| Project/Area Number |
62850111
|
|---|
| Research Category |
Grant-in-Aid for Developmental Scientific Research
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
資源開発工学
|
|---|
| Research Institution | TOHOKU UNIVERSITY |
|---|
Principal Investigator |
MATSUKI Koji Associate Professor, Faculty of Engineering, Tohoku University, 工学部, 助教授 (10108475)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OKUMURA Kiyohiko Technician, Faculty of Engineering, Tohoku University, 工学部, 文部技官 (40177184)
KOJIMA Takashi Research Associate, Faculty of Engineering, Tohoku University, 工学部, 助手 (20192057)
SUGIMOTO Fumio Research Associate, Faculty of Engineering, Tohoku University, 工学部, 助手 (80124585)
|
|---|
| Project Period (FY) |
1987 – 1988
|
| Project Status |
Completed (Fiscal Year 1988)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1988: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1987: ¥2,400,000 (Direct Cost: ¥2,400,000)
|
|---|
| Keywords | Rock / Hydraulic fracturing / Artificial slit / High speed waterjets / High water pressure / 溝切削 |
|---|
| Research Abstract |
In order to clarify the applicability of high speed waterjets technology to making a slit in deep borehole for hydraulic fracturing, the testing apparatus was manufactured first to simulate the slot cutting of rock in deep water up to 2000m and then, the effects of various cutting parameters such as driving pressure, standoff distance, nozzle diameter and traverse rate on the depth of cut, the slot width and the specific energy were investigated for Shirakawa welded tuff using the driving pressure up to 100 MPa and flow rate of 80 1/min.
The main results obtained in this study are summarized as follows;
1) Although the depth of cut rapidly decreases with circumferential water pressure, if finally becomes almost constant at about 10 MPa of water pressure. Maximum depth of cut was 32.2 mm under water pressure of 20 MPa for Shirakawa welded tuff.
2) Main cutting mechanism is cavitation errosion for the smaller cavitation number less than 0.05, and for larger cavitation number other mechamisms predominate.
3) Empirical formulae on the depth of cut were proposed for both regions where the depth of cut depends on circumferential water pressure and where it is independent of water pressure.
4) It is found that there exists an optimum water pressure and optimum standoff distance from the view point of energy consumption.
5) The width of slot rapidly increases with water pressure until it reaches almost constant value.
6) High speed waterjets can be applied to making a slit in deep borehole for hydraulic fracturing.
|
