Molecular Structure and Aggregation of Asphaltenes and Petroleomics (2005)

Molecular Structure and Primary Aggregation of Asphaltenes and Petroleomics Oliver C. Mullins; Oliver C. Mullins Schlumberger Search for other works by this author on: This Site Google Scholar Eric Y. Sheu Eric Y. Sheu Vanton Research Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. Paper Number: SPE-95801-MS https://doi.org/10.2118/95801-MS Published: October 09 2005 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Mullins, Oliver C., and Eric Y. Sheu. "Molecular Structure and Primary Aggregation of Asphaltenes and Petroleomics." Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2005. doi: https://doi.org/10.2118/95801-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 Annual Technical Conference and Exhibition Search Advanced Search AbstractTremendous strides have been made recently in asphaltene science. Many advanced analytical techniques have been applied recently to asphaltenes elucidating many asphaltene properties. The inability of certain techniques to provide correct asphaltene parameters has also been clarified. Longstanding controversies have been resolved. For example, molecular structural issues of asphaltenes have been resolved, in particular, asphaltene molecular weight is now known. The primary aggregation threshold has recently been established by a variety of techniques. Characterization of asphaltene interfacial activity has advanced considerably. The hierarchy of asphaltene aggregation has emerged into a fairly comprehensive picture - essentially in accord with the Yen model with the additional inclusion of certain constraints. Crude oil and asphaltene science is now poised to develop proper structure-function relations that are the defining objective of the new field - Petroleomics. The purpose of this paper is to review of these developments in order to present a more clear and accessible picture of asphaltenes - especially considering that the asphaltene literature is a bit opaque.IntroductionThe asphaltenes are a very important class of compounds in crude oils. [1–5] The asphaltenes represent a complex mixture of compounds and are defined by their solubility characteristics, not by a specific chemical classification. A common (laboratory) definition of asphaltenes is that they are toluene soluble, n-heptane insoluble. Other light alkanes are sometimes used to isolate asphaltenes. This solubility classification is very useful for crude oils as it captures the most aromatic portion of crude oil. Other carbonaceous materials such as coal do possess an asphaltene fraction but that often will not correspond to the most aromatic fraction.Petroleum asphaltenes, the subject of this paper, can undergo phase transitions that are an impediment in the production of crude oil. Figure 1 shows a picture of an asphaltene deposit in a pipeline; obviously asphaltene deposition is detrimental to the production of oil. Immediately it becomes evident that different operational definitions apply for the term asphaltene in the field vs. the lab. Indeed the field deposit is very enriched n-heptane insoluble, toluene soluble materials, but this field asphaltene deposit is not identically the standard laboratory solubility class. It is common knowledge that a pressure drop on certain live crude oils (containing dissolved gas) can cause asphaltene flocculation; the first step in creating deposits that are seen in Fig. 1. Highly compressible, very undersaturated crude oils are most susceptible to asphaltene deposition problems with a pressure drop. [6] Comingling different oils can result in asphaltene precipitation that can resemble solvent precipitation. In depressurization flocculation, the character of the asphaltene flocs is dependent on the extent of pressure drop suggesting some variations in the corresponding chemical composition. [7,8] Keywords: molecular structure, composition, asphaltene inhibition, mullin, spectroscopy, hydrate inhibition, petroleum asphaltene, asphaltene molecule, upstream oil & gas, remediation of hydrates Subjects: Production Chemistry, Metallurgy and Biology, Flow Assurance, Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene, Precipitates (paraffin, asphaltenes, etc.) This content is only available via PDF. 2005. Society of Petroleum Engineers You can access this article if you purchase or spend a download.