Patent ID: 9689858
Date: 2017-06-27
CPC Classifications: E21B,G01N

Claim:
1. A method comprising: receiving a crude oil having an initial pressure and temperature within a downhole tool inside a well; taking a first measurement of an optical density of the crude oil within the downhole tool; causing aggregation of asphaltenes in the crude oil by lowering the pressure of the crude oil within the downhole tool after taking the first measurement of the optical property; separating aggregated asphaltenes from the crude oil after lowering the pressure of the crude oil within the downhole tool, wherein separating aggregated asphaltenes from the crude oil includes routing the crude oil through a filter within the downhole tool to filter the aggregated asphaltenes from the crude oil; taking a second measurement of the density of the crude oil within the downhole tool after separating aggregated asphaltenes from the crude oil; determining an asphaltene onset condition of the crude oil through comparison of the first and second measurements of the optical property, wherein determining the asphaltene onset condition of the crude oil includes determining an asphaltene onset pressure of the crude oil; determining asphaltene yield of the crude oil at the initial pressure through comparison of the optical density of the filtered crude oil at the initial pressure to the optical density of the crude oil in which asphaltenes have not been removed by the filter; changing pressure of the received crude oil to a second pressure that causes aggregation of asphaltenes in the crude oil and is lower than the initial pressure of the crude oil received within the downhole tool; passing the crude oil through a filter of the measurement apparatus, causing aggregated asphaltenes in the crude oil at the second pressure to be filtered from the crude oil; and determining asphaltene yield of the crude oil at the second pressure.