Research On Formation Protection Technique During Injecting Water In Daqingzijing Area

Formation protection technology is a strongly systematic technology, which runs through the whole process from the drilling to the development and production, every steps of the reservoir protection can't be ignored. Most of the oil fields at home and abroad are using injected water to develop, the quality of injected water will have a direct impact on oil field development effect. In recent years, Jilin Oilfield in conventional water-flooding development has done a lot of work, but also has achieved fruitful results, particularly the complexity and low-permeability and concealed lithology oil reservoir in Daqingzijing Area is efficiently developed. But it reveals that the pressure of injection wells is elevating, oil production is declining rapidly, injected water and formation water has poor compatibility during the development process,which seriously impacts the speed and effectiveness of the oil field development. Therefore, how to improve water quality, reduce formation damage in the process of injecting water for protecting formation is becoming an important issue in Daqingzijing Oilfield.The internal injuries caused by injecting water in Daqingzijing area are researched by the comprehensive analysis of the reservoir seepage properties, micro-pore structure characteristics, sensitivity, compatibility, etc., it is clear that reservoir itself complexity and uncertainty lead to inconsistent water quality standards and can't generally use a kind of water quality standard for development.At the same time, it is clear that the external causes of reservoir damage in Daqingzijing oilfield is seriously exceeded water quality objectives, water quality failure by analysing the status quo of injected water quality.Taking into account the combination of internal and external damage cause, and can be compared on a single platform, while getting a clear formation damage degree due to internal and external cause ,it applys fuzzy gray-element theory to assess the adaptation extent of injected water to formation. Result proves that the approach is convenient and reliable. The article also has launched a swelling experiment, fluid compatibility tests and flow experiments about different water indicators. On the basis of the above given comprehensive study, water quality improvement measures in Daqingzijing oilfield are obtained to protect the reservoir and greatly enhance the effects of oilfield development.