Formation and decay rates of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon–argon mixtures over the pressure range 102 to 104 Torr. The results are interpreted to yield radiative lifetimes (4.6±0.3 and 99±2 nsec, respectively, for vibrationally relaxed 0u+ and 1u molecules), vibrational relaxation rates [7×10−11 and 6×10−12 cm3/sec for Xe2* (1u) in collisions with xenon and argon, respectively], the Xe2* (0u+) three-body formation rate from Xe(3P1) (5.3×10−32 cm3/sec), and rates for 0u+–1u mixing by collisions with xenon and argon.

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This paper presents our perspective of the shallow-water flow (SWF) problemin the Deepwater Gulf of Mexico (GOM). The nature of the problem, includingareal extent and overpressuring mechanisms, is discussed. Methods for sandprediction and shallow sediment and flow characterization are reviewed. Theseinclude seismic techniques, the use of geotechnical wells, regional trends, various MWD methods, and cements and settable spots. Finally, examples of flowincidents with pertinent drilling issues, including well failures andabandonment, are described. Total trouble costs due to shallow-water flow for all GOM operators probablyruns into the several hundred million dollars. Though the problem remains aconcern, advances in our knowledge and understanding make it a problem that ismanageable and not the "show stopper" once feared. Introduction SWF may occur while drilling shallow over-pressured formations at deepwatersites. It is a high profile problem in the GOM, though it does occur elsewhere(Ref. 1) and will likely be encountered in other deepwater regions (Fig. 1). Drilling shallow over-pressured sands may cause large and long lastinguncontrolled flows, well damage and foundation failure, formation compaction, damaged casing, and re-entry and control problems. Most spectacularly, eruptions from over-pressured sands may result in seafloor craters, mounds andcracks (Figs. 2 and 3). Eaton2, 3 has described the significant problems causedby SWF in the Ursa area. A recent inspection of 106 wells (Ref. 4) indicatedthat $175 MM has been spent on SWF and prevention and remediation on thosewells. Total industry costs due to SWF likely exceed several $100 MM. The problem is compounded by the difficulty in seismically imaging thesesands (Refs. 5 and 6). This stems from the relatively low sand/shale contrastin acoustic impedance. The impact of this problem on well site selection andwell design is significant, and makes drilling in SWF areas particularlychallenging.

Radiative!iI'eiimes of the first 'P; "state of Mgw, Call, Znll, Sru, Cd(i, and Balt are reported a~nieasured by the Hanle effect in a fast-flowing helium afterglow. They are, respectively, 3.65(0.12), 6.61(0.30), 2.4(0.3), 6.64(0. 10), 2.86(0.25), 6.78(0.40) in units of 10 ' sec. The ious in the afterglow are created by Penning ionization of the neutral metal atoms, thus providing a steady-state, field-free region for observation.Comparisons are made with measurements by other methods, and discrepancies are discussed.

Summary During the last several years, significant progress has been made in the use of fiber-optic technology for well and reservoir surveillance. While most effort in this field appears to be concentrated on the development of fiber-optic-based meters for temperature, pressure, and flow, comparably few publications have been made to date about the use of fiber-optic technology for monitoring deformations of well tubulars and casings. In this article, we report on recent advances in our development of a real-time fiber-optic-based casing imager. This device is designed for continuous, high-resolution monitoring of the shape of casings or well tubulars and, therefore, enables the determination of strain imposed on the well. Small-scale and full-casing-sized laboratory tests have demonstrated that the latest generation of this system is sufficiently sensitive to detect casing deformations of less than 10°/100 ft and covers compressive and tensile axial-strain ranges from less than 0.1 to 10%. We will discuss the background technology, measurement sensitivity and strain-response characterization, as well as the scaleup work that has been performed to date. Our article also includes an overview of field-test results and illustrates how real-time deformation monitoring could form a significant component of reservoir-surveillance strategies.