Abstract. Advances in manufacturing techniques and materials have led to an increase in the demand for reliable and robust inspection techniques to maintain safety critical features. The application of modelling methods to develop and evaluate inspections is becoming an essential tool for the NDE community. Current analytical methods are inadequate for simulation of arbitrary components and heterogeneous materials, such as anisotropic welds or composite structures. Finite element analysis software (FEA), such as PZFlex, can provide the ability to simulate the inspection of these arrangements, providing the ability to economically prototype and evaluate improved NDE methods. FEA is often seen as computationally expensive for ultrasound problems however, advances in computing power have made it a more viable tool. This paper aims to illustrate the capability of appropriate FEA to produce accurate simulations of ultrasonic array inspectionsminimizing the requirement for expensive test-piece fabrication. Validation is afforded via corroboration of the FE derived and experimentally generated data sets for a test-block comprising 1D and 2D defects. The modelling approach is extended to consider the more troublesome aspects of heterogeneous materials where defect dimensions can be of the same length scale as the grain structure. The model is used to facilitate the implementation of new ultrasonic array inspection methods for such materials. This is exemplified by considering the simulation of ultrasonic NDE in a weld structure in order to assess new approaches to imaging such structures.

Abstract. Use of full-matrix capture (FMC), combined with the total focusing method (TFM), has been shown to provide improvements to flaw sensitivity within components of irregular geometry. Ultrasonic immersion inspection of aerospace discs requires strict specifications to ensure full coverage -one of which is that all surfaces should be machined flat. The ability to detect defects through curved surfaces, with an equivalent sensitivity to that obtained through flat surfaces could bring many advantages. In this work, the relationship between surface curvature and sensitivity to standard defects was quantified for various front wall radii. Phased array FMC immersion inspection of curved components was simulated using finite element modelling, then visualized using surface-compensated focusing techniques. This includes the use of BRAIN software developed at the University of Bristol for production of TFM images. Modelling results were compared to experimental data from a series of test blocks with a range of curvatures, containing standard defects. The sensitivity to defects is evaluated by comparing the performance to conventional methods. Results are used to highlight the benefits and limitations of these methods relating to the application area of aerospace engine disc forgings.

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Introduction The paper describes the use of a ‘coupled’ surface network and 3-D 3-phase reservoir simulator in the reservoir management decisions of the Hanlan Gas Field in Western Canada. The black-oil and surface facility models were independently developed but were combined to produce the prediction forecast. The paper emphasizes:the importance of the dynamic exchange of data between the surface network and reservoir simulator, andthe creation of a reliable forecast for effective gas field management. Field History & Model Development The Hanlan Swan Hills Sour (H2s=10%) gas reservoir is a dolomitized devonian reef margin at a depth of 15400 Ft. The reservoir is in contact with an aquifer system in two directions. The OGIP of the field is estimated to be 1.6 tcf of raw gas. The field went on production in 1983. Currently there are 12 Swan Hills unitized (no. 1) wells and 3 non-unit wells including a horizontal well. Figure 1 displays the field outline and gathering system network. The 6000 grid block 3-D model for Swan Hills was history matched for gas production, gas/water ratios, and pressures for 13 years. It was used to evaluate aquifer activity and potential impact on gas recovery. The reservoir model was coupled to the surface facility network model and calibrated for production and pressure. The surface facility model provided a detailed description of pipeline network, facility constraints, contractual rates, swing factors and fuel usage. Working of Coupled Simulator The surface facility and reservoir simulators were coupled through an ‘Interface Subroutine’. In its working, the reservoir simulator first reads its input data file and determines the grid block pressures, gas/water ratios and well status. Next, the surface facility model reads its input data file and retrieves grid block pressures, and well status from the interface routine. The surface model computes sandface inflow performance for each well. Multi-phase pressure loss correlations are used to calculate wellbore pressure losses to compute wellhead deliverability. Multi-phase pressure losses in the gathering system are computed using user specified correlations. The flow rate for each well is calculated after accounting for contract limitations. A summary of calculated pressure and flow rates is then written to output file. The reservoir model retrieves this information from the interface routine to perform material balance. The surface model recomputes the system deliverability using the revised pressures and water/gas ratios. There are two limitations to the coupled simulator:the surface model cannot handle oil-gas system, andthe black oil model does not handle compositional changes in the reservoir and thus cannot be used for gas cycling or gas condensate reservoirs. Applications The combined Hanlan Model was developed for the following applications. Numerous sensitivity runs were planned for each application:Optimize reservoir depletion plan by evaluating timing, number and configuration of additional drilling, additional compression requirements and potential modifications to gathering Systems;Evaluate impact of increasing water/gas ratio on the gathering system;Evaluate impact of competitive drainage;Increase understanding of interaction of multiple reservoirs connected to the limited surface facility and impact of gathering system on ultimate gas recovery. Based upon simulation runs, a horizontal section of 1026 feet was re-entered at one of the existing vertical wells and is being evaluated at this time. P. 283^