Cost-Effective Sand Control Remediation in HPHT Gas Wells: A Rigless Through-Tubing Straddle System

Abstract

High-pressure, high-temperature (HPHT) gas wells that are completed across unconsolidated sands are vulnerable to formation sand production, which can significantly impact production performance, erode surface infrastructure, and pose long-term well integrity risks. This paper presents the design considerations, qualification testing, and field trial results of the rigless retrievable through-tubing gravel pack (TTGP) straddle system in HPHT gas wells. Conventionally, post-production sand control methods typically involve rig-based interventions–where a new sand control lower completion is installed following a sidetrack or section mill-out. This approach is capital-intensive with significantly elevated carbon footprint. As the industry shifts toward leaner, lower-emission operations, this paper presents rigless, retrievable TTGP straddle system that offers a technically viable, lower-impact and sustainable alternative. The new system enables targeted sand control restoration without the need for a rig, making it particularly suitable for HPHT assets where minimizing cost, downtime, and surface footprint is critical. This retrievable TTGP straddle engineering system is deployed through existing production tubing utilizing slickline for system installation and coiled tubing conveyance for the gravel pack operation. Designed for slim-bore access, the system incorporates high-strength, thermally resilient, sour and corrosive service large bore straddle packers and premium corrosion-resistant screens, enabling precise isolation and gravel placement across sand-producing intervals. The retrievable nature of the straddle ensures flexibility for future well re-entry or zone reconfiguration, which is critical in dynamic HPHT production scenarios. The proposed rigless through-tubing gravel pack straddle system demonstrates significant economic and operational advantages. Quantitative analysis confirms the solution reduces sand control intervention costs by up to 60% compared to conventional rig-based methods. This substantial cost reduction is achieved through three primary mechanisms: elimination of rig mobilization costs, reduction of total intervention time, and minimization of deferred production losses. Furthermore, the system delivers notable environmental benefits, including reduced fuel consumption and lower associated emissions. Field implementation confirmed the system's effectiveness in restoring production while maintaining complete well integrity under high-pressure, high-temperature conditions. Post-installation monitoring verified successful sand control with production rates stabilizing at target levels. This research presents the engineering design considerations, qualification testing, and field trial results of the rigless retrievable TTGP straddle system in HPHT gas wells. Emphasis is placed on system integrity under extreme conditions, deployment efficiency, sand control effectiveness, and overall operational value as a fit-for-purpose alternative to conventional workovers.