Simulating and evaluating method for acidification of carbonate heavy-oil reservoir

Abstract

The invention relates to a simulating and evaluating method for acidification of a carbonate heavy-oil reservoir. The simulating and evaluating method comprises the steps of i) sample preparation and parameter measuring: taking a rock core sample of an oil reservoir, performing oil washing on the rock core sample, and preparing an acidification simulating experiment rock core through replacing the rock core by crude oil; ii) linear flow acid-etching hole simulation and acidification evaporation: perform linear acidification on the acidification simulating experiment rock core, measuring various parameters, then scanning the rock core by means of a three-dimensional imaging analysis system, obtaining a three-dimensional digital picture of the acidification hole, and finally obtaining a tortuosity factor through analysis; and iii) radial flow acid-etching hole simulation and acidification evaluation: performing radial acidification on the acidification simulating experiment rock core by means of an acid solution, ending after radial breakthrough, scanning the cross section of the rock core by means of the three-dimensional imaging analysis system, and analyzing the obtained acid etching image for obtaining a fractal dimension.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and relates to an acidification simulation evaluation method for carbonate heavy oil reservoirs. Background technique [0002] Acidizing is one of the effective measures to increase the production of carbonate rock reservoirs. Due to the complex reaction mechanism between acid and carbonate rock, there are many influencing factors, and because of the unstable dissolution phenomenon in the acidizing process, that is, acid erosion wormholes, the carbonic acid It is difficult to predict parameters such as the effective action depth of acid liquid in the acidizing process of salt rock by pure theoretical calculation methods, and the optimization of construction parameters and effect prediction must also rely on indoor simulation methods. [0003] At present, there is no unified standard for carbonate rock acidification simulation evaluation. Usually, the linear displacement expe...

AI Technical Summary

Problems solved by technology

[0003] At present, there is no unified standard for carbonate rock acidification simulation evaluation. Usually, the linear displacement experiment is used to measure the breakthrough time and breakthrough volume of acid liquid, which can reflect the impact of core mineral distribution and pore throat structure on acidification to a certain extent. However, it is impossible to determine the morphological characteristics of acid-etched vugs in the radial flow of acid liquid, and only approximate methods can be used to deal with it, and it cannot reflect the influence of formation fluid properties on the formation and expansion of acid-etched vugs. However, for heavy oil reservoirs, since the crude oil contains colloidal asphaltenes, it is difficult for the acid liquid to contact the rock wall under formation conditions, which affects the acid-rock reaction, thereby affecting the formation and expansion of acid-etched pores. Conventional indoor acidification simulation evaluation method, the prediction results and the actual will inevitably have a large difference

Images