Shale oil reservoir stratum micro-pore structure characteristic and multi-type pore fluid identification method

Abstract

The invention discloses a shale oil reservoir stratum micro-pore structure characteristic and multi-type pore fluid identification method. The method comprises the following steps: 1) pretreating a rock core; 2) injecting a KCl solution at high pressure, and then injecting formation water at normal pressure to obtain a nuclear magnetic resonance T2 spectrum in a completely saturated water state; 3) dividing the pore structure into three types according to the distribution form of the nuclear magnetic resonance T2 spectrum in the completely saturated water state; 4) sequentially centrifuging under different rotating speed conditions, measuring the nuclear magnetic resonance T2 spectrum of the rock core in different centrifugal states, and determining the optimal centrifugal force; 5) repeating the step (2), carrying out heat treatment on the rock core centrifuged by the optimal centrifugal force, and respectively measuring nuclear magnetic resonance T2 spectrums of the rock core at different temperatures; and 6) according to the T2 spectrum distribution, calculating to obtain T2 cut-off values T2C1 of the movable water and the bound water and T2 cut-off values T2C2 of the capillary bound water and the unproduced water. By adopting the method disclosed by the invention, the pore structure characteristics and pore fluid occurrence and migration rules of the shale oil reservoir stratum can be determined.

Description

technical field [0001] The invention belongs to the field of oil and gas development, and relates to a shale oil reservoir microscopic pore structure feature and a multi-type pore fluid identification method. Background technique [0002] my country's shale oil and gas resources are rich and have great potential for development. However, shale oil reservoirs are characterized by low porosity, ultra-low permeability, poor pore structure, and serious heterogeneity, which have brought great challenges to large-scale commercial exploitation. How to optimize high-quality reservoirs is the key to determining whether shale oil can increase and stabilize production. [0003] Due to the complex mineral composition and pore structure characteristics of shale, the types of pore fluids vary widely. Accurately classifying different types of pore fluids is the key to selecting high-quality shale oil reservoirs. Generally, shale pore fluid types can be divided into mobile fluid and bound f...

AI Technical Summary

Problems solved by technology

At present, those skilled in the art use conventional sandstone evaluation methods when studying the NMR characteristics of shale. However, compared with ordinary sandstone, shale pore throats are denser, and the content of organic carbon and clay minerals is higher, so the pore structure characteristics must be obvious. Differences, due to the limitations of objective understanding and experimental methods, making the T 2C2 The research progress of T 2C2 The determination of the value is of great significance for evaluating the production performance of shale oil in the later stage

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