Study On Accident Prediction And Treatment Of Horizontal Well

Horizontal wells drilling technology has been an important method to efficiently develop oil&gas resources. Furthermore, pipe sticking accident is one of the downhole risks and it often happens in horizontal wells drilling process, which can cause other drilling accidents and complex situations, leading to serious damage and huge economic losses, however, the relevant measurements are complicated. That is the reason why experts and scholars focus on studying the measurements on how to prevent and deal with the sticking risks. Therefore, the subject6project21of the12th five-year national oil&gas plan sets a special’integrated system of drilling design’concentrating on preventing and handling various sticking problems. This paper has built a method for risks warning and analyzing combining with drilling design and construction data, which can timely forecast sticking risks and help to evaluate and make decision to deal with sticking accidents of horizontal wells.This paper has put a deep research on pipe sticking risks forecasting and dealing methods for horizontal wells. Based on RSI safety index theory of pipe sticking, pipe sticking risks forecasting model suits for Bingham model and Power Law model of drilling fluids have been established considering the influence of temperature on drilling fluid performance. And forecasting results can used to optimize drilling fluid performance and flow rate, thereby, pipe sticking index can be improved and pipe sticking risks can be reduced. Moreover, sticking position calculation method of combination string with iterative method has been founded through considering friction based on drill string and material mechanics, which is fit for sticking position calculation of horizontal wells. Mechanic model of jam releasing by jarring has been established through analyzing jam releasing by jarring process and its effect via using oscillation theory, momentum conservation law, energy conservation law and so on. This model has effectively reduced the influence of friction to jar force, which is suit for jar force evaluation of jam releasing by jarring for horizontal wells and extended reach wells. A software of pipe sticking forecasting and handling analysis has been developed on the basis of research above, which can effectively analyze sticking risks during horizontal wells drilling process and calculate the sticking position and provide enough evidence for accident handling methods analysis and jam release results evaluation.A software of pipe sticking forecasting and handling methods for horizontal well drilling has been developed on the basis of research in this paper, which combining with pipe sticking forecasting analysis and handling method evaluation. Then design projects of Yuanping1and V1008wells have been evaluated and their applications have been tested. The results show that the software is stable and it can systematically analyze pipe sticking risks and the relevant handling methods for horizontal wells, moreover, analysis results are reasonable, which can satisfy the application of drilling engineering.