Miscible or Near-Miscible Gas Injection, Which Is Better?

Abstract

Miscible or Near-Miscible Gas Injection, Which Is Better? F.B. Thomas; F.B. Thomas Search for other works by this author on: This Site Google Scholar Nancy Holowach; Nancy Holowach Search for other works by this author on: This Site Google Scholar XueLong Zhou; XueLong Zhou Search for other works by this author on: This Site Google Scholar D.B. Bennion; D.B. Bennion Search for other works by this author on: This Site Google Scholar D.W. Bennion D.W. Bennion Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, Oklahoma, April 1994. Paper Number: SPE-27811-MS https://doi.org/10.2118/27811-MS Published: April 17 1994 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Thomas, F.B., Holowach, Nancy, Zhou, XueLong, Bennion, D.B., and D.W. Bennion. "Miscible or Near-Miscible Gas Injection, Which Is Better?." Paper presented at the SPE/DOE Improved Oil Recovery Symposium, Tulsa, Oklahoma, April 1994. doi: https://doi.org/10.2118/27811-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Improved Oil Recovery Conference Search Advanced Search IntroductionMiscible flooding was invented many years ago, and in the 1950's it was viewed as one of the most promising techniques to use for improving oil recovery from a reservoir. Since that time many groups have researched what would be the most important parameters to optimize in the lab, have developed theoretical models to correlate these parameters, and then have implemented these "optimally designed" gas injection systems in the field. Amidst all the increase in technology and sophistication there is still ongoing debate as to whether one needs to achieve miscibility in order to optimize the recovery or whether a degree of immiscibilIty, characterized by the name "near miscible", is equally adequate for field implementation in enhanced oil recovery processes.This paper seeks to provide insight into these questions by reviewing some of the parameters which are at work in gas injection EOR as well as qualifying some of the techniques which can be used in designing gases for injection. Moreover, case histories are described herein where laboratory work was performed, phase behavior described, and then the gas injected into the reservoir. Results from the field are then shown and commentary included on the field performance.BackgroundGas injection for EOR is a very mature discipline applied throughout the world. Depending upon where in the world one is implementing gas injection and to whom one is speaking the post-mortem evaluations of "miscible flooding" may vary from being very successful to "miserable flooding" The reason for some floods being very successful and others less so may be as closely tied to how one measures the parameters of gas injection as to the nature of the process itself. In order to discuss the specifics of "miscible flooding" one needs to initially discuss the variables which are involved in the process. It is impossible to comment on all of these factors so only three will be referred to.Most importantly, the geology enters into the basis for successful gas injection processes. It is very difficult to have a successful process when the geology is inconsistent with that which one is trying to accomplish. The effects due to geology can be divided up into macroscale and microscale parameters.From a macroscale standpoint one encounters macroscale influences whenever one has different flow units in a reservoir. These heterogeneities may seriously impact the way fluids flow. For example, there are case histories where a horizontal impermeable barrier has been penetrated by a vertical fracture, caused by excessive injection pressures, or a previous hydraulic fracture treatment thus resulting in extremely poor flood performance.P. 307^ Keywords: injection, pore size distribution, saturation, gas injection, displacement, reduction, evaluation, flooding, upstream oil & gas, reservoir Subjects: Improved and Enhanced Recovery This content is only available via PDF. 1994. Society of Petroleum Engineers You can access this article if you purchase or spend a download.