Patent attributes
A process for plugging a wellbore, e.g. an oil or gas well, comprises installing a choke device (1) into the wellbore in order to increase the back pressure to allow better control when introducing cement to plug the wellbore. The device (1) has a cylindrical shape with a central through bore (6). On the external profile is a shoulder (4) which, when the device is installed in a wellbore, comes to rest against a nipple in the wellbore. The device (1) may free fall for all or part of the way down but would normally be pumped down at least for the last part of its delivery. In the bore (6) is a pump out ball (10) which blocks the through bore until the device reaches the nipple and stops, at which point pressure increases and the ball is ejected. Cement and other liquid may then be pumped through the choke device to the distal region of the well.
