Chinese scientific research team solved
the problem of complex deep well wall instability in the ocean
After 15 years of continuous research, Qiu Zhengsong's team relied on the pilot production base of the National Science and Technology Park of China University of Petroleum (East China), and with the project support of three major oil companies, "attacked" this problem that restricted my country's oil and gas development, and finally broke through the ocean Key technologies for deep, safe and environmentally friendly water-based drilling fluids have achieved a number of innovative research results. In terms of results and benefits, the environmentally friendly and efficient anti-collapse water-based drilling fluid in deep oceans developed by the team has solved the world-wide problem of well wall instability in complex deep oceans. The accident rate of well collapse and stuck pipes has been reduced by 83.3% compared with advanced foreign technologies; the safe density of the ocean is narrow The new method of strengthening the well wall of window deep drilling fluid and the new material of high temperature resistant and dense pressure-bearing sealing agent have reduced the rate of complex lost circulation accidents by 82.5%; the deep marine environmentally friendly and high temperature resistant water-based drilling fluid has exceeded the 215℃ of soil-free water-based drilling fluid. The technical bottleneck of high-temperature stability has achieved theoretical breakthroughs and technological innovations in high-temperature and high-density environmentally friendly water-based drilling fluids.
Innovation drives breakthrough bottlenecks
my country's deep ocean geological conditions and marine environment are very complex. During the drilling process, there are many technical problems such as the instability of the complex mud shale well wall, the loss of drilling fluid in the deep narrow safety density window formation, and the failure of the drilling fluid at high temperature. Qiu Zhengsong's team also encountered two major technical bottlenecks.
The instability of wellbore mud shale is an instability process under multi-field and multi-scale coupling. In order to accurately study the impact of hydration stress on the effective stress of the well wall during the hydration process of mud shale, it is necessary to establish a corresponding simulation evaluation method indoors. However, the relevant research on this device for simulating actual formation temperature and pressure conditions was blank in China at that time. .
The instability mechanism of mud shale, the development of anti-collapse treatment agents, and the development of efficient anti-collapse drilling fluids provide scientific and effective means. On this basis, the research team also created a basic theory of multi-dimensional collaborative well wall stabilization, which greatly reduced the rate of complex underground accidents.
The team also encountered a bottleneck period in the research of high temperature resistant treatment agents. When the downhole temperature exceeds 200°C or 240°C, the performance of drilling fluids will deteriorate sharply. The fluid loss performance of water-based drilling fluids under high and ultra-high temperature conditions is extremely difficult to control. At that time, ultra-high temperature fluid loss agents with excellent performance were all imported from abroad. The company imports them. Although the performance is good, the price is extremely high. In order to realize the localization of ultra-high temperature fluid loss reducer, the research team completed the drilling of two wells with the highest underground temperatures in China through systematic research such as molecular structure design, indoor synthesis and evaluation, product small and pilot tests, and created and maintained water This is the domestic record for the highest bottom hole temperature under drilling fluid conditions.
