First Successful Application of CT Sand Jetting and Multi-Stage Proppant Fracturing on Horizontal Well in Carbonate Reservoirs in Iraq

Abstract The ultra-low permeability carbonate S Formation (permeability <0.1 mD) in Iraq's X Oilfield accounts for 23% of total reserves, yet contributes only 0.3% of total production due to ineffective conventional development. Through pilot trials, 38 horizontal wells utilizing open-hole multi-stage proppant fracturing achieved an average production of 1,200 BOPD per well. Building on this success, ‌a pioneering casing-cemented well‌ integrating coiled tubing (CT) sand jetting with multi-stage proppant fracturing to achieve more frac stages was implemented in September 2024—the first application of its kind in Iraq. This paper analyzes the pilot well (H1X) to demonstrate the technical viability of this approach for ultra-low permeability carbonate reservoirs. To ensure the success of this campaign, a holistic technical study including geology evaluation, reservoir performance analysis, drilling trajectory design, completion and fracturing technique design have been carried out based on principle of "geology-engineering integration". This paper will present a comprehensive illustration including technical design (CT perforation, main completion-fracturing technique, total scale optimization, fracturing fluid, proppant), job execution and post-frac production performance for this successful campaign. Through holistic design, the pilot well(horizontal length: 1536 m) was optimized with 29-stage CT sand jetting & proppant fracturing, with a total fluid volume of 10099 m³ and a total sand volume of 1134.6 m³. The well has achieved a production breakthrough of 2227 BOPD (28/64″ choke) after frac. Compared with other open hole fractured horizontal wells, the estimated production index in is around 4.2 BOPD/psi, 2-4 times of other wells. As the Middle East's first cased-hole multi-stage fracturing in ultra-low permeability carbonates, this case study sheds light upon and provides ‌a replicable template‌ for unlocking similar challenging reservoirs.