Improvements in EOR Screening, Laboratory Flood Tests and Model Description to Effectively Fast Track EOR Projects

Abstract

Abstract One of the operator's main concerns on EOR projects is related to the time to reach the pilot test stage. This paper aims to support a fast tracking of the implementation of Chemical EOR Projects. The proposed techniques and tools shorten this time and reduce cost associated to carry out key phases such as the EOR Screening, the Laboratory Core Flood and the Geological and Reservoir Modeling by making use of simple yet effective techniques. A comprehensive Integrated and systematic Workflow is presented that allows a reduction of associated uncertainties and the implementation time and to serve as a tool for a comprehensive EOR Project Management. A developed EOR-Screening System utilizing algorithms of neural networks and genetic algorithms, enabled a rapid and reliable selection of the most appropriate EOR method from among 8 available methods (steam injection, miscible/immiscible CO2, miscible hydrocarbon, in-situ combustion, polymer injection, surfactant injection y ASP,). The EOR Screening method was applied to fields located in the Marañon basin of the Peruvian jungle fields of heavy and light crude, resulting in Steam-Injection and chemical ASP Injection as the most appropriate methods. The problematic of multiple Chemicals to be pre-selected in flood experiments is addressed by using a testing loop that incorporates a developed capillary model that utilizes predefined granulated sand in a glass holder that enables multiple tests in short time. Sets of Laboratory Flood Tests were carried out in 3 core flow model types; a capillary tube and a synthetic solid core, both showed good repeatability and significantly reduced time and cost for Core Flood Tests. Target reservoirs are usually real core constrained and synthetic cores are used, however those have a wide range of permeability rarely matching the required ones. Therefore, a solid synthetic core was developed based on a blend of sand, and chemically neutral additives that allow adjusting the permeability as needed. Both the Capillary model and the synthetic solid core allowed a fast qualitative and quantitative evaluation of multiple chemical EOR products. Specific geo-reservoir description best practices from prior EOR field applications are shared such as defining non-sealing faults, proper candidate selection prior numerical simulation, in the environment of data scarcity among others. Those aim to fast tracking EOR Projects. Specific Improvements to Fast Track EOR Projects are presented. The first one relates to a novel EOR Screening Method that expands the current systems by including more input variables and EOR Methods. The second one relates to laboratory core flood experiments that are improved by adding a capillary model to preselect the chemical and a solid core of adjustable permeability range to run slug size optimization experiments. The geological-reservoir model description is enhanced by using techniques that enable both defining nearby non-sealing faults and proper selection of the production-injection candidate wells using well-field production-pressure history, prior of using numerical simulation.