Effectiveness evaluation method for low-permeability clastic rock reservoirs based on the lower limit of development permeability

Abstract

The invention discloses a low-permeability clastic rock reservoir effectiveness evaluation method based on the lower limit of development permeability, belonging to the technical field of petroleum and natural gas exploration and development. The method includes: A. The step of obtaining the lower limit of the effective development permeability under the constraint of the initial oil production of the economic limit and the development thickness; B. The step of optimizing the evaluation parameters based on the difference in permeability and scoring a single item; C. Based on the gray relational analysis Steps for calculating the weight coefficient and comprehensive score; D. Steps for the classification and evaluation of the effectiveness of low-permeability reservoirs based on the initial economic fluid production. The method of the present invention solves key problems such as inaccurate calculation of the lower limit of physical properties, difficulty in determining reasonable evaluation parameters, and unclear practical classification standards in the effectiveness classification evaluation of low-permeability reservoirs, and improves the effectiveness classification evaluation of low-permeability clastic rock reservoirs accuracy and practicality.

Description

technical field [0001] The invention relates to oil and gas exploration and development technology, in particular to a method for evaluating the effectiveness of low-permeability clastic rock reservoirs based on the lower limit of development permeability. Background technique [0002] With the continuous improvement of oil and gas exploration and development, the target of clastic rock oil and gas exploration and development gradually shifts to low permeability, ultra-low permeability and ultra-low permeability reservoirs. Because low-permeability clastic rock reservoirs have the characteristics of fine pore throat, complex structure, poor pore-permeability correlation, nonlinear seepage, and strong heterogeneity, the physical properties of low-permeability reservoirs are worse than those of conventional oil and gas reservoirs. According to the classification standard of layers, low-permeability clastic rock reservoirs are all unfavorable reservoirs. In fact, there are also...

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Problems solved by technology

[0008] In view of this, the main purpose of the present invention is to provide a method for establishing actual geological conditions, effective development permeability lower limit, permeability difference (the difference between the reservoir permeability value at a certain depth and the corresponding depth effective development permeability lower limit) ), the economic initial fluid production (average daily fluid production minus the economic limit initial fluid production) is a classification and evaluation method for the effectiveness of low-permeability clastic rock reservoirs to solve the lower limit of physical properties in the effectiveness classification and evaluation of low-permeability reservoirs Improve the accuracy and practicability of the classification and evaluation of the effectiveness of low-permeability clastic rock reservoirs by addressing key issues such as inaccurate calculations, difficulty in determining reasonable evaluation parameters, and unclear practical classification standards

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