Liquid-measurement method for quantitatively evaluating penetration rate of natural-micro-fracture-development tight reservoir under pressure applying condition

Abstract

The invention relates to a liquid-measurement method for quantitatively evaluating the penetration rate of a natural-micro-fracture-development tight reservoir under the pressure applying condition. The liquid-measurement method is characterized by including the steps that geological modeling and numerical reservoir simulation serve as a basis, the concept of the water absorption intensity index is led into, a relationship chart between the water absorption intensity index of a water injection well and the penetration rate of a geologic model is built, and then the actual water absorption intensity index of the water injection well in a natural-micro-fracture-development area is counted; according to the principles of the same water absorption intensity index of the water injection well and the equivalent penetration rate, quantitative evaluation of the rock liquid-measurement penetration rate of the natural-fracture-development tight reservoir under the pressure applying condition is achieved. According to the liquid-measurement method, basic data is provided for evaluation of the yield of an oil-and-gas well, well network deployment and the later development technology policy.

Description

technical field [0001] The invention relates to a method for measuring permeability, in particular to a method for quantitatively evaluating the permeability of natural micro-fractures and dense reservoirs under overburden pressure. Background technique [0002] With the increasingly prominent contradiction between the world's oil supply and demand and the gradual scarcity of high-quality oil resources, the development of ultra-low permeability tight oil resources has become a new topic for the development of my country's petroleum industry. The permeability of ultra-low permeability tight oil reservoirs is generally less than 1mD, from According to previous studies of this type of tight reservoir in the Ordos Basin, natural micro-fractures are well developed in this type of tight reservoir, characterized by “small depth of cut, small opening, and small spacing”. Spacing ≤ 6cm accounts for about 80%, and fracture depth ≤ 20cm accounts for about 80%. The height of a single frac...

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Problems solved by technology

[0003] For the quantitative evaluation of rock permeability with natural micro-fractures, the biggest problem is how to obtain representative natural fractured reservoir cores from the reservoir. According to the literature research, there are three problems: (1) There is heterogeneity in the development of natural fractures, and the scale of drilling cores is small, which affects the representativeness of laboratory test results; (2) The cores with natural fractures taken out from the reservoir under overburden pressure disappear on the ground due to the pressure of the overlying rock , the opening of natural fractures becomes larger, which will lead to an order-of-magnitude increase in the permeability of reservoir rock under ground conditions. Even in the later stage, the test results of indoor reservoir rock permeability still deviate from the real permeability even in the laboratory experiment under the condition of overburden pressure. (3) During the core drilling process with natural fractures, the cores containing micro-fractures are easily broken, and it is difficult to complete the laboratory test; (Water measurement) The method of directly measuring the permeability of rocks with natural micro-fractures by laboratory experiments has great defects.

At the same time, there is no theoretical calculation method for this type of reservoir permeability in published literature.

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