Studies of Fracture Damage Caused by the Proppant Embedment Phenomenon in Shale Rock

Mateusz Masłowski,Piotr Kasza,Rafał Moska,Klaudia Wilk,Marek Czupski

doi:10.3390/app9112190

Mateusz Masłowski, Piotr Kasza + Show 3 more

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https://doi.org/10.3390/app9112190

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Abstract

This paper concerns the effect of proppant embedment related to hydraulic fracturing treatment. This phenomenon occurs if the strength of a dry reservoir rock is lower than that of proppant grains. The aim of this research was the laboratory determination of the loss of width of the proppant pack built of light ceramic grains. A laboratory simulation of the embedment phenomenon was carried out for a shale rock on a hydraulic press in a heated embedment chamber specially prepared for this purpose. Tests were conducted at high temperature and axial compressive stress conditions. The surfaces of cylindrical core plugs (fracture faces) were imaged under an optical microscope equipped with 3D software. The fracture faces were examined and compared before and after the embedment phenomenon. Analysis of the obtained images of the fracture face was done, based on a research method of the embedment phenomenon developed at the Oil and Gas Institute—National Research Institute. On the basis of the laboratory tests, the parameters characterizing the embedment phenomenon were defined and discussed. In addition, the percentage reduction in the width of the proppant pack was determined.

Highlights

Hydraulic fracturing is one of the main methods for stimulating unconventional hydrocarbon reservoirs
The material used for proppants can range from natural sand grains called frac sand and resin-coated sand to high-strength ceramic materials and resin-coated ceramic materials [11]
The material used for proppants can range from natural sand grains called frac sand and resin-coated sand to high-strength ceramic materials and resincoated ceramic materials [11]

Summary

Introduction

Hydraulic fracturing is one of the main methods for stimulating unconventional hydrocarbon reservoirs. The producing formation is fractured using hydraulic pressure, and proppants are pumped into the fractures with a fracturing fluid [11]. The industry has been making use of slickwater, where the proppant transport is governed by the high velocity of the injected water, unlike polymer-based fluids for which the transporting mechanism is based on viscosity [12]. The literature [12,13,14] has reported a significant use of hybrid technologies that combine slickwater and polymer fluids. In hydraulic fracturing, energized fluids are used (fluids with one compressible component such as nitrogen or carbon dioxide) [15]. The use of a gas component helps to reduce the hydrostatic pressure. It supports wellbore and fracture clean up. The material used for proppants can range from natural sand grains called frac sand and resin-coated sand to high-strength ceramic materials and resin-coated ceramic materials [11]

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