Research and Application of Long-life Water Injection Technology in High Water Cut Stage

The average service life of water injection strings in Shengli Oilfield is 3 years. In 2019, there were 20,060 workover operations, with workover costs reaching 6.297 billion yuan, and the oil production loss caused by workover occupancy amounted to 66,000 tons, which has seriously restricted the efficient development of the oilfield. Faced with the challenge of deteriorating overall development efficiency of water-flooded reservoirs in the high water cut stage of Shengli Oilfield, and based on meeting the full-life cycle functional requirements of separate-layer water injection strings for water wells, a multi-functional integrated separate-layer water injection string featuring "balance compensation + drillable bidirectional anchoring + multi-medium injection" was designed. It has been promoted and applied in 204 well times accumulatively, reducing 46 workover operations in total and saving 11.54 million yuan in expenses. This technology has prolonged the workover cycle of water wells and shown significant advantages in saving material input, reducing environmental pollution, and increasing effective production time. It has a very broad application prospect in oilfields both at home and abroad, and is of great significance for improving the sustainable and efficient development of water-flooded oilfields.