Enhancing Coiled Tubing Reach in Extended Reach Horizontal Wells Using Hydraulic Activated Friction Reduction Tool (HAFRT)

Abstract Managing highly deviated, extended-reach open-hole sections in horizontal wells poses considerable obstacles for coiled tubing (CT) operations, particularly during acid stimulation procedures where achieving adequate tool reach and precise fluid placement is essential. Excessive friction and drag frequently hinder the CT string from reaching target zones, leading to incomplete acid coverage and less effective stimulation outcomes. This paper details a successful field application of the Hydraulic Activated Friction Reduction Tool (HAFRT) designed to mitigate these challenges during open-hole acid stimulation in two horizontal water injector wells, referred to as Well X and Well Y. Both wells had previously experienced several unsuccessful CT interventions, primarily due to high frictional resistance that restricted CT's reach and prevented comprehensive stimulation. In the most recent campaign, a sequence of runs was executed: first with a standard bottom hole assembly (BHA), then with the same BHA combined with acid spotting, and finally with the HAFRT. The deployment of HAFRT was intended to generate axial oscillations along the CT string, minimizing contact with the wellbore and enhancing tool mobility in the challenging open-hole interval. By converting hydraulic energy into gentle oscillatory motion, HAFRT shifts static friction to dynamic friction, thus extending CT reach beyond previous lockup points. This improvement in reach enabled targeted acid placement and more efficient stimulation, which had previously been unattainable due to limited accessibility. The interventions using HAFRT achieved a notable reduction in friction, allowed the CT string to extend beyond historical lockup thresholds, and facilitated effective acid distribution along the entire intended open-hole section. HAFRT was activated at the entry of the open-hole section, which delayed lockup and allowed the CT to traverse challenging hole conditions without buckling, resulting in a significant increase in measurable CT weight at depth. Ultimately, the acid stimulation in Well X was successfully completed with full coverage of the open-hole section, a result not achieved in prior operations. In contrast, although Well Y saw improved access compared to prior CT attempts, complete coverage could not be achieved due to limitations in CT size—highlighting a critical learning point from this operation. Specifically, in Well X, the use of HAFRT improved accessibility by 92% compared to interventions without HAFRT, while the injectivity index (II) increased by 80%. In Well Y, the improvement in accessibility with HAFRT over previous methods was 117%, with a fivefold increase in the II. This paper reviews the application of HAFRT in extended-reach wells to enhance access to sections that conventional CT BHAs cannot reach, thereby enabling effective treatment of the entire open-hole interval. Additionally, it discusses the lessons learned from these case studies, which provide valuable insights for planning future interventions in similarly challenging extended-reach wells.