Completion method to allow dual reservoir saturation and pressure monitoring

摘要

A well completion method provides for monitoring of reservoir pressure and saturation levels for two reservoirs from a single monitoring well. The well completion extends vertically through an upper and a lower reservoir. The well is cased, cemented, and perforated across the lower reservoir. A cement free zone is formed by cementing the casing string within the wellbore above an external casing packer above the upper reservoir. The casing string is perforated to allow fluid from the upper reservoir to flow through the cement free zone. A tubing string is landed and set within the casing string. The tubing string is sealed above and below the perforation at the cement free zone to prevent communication between fluid from the upper reservoir and the lower reservoir. The upper reservoir is monitored at the cement free zone, and the lower reservoir is monitored below an end of the tubing string.

主权项

1. A well completion method comprising the steps of:
(a) drilling a wellbore through an upper reservoir and a lower reservoir that are within a subterranean formation, wherein the upper reservoir is at a higher elevation than the lower reservoir; (b) running a casing string through the upper and the lower reservoir; (c) setting a lower external casing packer between the upper and the lower reservoirs in an outer annulus between the outer diameter of the casing string and the wellbore; (d) setting an upper external casing packer in the outer annulus above the upper reservoir; (e) cementing the outer annulus below the lower external casing packer; (f) cementing the outer annulus above the upper external casing packer, thereby creating a cement free zone in the outer annulus between the lower external casing packer and the upper external casing packer to facilitate logging measurements of the upper reservoir; and (g) saturation logging in the cement free zone, after cementing the outer annulus below the lower external casing packer and after cementing the outer annulus above the upper external casing packer to obtain information about the subterranean formation adjacent the cement free zone.