Improve Plugging Efficiency in Fractured Sandstone Reservoirs by Mixing Different Preformed Particles Gel Size

Abstract

The oil recovery from fractured reservoirs is usually low, which is usually caused by the existence of areal formation heterogeneity. Preformed particle gel PPG has been used successfully use to reduce Heterogeneity and improve sweep efficiency. Low salinity waterflooding (LSWF) was recognized by the oil industry to increase displacement efficiency. The main objective of this study is to test the effectiveness of coupling these two technologies to increase oil recovery. Additionally, this study will determine the optimum PPG size to use with LSW to improve conformance control in the fractured sandstone cores. Semi-transparent five-spot model made of sandstone cores and acrylic plates were built to visualize the sweep efficiency from the coupled methods. Sandstone cores were saturated by 1.0% NaCl and then light oil was injected to simulate initial water saturation before the fracture was made. Brine at different salinities was injected initially into the fracture model to determine oil recovery. PPG with different sizes was injected later to reduce the fracture conductivity and increase sweep efficiency. Brine was injected again after gel treatment to determine the oil recovery improve after the gel injection. Laboratory experiments showed that the oil recovery factor and the water residual resistance factor (Frrw) increased when the low-salinity water was used for injection. However, the PPG extruded pressure decreased when the PPG swelled in a low-salinity water. Additionally, mixing different PPG size resulted in higher plugging efficiency than uniform PPG size and Frrw decreased as increased flow rate. Combining two different preformed particle gel sizes can improve plugging efficiency and, in turn, improve sweep efficiency and enhance conformance control.

Meeting Name

SPE Kingdom of Saudi Arabia Annual Technical Symposium and Exhibition 2017 (2017: Apr. 24-27, Dammam, Saudi Arabia)

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

The authors would like to express their grateful acknowledge to the financial support from DOE under the contract of DE-FE0024558.

Keywords and Phrases

Efficiency; Fracture; Mixing; Sandstone; Sodium chloride; Water injection; Well flooding, Conformance control; Displacement efficiency; Fracture conductivities; Fractured reservoir; Fractured sandstones; Initial water saturation; Laboratory experiments; Residual resistance factor, Petroleum reservoir engineering

International Standard Book Number (ISBN)

978-151084198-7

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Apr 2017

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