Gas Injection And Mobility Control In Fractured Oil Wet Carbonate Reservoirs

Author : Van Si Le
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.3/5 (795 download)

DOWNLOAD NOW!

Download or read book Experimental Investigations of Gas Injection Based Enhanced Oil Recovery Processes in Ultra-tight Oil Reservoirs written by Van Si Le and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tight oil reservoirs have gained immense interest from the global oil and gas industry as a promising alternative to the rapidly depleting conventional hydrocarbon resources. As only a small fraction of the original oil in place can be commercially recovered during the primary production stage, the remaining oil in the matrix has always been the target of various Enhanced Oil Recovery (EOR) techniques. In the first part of this study, the oil production from a fractured tight core sample was investigated under natural depletion and cyclic gas injection mechanisms performed above and below the bubble point pressure of the oil phase. For the first time, a whole core sample (4 inches in diameter) retrieved from an unconventional oil reservoir in North America was utilized for core-flooding tests under high pressure and high temperature (HPHT) conditions. After a primary depletion process, the first cycle of gas injection, whether commenced at a pressure above or below the P[subscript]bp, efficiently extracted and mobilized a considerable amount of oil from the tight matrix region. The efficiency of hydrocarbon gas on incremental oil recovery under a specific injection scheme was demonstrated. However, an effective methodology for better conformance control for the gas injection process was needed, which was addressed in the second part of this study. In the second part of the study, different experimental protocols were conducted to evaluate the essential role of foam in assisting the gas injection EOR processes. In the first stage of this research initiative, we systematically studied the impacts of key foam generation parameters, such as injected gas fraction (i.e., foam quality), surfactant concentration, brine salinity, operating pressure, and total injection rate, on foamability and foam stability of different foaming agents in the fracture media under extreme reservoir conditions. To this end, experiments were conducted on water-wet and oil-wet unconsolidated porous media. The performances of dynamic foam generated in situ with variations of multiple parameters were evaluated extensively to identify the optimal injection design for field applications. Among different surfactant candidates, one anionic and one amphoteric surfactant were selected for the pilot trials based on their performances in porous media of different wettability. The optimal foam quality and surfactant concentration for both foaming agents were identified to be about 85% and 0.4 – 0.5 wt%. In the final stage of this research section, we conducted two core flooding experiments to verify the critical role of foam in an EOR process using one of the selected surfactant candidates. Similar to previous core flooding tests, the experiments were conducted using a 4-inch diameter Minnesota outcrop sample applying identical testing procedures. After the primary production step, one cycle of foam injection boosted the fracture-matrix pressure gradient due to significant mitigation of gas mobility. However, the introduction of the aqueous phase was found to possibly trap a notable amount of oil within the fractured medium, as well as hinder the gas-oil countercurrent flow around the fracture-matrix interface.