Impact of Completion Technique on Horizontal Well Productivity
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Copyright 1999, Society of Petroleum Engineers, Inc. Open-hole completions are certainly the one most commonly used since the early years of horizontal wells. It is still in wide use today although several other completion options are available. The main reason for alternative well completions is that open holes do not allow flexibility for zonal isolation, future well management, or problem remediation. Thus, partial completions can be envisioned. These can include slotted and blank liner, separated by external casing packers (ECP’s) or segments of the well that are perforated, interspersed by segments that are left non-perforated. The open length of the horizontal well can be reduced and, in many cases, without substantial decrease in the productivity index over a fully open well. This work, using a comprehensive multi- and single-well semi-analytical well performance model shows that for a relatively thin reservoir 40% open to flow distributed into 5 segments would result in over 90% of the open-hole ideal production with all the well exposed to the reservoir. In a reservoir five times as thick the normalized productivity index for the same 40% would still be a very favorable 77%. The length of open intervals can be optimized by balancing incremental production benefits against the costs of well completion. Complete stimulation of the full horizontal is very expensive and cumbersome, while fluid placement is frequently unsuccessful. Furthermore, the very necessary zonal isolation requirements for proper fluid placement are much easier in partially completed wells.
author list (cited authors)
Retnanto, A., & Yamin, M.