High Medium Pressure Research Articles

Strength of solid pressure media and implications for high pressure apparatus

The stress-strain properties of talc, pyrophyllite, silver chloride, sodium chloride, boron nitride and graphite have been measured under confining pressures up to 8 or 10 kb at room temperature, and, in the case of talc, also at temperatures up to 900° C. The extrapolation and application of these results to solid medium high pressure apparatus of pistoncylinder type is discussed and a calculation made of the correction to nominal pressure (“friction correction”), taking into account the stress gradients in the medium and the shearing between the medium and the cylinder wall. Correction to the nominal differential stress measured in solid medium stress-strain apparatus is also discussed.

Studies on the Electronic Spectra of the Semiquinones of Anthracene and Its Related Heterocycles. I

Abstract Electronic absorption spectra of two types of half reduced acridine, i. e., C-radical (unpaired electron on 9-C-atom) and N-radical (unpaired electron on N-atom), of half-reduced anthracene and of xanthene deprived of one hydrogen atom, are measured in several rigid solvents at 77°K. It has been established that these radicals can be produced conveniently by irradiating the rigid solutions of the reduced forms, by a medium high pressure mercury lamp. It has been found that the absorption spectra of these radical species are generally classified into three groups, a) ∼250 nm (4.9 eV), b) ∼350 nm (3.5 eV) and c) visible (2.3–2.8 eV). Peculiar features for each radical species are; i) anthracene radical has no visible absorption, ii) acridine N-radical has no absorption at ∼250 nm, and iii) acridine C-radical has a prominent sharp peak at 281 nm. Flash photolytic and ESR studies have also been performed on the radical species produced upon irradiation of dihydroanthracene and xanthene; the results obtained have substantiated the assignment of the intermediates observed in rigid solvents.

Completing High Pressure Gas Wells - Mechanics and Problems

Introduction This discussion is limited to high pressure gas wells or wells with abnormal pressure gradients. It does not cover extreme high pressure gas wells such as have been recently completed on the Gulf Coast where shut-in tubing pressures have been recorded in the vicinity of 12,000 psi. It is realized that such wells would probably be of more singular interest; however, since relatively few have been completed to date, the data are very meager. It is the purpose of this paper to review some of the mechanics and problems involved in the completion of high pressure gas wells. Generally speaking, completion practice refers to operations which take place from the time the well is drilled through the productive zones and continues until the well is placed on production. The wells which will be discussed might be termed as medium high pressure gas wells having pressure gradients of about 0.8 psi/ft of depth. Three gas wells in this category were recently completed in the Gulf of Mexico approximately three miles off the Texas coast near Mustang Island. The completion of these wells will be discussed in detail. Casing Program The proper design of casing programs for high pressure gas wells is of utmost importance. This is particularly true of offshore wells where the safety of personnel and equipment is at stake. For this reason the factors of safety must be maintained well within the accepted limits. The program for all three offshore wells followed the same general pattern except for the 5-in. OD oil string. Due to trouble encountered with sticking in the deviated hole, the oil string was swaged to 4.5-in. OD at the bottom of the 7-in. OD casing at approximately 10,600 ft. The typical program is shown in Table 1. Total average weight of tubular goods used in each well was 1,257,000 lb or approximately 628 tons. For the sake of simplicity the details of completion of Well No. A–3 will be discussed since all three wells were completed in the same manner.