Downhole Fluids Accurately Sampled with New Wireline Tool

Abstract

Abstract A new sampler, which is run on solid wireline, collects downhole samples offluid under closely controlled conditions. The sample can be used for PVTstudies to determine the physical and chemical properties of reservoirfluids. The tool has very unusual design features that ensure that the propertiesand the volume of fluids and gases at the point of sampling are not altered inany way during the collection process. The integrity of this tool has beenproven by excellent results in field use. Introduction The object of bottom-hole sampling is to obtain a quantity of oil and gaswhich can be used to determine the physical and chemical properties of thefluids contained in the underground reservoir. These properties are, in turn, used to predict the production performance of the formation and also to determine the oil and gas reserves. Basically, this process expands a very small quantity of fluid to manymillions of times its original size. Any discrepancies that exist in theoriginal sampling process will be magnified accordingly when the final resultsare calculated. This establishes the real need for a bottom-hole samplingdevice that collects and preserves a true sample of thesubsurface fluid. The accuracy and integrity of the sample determine how valid the predictionscan be for the production performance of the well. The efficiency over theproducing life of the well will, in many cases, be dependent on the sepredictions and can drastically affect the total recovery to be achieved. Thesame qualities of accuracy and integrity of the sample will also determine the accuracy of the calculations of total reserves.