We studied renal function of 194 black subjects with duration of diagnosed NIDDM from 1 month to 36 years to determine the interaction of hypertension and diabetes on nephropathy. Renal function was assessed by isotopic GFR and RPF studies, and serum creatinine. One hundred seventeen of the 194 subjects had 24-hour urinary albumin excretion (AER). AER > 300 mg/24 h correlated with longer duration of NIDDM, decrease in GFR and RPF, and rise in serum Cr, and all subjects were hypertensive. AER 30 to 300 mg/24 h also correlated with a longer duration of NIDDM and 80% had hypertension. When 194 subjects were grouped according to duration of NIDDM and the presence or absence of hypertension, subjects who remained normotensive had normal renal function. In hypertensive subjects a decrease in GFR occurred with duration of NIDDM > 1 year and decrease in RPF with duration of NIDDM > 5 years. In hypertensive subjects with NIDDM > 10 years, 36% had impaired renal function (GFR < 80 ml/min/1.73 m2 or serum creatinine > 1.4 mg/dl) and 75% had microalbuminuria or clinical proteinuria. Within this group, those subjects who developed hypertension after their diagnosis of diabetes were likely to have evidence of nephropathy as compared to those subjects whose hypertension was diagnosed prior to or simultaneous with their diabetes: 17 of 20 (85%) versus 7 of 13 (54%), respectively (P = 0.05). These data provide insight into the relationship between hypertension and diabetes in the development of nephropathy in black NIDDM individuals.
Carbon dioxide capture and storage (CCS) has been actively researched as a strategy to mitigate CO(2) emissions into the atmosphere. The three components in CCS are monitoring, verification, and accounting (MVA). Seismic monitoring technologies can meet the requirements of MVA, but they require a quantitative relationships between multiphase saturation distributions and wave propagation elastic properties. One of the main obstacles for quantitative MVA activities arises from the nature of the saturation distribution, typically classified anywhere from homogeneous to patchy. The emerging saturation distribution, in turn, regulates the relationship between compressional velocity and saturation. In this work, we carry out multiphase flow simulations in a 2-D aquifer model with a log-normal absolute permeability distribution and a capillary pressure function parametrized by permeability. The heterogeneity level is tuned by assigning the value of the Dykstra-Parson (DP) coefficient, which sets the variance of the log-normal horizontal permeability distribution in the entire domain. Vertical permeability is a 10th of the horizontal value in each gridcell. We show that despite apparent differences in saturation distribution among different realizations, CO(2) trapping and the V(p)-S(w) Rock Physics relationship are mostly functions of the DP coefficient. When the results are compared with the well accepted limits, Gassmann-Wood (homogeneous) (A Text Book of Sound; G. Bell and Suns LTD: London, 1941) and Gassmann-Hill (patchy) models, the V(p)-S(w) relationship never reaches the upper bound, that is, patchy model curve, even at the highest heterogeneity level in the model.
This paper explores the importance of proper choice of three-phase relative permeability model for mixedwet media, in contrast with commonly available water-wet rock models, that is, Stone1 and Baker. The mixed-wet condition is likely the most frequently encountered wetting condition worldwide. 1,2 Two formulations are available under these conditions. Blunt 3 developed a model that is somewhat complex to employ in simulators. In contrast, Jerauld 4-6 formulated a model that is relatively easier to implement. Jerauld's model incorporates the effect of interfacial tension (IFT) between phase pairs, as well as the ability to model mixed wettability. In this paper, to evaluate the effect of three-phase relative formulation, Stone 1 is used as a paradigm of strong wetting and serves as a base comparison for a mixed-wet formulation, namely, Jerauld's model. We illustrate the differences in performance prediction in threephase oil relative permeability (k ro ) for the same two-phase relative permeability data sets. We show how Jerauld's formulation can be used in commercial simulators, though in a limited fashion. Recovery prediction differences as well as the effect of gas miscibility on oil relative permeability to water (k row ) are shown. Results show that three-phase k ro values, based on Jerauld's model, can be up to 2 times lower than those predicted by using Stone1 and consequently the calculated recovery using Stone 1 model might be overestimated by 21% at immiscible condition. Gas miscibility affects gas-oil relative permeability and oil-water relative permeability as well. Miscibility diminishes the oil-to-water relative permeability (k row ), resulting in lower recovery. The recovery predicted using Stone 1 model is overestimated by 13% at 80% miscibility with respect to Jerauld's model, if the effect of miscibility is only accounted for oil-gas relative permeability. We show the importance of using an adequate three-phase model in mixed-wet system in addition to accounting for the effect of gas miscibility on oil-water relative permeability.
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