Successful Deployment of Combined Mechanical and Chemical Solutions Enabled by Real-Time Coiled Tubing Services to Address Watered Out Well in Southern Europe

Abstract

An innovative intervention strategy is discussed, which was designed to enhance precision and reliability and optimize the performance of a well plagued by excessive water production. Through the unique combination of a mechanical tool, custom chemistry, and state-of-the-art real-time technology, the operator successfully isolated the old, completely watered-out zone and opened a new layer to deliver sustained oil production with 0% water cut (WC). This well presented several challenges; the main one was to ensure effective and reliable isolation of old layers, both inside and outside the liner, before the perforation of new intervals. The inner isolation was achieved through the deployment of a high-expansion bridge plug (HEBP) on real-time hybrid coiled tubing (RTHCT) after the closure of two sliding side doors (SSDs). To establish the annular barrier, a thixotropic organically crosslinked polymer (TOCP) system was combined with cement tail-in after the communication channel was opened at a 40° inclination with an abrasive perforation technique and an acid-soluble abrasive material (ASAM). The modular sensing bottomhole assembly (MSBHA) enabled precise installation of the HEBP for internal isolation of the string. The casing collar locator (CCL) sensor in the MSBHA allowed accurate placement of the HEBP in a low-extended sealbore inside the liner. The electrical setup of the HEBP ensured the placement with confidence and reliability, avoiding the coiled tubing (CT) stretching that occurs in traditional hydraulic setting with CT pressurization. The annulus between the liner and the open hole (OH) was isolated through a two-stage chemical treatment that created a reliable barrier to isolate the watered-out zone: ASAM and a high-pressure jetting tool (HPJT) established communication with the annulus above the HEBP 10 m3 of TOCP was pumped through the CT to penetrate and reduce injectivity of the watered-out zone 1.1 m3 of cement slurry was placed through the CT in the annulus liner/OH via additional perforations made by a HPJT The top of cement was tagged and successfully pressure tested up to 1,300 psi. The new layer was opened with through tubing perforations (TTP) using an electric wireline (EWL) and stimulated with acid. A test of the new layer indicated production of approximately 3,500 B/D with 0% WC, which validated the success of the intervention. The innovative intervention approach outlined confirmed the precision and reliability of RTHCT for an accurate HEBP installation as the mechanical barrier. It also demonstrated the effectiveness of the combined use of TOCP and cement to create a reliable, firm, and durable annular barrier to isolate a watered-out zone. The TOCP, as the first chemical treatment, reduced formation injectivity and provided support for the cement pumped in the next stage.