| Popis: |
Oil fields of the Samara region are at a late stage of development, which is reflected in declining of their production level and rapid growth of watercut. About 30% of the region's industrial hydrocarbon reserves are concentrated in carbonate reservoirs, which require stimulation. Low reservoir pressure, heterogeneity of the formation and the proximity of water-saturated interlayers significantly complicate the task of efficient field development and exploitation. In such conditions, the use of traditional methods for treating the bottomhole zone of carbonate rocks does not bring the expected results, and the worsening stock of exploited objects makes it necessary to look for new promising methods for increasing oil recovery. Carbonate reservoirs stimulation in the Samara region is carried out using a spectrum of various technologies of hydrochloric acid treatments, both to extend the life of old wells and to efficiently start new wells after drilling. In order to increase the effect from the performed hydrochloric acid treatments in 2016, the foam diverting technology was applied in the framework of pilot projects. This technology uses a stable non-damaging agent to form a nitrogen foam of 65% quality at the bottom hole. After the treatment, the foam breaks down into liquid and nitrogen, which in turn improves well flow back and helps to restore the natural flow. Despite the high degree of field development, the use of foam made it possible to achieve a 69% greater initial well productivity index than other methods. At the same time, the starting production rate of wells increased almost 2 times. The technology also allowed to reduce the specific volume of injected acid per meter of oil saturation by 25% without compromising the efficiency of the treatment, what has key importance from the point of view of economic feasibility. Based on the results of the performed pilot operations, nitrogen-foam acid treatments were included in the regular program of wells stimulation. |
