Coupled hydraulic, thermal and mechanical considerations for the simulation of hot dry rock reservoirs

A new method of drilling long boreholes in low permeability coal by improving its permeability

Quantitative estimation of joint roughness coefficient using statistical parameters

http://www.geothermal.ethz.ch/content/Geothermal%20publications/EvansEtAl_1999_Geothermics.pdf

Stress and rock mechanics issues of relevance to HDR/HWR engineered geothermal systems : review of developments during the past 15 years

Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and the rock particles. The recycling abrasive particles were then dried and sieved for determination of their disintegration behaviors. Before each cutting with recycling abrasives, the abrasive particles less than 106 μm were screened out. It is revealed that a considerable amount of used abrasives can be effectively reused in the rock cutting. The reusabilities of abrasives are determined as 81.77%, 57.50%, 34.37% and 17.72% after the first, second, third and fourth cuttings, respectively. Additionally, it is determined that recycling must be restricted three times due to the excessive disintegration of abrasives with further recycling. Moreover, it is concluded that cutting depth, kerf width and surface roughness decreases with recycling. No clear trend is found between the kerf taper angle and recycling. Particle size distribution is determined as an important parameter for improving the cutting performance of recycling abrasives.

D.A. Summers

Papers

The penetration of rock by high-speed water jets