Study On The Mechanism Of Dynamic Negative Pressure

Perforation completion technology has become the mainstream way of completion in nowadays. Especially the conventional static underbalanced perforating technology, which gets more general recognition of each oilfield company in the domestic and overseas. But, it is not sure for the conventional static underbalanced perforating technology to get a clean tunnel when it was used in low pressure reservoirs, low permeability reservoirs and dense reservoirs. In order to solve this problem, Schlumberger Company conducts a lot of theoretical and experimental research. They find that the reason why the static underbalanced perforating technology could not clean the perforation tunnel effectively is that it can’t rapidly form a pressure difference between the wellbore and formation. According to this research, Schlumberger Company put forward a new perforation completion technology which called dynamic underbalanced technology in the1990’s. This technology can not only form a larger dynamic pressure difference between the wellbore and formation rapidly, but can gain commercial oil and gas productivity without using the corresponding acid stimulation measures in most cases. It’s significantly improving the economic benefit of oil and gas exploitation.Needing further clarification, there is only a few oilfield companies carried out the original test for dynamic underbalanced perforating technology at present in our country. Our understanding for the mechanism and process method of dynamic underbalanced perforating technology is still in the introductory phase. It seriously hinders the technology to promote in our country. Based on the domestic status quo, this paper mainly has carried out the following research work:(1) Reviewing all kinds of basic mechanism and putting forward several new understanding for deficiency about dynamic underbalanced effect.(2) Establishing a mathematical model of calculating the amplitude of dynamic underbalance during detonation. This model quantifies the various basic mechanism of dynamic underbalanced effect in the true sense and provides a strong theoretical support for the successful application of dynamic underbalanced perforation technology.(3) Comparing and analyzing the related influence factors of dynamic underbalanced effect can make people understand the influenced principle and degree of the micro perforating parameters on the dynamic underbalanced effect.(4) According to the basic process principle of acquiring dynamic underbalanced effect, I design a new instrument which is not only simple in structure, but can recycle use. Besides, this tool also innovate the old face of dynamic underbalanced perforation technology in the domestic.(5) Developing a dynamic underbalanced perforation scheme optimization design software, It is not only filling the domestic blank in this field, but also making the dynamic underbalanced perforation technology truly become a set of systematic perforation completion technology.The research achievements gained from the above five aspects of the research work can not only improve people’s understanding of dynamic underbalanced perforation technology, but also can lay solid foundation for the promotion of dynamic underbalanced perforating technology in the domestic.