1. Gao, J.: Reflections on the high-quality development of overseas oil service business under the new situation. J. Beijing Inst. Pet. Manage. Cadres 02, 14–18 (2019)
2. Chen, J., Xu, G., Gu, C., et al.: Comparative analysis of technical service contracts between Ecuador and Iran. Int. Pet. Econ. 28(10), 61–66 (2020)
3. Diao, H., Wang, Q., Wang, P., et al.: Achievements and prospects of China’s utilization of overseas oil and gas resources. Nat. Gas. Ind. 34(8), 147–152 (2014)
4. Wang, T.: Research on Factors Influencing Drilling Costs and Measures to Reduce Costs and Increase Efficiency in Petroleum Enterprises. Capital University of Economics and Trade, Beijing (2013)
5. Li, Z.: Cost Drivers and Investment Planning Methods for Oilfield Production, pp. 106–108. Science Press, Beijing (2011)