Hazim Al-Attar

Curriculum assessment as a direct tool in ABET outcomes assessment in a chemical engineering programme

The chemical engineering programme at the United Arab Emirates University is designed to fulfil the Accreditation Board for Engineering and Technology (ABET) (A–K) EC2000 criteria. The Department of Chemical & Petroleum Engineering has established a well-defined process for outcomes assessment for the chemical engineering programme in order to ensure that its graduates achieve the programme educational objectives. Different direct and indirect tools are implemented in the assessment process. Among these tools, the greatest weight in the assessment process has been given to the curriculum (30%). The course and curriculum assessment usually plays an important role in improving the course content and quality; as it should provide considerable information on the effectiveness of an academic programme. This paper aims to discuss the methods used to assess the courses/curriculum of the chemical engineering programme as an important direct tool in the assessment process for ABET accreditation. Application of the curriculum assessment results in the continuous improvement of chemical engineering programmes is also addressed.

New Correlations for Critical and Subcritical Two-Phase Flow Through Surface Chokes in High-Rate Oil Wells

Summary The critical and subcritical multiphase flow through wellhead restrictions of a prolific oil field in the Middle East is investigated, and two sets of new correlations are presented. The first set of correlations is developed by using 40 field tests representing critical flow conditions. The second set of correlations is based on 139 field tests representing subcritical flow conditions of gas/liquid mixtures through wellhead chokes. For the critical multiphase flow condition, the predicted oil flow rates by the new set of correlations are in excellent agreement with the measured ones. The absolute average percent difference (AAPD) is between 1.88 and 4.37, and the corresponding standard of deviation (SD) is between 2.52 and 6.52. These results are found to be statistically superior to those predicted by other published correlations considered in this work. During the subcritical gas/ liquid flow conditions through surface chokes, the accuracy of oil flow rates predicted by the new set of correlations seems to be sensitive to the type and size of the choke being used. For Cameron LD type and 144/64-in. choke, the oil flow rates predicted by the proposed correlation are superior to those predicted by other methods available in the literature, with AAPD of 8.5. However, for smaller choke sizes of 96/64 and 64/64 in., the oil flow rates predicted by the new correlations and other methods are found to be close to each other. For Cameron F type and 144/64-in. choke size, the oil flow rates predicted by the new correlation are closely matched by those predicted by other published methods, with AAPD of 13.7. For smaller choke sizes of 80/64 and 64/64 in., few field tests are available, and the predications of all methods, including the proposed ones, show similar statistical results. The above findings for Cameron F choke also seem to apply to beaned wellhead assemblies for this particular oil field.

A General Approach for Deliverability Calculations of Gas Wells

article This paper presents a general and a simplified method for deliverability calculations of gas wells, which among other advantages, eliminates the need for conventional multipoint tests. The analytical solution to the diffusivity equation for real gas flow under stabilized or pseudo-steady-state flow conditions and a wide range of rock and fluid properties are used togenerate anempirical correlation forcalculatinggas well deliverability.The rock, fluid and system properties, used in developing previous correlations found in literature, were limited to reservoir pressure, reservoir temperature, gas specific gravity, reservoir permeability, wellbore radius, well drainage area, and shape factor. Additional key properties such as reservoir porosity, net formation thickness and skin factorare included inthiswork to developa more generaldimensionless Inflow Performance Relationship(IPR).It isfound that the general correlation, developed is this study, presents the observed field data much closer than previous ones found in the literature. In addition, based on the larger data set, an empirical relation to predict future deliverability from current flow test data is also developed. The two modified and general relations developed in this work provide a simple procedure for gas deliverability calculations which greatly simplifies the conventional deliverability testing methods. The required data can be obtained from a buildup test, or a single-point flow test, instead of an elaborate multipoint fl ow test. Further, the broad range of practically all rock and fluid properties used in developing the modified dimensionless IPR curves shouldcoverthemajorityofthe fieldsituationsgenerallyencountered.Theuseof themodifieddimensionlessIPR curves, the pseudopressure formulation and the sensitivity analysis indicate a generality of the approach presented in this paper, irrespective of the gas reservoir system under study.