An Evaluation Method for Screen-Only and Gravel-Pack Completions

Abstract

Abstract Screen-only and screen with gravel-pack completions have become more commonplace in long horizontal wellbores in poorly consolidated reservoirs. Several of the formations currently being completed pose challenges in selecting effective sand-control screens due to their non-uniform particle size distributions and the large amount of very small particulates. Early screen and gravel-pack studies, from which common scaling factors were derived, did not always contain the smaller particle sizes that are encountered in poor quality reservoirs. Later studies have shown that both the fines content and the uniformity of the sand impact the performance of the completion7-13. This paper presents an evaluation method for screen-only and gravel-packed completions utilizing formation sand samples. The method determines the amount of solids produced through the screen and the change in flow capacity of the screen and formation sand pack with increasing stress. The flow capacity data is useful in estimating production changes as wellbores collapse around the screen and the formation porosity around the screen decreases. The amount of formation particles that pass through the screen or the gravel-pack and screen is useful in estimating the solids production. Data is presented which illustrates the amount of small particles, which can penetrate wire-wrapped and premium screens, along with gravel-packs and gravel-packed screens. Data will be compared for gravel-packs based on conventional scaling factors of 5-6 times the median diameter and other scaling factors.