The presence of asphaltenes in a crude oil does not necessarily mean that sludge will form on contact with acid. The crude oils that have acid-sludging characteristics seem to be concentrated in the California, Rocky Mountains, Canadian, and South American producing areas. In laboratory tests, this sludge usually manifests itself as a very viscous layer or collar between the acid and oil after they have been agitated vigorously and allowed to stand. A sludge layer can be quickly detected if the test sample is heated, centrifuged, or filtered, but it may take several hours for the collar to form just by standing. Note, however, that other conditions can cause a collar to form besides sludge, such as a stable emulsion, paraffin, or oil-wet organic solids.
Further testing can determine the specific source or condition.
Sales of Halliburton products and services will be in accord solely with the terms and conditions contained in the contract between Halliburton and the customer that is applicable to the sale.