Unconventional Approach to Managing Kick During Gas Well Drilling

Interruption in drilling operation occurs when drilling bit penetrates permeable gas sand with formation pressure greater than the pressure exerted by the drilling fluid in use. Consequently, due to pressure imbalance, there is an extraneous influx of gas into the wellbore, which would bring the drilling progress to a stop as it is necessary to restore pressure/fluid equilibrium throughout the system to contain the kick. This study presents a case study where a gas kick was unconventionally managed. While drilling 8 ½" hole at 11,682 ft, a mud gush shooting up through the rotary table to the stabbing board was observed. In attempt to shut-in the well, an accidental shear of the pipe at the surface occurred with the top of fish at 51 ft and with no means of circulating out the influx from the bottom of the well. Due to the well control issue, the cut pipe could not be reached to mill the top of the fish, prior to engaging same. The well was therefore put under control employing Lubricate and Bleed (LB) approach, which is a well control procedure applied in peculiar cases or situation, this is a method or procedure of removing gas in hole when there is no possible way of circulation. The sheared pipe located at about 52 ft below rotary, the Top Of fish was dressed from 51ft to 52ft and the string was eventually severed at 11460 ft, the rest 222 ft of fish was recovered using Overshot, Burn Shoe and Wash-Over assembly. With the effective application of the LB approach, the well was restored, and fish recovered within a relatively short period of time such that values weren't eroded. The approach employed in this study could be applied in a case of accidental shearing of the pipe such that the whole drilling progress is not brought to a total stop. The consequence of not exploring this approach is an additional cost of drilling a sidetrack well or totally abandoning the well. This paper can be used as a training tool to sharpen and build confidence in tackling well control using volumetric bleeding method. As this method is rare, and not simulated for during most well control certification exercises, it will be beneficial to a practicing engineer and can reduce some of the errors that could occur in a rare case of sheared pipe / well control.