Conventional Trap Research Articles

A Battery-Powered Light Trap Giving Two Years’ Continuous Operation2

A battery-powered light trap giving 2 years’ continuous field operation was developed for portable use in almond orchards. Parts (battery, electrical components, and trap body) cost about $30.00 for the completed trap. Navel orangeworm, Paramyelois transitella (Walker), catches were almost as large with a battery-powered trap as with a conventional line-powered trap.

Formation Evaluation by Analysis of Hydrocarbon Ratios

The ratio of methane to the heavier hydrocarbon components ethane, propane, butane, and pentane is indicative of gas, oil and water propane, butane, and pentane is indicative of gas, oil and water productive potential. The Steam Still-Reflux Unit, used in conjunction productive potential. The Steam Still-Reflux Unit, used in conjunction with mud logs and gas chromatographs yields a quantitative analysis from which this ratio can be plotted. Introduction Mud logging was first offered commercially in Aug., 1939. This logging method quickly gained favor among many operators because the type of fluid in the formation could be determined within minutes after the formation was drilled. The presence and magnitude of the methane show was and is the most important factor in mud log interpretation. However this magnitude in some instances was improperly understood, and as a consequence some operators still do not use mud logging, even though the early technique frequently made the difference between a successful well and an abandoned hole. Both the "hot wire" log of gas combustibles in the sample and the percent-of-gas log obtained with the conventional gas percent-of-gas log obtained with the conventional gas trap and the gas chromatograph indicate only that the reservoir in question contains hydrocarbons. These methods do not necessarily indicate the quantitative amounts of the various hydrocarbons in the mud. The addition of a new Steam Still-Reflux gas sampling system to gas chromatography enables accurate determination of the composition of the mud gas sample. A knowledge of gas composition makes it possible to establish the relationship of methane to possible to establish the relationship of methane to the heavier hydrocarbon shows. An awareness of this relationship led to a new, additional mud log interapretative technique that permits relating the quantitative amounts of methane (C1), ethane (C2), propone (C3), butane (C4), and pentane (C5) in-place propone (C3), butane (C4), and pentane (C5) in-place reservoir fluid content. A long-accepted premise is that as formations are drilled, the drilling mud filtrate partially flushes the formation fluid ahead of the bit. It was generally thought that the formations were flushed to an irreducible minimum generally considered to be about 30 percent of in-place fluid. Experience in mud logging, however, has shown that this rarely happens. This partial flushing does not prevent mud logging from successfully determining productive or nonproductive formations. Experienced logging engineers, in possession of quantitative gas analyses, make interpretations that take into account the flushing that results in rocks of various permeabilities, the effect of overbalanced mud weight and the effect of initial filtrate loss. Method Ordinarily, when formation cuttings are drilled they retain much of the formation pore fluid. This fluid is released to the mud column as the cuttings travel up the annulus. Most of the formation fluid in the cuttings will be "produced" into the drilling mud during the top 500 ft of hole travel. Conventionally, a mud sample is diverted to a mechanically operated gas trap to obtain a sample of the gas in the mud. The efficiency of this trap is from 15 to 70 percent, depending upon the gel strength of the mud, the amount of mud flowing through the trap and the rotation speed of the trap impeller. JPT P. 665

Dye Excretion as a Method for Determination of Small Mammal Home Ranges

One hundred and twenty dyes and biological stains were tested in the laboratory for possible use in determining home ranges by excreted dyes. Dyes were mixed with beeswax, made into pellet form, and placed subcutancously in Mus musculus and Microtus ochrogaster. Nine dyes colored the urine for four or more days (using 60-95 mg pellet) and did not depress activity as measured by activity wheels. In field tests, dropping boards covered with filter paper were placed in a grid for recovery of colored urine from M. ochrogaster implanted with pellets. Home ranges calculated from the excreted dye spots corre- sponded closely to home ranges calculated from live trapping data for the same animals (using minimum area method). Dyes in the same color range were found to be usable on different animals in the same area if one changed color when drops of weak acid or base solution were placed on the spots. Most techniques designed to determine the home ranges of small mammals utilize some type of live trapping and recapture procedure. Many criticisms have been leveled against this method (Davis, 1953) but no clearly superior technique has replaced it. The purpose of this study was first to develop a new method for determining home ranges which would eliminate some of the objec- tionable features of live trapping studies. The procedure developed was to implant pellets of dye into animals and determine movement by recording colored urine spots on dropping boards (Emlen et al., 1957). Secondly the home ranges of some individuals were determined by conventional live trapping methods and then by the new technique to compare results obtained by these methods. MATERIALS AND METHODS LABORATORY Initially 120 dyes were screened to determine their usefulness. Each dye was separately tested by preparing a pellet composed of a 1: 1 ratio of dye to beeswax. Beeswax was used to form a matrix which prevented crumbling, and also slowed and prolonged absorption of dye from the pellet. Homogeneous mixing of dye and beeswax was accomplished by placing the weighed mixture of beeswax and dye granules in a paraffin oven at 560 C until the beeswax melted. This semi-liquid mixture was then removed from the oven and stirred with a glass rod until it hardened. The quantity of dye-beeswax prepa- ration desired for a pellet was weighed in milligrams on a Roller- Smith torsion balance and then placed in a glaze-finished crucible for pulverization by a pestle.