Research and Application of Bridge Eccentric Zonal Water Injection Technology with Continuous Adjustment and Surface Monitoring
Authors: Liu Yang , Song Zuchang , Wang Xudong , Gai Xubo , Lai Xueming , Hu Shifeng , Liu Baoyou , Zheng Jie 
Published: November 2020

Bridge eccentric zonal water injection is a mainly technology for zonal water injection. However, there are some disadvantages of existing bridge eccentric zonal water injection technologies, such as fixed water nozzle size requires multiple fishing operations, multiple tests and nozzle replacements. In addition, whether the replacement of the nozzle is appropriate depends on the experience of the operator. The disadvantages also include low accuracy of downhole flowrate test for each layer, high difficulty of sealing test for packers, low operational efficiency, etc.

This paper proposes a bridge eccentric zonal water injection technology with continuous adjustment and surface monitoring. This new technology includes continuously adjustable downhole regulator, bridge eccentric water distributor, integrated measurement and adjustment technology of downhole water injection rate and electrically controlled sealing test for packers.

The continuous adjustable downhole regulator had been designed with a brand new water nozzle construction. The water nozzle is composed of two parts. The outer nozzle is fixed. The inner nozzle can move up and down in order to adjust water injection rate continuously. In this way, water distribution accuracy can be improved. The regulator can be installed in the side pocket of water distributor. It also can be fished out in order to replace it in some conditions. Bridge eccentric water distributor adopts the new design of right-angled bridge channel, which will effectively eliminate the influence of inter-layer interference and benefit sealing tests for packers. With integrated measurement and adjustment technology, downhole water injection rate for each layer can be measured and adjusted by using a test instrument that can be run in hole via a cable and docked to downhole regulator. The entire measurement and adjustment process can be controlled from surface via the same cable. This technology can obtain injection rate, pressure and temperature of each layer online. Packers' sealing status can be tested by using electrically controlled sealing test. The test instrument runs in hole by using a cable. Furthermore, the setting and unsealing of the rubber sleeve in the seal test instrument can be controlled from the ground. Test result also can be monitored from the ground through cable.

Until recently, this technology had been applied in 612 wells with maximum depth 2250m, maximum deviation 43.4°, up to 5 injection layers. Compared with existing technology, water distribution accuracy of a single well is improved by 22 percentage points. Besides, the time cost of flowrate measurement, adjustment and packer sealing test is shortened from 3-5 days to 4-6 hours. The efficiency is significantly improved. The result of research provides a brand new zonal water injection technology with continuous adjustment for oilfield development and management home and abroad. This technology has broad application prospects.