The equipment commonly used in managed pressure drilling (MPD) allows alternative responses to kicks that do not need to stop the pump or shut in the well. The pivotal issue of kick control for MPD is the early gas influx detection and the optimal initial response when the kick was detected during drilling. The careful research on gas influx detection and the corresponding control method is very important.

Firstly, the valve opening, bottom hole and well head pressure variation characteristics were analyzed based on the real-time measured data, and then the valve opening and pressure signature of gas influx for different MPD modes (CBHP, CWHP, MFC) was obtained based on the theoretical and model analysis, in which the pressure variation caused by the tripping, ROP and flow rate variation were taken into account, through which the gas kick can accurately detected as soon as quickly. Secondly, the influence factors for initial response selection of kick control was analyzed, and then the comprehensive optimization schedule of response for kick control was established, in which several factors were took into account, such as formation characteristics, drilling conditions, influx intensity and so on, through which the best mode for kick control can be obtained easily. Moreover, integrated software that combined kick detection and gas kick control simulation was developed based on which the best pressure control procedure and kick initial response can be obtained easily.

The gas influx detection and control technique has been applied in Fuling shale gas field of SINOPEC, which is the first large-scale commercial development shale gas field of China. The results show that we can make precisely gas detection based on the new early gas influx detection method and the kick can also be control very well based on the optimization method. Based on the proposed method for kick detection and control, the NPT have been reduced more than 60%.

This study will presented a novel gas kick detection theoretical model for all common MPD modes, and the gas influx control optimal procedure. Through the field application in shale gas drilling, the results show that the NPT has been reduced obviously, and the optimal kick control was designed has successfully prevented the serious kick and reduced the drilling cost.

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