Electrical and Other Effects Related to the Formation and Prevention of Asphaltene Deposition Problem in Venezuelan Crudes
Authors: Lichaa Pierre M. , Herrera Lenin 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for International Symposium on Oilfield Chemistry of the Society of Petroleum Engineers of AIME, to be held in Dallas, Texas, Jan. 16–17, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

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Formation of asphaltene deposits has been a serious problem in many areas in Venezuela. Simple laboratory displacement measurements show that severe sand permeability reductions occur upon acid contact with asphaltenic crudes. Commercial products partially prevent the deposition of products partially prevent the deposition of asphaltenes, however the injection of a slug of Boscan mix before the acid treatment gave better results than the commercial products used in this study. Oxidation of the asphaltenes increases the viscosity of the crude and enhances the coalescence and precipitation of the asphaltene particles. particles. Electrodeposition experiments removed asphaltene particles from the crudes studied except when Boscan refined oils were added to the same crudes. These particles possess a positive charge; they migrate to the cathode upon application of the electric field. Based upon these studies, it is believed that controlling the electrodeposition of the asphaltenes can lead to development of preventive techniques.

Introduction

In the production of petroleum, conditions often exist which permit the formation and precipitation of asphaltene sludges in the precipitation of asphaltene sludges in the producing formation around the wellbore, on the producing formation around the wellbore, on the flow conduits and accessory equipment. Although this has been a problem for many years and many commercial products have been developed for removing these deposits, there is no information in the literature on any successful inhibitor being used with asphaltenes. The development of the more desirable alternative of preventing these deposits has lagged, apparently because of a lack of understanding of the mechanism involved in the deposition process.

In many areas in Venezuela, the formation of these sludges after shutting the well temporarily and/or after stimulation treatments by acid, has resulted in partial or complete plugging of the well. More recently the plugging of the well. More recently the severity of this problem has been observed in Mata-Acema field in Eastern Venezuela and to a lesser extent in some of Lake Maracaibo wells.

This paper, intended toward an attempt to develop techniques for preventing asphaltene deposition, has the following objectives:To evaluate the asphaltene contents in the crudes.To study the effect of acidification of asphaltenic crudes upon sand permeability changes using hydrochloric acid in different concentrations.