4,359 research outputs found
Recommended from our members
Secondary Natural Gas Recovery: Targeted Technology Applications for Infield Reserve Growth in Deltaifc Sand-Rich Low to Conventional Permeability Reservoirs in the Wilcox Group, Lake Creek Field, Texas
The potential for secondary incremental recovery of natural gas exists in complex fluvial-deltaic reservoirs of the Texas Gulf Coast. Four deltaic parasequences were identified using well logs calibrated to cores in the G sandstone. Engineering evaluations of production performance and pressures are compared with reservoir facies; these evaluations demonstrate the importance of identifying reservoir facies in maximizing recovery of natural gas. A well-log-based model to predict the free-water level and effective gas permeabilities was tested and calibrated using Wilcox gas reservoirs. Key reservoir parameters of porosity, water saturation, permeability, and capillary pressure are related in a single equation. Analysis of natural gas reservoirs from the Wilcox Deltaic sandstones in the Houston Embayment (WX-1) in East Texas indicates that reserve growth potential of approximately 60 percent over the current estimate of ultimate recovery is possible in deltaic sandstone reservoirs in the Lake Creek Unit. Detailed geologic, engineering, and petrophysical evaluation of the G sandstone reservoir in the Lake Creek Unit indicates that the maximum additional incremental gas opportunities exist in the flank region adjacent to the area currently developed in the Lake Creek field. The location, number, and economic feasibility of additional wells required to convert this resource to producible reserves were not evaluated.Bureau of Economic Geolog
The aluminium-copper-gold ternary system
Despite Au, Al and Cu being individually very well-known elements, their ternary phase diagram has not been studied in as much detail as those of many other Au-containing ternaries. Here we review what is known, and consider the prospects for technological exploitation of some of the ternary compositions. The components of greatest interest in Al-Au-Cu may be the β-phases, at least two of which have shape memory properties. Of these, 'Spangold', which has the nominal stoichiometry Au7Cu5Al4, has received some attention for jewellery applications, while the edge compound Cu3Al is a well-known shape memory composition with corresponding specialised industrial uses. The properties of other β-phase compositions in the system have been scarcely investigated. The system also contains an extensive γ-phase, Al4AuxCu9-x, where x ranges from 0 to ~6.5, and the purple gold phase AuAl2
Recommended from our members
Secondary Natural Gas Recovery: Targeted Technology Applications for Infield Reserve Growth in Fluvial Reservoirs, Stratton Field, South Texas
Integrated evaluations of geology, geophysics, reservoir engineering, and petrophysics were conducted for mid-Oligocene-age fluvial reservoirs in Stratton field as part of this study. Located in South Texas within the Frio Fluvial-Deltaic Sandstone along the Vicksburg Fault Zone play (FR-4), Stratton field represents a mature gas field with significant opportunities for natural gas reserve appreciation. These fluvial reservoirs exhibit heterogeneity and often contain multiple compartments.
The study identifies a considerable potential for reserve appreciation, with documented opportunities for a 100 percent increase in reserves within a large contiguous area of Stratton field, despite 40 years of prior development. Remaining natural gas reserves can be accessed through recompletion of existing wells that have bypassed reservoir compartments or by drilling infield wells to target compartments not effectively drained at current well spacing.
Exploration efforts to discover new reservoirs, identify incompletely drained compartments, or tap bypassed gas zones in old fields can benefit from detailed geological studies integrating engineering, petrophysical, and geophysical methodologies. Various geophysical techniques, including 3-D surface seismic, vertical seismic profiling, amplitude versus offset, and 2-D seismic inversion, were utilized to visualize subtle changes in reservoir topology and compartment boundaries at depths as low as 6,800 ft.
The study delineates three classes of compartment sizes based on analysis of ten groups of Frio reservoirs. Forward stochastic modeling of maximum gas recovery suggests that well spacings of 340, 200, and 60 acres (or less) offer optimal gas-contact efficiency in large, medium, and small compartment size reservoirs, respectively.Bureau of Economic Geolog
C-Reactive protein and risk of ESRD: results from the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT)
Background:
To better understand a potential association of elevated C-reactive protein (CRP) level with progression of chronic kidney disease (CKD), we examined the relationship of CRP level with the development of end-stage renal disease (ESRD) in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT).
Study Design
Post hoc analysis of a randomized controlled trial.
Setting & Participants:
4,038 patients with type 2 diabetes, CKD, and anemia in TREAT.
Predictor:
Baseline serum CRP concentrations.
Outcomes:
The primary outcome was development of ESRD; secondary outcomes included doubling of serum creatinine level, a composite of ESRD/serum creatinine doubling, and a composite of death or ESRD.
Measurements:
We fit unadjusted and adjusted Cox regression models to test the association of baseline CRP level with time to the development of the outcomes of interest.
Results:
Mean age of participants was 67 years, 43% were men, and 64% were white. Approximately half (48%) the patients had CRP levels > 3.0 mg/L; 668 patients developed ESRD, and 1,270 developed the composite outcome of death or ESRD. Compared with patients with baseline CRP levels ≤ 3.0 mg/L, those with moderately/markedly elevated CRP levels (≥6.9 mg/L; 24% of patients) had a higher adjusted risk for ESRD (HR, 1.32; 95% CI, 1.07-1.63) and the composite outcome of death or ESRD (HR, 1.41; 95% CI, 1.21-1.64). Although nonsignificant, similar trends were noted in competing-risk models.
Limitations:
Results may not be generalizable to nondiabetic CKD or diabetic CKD in the absence of anemia.
Conclusions:
Elevated baseline CRP levels are common in type 2 diabetic patients with anemia and CKD and are associated with the future development of ESRD and the composite of death or ESRD
Transfer Pricing and Environmental Taxation: Carbon Credits
This article discusses the authors' perspectives on the global commitment to reduce Green House Gas emissions and how international coordination is necessary to aid and encourage compliance by resolving administrative and legal challenges or inconsistencies so that companies and investors may benefit from clear and consistent treatment for tax and transfer pricing purposes
- …