Executive Summary

Anthony R. Kovscek, Stanford University

In March's executive summary, I noted an increase in the diversity of papers received for review and publication consideration in the SPE Journal. One area of increased activity is that of enhanced oil recovery (EOR), and you will find that approximately one-third of the manuscripts in this issue have some basis in enhanced recovery. Enhanced-recovery research is evolving in scope and topic, however. For example, this issue contains a paper on the in-situ upgrading of oil shale using heat along with the traditional enhanced-recovery topics of polymers, surfactants, foams, phase behavior, and miscible injectants.

The remaining papers also reflect the breadth of research embraced by the SPE Journal. They include optimization for history matching, data integration, and production improvement. Of the papers on optimization, a number implement the ensemble Kalman filter and are representative of a clear trend in this area. Out of curiosity, I searched and found that "ensemble Kalman filter" has a detailed Wikipedia entry already. As a search string, it returns more than 50,000 results, but the number narrows to approximately 2,500 when "petroleum engineering" is included. OnePetro returns approximately 260 results, and this number is sure to grow. The pipeline of manuscripts for the SPE Journal includes a good number of additional papers implementing the ensemble Kalman filter, and you will see these papers in upcoming issues. Other topics in this issue include geomechanics, hydraulic fracturing, scale, and carbon sequestration.

Now, I would like to return to enhanced recovery. In April, I attended the SPE Improved Oil Recovery (IOR) Symposium in Tulsa, where the majority of papers were really about enhanced recovery. The distinction (for me) is that enhanced recovery uses injectants not typically found in an oil reservoir or stimulates oil production and fluid flow in an advanced fashion. It was interesting to see the renewed interest and resurgence of research in chemical-based recovery methods. Approximately one-half of the technical sessions were devoted to chemical applications in one form or another. Some of the sessions on polymer flooding were standing-room-only events, which was unheard of at earlier IOR symposia in recent years and a welcome change.

The impending rise of research into nanotechnology was quite apparent at the IOR Symposium. I am not quite sure how we will ultimately categorize nanotechnology because it has a variety of applications. From some perspectives, nanotechnology for enhanced recovery seems to resemble chemical EOR. Nanoparticles are being investigated to stabilize water/oil emulsions and to reduce the mobility of supercritical CO2. In this sense, nanoparticles might be applicable for environments in which surfactants cannot be easily developed or deployed. On the other hand, nanotechnology might be put to use for simultaneous reservoir monitoring and delivery of some enhanced-recovery agent to a targeted area. Similarly, nanomaterials might be sensitive to a particular frequency of radiation such that they activate when placed optimally. Perhaps we are seeing the rise of a new branch of EOR, so-called nano-EOR. The potential definition and the underpinnings of this new branch will likely be played out on the pages of theSPE Journal.