Koloda, A. V. (Gazprom Neft Shelf LLC) | Morozov, O. N. (Gazprom Neft Shelf LLC) | Panarin, A. T. (Gazprom Neft Shelf LLC) | Mukhametshin, I. R. (Schlumberger) | Bulygin, I. A. (Schlumberger) | Shestov, S. A. (Schlumberger) | Ksenofontova, A. A. (Schlumberger)
The pdf file of this paper is in Russian.
The reservoir of Prirazlomnoye field is composed of carbonate rocks. Premium port completion technology—a valve with an inflow/injection control device—was piloted in the Arctic offshore environment, allowing selective stimulation of the bottomhole pay zone and high-rate injection via both the ports and an inflow control device (ICD). This technology mitigated the risks of premature water breakthrough in the production well and improved the waterflood performance. The project began with the analysis to justify the use of premium port technology with ICD in the horizontal well based on the reservoir simulation model. The use of a slotted screen was compared against the premium port with ICD scenario. Then the project entered the second phase that involved well operations. Following the drilling and petrophysical interpretation of well logging data, the completion system parameters were computed to identify the number of premium port valves, packer installation intervals, and the number and sizes of ICD nozzles for each zone. This was followed by selective treatment with hydrochloric acid at specific pressures and injection rates. The horizontal hole was divided into five sections, each having a premium port valve for injection with ICD and an acid injection premium port. The intervals were separated by inflatable annulus packers. Every successful opening/closure of the valve was clearly observed at the surface. After the acid stimulation job, the well was successfully tested and brought into injection. The joint efforts of the drillers, completion engineers, and reservoir simulation engineers resulted in the selection and installation of suitable premium port valves and ICDs, driving the well performance close to its design parameters.
The simulation of the proposed technology using a sector model has shown a 5% increase of cumulative oil production against a 10% decrease of cumulative water production. Implemented in the existing offshore Arctic field, premium port technology has enabled selective acid treatment in individual reservoir zones, making it possible to reduce the skin to–1.4 on the average. This experience may be of interest to engineers in charge of selection of downhole equipment for challenging environments both on the continental shelf of Russia and beyond.
This paper offers an entirely new approach to the completion of horizontal wells enabling selective stimulation and injection management without the use of intelligent well completion systems in the harsh environment of the Arctic shelf. This technology has made it possible to mitigate the risks of water breakthrough into the production well and to improve the performance of the waterflood system.