The limits of superheat of thirteen light hydrocarbons and four light halocarbons were experimentally measured at one atmosphere using a superheating column. While there was some variation in the number of degrees to which a compound could be superheated before boiling explosively, in all cases the reduced limits T L / T , were close to 0.88. The measured superheat limits of three binary hydrocarbon systems and several ternary mixtures were close to mole fraction averages of the limits of the pure components. The results of both pure components and mixtures paralleled predictions of Beegle (1973), based on thermodynamic stability theory. Limits of pure components agreed closely with limits predicted from homogeneous nucleation theory. WILLIAM PORTEOUS SCOPEStudies have shown that when no gas phase is present and nucleation sources are removed, liquids held at one atmosphere can be heated to temperatures considerably above their normal boiling point. Studies have also shown that there is an upper temperature limit to which liquids can be heated without vaporization. At this temperature, referred to as the limit of superheat, homogeneous nucleation takes place with an extremely rapid liquid-to-gas phase transformation.While earlier investigations in this area were done primarily out of scientific curiosity, it now appears that superheat phenomena have practical importance. It has been hypothesized that superheating is the initiating cause of liquid natural gas (LNG) vapor explosions. These are nonchemical flameless explosions that sometimes occur when LNG is spilled on a warmer liquid.In order to determine whether superheating is the cause of LNG vapor explosions, it is necessary to measure the limits of superheat of hydrocarbons and their mixtures. Previous investigators had found that the limit of superheat for a pure component occurred in a narrow temperature range close to 89% of the critical temperature. Only limited data were available for mixtures and only one study had been done on molecules with three or less carbons. This study was undertaken to determine experimentally the limit of superheat of light halocarbons and hydrocarbons and their mixtures. The technique used to measure the limit involved a superheating column in which droplets of a volatile material rise in a denser immiscible medium. This medium is hotter at the top than at the bottom. The droplets increase in temperature as they rise until they nucleate and boil explosively. The temperature at which they nucleate is referred to as the limit of superheat.Thirteen light hydrocarbons, Cz's to Cd's, and four halogenated hydrocarbons were tested. Three binary systems and several ternary mixtures were also studied. These systems included mixtures of ethane, propane, 2-methylpropane, and n-butane. CONCLUSIONS A N D SIGNIFICANCEThe compounds studied could be superheated 84O to 117OC above their boiling points at atmospheric pressure, although the reduced temperature limits T J T , of the hydrocarbons and halogenated hydrocarbon3 varied over the narro...

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Hydraulic Fracturing of the Rewan and Showgrounds formations in the Namarah-Parknook fields of the Red Cap Block was performed in an attempt to establish commercial rates of gas production from a large volume of potential gas reserves in the Surat Basin. These formations had not been previously-fractured in Australia. A geological and engineering study was made of the subject area before proceeding with the fracture treatments. This quantified the available gas-in-place and allowed selection of the best candidate wells for stimulation. Several cores were available from wells in the area and selected lengths were sent to the service company stimulation laboratory in the U.S.A. for detailed analysis to determine the best parametric values to employ in the computer-assisted design of the proposed fracturing treatments. Four stimulation treatments were carried out on three wells in the area, with varying results. Similar sized fracture treatments were performed, but many changes were made to the pre-frac completions as well as the treatments themselves as they progressed. The changes were made to optimize designs, based on experience gained, and reduce costs while still achieving well-contained deep fractures in the pay zones. The first treated well, Namarah No. 2 was extensively production tested before stimulation, to allow an accurate comparison with post-frac production rates. Selection of the proppant was based on the crushing forces on the proppant as well as on the ultimate reservoir pressure at depletion of the formations proposed for fracturing. Pumping rates were determined by the thickness of the pay zone to be fractured and the estimated degree of containment which could be expected from the natural barriers to fracture propagation contained in surrounding formations. Size of the treatment was based on the natural permeability-thickness of the reservoir rock and drainage area, as well as the need to achieve commercial gas flow rates from successful wells. Extensive use of computerized on-site monitoring technology and equipment was employed.

A number of computational methods have been applied to the calculation, from dilatometric data, of rate constants for the alkaline hydrolysis of 2-chloroethanol in aqueous and aqueous-alcoholic solutions at 25".

A tool designed for formation sampling during drilling has been placed in Canadian field operations for over two years. Relatively large fluid samples are recovered and a formation pressure build-up obtained without retrieving the drill pipe. This paper discusses the mechanical operation of the tool as well as the characteristics of sample recoveries and pressure data. Typical examples are given.Qualitative reservoir information may be obtained to assist the operator in further evaluation and completion operations. Special applications include aid in the location of gas-oil and oil-water contacts, the calculation of potentiometric surfaces and the determination of reservoir continuity or segregation. An economic comparison with conventional drill-stem testing is made to illustrate the possible extent of savings. A summary of operations is given, describing the tool's performance and the results achieved.