A Comprehensive Methodology For Well Ramp-up of Open Hole Stand-Alone Screen Completions
Following the unloading of completion fluids, wells face the most critical step of ramping up production toward a peak rate for the first time. The challenge is delivering the maximum rate with limited well performance information and without damaging the completion integrity at the same time. This research develops a production surveillance methodology to monitor and ramp-up production for open hole stand-alone screen (OH-SAS) completion that optimizes production by considering risks of production impairment and screen erosion failure. Laboratory evaluations of drill-in fluids showed non-uniform filter cake clean-up or presence of “pinholes” resulting in concentrated inflow around the wellbore. A combination of laboratory return permeability tests, CT scans and a developed reduced order model determines the pinhole size and filter cake properties to calculate the total pinhole flow area or concentrated inflow velocity using an established relationship. The pinhole inflow velocity is distributed into the radial and axial annular flow velocities in the OH-SAS wellbore using a network flow model to assess the screen erosion failure risks from direct impingement and convergence at the top of the screen assembly, respectively. The ramp-up strategy is to use successive PBU data of increasing production rates and evaluate the absolute and relative changes of completion pressure drop and velocities against established failure criteria. The application of filter cake properties and PBU data showed the internal filter cake permeability has the most dominant effect on the inflow velocity. The completion pressure drop as a function of flow rate is non-linear and higher than the case without pinholes. Results from the network model showed that convergent velocity is higher than the impingement velocity. Adding screen above the pay interval reduces the screen impingement erosion risk but increases the annular scouring risk. Scouring velocity is found to be significantly higher than the convergent velocity. This highlights the need to consider screen and borehole failure due to scouring erosion. The convergent velocities for pinhole and non-pinhole cases were similar and the implementation of pinhole in this methodology only affected the completion pressure drop or the completion impairment risk.