DEVELOPING A NEW FORMULA FOR PREDICTING OIL RECOVERY FACTOR IN WATER FLOODED-HETEROGENEOUS RESERVOIRS

In this work, two sets of empirical correlations were developed for predicting the recovery factor (RF) in water-flooded layered oil reservoirs. The first set of these correlations encompasses four key parameters believed to have a significant impact on waterflooding performance, namely, reservoir heterogeneity (permeability variation coefficient), injected water viscosity, permeability anisotropy (ratio of vertical permeability to horizontal permeability), and water injection rate. This first set consists of two expanded forms, one for predicting the RF at water breakthrough time (BT) and the other for predicting the RF at the end of the project (EOP). Out of the aforementioned four key parameters, the second set of the developed correlations only considers the parameters that have been found most effective in the process of water flooding. Thus, the second set consists of two reduced forms, one for predicting the RF at BT (RFBT) and the other for predicting the RF at EOP (RFEOP). In the development process of the new correlations, the ECLIPSE simulator was used to generate a large number of data points representing, among other profiles, the RF and water cut performances for various combination scenarios of the above key parameters. These simulation-generated data were then processed by the General Linear Model analysis technique to develop the target empirical correlations. When tested against 144 simulation-generated data points used in their development, the expanded forms of the new correlations have been found to give reliable estimates of RFBT and RFEOP with AAPCD of 6.9 and 1.02, respectively. The reduced forms were found to yield a slightly higher AAPCD for the same data set. When tested against 48 simulation-generated data points not included in the development of the proposed correlations, the expanded forms of the new correlations have been found to give good estimates of RFᴮᵀ and RFᴱᴼᴾ with AAPCD of 6.5 and 14, respectively. The new correlations have been found to give more accurate estimates of RFᴱᴼᴾ than for RFᴮᵀ. The highest RFᴱᴼᴾ of 50.6% was achieved for a combination scenario defined by: qi = 10,000 bpd, μw = 1.0 cp, kz/kx = 1.0, and V = 0.1. When tested against two published empirical correlations using a single field data point, the proposed correlations were found to give relatively high APCD but still comparable to the API method

The determinants of forward-looking information in annual reports of UAE companies

Purpose To empirically explore empirically the underlying factors that may affect the extent to which forward-looking information is disclosed. Methodology This study uses a list of forward-looking keywords to demonstrate the differences, if any, in the level of disclosure among firms and between sectors. The sample includes 46 companies listed in either the Dubai financial market or Abu Dubai securities market. Statistical analysis is performed using a backward regression. Findings Debt ratio and profitability are found significant; however, sector type, firm size, and auditor size are found to have insignificant association with the level of forward-looking information disclosed in UAE annual reports. Practical implications A number of users, such as investors, lenders, and auditors, may find these results beneficial. These users may consider the results of this study when they are dealing with firms that have low profitability and high financial risk. Accordingly, they may wish to extend their investigations and verify such reporting practices. By doing this, the quality of information that is available to the public may be enhanced; and hence, users of annual reports may be better served. Originality/value It is important to note that the association between the extent of disclosure and the selected corporate attributes is still ambiguous. There are very limited number of studies that have examined disclosure of forward-looking information in developing countries and even fewer such studies may be found in the Middle Eastern countries. To the best of the authors' knowledge, no study yet has examined the forward-looking information disclosure issues in the UAE or Middle Eastern countries

Corporate governance mechanisms and capital structure in UAE

Purpose – The purpose of this study is to examine the impact of corporate governance mechanisms on corporate financial decisions in one of the emerging economies, United Arab Emirates (UAE). In particular, the paper examines the degree to which internal corporate governance mechanisms and an external corporate governance mechanism affect UAE firms' capital structure. Design/methodology/approach – The paper uses a multiple regression analysis to examine the association between corporate governance and capital structure for a sample of 71 UAE firms listed either in the Dubai financial market or the Abu Dhabi securities market during 2006. Findings – The paper finds that institutional investors have a negative impact on debt-to-equity ratio. This result does not support the "active monitoring hypotheses" where institutional investors are expected to exercise their voting rights effectively in order to prevent managers from reducing their "employment risk" at the expense of the interests of shareholders. It also finds that dividend policy is negatively associated with debt-to-equity ratio, while firms' size is positively associated with debt-to-equity ratio. Research limitations/implications – Empirical analysis suggests that corporate governance mechanisms have important implications for UAE firms' financial policies. UAE managers should be aware of the benefits of the implementation of effective internal and external corporate governance mechanisms while embracing international corporate governance standards. An effective implementation of the codes of corporate governance should improve the efficiency and effectiveness of UAE firms and the UAE stock markets. Originality/value – To the best of the authors' knowledge, there is no study that has yet empirically examined the effect of the corporate governance mechanisms on capital structure in UAE or Middle Eastern countries. This study offers the first evidence of the impact of corporate governance mechanisms on capital structure in UAE

Corporate governance mechanisms and capital structure in UAE?

Purpose – The purpose of this study is to examine the impact of corporate governance mechanisms on corporate financial decisions in one of the emerging economies, United Arab Emirates (UAE). In particular, the paper examines the degree to which internal corporate governance mechanisms and an external corporate governance mechanism affect UAE firms’ capital structure. Design/methodology/approach – The paper uses a multiple regression analysis to examine the association between corporate governance and capital structure for a sample of 71 UAE firms listed either in the Dubai financial market or the Abu Dhabi securities market during 2006. Findings – The paper finds that institutional investors have a negative impact on debt‐to‐equity ratio. This result does not support the “active monitoring hypotheses” where institutional investors are expected to exercise their voting rights effectively in order to prevent managers from reducing their “employment risk” at the expense of the interests of shareholders. It also finds that dividend policy is negatively associated with debt‐to‐equity ratio, while firms’ size is positively associated with debt‐to‐equity ratio. Research limitations/implications – Empirical analysis suggests that corporate governance mechanisms have important implications for UAE firms’ financial policies. UAE managers should be aware of the benefits of the implementation of effective internal and external corporate governance mechanisms while embracing international corporate governance standards. An effective implementation of the codes of corporate governance should improve the efficiency and effectiveness of UAE firms and the UAE stock markets. Originality/value – To the best of the authors’ knowledge, there is no study that has yet empirically examined the effect of the corporate governance mechanisms on capital structure in UAE or Middle Eastern countries. This study offers the first evidence of the impact of corporate governance mechanisms on capital structure in UAE

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population