Publications

A major operator in Sumatra Indonesia has both heavy and light oil fields. The heavy oil is located in Duri field. Duri reservoir consists of three main zones, Rindu, Pertama and Kedua, with open hole and case hole gravel pack completions. The reservoirs are injected with steam to provide sufficient heat to decrease viscosity of the oil to make it flow easily. Most of the crudes in the area have a high content of asphaltene and wax, causing organic deposits (locally called “congealed oil) in the liners, which will lead in to production decline. Organic deposition worsens and accumulates if left untreated.The operator has tried to increase the injection rate of the steam to get the congealed oil dissolved and able to be produced, with poor results. A method for dissolving the accumulated organic deposition caused by asphaltene and wax content was required. A mixture of Xylene (Aromatic solvent), mutual solvent, and diesel to dissolve asphaltene and wax content was selected and lab test was performed to test the solubility of the congealed oil when mixed with mixture of xylene, mutual solvent, and diesel. Coiled tubing was selected for placement of the fluid. The solvent mixtures were conveyed to the selected zones. A mechanical rotating jetting toolwas used to clean the plugged liner from organic deposition. The combination of methodical candidate well and zone selection, lab tested fluids (xylene, mutual solvent and diesel), a rotating jet tool, and Coiled Tubing conveyance resulted in improved production results. A multi well campaign was performed and the results are discussed.