Asphalt formation and precipitation under primary oil recovery conditions as well as secondary recovery by immiscible gas injection were studied. The crude oils were from a carbonate and highly fractured reservoir. No asphalt precipitated under these conditions. Since the oil reservoir had experienced significant formation damage and plugging of its well＇s tubing due to asphalt formation and precipitation, the absence of asphalt precipitation in our experiments points to the important influence on asphalt formation of flow of the oil, the streaming potentials arising from the flow, and their interaction with the electrical properties of the asphalt aggregates. Also investigated was asphalt precipitation when an enriched gas was injected into the oil under dynamic (multiple contact) miscibility conditions. Only trace amounts of asphalt precipitated when the dilution ratio R was high enough. However, significant asphalt precipitation occurred in completely miscible injections. For this case, we report extensive new experimental data for the amount of the precipitated asphalt formed with various precipitation agents over wide ranges of pressure, temperature, and crude oil composition. Increasing the pressure decreases the amount of asphalt precipitation. However, depending on the crude oil, two opposite trends in the amount of the precipitated asphalt were observed when the temperature of the system was raised. A scaling equation of state is shown to provide accurate predictions for the data. The scaling equation also yields a novel analytical equation for R-c, the critical dilution ratio (measured in cm(3) of the diluent or the precipitation agent per gram of crude oil) at the onset of the precipitation given by R-c = c(MT)(1/4), where M is the (average) molecular weight of the precipitation agent, T is the temperature in degrees C, and c is a constant on the order of 10(-2). The predictions of this equation are in excellent agreement with the experimental data. Thus, this equation may be used in the design of gas injection operations for enhanced oil recovery, such that precipitation of the asphalt aggregates in the reservoir can be prevented.