Publications

This paper highlights the process and results of stimulating a re-entry well with an existing 10-stage completion system on a 5-in., 18 ppf liner using a 2 ⅞-in. lower completion tubing, at a true vertical depth (TVD) of 6,592 m and a total depth (TD) of 7,164 m, with a horizontal section length of 447 m. Several methods of acid fracturing such as bullheading, ball sealers and limited entry perforation techniques were considered, however, due to their inherent limitations, the effectiveness of these conventional methods is typically restrictive for horizontal wells in a heterogeneous reservoir. The complexity and operational inefficiency of deploying coiled tubing at this location caused the operator to explore completion options other than the mechanical diversion method of plug and perf technique for multistage stimulation. The operator selected a field-proven multistage completion system using hydraulically set mechanical packers to straddle and isolate each of the perforation sections. Ball-actuated fracture ports were utilized for accurate placement of treatment fluids in each section of the well. A 10-stage acid fracture stimulation was planned in order to achieve precise placement of treatment fluids along the entire length of horizontal sections in the targeted Ordovician carbonate-fractured cavern reservoir buried deep in the Hanilcatam field of the Tarim Basin. With high treating pressures and pump rates anticipated for the job, the slimhole cased hole re-entry completion system needed to be robust while still being able to be deployed through the existing 5-in., 18 ppf, 109 mm (4.276-in.) liner. The re-entry completion system also needed to provide the largest possible inside diameter (ID) to lower the pumping friction back pressure. The paper also captures some techniques used for smooth execution of the stimulation treatment, and how this system enabled the operator to achieve the desired operational efficiencies and improve production flowback as a whole.