Summary Often, pressure gauge systems for surface read-out (SRO) wireline work or for permanent installations do not perform according to their specifications i.e. the pressure resolution obtained is lower than the gauge design values. This seems natural because the borehole environment is nastier than the quiescence of laboratory calibration setup. Nevertheless, it is difficult to attribute the loss of resolution to a single problem. This paper introduces the functional components of the pressure gauge system where loss of resolution may occur. Specifically, cable related problems, crossover, signal transmission, signal processing, time stamping and temperature compensation are addressed. Determination of pressure resolution from a processed signal is shown via example calculations. The role of transducer specifications on overall data quality is addressed. In other words, what causes a 0.01 psi rated transducer to yield a signal of only 0.75 psi quality? Field data from prospects Tahoe and Bullwinkle are used to illustrate some of the gauge related problems and the solutions being proposed by the industry to overcome some of them. Introduction The ability of the pressure gauge systems to resolve to the gauge manufacturer's specifications requires a unique set of laboratory type circumstances. In general, the end user pressure resolution is lower. In certain situations, it may be necessary to spend more effort in designing the gauge system to meet the user requirements. Examples of such situations may be the high permeability Gulf of Mexico (GOM) sands or a permanent downhole gauge (PDG) installation or a surface read-out (SRO) wireline gauge in a deep/hot well. Each of these examples will be illustrated in the paper There are a number of reasons for having the system resolution close to the transducer resolution. One of them being the use of pressure derivative methods in pressure transient analysis. In addition, use of rate deconvolution methods require precise data acquisition. Other more physical reasons may be that in high permeability sands, the analyzable part of the pressure buildup signal could be only 2-4 psi cumulative. If the system resolution is within the same order of magnitude it would be difficult to distinguish the signal. This is illustrated in Figure 1 which shows a few examples of the magnitude of pressure signals in GOM reservoirs. The graph shows the change in pressure for a shut-in well after 0.1 hours, assuming that the wellbore storage and momentum effects in the well have subsided by then. If the wellbore effects last longer (e.g thermal effects in injectors), the magnitude of signals would be even smaller. As reservoir/production engineers we concern ourselves with the quality of the pressure gauge that is put in the hole but do not usually worry about the total system of measuring, transmitting, processing and storing data. The system, as a whole, contributes to the ultimate pressure resolution rather than the gauge alone. Veneruso and Economides' (1989) discuss some of the potential noise and non-signal components of the data. As the system components vary with the application type, a description for a permanent downhole gauge and the techniques of data measurement and transmission is outlined below, in order to cover the most comprehensive systems used today.