The deposition of scale in the near-well formation and production string can result in a significant decrease in well productivity. Properly designed scale inhibitor squeezes can successfully prevent scale deposition and extend well performance. Even though most wells in the Tengiz field produce virtually water free oil (less than 1% watercut (WC)), inorganic scales have been observed in many of these wells. Frequent acid stimulations are required to maintain the optimum well performance.
An extensive research project was initiated to reduce the need for frequent acid treatments and still maintain well deliverability at sustained rates. To identify an effective scale inhibitor product, inhibitor-brine compatibility testing and dynamic tube-blocking performance testing were conducted. Field application of the selected inhibitor in both low and high rate wells has verified the effectiveness of the squeezes. Treatment with the scale inhibitor attained sustainable well productivity and delayed the need for subsequent acid stimulation treatments.
This paper will share the best practices in scale inhibitor design, inhibitor selection, identification of well candidates, the execution and post treatment surveillance stages. Case studies shown to illustrate the performance of scale inhibitor squeezes in Tengiz.