A Well Test Interpretation Method for Reservoir Fracture-Vug Characteristic Parameters

Abstract

The invention provides a well test interpretation method for characteristic parameters of fractures and vugs in oil reservoirs, comprising the following steps: establishing a well test model according to the combination relationship between fractures, caves and wellbore and oil reservoir parameters; obtaining Laplace according to the well test model space bottom hole pressure solution function, and calculate the theoretical bottom hole pressure data according to the bottom hole pressure solution function; fit the theoretical bottom hole pressure data and the measured bottom hole pressure data to obtain the fluid in the fractures and caves. The parameters of passability, wellbore storage coefficient, channeling coefficient when karst caves supply fluid to fractures, fracture-vug storage capacity ratio, fracture length and cross-sectional area, and karst cave volume parameters. Compared with the numerical simulation discrete model, the model of the present invention is simpler and more convenient to solve, and can directly explain the volume of large-scale karst caves and characteristic parameters of fractures, and can directly give the size of the karst cave volume, and at the same time, the length and cross-sectional area of ​​the fracture system can also be obtained. It can be easily used to calculate the reserves of a single well.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and more particularly relates to a well test interpretation method for oil reservoir fracture-cavity characteristic parameters. Background technique [0002] The reservoir space of carbonate fracture-cave reservoirs is dominated by karst caves. Currently, the commonly used methods for interpreting the characteristic parameters of fractures and caves include seismic fracture-cavity carving method, material balance method and well testing method. [0003] The seismic fracture-cavity carving method is based on the fine processing of seismic data. First, the attributes of seismic energy bodies are extracted and spatially carved, and then the volume of energy bodies is calculated. Finally, seismic anomalies and geological anomalies are obtained through a large number of forward modeling results. The correction coefficient between the two, so as to obtain the real characteristic p...

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Problems solved by technology

[0007] However, in the above method, the characteristic parameters of fractures and caves obtained by the seismic fracture and cave carving method are the characteristic parameters of fractures and caves of seismic anomalies, not the characteristic parameters of fractures and caves of geological anomalies. It is difficult to determine the conversion coefficient between them; the material balance method to calculate the characteristic parameters of fractures and caves needs to calculate the comprehensive compressibility coefficient, formation pressure, water influx and other parameters more accurately, and it is difficult to determine these key parameters of fractured cave reservoirs. large, leading to low accuracy of calculation results

The existing continuum well test interpretation method has poor adaptability to large-scale fractured-cavity reservoirs, and cannot calculate key parameters such as cave volume in fractured-cavity reservoirs

The modeling process of discrete fracture-vuggy network well test interpretation method is complex and costly, which is not conducive to the widespread use in oilfields

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