Sand-Control Reliability: Finding the Sweet Spot

Abstract

Guest editorial Sand control represents a diverse range of technologies designed to meet the demands of hydrocarbon recovery from weak sandstone formations. Although the technology is developing and improving, industry adoption of new sand-control techniques is typically much slower than for oilfield technologies in general. While is it often necessary to control the unwanted production of reservoir sand into the wellbore, sand-control techniques to varying degrees add cost and complexity, yet are operationally unforgiving and have relatively poor long-term reliability. Added to that is a single-point critical failure mode in a completion that is often both unrecoverable and unrepairable. The challenge, then, is to provide sand-control technology that addresses these weaknesses and to select solutions that will maximize value for any given application. This fundamental challenge is unchanged from the time when sand control was first installed in wells more than 100 years ago; what has changed is the variety and complexity of applications. For example, extended reach, high rate, deep water, high-pressure/high-temperature, heavy oil, multilateral well construction, and reservoir segmentation all place differing demands on the sand-control completion but all represent higher-cost environments in which maximizing the return on investment is essential. In response to this increasing diversity and criticality, the industry has seen an increasing range of sand-control techniques. There are now at least 20, many of which are “new,” have evolved, or are under development. But since none is a panacea, how do we evaluate and rank this increasing range of options and application challenges to maximize net present value (NPV)? There are three key factors in determining NPV: cost, performance, and reliability. The cost element is relatively simple. Operating expenditure, capital expenditure during installation, and the cost of failure—lost production and remediation—can be readily quantified. And generally, even for new techniques, the tools exist to model the well performance and confidently predict (at least) relative performance. While the performance of sand-control completions for some solutions is determined by the productivity reduction that occurs due to skin damage or wellbore size reduction, performance can also be positively influenced. Sand control with stimulation techniques or chemical treatments can increase productivity, and inflow-control technology can be combined to aid wellbore cleanup and improve ultimate hydrocarbon recovery. More recently, options for additional functionality have been introduced to provide degrees of reservoir management. Having quantified cost and performance, what is left is reliability, and herein lies the challenge that is in many ways unique to sand control.