Classification Standard and Fine Evaluation of Tight Oil in Fuyu Layer in Northern Songliao Basin

Abstract

Fuyu reservoir in the north of Songliao Basin belongs to the typical subtropical tight oil type. The effective evaluation method of tight reservoir is mainly embodied in two aspects: fine classification and vertical subdivision. The purpose is to realize the remaining resource potential of tight oil and find more accurately favorable enrichment areas. Combined with the study of sedimentary and sand body characteristics, By means of constant pressure mercury injection, high pressure mercury injection and microcosmic nano-analysis, it confirms the tight reservoir in Fuyu oil layer can be divided into three categories, namely I-1, I-2 and II. The boundary between tight oil reservoir and conventional reservoir is porosity 12%, permeability 1 mD, pore throat radius is 350 nm. The remaining I-1 and I-2 classes, as well as the I-2 and II standards, respectively, with porosity of 10% and 8%, the permeability of 0.25 mD and 0.1 mD as the boundary, corresponding to the pore throat radius are 150 nm and 75 nm. Based on the fine study of the longitudinal subdivision layer, each layer of sand groups contains only 1–2 sand bodies. It further defines that the I class reservoir mainly develops in FI2-1, FI3-1 and FII2-2 sand group. The remaining resources of different types of tight oil are implemented by layer, and through tight oil horizontal well drilling and large volume fracturing, tight oil resources can be used effectively.

Copyright 2019, IFEDC Organizing Committee.

This paper was prepared for presentation at the 2019 International Field Exploration and Development Conference in Xi’an, China, 16–18 October, 2019.

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