Optimization of perforated liner parameters in horizontal oil wells

Nowadays, horizontal wells play a vital role in the production from thin heavy oil reservoirs. Designing a suitable completion for this kind of reservoirs is a decisive factor to boost the efficiency of durable production. This study deals with the optimization of perforated liner design for horizontal wells in Sarvak oil reservoir, which is located in the southwest of Iran. Sarvak is a carbonate oil reservoir, but it contains shale and mudstone. To avoid solid production and formation collapse, the screen liner was selected as a cost-effective solution. There were two choices, either perforated liner or slotted liner. The perforated liner was selected by finite element analysis and strength checking, which was proven by laboratory experiments. Sensitivity analysis was performed on various perforated parameters such as phase angle, hole density, hole diameter and hole distribution to determine the pattern of the holes so that enough strength of the liner was maintained while maintaining the maximum hole density. Then, parameters of perforated liner were determined by calculated loss of the flowing path, collapse resistance strength and tensile strength of casing pipes after perforated. As a result, hole density, hole size and perforated pattern were selected 100 HPM, 10 mm and 4-thread-line, respectively, in 4 ½” liner with 13.5 ppf. The ratio of the strength of the optimized perforated liner was less than 8% for collapse and 5% for tensile compared to the same specification casing.