Paper Number: 4323
Research on elevated temperature resistant aluminum alloy drilling pipe for deep and ultra-deep wells
Shaoming Ma 1, 2, Youhong Sun 1, 2, Baochang Liu 1, 2, Huiyuan Wang 3, Chi Zhang1, 2
1School of Construction Engineering, Jilin University, No. 938 Ximinzhu Street, Changchun 130026, P.R. China.
2Key Laboratory of drilling and exploitation technology in complex conditions, Ministry of Land and Resources of China, No. 938 Ximinzhu Street, Changchun 130026, P.R China
3Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025, P.R China
Email address: masm14@mails.jlu.edu.cn
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Drill pipe as part of one of the most important components in drilling engineering, is the media to connect the drilling rig on the ground and drilling bit in the bottom of well. Moreover, it has the function of transmitting weight on bit (WOB), torque and drilling fluid to the drilling bit [1].
As an important approach to geosciences research, scientific drilling has been attracting world-wide attentions [2]. Since International Continental Scientific Drilling Program (ICDP) was founded in 1996, great advances have been brought about in many fields of earth science by continental scientific drilling, among which is the Kola Super-deep Borehole (SG-3 Well) in Former Soviet Union [3] and SongKe-2 well in China. Lightweight and high strength aluminum drilling pipe have been used in SG-3 well for its advantage of higher special strength and higher corrosion resistance. It is more power saving and efficient than traditional steel drill pipe in deep and ultra-deep wells. Unfortunately, the formation temperature increases as drilling deeper (usually 3-4 ºC/100m). The mechanical properties of conventional aluminum alloy drill pipe decreases rapidly when soaking at elevated temperature under ultra-deep drilling wells [4], which will result in a great security question.
In this paper, we investigate an elevated temperature resistant aluminum alloy drilling pipe material for deep and ultra-deep wells. As preliminary research, we study Mg2Si reinforce Aluminum alloy. Mg2Si is an intermetallic compound which is frequently used to reinforce the light alloys. Mg2Si exhibits a high melting temperature (1085 ºC), low density (1.99 × 103 kg m−3), high hardness (4.5 × 103 MPa), a low coefficient of thermal expansion (7.5 × 10−6 K−1) and a high elastic modulus (120 GPa) [5]. After the combined addition of Sr–Sb modifiers, the morphology of primary Mg2Si in as-cast Al–18Mg2Si–4.5Cu alloys transforms from equiaxed-dendrite to cube, and the particle size decreases from ~50 to ~20 μm. Eutectic Mg2Si changes from Chinese script to short rod shape. The UTS increases from 229 to 288 MPa in hot-extruded Al–18Mg2Si–4.5Cu alloys at room temperature, while it increases from 231 to 272 MPa at 100 oC. The microhardness improves from 116 to 141 Hv. The tensile strength of the alloy at room temperature and 100 ºC improves by 59MPa and 41MPa, respectively. The mechanical properties are strongly dependent on the morphology and size of Mg2Si. The thermally stable Mg2Si phase can effectively improve the high temperature mechanical properties of aluminum alloys [6], which makes it possible to manufacture drilling pipes for ultra-deep exploration with Mg2Si/7075Al and Mg2Si/2024Al alloys for continents and oceans.
References:
[1] J.S. Mao, Y.H. Sun, B.C. Liu (2013) Applied Mechanics and Materials 415(3): 623-626
[2] Y.H. Sun, J.S. Mao, B.C. Liu (2014) International Journal of Earth Sciences and Engineering 07(01): 5-15
[3] POPOV A, PEVZNER L, PIMENOV P, ROMUSHKEVICH A. (1999) New geothermal data from the Kola superdeep well SG-3. Tectonophysics, 306(3-4):345–366
[4] J. Liang, J.H. Sun, X. Li, Y.Q. Zhang, P. Li, (2014) Process Engneering. (73) 84–90.
[5] C. Li, Y. Y. Wu, H. Li, X. F. Liu, (2011) Acta Materials. (59) 1058–1067.
[6] R. Alizadeh, R. Mahmudi, (2011), Journal of Alloy Compound (509) 9195–9199.