Abstract: In general, in one aspect, embodiments relate to a method, that includes lowering a downhole tool to a target depth of a wellbore, sampling reservoir fluid containing asphaltene at the target depth using the downhole tool, controlling a pressure of the sampled reservoir fluid while downhole to induce one or more phase transitions of the asphaltene, measuring the sampled reservoir fluid after inducing the one or more phase transitions, and identifying fluid composition of the reservoir fluid based on the measuring.

Abstract: A system and method for a fluid sampling tool. The fluid sampling tool may include a probe section. The probe section may include one or more probes, one or more stabilizers, and a housing that houses a bi directional piston pump. The method may include disposing a fluid sampling tool into a wellbore at a first depth, pressing the one or more probes into a surface of the wellbore, drawing a reservoir fluid from the wellbore through the one or more probes, placing the reservoir fluid into the housing, isolating the housing from the one or more modules of the fluid sampling tool with one or more shut in valves, depressurizing the housing with the bi directional piston pump, and measuring the asphaltene precipitation of the reservoir fluid within the housing.

Abstract: A system and method for a fluid sampling tool. The fluid sampling tool may include a probe section. The probe section may include one or more probes, one or more stabilizers, and a housing that houses a bi directional piston pump. The method may include disposing a fluid sampling tool into a wellbore at a first depth, pressing the one or more probes into a surface of the wellbore, drawing a reservoir fluid from the wellbore through the one or more probes, placing the reservoir fluid into the housing, isolating the housing from the one or more modules of the fluid sampling tool with one or more shut in valves, depressurizing the housing with the bi directional piston pump, and measuring the asphaltene precipitation of the reservoir fluid within the housing.

Abstract: Methods and system to calculate a skin effect using wellbore temperature measurements are described herein. In a generalized method, data corresponding to wellbore characteristics, reservoir characteristics, and a preliminary pressure drop around a wellbore due to a Joule-Thomson (“J-T”) effect are obtained downhole. The data is then input into a wellbore fluid temperature model and/or a reservoir fluid temperature model to calculate a wellbore fluid temperature profile and/or reservoir fluid temperature profile, respectively. The calculated wellbore and/or reservoir fluid temperature profiles may be calibrated using fluid temperatures measurements in the wellbore. The calibration may involve comparing the calculated temperature profiles to the measured temperature profiles to ensure the difference between the two profiles does not exceed an error threshold.