Research on Experimental System for Partial Underbalanced Drilling by Coiled Tubing

Coiled tubing modulation locally underbalanced drilling can effectively control the near bit annular pressure at the bottom of the well, and ensure the stability of the borehole above the packer at the same time as the near bit underbalanced drilling is realized. In order to study the underbalance situation of the drilling technology and the law of cyclic pressure loss, the experimental system and device of the continuous tube modulation partial underbalanced drilling were designed and developed, and the pressure distribution and the microspace debris migration test were preliminarily carried out. The analysis results show that the continuous tube modulated local underbalanced drilling test device is mainly composed of test frame, reflux device, rotating sealed rock drainage device and so on. It can simulate the local underbalanced drilling process of continuous tube modulation, and the test system can carry on the change law of the pressure difference near the bit near the bottom of the well, the law of the near bit drilling fluid carrying rock and the micro drilling fluid. Study on the law of carrying rock in annular drilling fluid. The conclusions can provide reference for the field application of continuous pipe modulated partial underbalanced drilling technology.