METHOD AND SYSTEM FOR DETERMINING ASPHALTENE ONSET PRESSURE USING A USING DEPRESSURIZATION AND PRESSURIZATION

摘要

Methods and systems for determining for determining asphaltene onset pressure of a formation fluid are described herein. The method includes the following processes: (a) transmitting light through a sample of the formation fluid; (b) decreasing pressure of the sample; (c) detecting intensity of the transmitted light during depressurization; (d) identifying a change in intensity of the transmitted light during depressurization; (e) increasing pressure of the sample to a fixed pressure; and (f) detecting intensity of the transmitted light at the fixed pressure and at an equilibrated light intensity. Processes (a) to (f) are repeated for a number of different fixed pressures. The asphaltene onset pressure of the formation fluid sample can be determined using (i) the intensity of the transmitted light during each depressurization and (ii) the intensity of the transmitted light at each of the different fixed pressures.

主权项

1. A method for determining asphaltene onset pressure of a formation fluid, the method comprising:
(a) transmitting light through a sample of the formation fluid; (b) decreasing pressure of the formation fluid sample; (c) detecting intensity of the transmitted light during depressurization; (d) identifying a change in intensity of the transmitted light during depressurization representative of asphaltene flocculation; (e) increasing pressure of the formation fluid sample to a fixed pressure; (f) detecting intensity of the transmitted light at the fixed pressure; (g) repeating processes (a) to (f) for a plurality of different fixed pressures; and (h) determining the asphaltene onset pressure of the fluid sample using (i) the intensity of the transmitted light from each process (c) and (ii) the intensity of the transmitted light from each process (f).