Production of hydrocarbon from wells drilled into oil bearing zones for sustained period of time could result in wellbore integrity damage, which is capable of shutting down oil and gas production. To detect such problems, a diagnostic operation is performed to acquire and identify the source(s) of the wellbore integrity damage. The result of this, is raw subsurface well data, requiring further qualitative interpretation to establish causes and solutions to wellbore problems. To improve the accuracy of subsurface well data qualitative interpretation, the data acquiring process must be efficient and painstakingly performed. This work outlines and describes process of acquiring data through well diagnostics. This technique is applied to a well in the Niger Delta area operational for 10 years. The production volume from the well was about 68% lesser than expected rate from the DST result. Magnetic Thickness detection (MTD) and SNT-Temperature log were deployed as a wellbore diagnostic tool. The MTD tool run in the long string of the well from 13,742ft to 10,302ft, helps in detecting End of Tubing of the short string at 10,562.6ft, corrosion detection (Tubing Wall loss) at 12% maximum, perforation depth and casing conditions. The SNT-Temperature tool was run through the entire length of the tubing. It helped in detecting tubing leak at 13,391ft, formation activity between two reservoirs at 13,530ft – 13,560ft and fluid flow from perforation depth. These diagnostic analysis helps in identifying uncertainties in the well bore, thereby postulating direct solutions for the well.

Gas productivity in a gas condensate reservoir declines due to the presence of two-phase fluid present near well bore due to bottomhole pressure lower than dew point pressure. This accumulated condensate reduces relative permeability to gas impairing flow rate and causing a reduction in productivity. This paper introduces a method of injecting gas into near wellbore region to re-vaporize the condensates and improve the permeability of gas and increase productivity. This is achieved by conducting numerical simulations of gas injection techniques by comparing a no-injection case scenario and an injection case scenario. The effect of temperature and compositional effect of injected gas into the reservoir is analyzed, and its impact on increased productivity from the reservoir is recorded. The reservoir is modeled with an in-depth analysis of fluid phase behavior and composition and simulated using Compositional simulation tools from CMG. Results from simulation shows an increment of about 7.5% increase in gas production and about 8% increase in oil produced at a temperature of about 200 deg F considerably higher than 2.4% and 4% gas and oil produced at lower injected temperature of 120 deg F. The above results are also dependent on composition of injected fluids.

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.