In tight oil reservoirs

the upper limit value of permeability is an important parameter

which is used to determine the tight oil reserves and reasonable development way. The existing calculation or determination methods can

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t fully and accurately reflect the geology and development characteristics in tight oil reservoirs. It can

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t even better reflect the characteristics of the seepage and the current unity understanding which is embodied in the development way of tight oil reservoir at home and abroad. On the basis of the research on the methods for calculating the upper permeability limit in tight oil reservoir at hom

e and abroad

by using the seepage theory

and from dense reservoir development and production practice

we proposed a new method

which is used to calculate the upper limit value of permeability in tight oil reservoir by the power function relationship between the air permeability and start-up pressure gradient. The studies show that based on the unified understanding on the development of the tight oil reservoir

although there are some difficulties during it

the tight oil reservoir could realize the effective economic usage through the technology research

and the tight oil reservoir could be difficult to achieve the economic usage of the reservoir under the condition of the development technology. This understanding determines that the calculation and determination of the upper limit value of permeability in tight oil reservoir must fully and accurately reflect the characteristics of the non-Darcy seepage in the tight oil reservoir

which is affected by the start-up pressure gradient. The new method has the theoretical basic. At the same time

the new method not only relies on the mathematical theory

but also is more sufficient in theoretical basis

and more reliable

reasonable and practical than the previous calculation methods. Therefore

it has better promotion value.