ASP Flood Application for a High-Temperature, High-Salinity Carbonate Reservoir

Abstract

The goal of this work was to develop a highly efficient alkaline-surfactant-polymer (ASP) process applicable to a high temperature (~100 °C), high salinity (~60,000 ppm) giant carbonate reservoir with very low surfactant retention, an essential requirement for low chemical cost. Phase behavior tests were conducted with anionic surfactants, alkali, co-solvents, brine, and crude oil to identify chemical formulations with ultra-low IFT under reservoir conditions. Corefloods were first conducted in outcrop carbonate cores and then in reservoir cores. The effluent was analyzed for oil, surfactant, pH, salinity and viscosity. Pressure drop was monitored across 4 sections of the core to monitor front propagation. Surfactant adsorption on carbonate surfaces decreases at high pH. The conventional alkali used for ASP floods of sandstones is sodium carbonate. However, sodium carbonate cannot be used in formations containing anhydrite, which is the case for the target reservoir. For this reason, ammonia, sodium hydroxide and a new organic alkali were studied for this application. Ultralow IFT (~0.001 dynes/cm) was achieved with several ASP formulations using the reservoir oil. Coreflood experiments using both outcrop limestone and carbonate reservoir core were conducted using these alkalis. The coreflood results showed good oil recovery and low surfactant retention.

Improving heavy oil recovery, part (I): synthesis and surface activity evaluation of some novel organometallic surfactants based on salen–M complexes

“…The b value is a measure of the counterions present in the stern layers, which counterbalance the electrostatic forces of repulsion among polar head groups. [34][35][36] As temperature increases, the value of b increased showing an increased tendency to micellization in the bulk phase. As a result, DG mic was observed to increase on the negative side with a temperature rise, showing increased micellization spontaneity.…”

Low-tension gas process in high-salinity and low-permeability reservoirs

“…Upamali et al (2016) reported up to 90% oil recovery post-waterflood at 68 °C using a blend of ethoxylated propoxylated carboxylates and IOS. Abalkhali et al (2019) reported tertiary oil recovery up to 90% in ASP corefloods using a blend of ethoxylated propoxylated carboxylates and IOS for carbonate rock at 100 °C and 60,000 ppm salinity.…”

Surfactant Adsorption on Shale Samples: Experiments and an Additive Model

“…They reduce interfacial tension between oil and water and help mobilize trapped oil after water flooding. Surfactant flooding has shown promising results in both laboratory and field-scale efforts. − The use of surfactants in shale reservoirs is relatively new. Kim et al reported that oil recovery from surfactant-treated Eagle Ford shale cores improved significantly compared to cores treated with a baseline fluid containing no surfactants .…”