Early diagnosis and successful antimicrobial therapy have diminished the frequency of embolomycotic aneurysms, but infected aortic and small vessel aneurysms, arteriosclerotic plaques, and prosthetic grafts are becoming more common. A broad spectrum of pathogens, including Staphylococcus, Salmonella, Enterobacteriaceae, Pseudomonas aeruginosa, and some unusual organisms, are associated with this change. We treated four patients (three with abdominal aortic aneurysms and one with a prosthetic graft) with arterial infections caused by Listeria monocytogenes. Only seven other cases have previously been recorded in the world literature. Infection is suspected when a palpable or radiographically defined aneurysm is present with an otherwise obscure febrile illness. In about one-third of patients, blood cultures have yielded the pathogen. Newer imaging techniques have helped confirm the diagnosis. These infections are best managed by surgical resection in combination with long-term, appropriate antimicrobial therapy with ampicillin or sulfonamides. Unlike other adult listerial infection, except endocarditis, in arterial infection, immunosuppression and malignancy are not predisposing factors.

Summary In March 1982 a CO2 well in the Sheep Mountain Unit, CO2 blew out. This well was brought under control in early April 1982 by the dynamic injection of drag-reduced brine followed by mud. This paper discusses the events and field activities that followed the blowout and led to the successful kill operation. Also included is a discussion of two initial, unsuccessful kill attempts, associated mechanical problems, and the understanding gained therefrom. Analyses of wellbore and reservoir hydraulics led to an understanding of the freely flowing well. Injection of kill fluid down the drillpipe was possible, but the small pipe diameter, particularly that of the heavy wall drillpipe. pipe diameter, particularly that of the heavy wall drillpipe. significantly limited the rate of kill-fluid injection. The kill operation was further complicated by the high flow capacity of CO2 from the reservoir. The high CO2 flow rate efficiently gas-lifted the kill fluid up the annulus and thus tended to maintain a low bottomhole pressure (BHP). Further analysis of the hydraulics of the system suggested two alternatives for dynamically killing the well:use of highly drag-reduced fluids of moderate density such as water or brine, anduse of non-drag-reduced mud with a density greater than about 18 Ibm/gal [2100 kg/m3]. The well was killed successfully with 10.5-lbm/gal [1260-kg/m3] brine, which exhibited 72% drag reduction in surface lines and drillpipe at an injection rate of 60 bbl/min [570 m /h]. Introduction On March 17, 1982, CO2 Well 4–15-H in the Sheep Mountain Unit, CO2 blew out. Four unsuccessful attempts were made to kill the well with conventional weighted-mud techniques in the period from March 17 to March 23, 1982. By March 24, the well was blowing out of surface fissures on the west slope of Little Sheep Mountain directly above the drillsite. Two factors were the primary causes of the failure of the conventional kill technique. First, while injection of kill fluid down the drillpipe was possible, hydraulic constraints and pressure limitations significantly limited the rate of kill-fluid injection. Second, the kill operation was further complicated by the high flow capacity of CO2 from the reservoir, estimated at that time to be in excess of 90 ⨯ 10 scf/D [2.5 × 10 m/d] (later calculated to be at least 200 × 10 scf/D [5.6 ⨯ 10 m /d]), which efficiently gas-lifted the kill fluid up the annulus. Because no progress had been identified by use of the weighted-mud methods, the dynamic kill technique was used. Basically, this technique uses frictional pressure losses to supplement the hydrostatic pressure of a lightweight kill fluid injected at high rate at or near the bottom of the well. On April 3, 1982, the well was successfully contained by this technique using drag-reduced calcium chloride (CaCl,) brine as the kill fluid followed by weighted mud loaded with lost-circulation material to rebuild the filter cake on the producing zone. Description of the Sheep Mountain Unit The Sheep Mountain Unit is located in Huerfano County, in south central Colorado. The unit is topographically dominated by Sheep Mountain (elevation 10.635 ft [3242 m]) and Little Sheep Mountain (elevation 9,616 ft [2931 m]). Slopes vary from nearly level, in bottoms and on terraces, to 40% in the foothills and to 60% on the talus slopes of the two mountains. As a result of this topography, all development wells are directionally drilled from centrally located drillsite pads to develop the underlying Dakota and Entrada CO2 reservoirs properly. The surface spacing of the wells on a given drillsite is 100 ft [30 m] center-to-center. The bottomhole spacing is 1,000 ft [305 m] nominal distance between wells at the target depth, which is the Dakota formation (+/–3,500 ft [ +/–1070 m]). General Well Design The general well design called for 10 3/4 -in. [27-cm] surface casing to be preset at 300 ft [91 m] below ground level and cemented to surface by use of a small, highly mobile rotary spud rig. A rotary drilling rig would then be moved over the 10 3/4-in. [27-cm] surface casing, and the well would be directionally drilled to total depth (TD). Oil-based mud was used for the drilling fluid to inhibit the water-sensitive Pierre shale interval (surface to1,500 ft [ +/–457 m]) and to control differential sticking in the Dakota and Entrada sands. A production string consisting of 7 5/8-in. [ 19.4-cm] casing would be run to TD and cemented to surface. The well would then be completed with a workover rig at a later date. History of Well 4–15-H Well 4-15-H was the fourth development well to be drilled from Drillsite 2. The well was planned to penetrate the Dakota sand in a highly productive area of the CO2 reservoir. JPT P. 1267

Two cases demonstrating the computed tomographic (CT) appearance of inferior vena cava (IVC) duplication are presented, and the embryological, clinical, and radiological significance are discussed. Knowledge of caval anomalies can prevent misinterpretation of mediastinal masses, iliac occlusion with venous collaterals, or paravertebral lymph node enlargement. A duplicated IVC can be distinguished from para-aortic lymphadenopathy either by recognition of renal vein drainage or through intravenous contrast enhancement of the venae cavae.

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Microseismic monitoring is routinely used by block and panel caving mines worldwide to track cave shape development. The standard practice is to use the cloud of seismic event locations as a proxy for cave growth below. Careful seismic sensor array planning overcomes problems with event location reliability due to seismic-ray bending around the unknown cave. However, the aseismic gap-the (unknown) zone between actual cave back and bottom of the seismic event cloud-complicates estimation of cave geometry. More information than simple seismic event locations can be used to infer the cave shape and position. Since seismic events slip according to the stresses acting locally at the source locations, an analysis of source mechanisms yields indications of principal stresses around the cave. These stresses are the result of the virgin stresses perturbed by the cave shape, and this yields information about the cave shape. The apparent seismic wave arrivals under the straight-ray assumption are retarded when rays bend around the cave. These anomalous travel times are used to create 'spaghetti'-3D curved lines indicating the likely ray path followed. Analysis of these curved rays in space and time suggests where the cave is and where it is growing. All of this indirect information is now routinely used at Cadia East mine in Australia to estimate the cave shape, helping geotechnical engineers to better manage the cave. A direct verification of the estimated cave shape with an open hole drilled to the cave back in early 2017 provided some validation of these seismic data techniques.