Enhanced oil recovery water requirements

Water requirements for enhanced oil recovery (EOR) are thoroughly evaluated using publicly available information, data from actual field applications and information provided by knowledgeable EOR technologists in fourteen major oil companies. Water quanity and quality requirements are estimated for individual EOR processes (steam drive,in situ combustion and carbon dioxide, micellar-polymer, polymer and caustic flooding) in those states and specific geographical locations where these processes will likely play major roles in future petroleum production by the year 2000. The estimated quantity requirements represent thetotal water needed from all sources, e.g. aquifers, lakes and produced water. A reduction in these quantities can be achieved by reinjecting all of the produced water potentially available for recyle, e.g. some is lost in oil and water separation and water treatment processes, in the oil recovery method. For injection water quality requirements, it is noted that not all of the water used for EOR needs to be fresh. The use oftreated produced water can significantly reduce the quantities of fresh water that would be sought from other sources. Although no major EOR project to date has been abandoned because of water supply problems, competing regional uses for water, drought situations, and scarcity of high quality, e.g. low total dissolved solids, surface water and ground water could be impediments to certain projects in the near future.     

Usefulness of linkage disequilibrium of KM-19 and XV-2c DNA probes for genetic counselling in a high-risk cf family

A French couple with an individual risk of carrying the cystic fibrosis (CF) mutation of 1/2 sought genetic counselling. From the DNA haplotypes generated by XV-2c and KM-19 RFLPs, it could be deduced that only one subject was a carrier, lowering the risk of having a CF baby from 1/16 to 1/200. The strong linkage disequilibrium between these RFLPs and the CF allele observed in France reduced the risk to 1/1600.     

Resource partitioning by reef corals as determined from stable isotope composition

The pattern of resource partitioning vs depth by corals collected in February 1983 from Jamaica and the Red Sea was determined from their stable carbon isotope composition. Observations were made on isolated zooxanthellae and corresponding algae-free animal tissue from eight species at four depths over a 50 m bathymetric range. Zooxanthellae ¹³C was high in shallow water and became lower as depth increased. This trend correlated significantly with the anual integrated photosynthetic rate. The trend is interpreted according to a depletion-diffusion hypothesis; in shallow water, at high rates of photosynthesis, metabolic CO₂ is nearly depleted and the supply of CO₂ from seawater bicarbonate is limited by diffusion. Since most of the available CO₂ is fixed, isotope fractionation is minimal. In deeper water, at lower rates of photosynthesis, metabolic CO₂ is ample, and isotope fractionation is greater. Animal tissue ¹³C was slightly lower than corresponding zooxanthellae values in shallow water. As depth increased the difference between zooxanthellae and animal tissue ¹³C increased and the latter approached the ¹³C of oceanic particulate organic carbon. These data suggest that carbon is translocated at all depths and that deep-water corals draw significantly on allocthonous sources of carbon.Contribution No. 436 of the Discovery Bay Marine Laboratory of the University of the West Indies     

Understanding traffic crash under-reporting: Linking police and medical records to individual and crash characteristics

Objective: This study aligns to the body of research dedicated to estimating the underreporting of road crash injuries and adds the perspective of understanding individual and crash factors contributing to the decision to report a crash to the police, the hospital, or both.

Method: This study focuses on road crash injuries that occurred in the province of Funen, Denmark, between 2003 and 2007 and were registered in the police, the hospital, or both authorities. Underreporting rates are computed with the capture–recapture method, and the probability for road crash injuries in police records to appear in hospital records (and vice versa) is estimated with joint binary logit models.

Results: The capture–recapture analysis shows high underreporting rates of road crash injuries in Denmark and the growth of underreporting not only with the decrease in injury severity but also with the involvement of cyclists (reporting rates of about 14% for serious injuries and 7% for slight injuries) and motorcyclists (reporting rates of about 35% for serious injuries and 10% for slight injuries). Model estimates show that the likelihood of appearing in both data sets is positively related to helmet and seat belt use, number of motor vehicles involved, alcohol involvement, higher speed limit, and females being injured.

Conclusions: This study adds significantly to the literature about underreporting by recognizing that understanding the heterogeneity in the reporting rate of road crashes may lead to devising policy measures aimed at increasing the reporting rate by targeting specific road user groups (e.g., males, young road users) or specific situational factors (e.g., slight injuries, arm injuries, leg injuries, weekend).