Current Status and Future Trends of Jet-Bit Drilling in China
- Kexiang Li (Dept. of Drilling, Ministry of Petroleum Industry)
- Document ID
- Society of Petroleum Engineers
- SPE Drilling Engineering
- Publication Date
- August 1986
- Document Type
- Journal Paper
- 257 - 266
- 1986. Society of Petroleum Engineers
- 1.11.4 Solids Control, 1.6 Drilling Operations, 1.5.4 Bit hydraulics, 1.10 Drilling Equipment
- 0 in the last 30 days
- 141 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
Summary. Three levels in the development of jet-bit drilling in China are discussed, showing significant economic results for each higher pump-pressure level. Drilling practice in China has shown that there is still much room for a further increase of pump pressure and specific hydraulic horsepower. The development of jet-bit drilling is the main direction in upgrading drilling techniques in the near future. Laboratory studies have proved significant rock-cutting action by the combination of hydraulic and mechanical power. Bit hydraulics can do much more than bottomhole cleaning, and hydraulic parameters can be selected beyond the range of the Fullerton chart or the Amoco hydraulic drillability curve. More attention should be paid to rock-cutting by hydraulic power. The bit-weight/rotary-speed selection and mud performance should be optimized along with the best use of hydraulic power. This approach should be followed as long as it results in a higher drilling rate and lower cost.
Research on jet-bit drilling in China started in the 1960's. A systematic study on jet characteristics and nozzle structure mas made at the Peking Petroleum Inst. in 1964 and data on nozzle hydraulics and equations for design were obtained. The first specialized jet-bit-drilling team was organized in 1974. On the basis of jet-drilling experience at home and abroad, comprehensive jet-bit-drilling tests were performed in eastern China with marked results. Since 1978, new techniques-such as jet-bit drilling, lowsolids mud, and the jet-type insert rock bit with sealed journal bearing-have been popularized, resulting in a great increase in drilling rate. We have changed the previous practice of drilling by the seat of our pants and have come to a singe of drilling with well-designed programs. Jet-bit drilling in China has progressed from its initial stage in 1978 to a higher plateau.
Current Status of Jet Drilling in China
There are 540 drilling teams practicing jet-bit drilling in China. The drilling rigs used are Daqing 1, Daqing 2, F320, ZJ45, etc. (See Table 1 for rig specifications.) A marked increase in drilling rate has been observed since the use of jet-bit drilling began. For the drilling teams that use jet-bit drilling in the Liaohe oil field, the average well depth was 2592 m [8,504 ft] and the annual footage per rig was 13 005 m [42,667 ft] in 1980. For drilling teams that did not use jet-bit drilling, the average well depth was 2236 m [7,336 ft] and annual footage per rig was 7534 m [24,718 ft]. In northern Xi Jiang, for the drilling teams that used jet-bit drilling, the average well depth was 1989 m [6,526 ft] and annual footage per rig mas 11 370 m [37,303 ft] in 1980. For drilling teams that did not use jet-bit drilling, the average well depth was 1766 m [5,794 ft] and annual footage per rig was 5939 m [19,485 ft]. For the drilling teams that used jet-bit drilling in the Shengli oil field, the average well depth was 2313 m [7,589 ft] and annual footage per rig was 15 085 m [49,492 ft] in 1980. For those that did not use jet drilling, the average well depth was 2437 m [7,995 ft] and annual footage per rig was 11 015 m [36,139 ft].
In early 1983, among a total of more than 700 drilling rigs, some 540 rigs used jet-bit drilling in which pump pressures of 10.1 to 12.2 MPa [100 to 120 atm] (Level 1) accounted for 60%, pump pressures of 14.2 to 15.2 MPa [140 to 150 atm] (Level 2) accounted for 30%, and pump pressures of 18.2 to 20.3 MPa [180 to 200 atm] (Level 3) accounted for 10%. Drilling rigs with Level 1 pump pressures were mostly F200, Daqing 1, and Daqing 2. Drilling rigs with Level 2 pump pressures were Daqing 1, Daqing 2, and some ZJ45's. Drilling rigs with Level 3 pump pressures were mostly F320, ZJ45, and Daqing 2 (with pumps of 597 or 746 kW [800 or 1,000 hp]). Therefore, in early 1983, 60% of our drilling rigs operated with Level 1 pump pressure, 30% with Level 2 pump pressure, and 10% with Level 3 pump pressure. At the end of 1983, the percentage of rigs operating under Levels 1 through 3 accounted for 45, 36.5, and 16.4 %, respectively. At the end of 1984, Levels 1 through 3 accounted for 29.3, 37, and 33.7%, respectively.
Because the percentage of Level 3 rigs in 1984 was higher than in 1983 (from 16.4 to 33.7%), the rate of penetration (ROP) of all rigs in China in 1984 was 0.64 m/h [21.1 ft/hr] higher than in 1983. For this reason, the footage in 1984 was 1 x 10(6)m [3.3 x 10(6) ft] higher than in 1983.
An analysis of the performance of drill rigs with three levels of pump pressure follows.
Level 2 vs. Level 1. For basically the same mud type and performance and the same bit selection, higher pump pressure resulted in a higher drilling rate and lower cost. Case studies from Shengli, Hua Bei, Sichuan, and Xi Jiang are provided (see Fig. 1 for location of oil fields). Tables 2 through 8 show the comparison between Levels 1 and 2.
|File Size||607 KB||Number of Pages||10|