Semianalytical Productivity Models for Perforated Completions


This paper discusses the effects of various perforation and reservoir parameters on the productivity (or injectivity) of perforated completions. Because of the complex, 3D flow into a spiral system of perforations, productivity analysis of perforated completions is not easily amenable to analytical treatment. This paper presents a semianalytical solution for the estimation of skin in perforated completions. Results are presented for two separate cases: the 2D-plane-flow problem, which is essentially valid at small dimensionless perforation spacings (large perforation penetrations or high perforation shot densities) and the general 3D problem, where the vertical convergent flow into perforations is significant. In these analyses, the wellbore and vertical-flow effects are quantified in terms of pseudoskins obtained by accurate finite-element simulations. The effects of perforation damage and formation anisotroyp are also included. The results provide a better understanding of the relative role of various perforation parameters in affecting well productivity. Because they are based on theoretical considerations, the correlations allow reliable estimates of the skin in perforated completions. New relations are provided for estimating productivity of perforated completions with formation permeability damage. Results indicate the importance of angular phasing, in addition to perforation penetration, in overcoming the effects of formation damage on well productivity.


Mining Engineering

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Article - Journal

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© 1991 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Jan 1991