A Porosity Correction Method of Clay Altered Volcanic Rocks

Abstract

The invention discloses a method for correcting the porosity of a volcanic rock suffered from clay alteration. The method comprises the following steps: selecting a representative volcanic rock core,determining whether there are alterations and alteration types, and measuring the conventional porosity and clay content of the rock core suffered from clay alteration; analyzing the response characteristics of the volcanic rocks suffered from clay alteration on conventional logging curves, and selecting four conventional logging curves which are sensitive to clay alteration; considering the weight of influence of each curve and determining formula combination forms so as to construct a curve which can comprehensively reflect clay alteration degree of the volcanic rock through a sensitive logging curve; constructing a target stratum clay content calculation model through the clay content and the calculated alteration degree curve obtained from the whole rock mineral analysis; and finally correcting the porosity of the volcanic rock suffered from clay alteration by the physical model of the study area in combination with clay content curves. The method achieves continuous correction ofthe porosity of the volcanic rock suffered from clay alteration and improves the calculation accuracy of the porosity of the volcanic rock suffered from clay alteration.

Description

technical field [0001] The invention belongs to the technical field of well logging evaluation of complex oil and gas reservoir formations in petroleum exploration, and in particular relates to a method for calibrating the porosity of volcanic rocks by clay alteration. Background technique [0002] In oil and gas exploration, an important parameter in logging interpretation is the quantitative calculation of porosity. The calculation of formation porosity mostly adopts three-porosity curve, which is the basis of porosity calculation and plays an important role in logging evaluation. It has been widely used both in conventional clastic rocks and in complex lithology reservoirs. [0003] With the continuous deepening of oil and gas exploration, complex formations such as volcanic rocks have gradually become the focus of exploration. Compared with clastic rock reservoirs, volcanic rock reservoirs generally have a larger burial depth, various rock types, and strong heterogeneit...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for calibrating the porosity of clay-altered volcanic rocks in view of the problems existing in the prior art. The method utilizes core petrophysical experiment data and conventional logging data to establish clay-altered volcanic rock porosity calculations model to address the high porosity calculations of clay-altered volcanic rocks

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