Title: Experimental evaluation of imbibition effect in Mahu conglomerate reservoirs

Authors: Jing Zhang; Jianhua Qin; Xibin Fan

Addresses: Research Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, China ' Research Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, China ' Research Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, China

Abstract: Since hydraulic fracturing fluid plays a significant role in the soaking process, it is interesting to present a study of the imbibition effect by slickwater, brine and guar gum. In this paper, we conducted an experimental study of the imbibition effect on recovering the tight Mahu field, which are the largest discovered conglomerate reservoirs. The recovery performance by different imbibition fluids was compared. Nuclear magnetic resonance (NMR) technique was used to understand what type of pore scale contributes mostly to the imbibition recovery process. Laboratory results indicated that the lowest interfacial tension in some sense is adverse to spontaneous imbibition. The imbibition rate with the largest interfacial tension is the highest. When the bond number falls in a value where both capillary forces and gravity drainage play a role in the recovering process, the oil recovery factor is significant in this case. The oil recovery factor by slickwater imbibition is 40.76%, which is much higher than brine and guar gum. It is observed that the slickwater displacement still recovered additional oil after the imbibition process. [Received: August 17, 2021; Accepted: January 2, 2022]

Keywords: imbibition; conglomerates; bond number; recovery mechanism.

DOI: 10.1504/IJOGCT.2022.126372

International Journal of Oil, Gas and Coal Technology, 2022 Vol.31 No.3, pp.280 - 296

Received: 16 Aug 2021
Accepted: 02 Jan 2022
Published online: 24 Oct 2022 *

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