A new type of experimentally proposed in situ heat/gas clean foam fracturing fluid system

Abstract

When cold fluid is injected into low-temperature, low-pressure, low-permeability reservoirs containing wax-bearing heavy oil, cryogenic paraffin deposition and heavy oil condensation will occur, thus damaging the formation. Moreover, the formation pressure coefficient is low and the working fluid flowback efficiency is low, which affects the fracturing stimulation effect. Therefore, an in situ heat/gas clean foam fracturing fluid system is proposed. This system can ensure that conventional fracturing fluid can create fractures and carry proppant in the reservoir, generate heat in situ to avoid cold damage, reduce the viscosity, and improve the fluidity of crude oil. The in situ heat fracturing fluid generates a large amount of inert gas while generating heat, thus forming foam-like fracturing fluid, reducing fluid loss, improving proppant-carrying performance, improving gel-breaking performance, effectively improving crack conductivity, and is clean and environmentally friendly. Based on the improved existing fracturing fluid system, in this paper, a new type of in situ heat fracturing fluid system is proposed, and a system optimization evaluation is conducted through laboratory experiments according to the performance evaluation standard of water-based fracturing fluid. Compared with the traditional in situ heat fracturing fluid system, the fracturing fluid system proposed in this study generates a large amount of inert gas and form foam-like fracturing fluid, reduces fluid loss, enhances the proppant-carrying capacity and gel-breaking performance, improves crack conductivity, the gel without residue and that the gel-breaking liquid is clean and harmless.

Numerical Simulation of Rock Breaking by High-Temperature and High-Pressure Water under Thermal Driving

“…This method takes advantage of the low viscosity, high expansion rate, and high diffusivity of high-temperature fluids and gets satisfactory fracturing results. Until then, some scholars have studied the influence of temperature on rock breaking, but these studies are limited to cracking caused by crude oil viscosity reductions [32] or temperature differences [29]. Therefore, on the basis of relevant previous work, this paper studies the mechanism of the rapid rock-breaking process by high-temperature and high-pressure fluid under thermal driving through numerical simulation.…”

Study on Micro Displacement Mechanism of Hydraulic Fracturing by Oil Displacement Agent at High Pressure

“…Its high viscosity and low fluid loss can satisfy the needs of fracturing and carrying sand [25][26][27]. In order to further improve the fracturing performance effect, various fracturing fluid systems have been developed successively, such as crosslinked polymer gel fracturing fluid system [28], foam fracturing fluid system [29], VES fracturing fluid system [30,31], cellulose fracturing fluid system, and so on [32]. These developments have improved the temperature resistance, shear resistance, sand carrying capacity, and wall building performance of the fracturing fluid system.…”

Study on gelation, temperature resistance and micromorphology of modified nano-ZrO2 crosslinked hydroxypropyl guar gum

“…With the continuous development of oil and gas resource exploitation technology, the formation reconstruction technologies, such as waterflooding (Bryant et al 1993), acidification (Evans et al 2001) and fracture (Wang et al 2013), have been paid more and more attention and widely used in the field of oil and gas fields, especially fracture plays an irreplaceable role. Fracturing fluid is mainly divided into water-based fracturing fluid (Geetanjali and Amit 2017; Zhang et al 2020), oil-based fracturing fluid, foam fracturing fluid, slippery water fracturing fluid and so on, and among which water-based fracturing fluid is the most widely used in oil and gas resource exploitation (Pei et al 2020). According to the type of thickener (Fu et al 2017), water-based fracturing fluid can be divided into hydroxypropyl guar gum fracturing fluid, carboxymethyl guar gum fracturing fluid, hydroxypropyl-carboxymethyl guar gum fracturing fluid, cellulose fracturing fluid and xanthan gum fracturing fluid and hydroxypropyl guar gum (HPG), a high-performance organic polymer (Azzahari et al 2018), is widely applied in oil and gas exploitation because of its environment-friendly (Wang et al 2008;Singha et al 2017), low price (Jain et al 2005;Manjunath et al 2016), abundant resources (Yang et al 2018;Jayachandrabal and Thirugnanasambandam 2018) and excellent performance (Li and Liu 2008;Carvalho et al 2018).…”