How Many Back Up Prepared For Asphaltene Onset Pressure Measurement Using Costly Collected Single Phase Bottomhole Fluid Samples?

摘要

For more accurate understandings of asphaltene flow assurance, nobody doubts the importance of asphaltene onset pressure (AOP) as direct information from live oil. For this purpose, a single phased bottomhole sample (BHS) has been taken as a standard process of the asphaltene flow assurance study even though expensive. This fluid sample is storing the closest information to the most representative in-situ asphaltene condition. Because of costly collected fluid sample, its handling and the examination using such a sample are carefully carried out to avoid unfavorable results and/or waste of sampling cost. However, unexpected experimental difficulties sometimes cause to result failure of AOP detection. In our AOP measuring experience, the latest method: laser light scattering technique (LST) has been applied because of its convenient and no time-consuming procedure. Our measuring equipment consists of the solid detection system (SDS) using LST as main function to judge AOP by power of light transmitted (PLT). In addition to the SDS, the apparatus consists of other measuring functions simultaneously: namely high pressure microscope (HPM) to observe asphaltene particle count and size visually, densitometer and viscometer to investigate the fluid kinetics. In this paper, these measuring functions were demonstrated as quite useful back up options to judge AOP when the SDS PLT results could not decide AOP solely. This demonstration can contribute maximizing data acquisition and use of the costly sample as much as possible. Furthermore, the paper describes that the AOP interpretation based on each kind of measured data would be aligned in order related to asphaltene particle growing condition because detection limits in each measurement were reflected into the AOP interpretation. In summary, the comprehensive interpretation can achieve AOP quality higher, and different measuring types of data basis interpretation would be possibly used as support data in each.