Deep Well Cementing Gas Channeling Mechanism And Application Technology Research

With the development of the exploration, more and more deep natural gas is exploited. However, the annular gas channeling seriously restricted the development. The major hazard of the gas channeling reflects in: destructing the integrity of the cement sheath; impacting on the cementing quality; impacting on the testing evaluation and reasonable exploitation of the reservoir; causing wrong judgments because of the reservoir pollution; impacting on the subsequent operation of oilfield development such as acidification fracturing and layer exploitation and so on; involving the safety of the personnel, equipment and field operation because it could cause blowout accident after cementing. So how to prevent and control the annular gas channeling has been an industry research focus. Now there are many theories, methods and means to prevent and control the gas channeling, but the gas channeling problem remains unresolved and the success ratio to prevent the channeling is still low.By means of introducing and improving the gas channeling simulation experiment device, the gas channeling factor method evaluation mathematical model and its computer software are established. The device combines the theoretical derivation with experiment to study the gas channeling formation causes, leading way and its prevention and control technical measures; analyzes the migrational mode of the gas in the annulus borehole; evaluates factors like the cementing slurry system, operation technology and well structure's influences on annular gas channeling. Based on the study of the mechanism evaluation, a high temperature-resisting cement slurry system to prevent gas channeling is developed, which can resist the high temperature to 180℃. The system meets the technical requirements of the deep well and be benefical to prevent gas channeling.