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Chapter 11 – WELL CONTROL                                        275






                    Instead of a BOP designed to close in the well, a diverter is used during

                 drilling (fig. 11–12). This is comprised of a large bag preventer, underneath
                 which are two large side outlets (up to 12" diameter) with some kind of full

                 opening valve system. Once the well starts to flow, the side outlet facing
                 downwind is opened, and the bag preventer is closed. Flow from the well
                 gets diverted downwind, away from the rig.


































                 Fig. 11–12. Diverter with large-diameter side outlets
                                                              Photo courtesy of Schlumberger.

                    Dynamic kill


                    Dynamic  killing  is  a  method  for  stopping  an  influx  by  increasing


                 annular pressure losses (that is, the pressure required to force mud to flow

                 in the annulus). This pressure increase comes from pumping fluid as fast
                 as possible into the well.











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