Abstract
Having full knowledge of the reservoir is crucial for the development of any hydrocarbon reservoir. Beyond gathering information about skin, boundaries, effective permeability, and production rates, knowing what type of hydrocarbons are being produced is often the key to optimizing the reservoir's production (i.e., reducing costs and raising profits). This paper describes the process of using wireless acoustic technology during downhole sampling to obtain important information to aid in the development decisions for a reservoir.
During the sampling process, valuable insight is gained about fluid sample collection, retention, and basic composition. This information can help the operator gain a better understanding of what is occurring during the lifecycle of the sampling event—before and after sample collection, during sample recovery to the surface, and in the sample transfer. Being able to follow each stage of the sampling process in real time provides important data that confirms whether the sample remained in single phase, as a representative fluid sample, for the entire duration of the well test. It is important to keep the sample at high pressure during the recovery process to ensure a monophasic sample. This is accomplished with a nitrogen pressure-compensation system to maintain pressure during recovery.
In addition, using the pressure from the common nitrogen chamber inside the sampling system in conjunction with the new data interpretation system, it is possible to confirm, in real time, the basic composition of the samples (black oil, volatile oil, condensate, dry gas, water) that are captured inside the sampler chamber housings. Additionally, the number of samples collected and the retention of those samples can be determined.
This type of knowledge about the sampling event is normally obtained once the toolstring has been pulled to surface and after the sampling cylinders have been sent off to the lab for pressure, volume, and temperature (PVT) analysis. Gaining insight into the characteristics of the reservoir in real time allows for operational decisions to be made quickly, ensuring necessary sample collection, thereby saving time and money.
