Study On The Principle And Optimization Of Nitrogen-assisted Production Increase In Steam Huff And Puff Wells

Nitrogen injection has a good improvement effect on all kinds of problems in the process of steam huff and puff,clarify the principle of increasing production and optimize the process,which will enhance the effect of auxiliary nitrogen measures under different production conditions.In this paper,taking the typical well groups in the 3 block of Jinglou and 67 block of Biqian as examples,the research on the principle of increasing production and the optimization of nitrogen assisted drainage and nitrogen water plugging measures are studied.Through the comparison of the effect of three-dimensional physical simulation experiment and numerical simulation,the principle of increasing production of two measures is clarified,and the main control factors are studied by orthogonal experiment.According to the analysis of development status of two numerical reservoir model,the well with the advantage of carrying out auxiliary nitrogen measures are selected,and their injection and production schemes are optimized.An optimization model for nitrogen injection is established with the optimization results,and the end time of the auxiliary nitrogen measures is further studied,and the application chart of end time is drawn.Through the analysis of temperature distribution,pressure changes and oil saturation,it is clear that expanding the range of steam heating,supplementing formation energy,restraining edge water invasion and decreasing the water cut are the main principle of nitrogen assisted measures to increase production.Through the analysis of orthogonal experimental results,the main control factors of nitrogen assisted measures are determined as reservoir thickness,recovery degree and edge water energy.The nitrogen injection volume of 8 wells in two reservoirs is optimized,and the mathematical optimization model of nitrogen injection is established.The oil-steam ratio chart under different thickness and recovery degree is drawn,and the range less than the extreme oilsteam ratio is taken as the end time of auxiliary nitrogen measures under various production conditions.