| Popis: |
Many West Africa Offshore Fields are maturing and operators are completing secondary targets in their wells to maintain the economic operation of their valuable assets. However, off-shore environment makes the capital expenditure associated to this kind of interventions of critical importance. It follows that the selection of the right and most remunerative activities is crucial. In the Kitina Field, offshore Congo, deeper sands have been produced to economic depletion and reservoir studies allowed the determination of alternative production intervals for production maintenance. Large quantities of reserves can be found in low permeability, consolidated, formations as well as in very deep and remote culminations. During the first semester of 2007, the Kitina field production increased of 160% reaching a production level lost since early 2004. This was achieved with a variegate set of actions on different reservoirs: 1st) infilling the Kitina South culmination with the long reach and ultra deep well KTM-SM5, 2nd) a massive multistage hydraulic fracturing campaign carried out on the three wells draining the low permeability 3A reservoir and 3rd) with the sweep optimization of the reservoir 1A. Eight propped hydraulic fractures were placed in three re-completed, cased-hole wells with very significant production improvements. These represented the first applications in Congo of different technologies opening a wide range of further applications in similar environments. The paper describes the 2007 and 2008 Kitina rejuvenation campaign with an eye to all the disciplines involved, from reservoir engineering and modeling, to operation geology, drilling and completion, production. The papers focuses with more detail on the successful multi-stage hydraulic fracture campaign from the preliminary design and production forecast pre-job to the reservoir model history match and forecast phase post-job. Interesting reservoir engineering overviews of the future development of the field via improved and enhanced oil recovery techniques are also presented. |
