Wax formation in oil pipelines: A critical review

The behavior of asphaltene in live oils was investigated using a fully visual PVT cell equipped with a laser-based particle detection system. Through a series of isothermal pressure depletion experiments, the asphaltene stability envelope was established for several Gulf of Mexico oils. These tests were performed under pressure and temperature conditions typical of a field production system. Evidence of asphaltene precipitation above and redissolution below the saturation pressure was observed. Significantly, these tests also showed that pressure depletion-induced asphaltene precipitation is a highly reversible process. This latter observation helps to resolve a long-running debate in the literature concerning the reversibility of the asphaltene precipitation and flocculation process.

Asphaltene Precipitation from Live Oils: An Experimental Investigation of Onset Conditions and Reversibility

With the ever increasing demand for energy to meet the needs of growth in population and improvement in the living standards in particular in developing countries, the abundant unconventional oil reserves (about 70% of total world oil), such as heavy oil, oil/tar sands and shale oil, are playing an increasingly important role in securing global energy supply. Compared with the conventional reserves unconventional oil reserves are characterized by extremely high viscosity and density, combined with complex chemistry. As a result, petroleum production from unconventional oil reserves is much more difficult and costly with more serious environmental impacts. As a key underpinning science, understanding the interfacial phenomena involved in unconventional petroleum production, such as oil liberation from host rocks, oil–water emulsions and demulsification, is critical for developing novel processes to improve oil production while reducing GHG emission and other environmental impacts at a lower operating cost. In the past decade, significant efforts and advances have been made in applying the principles of interfacial sciences to better understand complex unconventional oil-systems, while many environmental and production challenges remain. In this critical review, the recent research findings and progress in the interfacial sciences related to unconventional petroleum production are critically reviewed. In particular, the chemistry of unconventional oils, liberation mechanisms of oil from host rocks and mechanisms of emulsion stability and destabilization in unconventional oil production systems are discussed in detail. This review also seeks to summarize the current state-of-the-art characterization techniques and brings forward the challenges and opportunities for future research in this important field of physical chemistry and petroleum.

Interfacial sciences in unconventional petroleum production: from fundamentals to applications

Asphalts used in the construction of pavements exhibit unique properties at the micron and nanometre scale. Atomic force microscopy (AFM) images of asphalts and asphalt chromatographic fractions prepared as thin films clearly show that a variety of ‘microstructures’ can develop on the surface of these types of materials. Structure develops to different degrees and in different forms depending on the residua crude source from which the asphalt or asphalt fraction is derived, the thermal history of the sample and the sample thickness. Based on our current best interpretation of a very large number of AFM images obtained over several years, we hypothesise that the interaction between crystallising paraffin waxes and the remaining asphalt fractions is responsible for much of the structuring, including the well-known bee structures (Loeber et al. 1996, Journal of Microscopy, 182 (1), 32–39), which has been observed with asphalt materials.

Morphology of asphalts, asphalt fractions and model wax-doped asphalts studied by atomic force microscopy

Marine dissolved oragnic matter contains roughly as much organic carbon as all living biota on land and in the oceans combined. New techniques in analytical chemistry show that a significant portion of this material has undergone thermal alteration, either on land or in sediments deep below the sea floor.

A heat-induced molecular signature in marine dissolved organic matter

The first € price and the £ and $ price are net prices, subject to local VAT. Prices indicated with * include VAT for books; the €(D) includes 7% for Germany, the €(A) includes 10% for Austria. Prices indicated with ** include VAT for electronic products; 19% for Germany, 20% for Austria. All prices exclusive of carriage charges. Prices and other details are subject to change without notice. All errors and omissions excepted. O.C. Mullins, E.Y. Sheu, A. Hammami, A.G. Marshall Asphaltenes, Heavy Oils, and Petroleomics

https://www.springer.com/productFlyer_978-0-387-31734-2.pdf?SGWID=0-0-1297-122343668-0

Asphaltenes, Heavy Oils, and Petroleomics

Methods and tools are described to reduce sanding including the steps of fracturing the cement sheath (13) in a localized zone around the casing (111) and having the fractured zone act as sand filter between the formation and openings (113) in the casing (111), with the openings being best pre-formed but temporarily blocked so as to allow a conventional primary cementing of the casing. The fracturing step can also be used for remedial operation to reopen blocked formation or screens.

Methods and apparatus for completing a well

Compositions and methods of using same are described for negating asphaltene deposition in a formation, wellbore, near wellbore region, and production tubing. Compositions of the invention comprise an asphaltene solvent and a viscosity reducing agent, the asphaltene solvent and viscosity reducing agent present in a ratio so as to substantially reduce viscosity of an asphaltene-containing material while substantially negating deposition of asphaltenes either in a reservoir, in production tubing, or both when mixed or otherwise contacting the asphaltene-containing material. Methods of the invention comprise forcing a composition comprising an asphaltene solvent and a viscosity reducing agent to contact an asphaltene-containing hydrocarbon in an underground geologic formation, and producing from the formation a production composition comprising at least some of the treatment composition and at least some of the asphaltene-containing hydrocarbon under conditions sufficient to substantially negate deposition of asphaltenes in the formation.

Compositions and methods of using same in producing heavy oil and bitumen

The movement of production systems to deepwater and subsea environments in recent years has increased the importance of fluid property related flow assurance issues. Asphaltene precipitation and deposition is one of these potential problems. While not as common as wax or scale, the impact of asphaltene is often catastrophic. Asphaltene can cause reservoir impairment, plugging of wells and flowlines through deposition, separation difficulties, and fouling in facilities. Offshore, the cost of remediating an unexpected asphaltene problem is excessive. It is imperative that the behavior of asphaltenes in an offshore production system be understood in the design stage of the project. Proper control and remediation strategies must be built into the system from the beginning. In this chapter, we will review the current process of sampling and analysis that provide the initial assessment of asphaltene stability in the reservoir fluid. We will relate these measurements in the laboratory to expected behavior in the field and address uncertainties. We will then discuss how improved characterization and deposition measurements will decrease uncertainty and allow less conservative design and operation strategies. Finally, we will briefly review the types of asphaltene precipitation models and discuss their respective underlying assumptions. Land-based sources of conventional crude oil and gas have been decreasing for the last couple of decades. As a result, the petroleum industry has turned to explore, develop, and produce hydrocarbon fluids from more challenging fields including deep and ultra deep offshore areas such as the North Sea, Gulf of Mexico, West Africa, and East coast Canada.1 Productions in these regions are under extreme conditions where temperature can be near freezing point, and pressure drops from reservoir to production facility are quite large. These conditions often lead to

Precipitation and Deposition of Asphaltenes in Production Systems: A Flow Assurance Overview

The terminology “cloud point” has been traditionaly adopted by the American Society for Testing and Materials (ASTM) D2500 to refer to the temperature at which “cloudiness” of a relatively transparent petroleum fluid is observed upon cooling. The cloudiness forms as a “finite and detectable” amount of wax and/or paraffins precipitates from the test fluid contained in a 1½-in (˜30 mm) diameter glass tube. Nowadays, more sophisticated techniques of differing measurement principles and varying degrees of sensitivity have been developed to measure cloud points of petroleum fluids including opaque hydrocarbon systems (dark oils). Alternative terminologies like wax appearance temperature (WAT) and wax precipitation temperature (WPT), amongst a few others, have also emerged and are used interchangeably. Meanwhile, numerous characterization and modeling efforts have been made to simulate “measured” cloud points of petroleum fluids. The goals of this paper are to provide an objective review of the concept...

/pdf/cloud-points-can-we-measure-or-model-them-isxfh98zko.pdf

Ahmed Hammami

Papers

Asphaltenes, Heavy Oils, and Petroleomics

Methods and apparatus for completing a well

Compositions and methods of using same in producing heavy oil and bitumen

Precipitation and Deposition of Asphaltenes in Production Systems: A Flow Assurance Overview

Cloud points: Can we measure or model them?