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Abstract The determination of the optimal multilateral well configuration for different kinds of reservoirs is extremely challenging due to the wide varieties of possible well type. In this paper, we propose a novel method to determine the number of laterals, lateral length and lateral spacing in the multilateral well. The objective in the design is to fully exploit the entire reservoir within a certain period of development time. A geological map is constructed based on the reservoir properties. The fast marching method is used to calculate the drainage area of each lateral in the development time. The drainage area of the designed multilateral well configuration can cover the entire reservoir. The results have been validated by analytical method and specific steps of the method are presented. The applications in both homogeneous and heterogeneous cases are studied. Longer development time can lead to less number of laterals, shorter lateral length and larger lateral spacing. The drainage area is irregular in the heterogeneous case. The algorithm can automatically determine the number of laterals, lateral length and lateral spacing based on the geological characteristics to exploit the reservoir efficiently. The proposed method is appropriate for the field application due to the short computational time. Highlights • A semi-analytical method for the design of multilateral well is presented. • The lateral number, length and spacing are optimized based on the drainage area. • Applications in homogeneous and heterogeneous reservoirs are investigated. [ABSTRACT FROM AUTHOR]

Abstract: The largest rivers draining to the Gulf of Mexico in Texas are at more advanced stages of valley filling than rivers with smaller drainage areas, with corresponding differences in alluvial morphology and architecture, and avulsion style. This seems to imply that the larger fluvial systems either produce more sediment relative to the accommodation space in the alluvial valleys, or that they have undergone longer periods of valley aggradation. However, it is not clear that either of these is the case. This paper presents a theoretical analysis showing that fluvial systems with larger drainage areas can produce more advanced stages of infilling than those with smaller drainage areas (but with identical histories and sediment production per unit area) due to the nature of the scaling relationships between drainage basin area and incised valley size, and between basin area and sediment yield. Data for rivers in the region shows a strong linear relationship between valley width and drainage area. The nonlinear relationship between drainage area and proportion of the incised valley filled is somewhat weaker, but still significant, and major deviations are readily explained in terms of local inherited morphology or tectonic features. Results show that major differences in the degree or stage of valley filling could occur due to differences in drainage basin size alone. This indicates caution in interpreting incised valley fills of drainage basins of different sizes in terms of sediment supply. [Copyright &y& Elsevier]

Abstract: This paper examines the spatial variation of sediment yield in the Yangtze basin in China, a large basin with complex geology, climate, land-use history, and extensive sediment monitoring. 287 stations with drainage area less than 10,000km2 were used to study the scale effects of sediment yield. In order to develop scale relations for regional sediment yield, the whole study area was divided into eight sub-basins. Relation between specific sediment yield and drainage basin area was built for each sub-basin. Regional scaling relation was analyzed based on landforms, geology, lithology and land-use of each sub-basin. Three regional trends were identified in relation to the drainage area: (1) a declining trend, due to soil erosion on heavily cultivated steep land and the storage of sediment in floodplains; (2) a flat trend, due to mass movement on the upper reach and heavy agricultural disturbance on the middle and lower reaches; and (3) an increasing trend, due to downstream recruitment of sediment from land downstream where slope farming and deforestation occurred. Using these developed relations, areally adjusted sediment yield maps were created over the entire Yangtze basin. [Copyright &y& Elsevier]

This paper provides a review of existing methods for determining paleohydraulic parameters applicable to ancient lithified fluvial strata and attempts to update these formulae using empirical re-evaluation of modern stream data. Linear regression analysis was used to produce a series of equations that can readily be applied to ancient fluvial strata. These new formulae were developed using information from >4000 modern rivers, with depth, width, and grain size, as independent variables, as these can be directly estimated with varying degrees of confidence in the ancient stratigraphic record. Existing methods of estimating paleo-depth from crossbeds may reflect thalweg depth rather than average bankfull stream depth. Dune height (H d), when corrected for compaction, is considered equal to 2.52 ± 0.7 times the average height of trough crossbeds (H x). Thalweg depth (d max) is calculated as 6.5058 x H d 1.111. From this average bankfull stream depth (d bf) is calculated as 0.6095 x d max 0.973. Bankfull channel width (w bf) is then calculated as 16.293 d max 1.198 for low sinuosity rivers (P < 1.3), 17.338 d max 1.168 for intermediate sinuosity rivers (1.31.7), and 17.458 d max 1.230 for high sinuosity rivers (P>1.7). Bankfull discharge (Q bf) can be calculated as 17.359 d max 1.270. Drainage basin size (DA) can be calculated from bankfull depth as 241 d bf 2.17. Slope (S) can then be calculated from bankfull width as 0.0341 w bf -0.7430. Estimates of slope, discharge and drainage area can be further refined using formulae developed for specific Köppen-Geiger climate zones and sub-zones. With all of the above formulae a high degree of uncertainty remains due to the scatter of original data. In addition it is not always possible to establish climate variables in ancient strata. A further complication in comparing modern and ancient systems is discharge variability. This is related both to climate and to potential differences in surface runoff rates linked to the evolution and spread of rooted terrestrial vegetation. [Display omitted] [ABSTRACT FROM AUTHOR]

• A 4%-increase of drainage area in slatted rubber pens did not improve bull hygiene. • Season of the year had the greatest influence on the hygiene of the bulls. • Wider slots did not prevent against claw shape defects or infectious diseases. • Very few atypical standing up/lying down movements were recorded on both floorings. • Wider slots allowed bulls to adopt comfortable postures during lying. This study investigated health and welfare of 119 Swedish fattening bulls when allowing wider slots in fully slatted rubber mats pens. On arrival Light bulls (around 120 ± 28 kg at 4.7 ± 1.3 mo of age) were allotted to 6 pens with fully slatted rubber mats, of which 3 Control pens had 30 mm slot openings and 100 mm slat width and 3 Test pens had 35 mm slot openings and 90 mm slat width. Reaching >400 kg (Heavy bulls), Control bulls were moved to 3 larger pens having 35 mm slot openings and 100 mm slat width and Test bulls to 3 pens having 40 mm slot openings and 100 mm slat width. Pens hosted 5–7 bulls. Bulls stayed in the same group (Control/Test), and were observed until slaughter (around 600 kg for 20.5 ± 2.1 mo). Total drainage area was 14% for Control and 18% for Test floors. Bull body condition, hygiene, locomotion and leg lesions were assessed on eight days during the 18 months study. At slaughter, hind feet were measured, trimmed, and evaluated for claw disorders. Two pens/floor were filmed during two 14-h sessions to monitor animal activities, social interactions, and lying postures. Wider slots did not affect body condition or hygiene on farm, although 3 Control and 1 Test bulls were penalised at slaughter for poor hygiene. Light bulls were dirtier than Heavy bulls, especially on thigh/flank areas. Bulls became dirtier in winter. Percentage of bulls showing locomotor problems was generally low and not affected by wider slots (1.09 vs. 0.91% for Control and Test bulls, respectively). Test bulls showed a slight tendency to develop more swelling on hock and carpus (0.55 vs. 3.18% for Control and Test bulls, respectively). Rubber mats did not cause toe overgrowth (mean dorsal wall of outer claw = 87.5 mm) and Test bulls showed lower prevalence of asymmetric claws (38.5 vs. 13.3% for Control and Test bulls, respectively). Interdigital hyperplasia and white line fissure were detected only in Control bulls. Outcomes of this study suggested that the 4%-unit increase in drainage area of fully slatted rubber mat floors did not impair bull behaviour, since few atypical transitions and lying sequences were recorded, or even improve flooring and animal hygiene. However, some limitations of the research require further investigations to provide evidence supporting the widening of slot openings in fully slatted rubber mat floors for fattening bulls' welfare purpose. [ABSTRACT FROM AUTHOR]