Comparative Mechanistic Simulations to Design an ASP Field Pilot in La Salina, Venezuela

Abstract

In La Salina field, located in the Maracaibo Lake, Venezuela, which produces a medium gravity crude oil (25 ° API) from a Miocene reservoir at 3,000 feet, a series of EOR processes were proposed to be evaluated under field conditions. Results from laboratory tests indicated that Alkali-Surfactant-Polymer technology (ASP) might be a potential EOR process to improve the oil recovery factor. However, ASP processes involve the injection of a significant volume of chemicals, therefore, costs associated with this technology could exceed the economical limit permissible. For this reason, it is necessary to use simulation tools to predict reservoir production response when this technology is applied.Results from early ASP simulations have been reported elsewhere [1,2].The present study shows the results of modeling the injection of ASP in a pilot area of La Salina field, using two commercial simulators. The pilot area has been partially depleted by waterflooding, therefore the reservoir still contains mobile oil saturation. Based on laboratory history matches of radial core floods, several field predictions were carried out which show an incremental oil recovery factor between 6% and 16.7% compared to waterflooding, depending on the selected well arrangements and the volume of injected chemicals. The results of the two simulators were compared at both PETROLEUM SOCIETY CANADIAN INSTITUTE OF MINING, METALLURGY & PETROLEUMscales, and in spite of formulation differences between them, the answers were very similar. Additionally, sensitivities on certain critical variables that can influence the success of future tests were established. These include chemical formulation variables such as interfacial tension reduction and component adsorption levels, as well as field injection rates, treatment volume, and injection time. Also, different well arrangements were evaluated, including drilling and positioning of infill wells. The simulations have given confidence with regard to the applicability of ASP in the La Salina field, and preparations for a pilot test are underway.

A comprehensive review of alkaline–surfactant–polymer (ASP) flooding

“…The EOR studies on the Caracara Sur field in Llanos Basin, Columbia were conducted, but a field pilot or an application has not been seen reported. Several papers have been presented about the design and preparation of the offshore ASP pilots in two fields, St. Joseph in Malaysia and La Salina in Venezuela . The field application results have not been seen reported in the literature.…”

Laboratory evaluation and numerical simulation of the alkali–surfactant–polymer synergistic mechanism in chemical flooding

“… 21 Using commercial simulation software CMG to design and simulate field pilot, Moreno et al and Van et al indicated that it is possible to increase oil recovery dramatically by ASP flooding. 22,23 Farajzadeh et al coupled a multi-purpose dynamic reservoir simulator (MoReS) and geochemistry software program (PHREEQC) to provide a versatile tool for ASP flooding numerical simulation. 24 …”