GAUGING OUTPUT OF WELLS There are several ways in which the amounts of water and of oil coming from a well may be determined. It is not always possible to get absolutely accurate figures. The following methods of gauging or estimating differ in accuracy and can be applied to properties of various types.
Actual Daily Gauge.—The most accurate figure is, of course, jbtained by running the entire daily output of a well into a tank. The total volume can then be measured, the water drained off, and the remaining oil again measured and sampled for emulsion, or water in suspension. Such a system is applicable to wells producing high grade oil carrying a small amount of water and other impurities.
This system provides for the careful segregation and marketing of the more valuable grades of oil, and also supplies accurate facts as to the income received from the well.
Continuous Flow and Estimate.—A fairly accurate estimate of the amounts of oil and cf water produced by a well can be made by passing the entire fluid output through an automatic settling tank. A valve near the bottom of the tank is adjusted so that the water drains off constantly, while the oil passes out at a higher outlet. The quantity of water is determined by observing the time taken to fill a five-gallon can. The quantity of oil flow ing is determined by closing its outlet valve and measuring the rise of the fluid in the tank during a certain period of time. Tki method is adapted to large amounts of fluid, and particularly , free water, where the oil is not of the highest grade and Et. 1 susceptible to great loss by evaporation. The accompanyir. sketch (Fig. 24) shows the arrangement of tank and connection, A modification of this method may be applied to an open sump instead of a tank, but it is less accurate.
Sump Hole Estimate.—A rough estimate of the of oil and water can be had by computing the cubic conter of a sump hole and then observing the depth of fluid, either oil or water.
Lead Line Sample.—Some idea of output may be had by catet ing the flow from the lead line in a five-gallon can. The
taken to fill the can is observed and the total flow computed The amount of water is determined by ascertaining its percentage by a centrifugal machine, commonly called a "centrifuge,' or by merely allowing the water to settle. This method i, inaccurate because the rate of flow of wells is seldom regular and the proportions of oil and water are still less uniform.
Mere Inspection and Guess.—An experienced person can ge: some idea of the flow of a well by merely looking at the discharge end of the lead line. This method is subject to a possible of from 100 to 200 per cent., or even larger. However, even thii method, if regularly applied, would lead to an improvement d operating conditions at some properties.
Accurate observations of conditions accompanying oil pro duction will not render the utmost value unless systematically recorded. Where complete records of production have been made over some considerable period of time, it is possible to make comparisons and find reasons for various occurrences. The form of such reports is not material so long as adequate information is supplied. The following form of monthly report has been widely and profitably used.
Due to the fact that the water frequently is not free to settle out, but is carried in the form of emulsion, the report blank does not fully meet the usage of the most careful operators. A more complete form can be devised about as follows: Quality of Oil.—In some localities the oil produced is so uniform in character that no particular care need be taken to segregate the output of various wells.
Where there is great variation in the quality of oil from various sands and wells, it is of course important to separate the more valuable oil from the lower grades. In some cases this segrega tion requires analysis of each grade, while in other cases the specific gravity of the oil roughly indicates its value.