A Successful Polymer Pilot of 18%Stooip Drives a Fast Sweet-Spot Based 80-Injectors Modular Polymer Expansion
Authors: Juri Dr Juan-E. , Schein Florencia , Ruiz Ana , Serrano Viviana , Guillen Paula , Thill Mercedes , Kichick Lucas , De Miranda Victor , Mac Donald Walter , Figueroa Emilio , Robina Nestor , Vera Maximiliano , Figueroa Emilio , Di Pauly Fernando , Rojas Walter , Ojeda Natalia , Lucero Ariel , Alonso Pablo , Funes Fernando , Campos Hector 
Published: August 2020

After the successful pilot (18%STOOIP incremental oil, Juri et al. 2017 and utility factor of 1,76 kg polymer/bbl) of two technologies, 0.3 pore volume (PV) continuous polymer injection followed by 0.3PV high-frequency water-alternate-polymer, a series of multiple simulations cases indicated an optimal extension of 3-year cycle −0.4 to 0.6PV of polymer injection- in a cyclic modular development.

Despite all the advantages of polymer injection, few full-field expansions emerge because there are many challenges in integrating multiple disciplines -lab studies, subsurface reservoir modeling, engineering, energy, procurement, logistics, storage, project management-. All parties find it difficult focusing on a common goal and streamline the decision process.

It has long been thought that the EOR road map means planning for large scale EOR. However, that is false in the sense that there are very few full-field injections. The past strategy in EOR has led to a few pilot extensions implemented. Planning for large-scale EOR suffers from having incremental oil, uncertainty in oil price, uncertainty in economic drivers, uncertainty in technical solutions for the expansion and management uncertainty in the same time frame, which undermines economics. What it seems to be the only way to make progress with EOR is that EOR should align with planning for quick oil response in a time frame of three to five years.

We present here the steps to accelerate EOR in the Grimbeek field from a 4-injectors pilot to 80 new injectors in a fast, less than 18 months deployment. We compare the capital and operating cost of multiple expansion scenarios. The scope is to accelerate EOR deployment opposite to the slow typical EOR workflow. We have seen the opportunity in accelerating the oil focusing on a simple modular strategy rather than iterating multiple possible engineering solutions to distribute the polymer across the field. NPV of the overall project is higher than the costs of delaying the injection or having to redo parts of the implementation along with the deployment. Future optimization is necessary for options of logistics, storage, in-situ skid connection and mounting along with by-pass remote control valves and remote control of injection skids.

The building blocks of the strategy are containerized mobile skids containing ten pumps, polymer dispersion unit, and 30-metric ton silos that target the by-passed oil zones, so-called sweet-spots. These sweet-spots emerge from detailed 3D subsurface simulations. The mobile skids plug-in the waterflooding manifolds in an easy and fast connection. We risk saying that standard modeling lacks showing a complete mapping of the remaining oil in the subsurface and therefore we could under-predict polymer flooding potential.

This injection scheme distributes polymer using the already implemented waterflooding in-situ installation. We focus on having a simple, standard and mobile system targeting fast implementation and fast oil response that can move to the next sweet-spot to increase rapidly the production rather than large facilities that take longer to design and construct and have limited flexibility.

The oil response shows a faster response than expected in the range of three to four months despite a reduction in the target polymer injection rate because of issues in the water availability. The oil rate displayed good recovery values, thus, demonstrated the efficiency of the proposed higher concentration dosage mechanism for inducing additional crossflow.