressure gas earlier and reduce overall well costs. This spin-off application was explored via a separately funded grant from the Department of Energy Small Business Innovative Research (SBIR) program.

Results:

The testing for the HydroPulse™ tool was conducted at the Baker-Hughes Experimental Test Area (BETA) in September 2003. A total of 24 hours of drilling with a footage of 651 feet was completed with two valve assemblies in a deviated well. A measurement-while drilling system was used to record downhole drilling parameters. Drilling objectives of the test were to evaluate effects of suction pulses on stick slip behavior of pump down cement and roller cone bits, to demonstrate pulse drilling operations with a downhole motor, and to evaluate component wear. A fourth objective was to observe the seismic signal generated by the seismic version of the tool—HydroSeis™. For more information on the results of the seismic-while-drilling demonstration, see project DE-FG03-00ER83 111, Real-Time Pore Pressure Prediction Ahead of the Bit Using a Suction Pulse Seismic Source.

Initial wear testing resulted in failure of the flow-cycling valves after only a few hours of operation. A second-generation valve has been designed and is undergoing testing. Pressure drilling tests have confirmed large increases in rate of penetration in shale while drilling with heavy mud in a high-pressure test stand. The effects on penetration rate increase with flow rate and pulse amplitude. These tests show that a pulse amplitude of 1,450 psi (10 MPa) is required to influence drilling rate in pressure-sensitive shales. Only a small increase in drilling rate was observed during full-scale drilling tests in hard sandstone. The drilling test results confirm rock mechanics models of the effects of rapid suction pulses on rock strength.

Hydraulic pulses with an amplitude of 550 psi (3.8 MPa) had a substantial effect on stick slip and bit bounce of a roller cone bit while drilling in a shallow, deviated well. The weight on the bit required to stall a pump down cement bit was increased 60 percent by the hydraulic pulses. Very high rates of penetration were achieved in hard and soft formations with a pump down cement bit at maximum bit weight with no stalling at normal rotary speed with a motor. Drilling tests with a thruster assembly to decouple the bottom hole assembly (BHA) from the drill collars and longer flow course housing are also being considered to enhance hard rock penetration performance.

This next generation tool incorporated lessons learned from laboratory and field testing. The valve incorporates a diverter design to eliminate bypass ports and to ensure circulating flow regardless of tool failure mode. The diverter design also reduced upstream pressure pulses in the tool that contribute to wear. The tool housing incorporated smaller flow courses to generate minimum suction pulse amplitude of 1,450 psi (10 MPa) to ensure an impact on drilling rates in deep formations. Wear and drilling tests in a flow loop facility have demonstrated reliable operations for 50 hours with nominal wear.

All tasks are complete and a final report has been submitted and accepted.

$2,207,728

$1,168,335

NETL - William Gwilliam (304-285-4401 or william.gwilliam@netl.doe.gov) 
Tempress Technology - Jack Kolle (425-251-8120 or jkolle@tempresstech.com)

Final Report [PDF-1179KB]

HydroPulse™ System Test [PDF-229KB]

Pertinent Publications:
Kolle, J.J. (2000) "Increasing drilling rate in deep boreholes by impulsive depressurization," Fourth North American Rock Mechanics Symposium, July 31-August 2.

Kolle, J.J. and K. Theimer (2005) "Seismic-while-drilling using a swept impulse source," SPE/IADC Drilling Conference, Amsterdam, 23-25 February, SPE/IADC 92114.

Kolle, J.J. and Marvin, M. (2001) "Impulsive suction pulse generator for borehole applications," U.S. Patent No. 6,237,701, May 29.