Method for obtaining effective thickness lower limit of mine reservoir

Abstract

The invention discloses a method for obtaining effective thickness lower limit of a mine reservoir. According to the basic principle, the method comprises the following steps: taking a core from a reservoir to be tested, and respectively performing laboratory test and analysis on the core, so as to obtain porosity data and permeability data of the core; injecting mercury into the core to obtain capillary pressure corresponding to the condition that the injected mercury saturation is 50%, namely mercury saturation medium-value pressure; fitting the mercury saturation medium-value pressure with the core porosity and the core permeability, respectively, so as to obtain a regression relation; and solving a maximum curvature value of a power function curve by use of a first-order derivative, a second-order derivative and the like, so that the corresponding porosity and permeability are the lower limit values. The method is used for calculating the lower limit values of the reservoir physical property by use of mercury saturation medium-value pressure parameters which are capable of well reflecting a pore throat structure of rock, thereby covering the shortage that a conventional method is capable of obtaining the lower limits of the reservoir physical property only by use of an empirical statistical method, and therefore, the accuracy of the obtained lower limits of the reservoir physical property is improved, and meanwhile, the efficiency of obtaining the lower limits of the reservoir physical property is improved.

Description

technical field [0001] The invention relates to the technical field of geophysical logging, in particular to a method for obtaining the lower limit of the effective thickness of a mine reservoir. Background technique [0002] In the process of exploration and development of oil and gas fields, logging technicians are required to timely interpret the obtained downhole logging data and divide effective reservoirs (oil layers, gas layers). The key to the work is to determine the criteria for dividing effective reservoirs ( That is, to determine the lower limit of porosity and permeability). The existing method for obtaining the lower limit of the effective thickness of mine reservoirs is the oil-bearing occurrence method. This method is recorded in detail in the enterprise standard Q / HXJ3026-93 of CNOOC Nanhai West Company. However, in the long-term production practice, the technicians found that the above The accuracy of the lower limit of the effective thickness of the mine ...

AI Technical Summary

Problems solved by technology

The existing method for obtaining the lower limit of the effective thickness of mine reservoirs is the oil-bearing occurrence method. This method is recorded in detail in the enterprise standard Q / HXJ3026-93 of CNOOC Nanhai West Company. However, during long-term production practice, technicians found that the above The accuracy of the lower limit of the effective thickness of the mine reservoir obtained by the method is low. The main reason is that the method is more subjective and uses many estimation processes.

In addition, an important measurement parameter in this method is oiliness, which is not suitable for gas fields

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