The technologies to steady pressure and injection rate and that to reduce pressure and increase injection rate are along with multiple stages of secondary and tertiary oil recovery. The ongoing injection process will subject most wells to pressure rise, reduced injection volume, fouling and plugging of reservoir, and corrosion of tubing string. In this paper, a portfolio of feasible measures can be provided for the steady injection in injection well life cycle by taking a closer look at cleaning & anti-swelling & anti-migrating technology, interlayer pressure influence balancing technology, slow releasing solid acid unpowered acidizing technology, low damage & low reaction rate acidizing technology, and degrading & acidizing technology for polymer injection wells.

Heavy oil reservoirs are widely scattered across China with proved reserves over 10 billion tons, most of which are unconsolidated sandstone reservoirs. As a consequence, some problems are encountered as to the choice of production stimulation and stabilization process. This paper attempts to provide a summary of the geological characteristics of heavy oil unconsolidated sandstone reservoirs and the difficulties of production stimulation reconstruction process, in order to preferably choose the system for cleaning, viscosity reducing, acidizing and unplugging, optimize the construction process of viscosity reducing and acidizing, guarantee that service fluids can enter reservoirs uniformly, and improve the deliverable of chemical production stimulation, which would be taken as a good reference for chemical production stimulation construction of heavy oil unconsolidated sandstone reservoirs.

Corrosion and scale formation of near well-bore zone are common reasons that affect the effectiveness of injection wells. Although conventional stimulation treatments can remove the blockage, many disadvantages occur such as short-term effectiveness, long occupation period, large amount of waste fluid, big environmental impact and limited transportation procurement. In this paper, an environment friendly descaling and formation unblocking technique was found which includes two kinds of treatments. One is called neutral descaling, anti-swelling, liquid circulation cleaning technique(NALC) and the other is called slow release anti-scaling solid acid treatment(SASA). The environment impacts of well stimulation treatments are significantly reduced which would meet the requirements of the “Green Mine” needs.

Injecting polymer materials is an important means to improve the ultimate recovery, maintain stable production and improve the development effect of the oil field in the high water cut period. However, in the development process of polymer flooding, with the continuous increase of the cumulative polymer injection, the problem of high-pressure under-injection frequently occurs in the injection well. In this paper, based on geological characteristics and plugging material analysis, the causes of high pressure/under-injection and production characteristics of different types of measure wells. To study and optimize the rubber breaking, degradation and synergistic acidification liquid system that are applicable to different blockage conditions can effectively improve the adaptability of the blockage liquid system; Meanwhile, the formation of a quick plugging process with the characteristic of “single-stage single-step injection + prescription formula structure” can effectively improve the success rate of polymer plugging process measures, providing strong technical support for polymer flooding technology.

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