Four expandable completion liners (ECLs) have been run in Algeria in two fields - these are the first ECLs in Algeria, the first worldwide in gas wells and the first worldwide in multilateral wells. This paper is the first detailed benchmark study of ECL performance.
All systems to date have been run in 8 ½″ hole using 5-1/2″ base pipe ECL compliantly expanded, and the installations went well.
It has been possible to compare ECL performance data against a comprehensive surveillance data set for the two fields where data from existing openhole completions allow meaningful comparisons. The other completions consist largely of slotted liners and some barefoot completions. The tested production rates in each of the wells have been high relative to normal field trends; however, the predominant factor in this is the reservoir character. PBU analysis indicates that the second well has reduced Darcy skin, while it is considered unproven in the first well (more data over time is needed). There is, however, consistent evidence for a reduction in rate-dependent proportion of total skin in both wells. This is supported by other studies and a consideration of basic principles.
The reduction in the rate-dependent proportion of skin has given an increase in production rate of 5-20% as compared to the computed rate from a slotted liner. This difference assumes no borehole collapse, with analyses and discussion presented of the effect on well performance should borehole collapse occur.