fax 01-972-952-9435. AbstractAn integrated transient wellbore/reservoir model is described and applied to investigate the liquid loading in a gas well. The well produces from a storage reservoir with water coning from its aquifer.The integrated model shows that the water cone causes the gas flow rate from each gas layer to decrease and the liquid holdup in the wellbore to increase. Depending on reservoir conditions, the well may enter into a mode of unsteady production during which the gas flow rate cycles over a period of several days. The reason for this unsteady flow is uncovered by the simulation.Simulation results are compared with operational experience and full field reservoir simulations. The integrated model provides more realistic results compared to methods where the reservoir and the wellbore are modeled separately.

fax 01-972-952-9435. AbstractAn integrated transient wellbore/reservoir model is described and applied to investigate the liquid loading in a gas well. The well produces from a storage reservoir with water coning from its aquifer.The integrated model shows that the water cone causes the gas flow rate from each gas layer to decrease and the liquid holdup in the wellbore to increase. Depending on reservoir conditions, the well may enter into a mode of unsteady production during which the gas flow rate cycles over a period of several days. The reason for this unsteady flow is uncovered by the simulation.Simulation results are compared with operational experience and full field reservoir simulations. The integrated model provides more realistic results compared to methods where the reservoir and the wellbore are modeled separately.

A very promising alternative to the state-of-the-art static volume measurements for liquefied natural gas (LNG) custody transfer processes is the dynamic principle of flow metering. As the Designated Institute (DI) of the LNE (‘Laboratoire National de métrologie et d’Essais’, being the French National Metrology Institute) for high-pressure gas flow metering, Cesame–Exadebit is involved in various research and development programs. Within the framework of the first (2010–2013) and second (2014–2017) EURAMET Joint Research Project (JRP), named ‘Metrological support for LNG custody transfer and transport fuel applications’, Cesame–Exadebit explored a novel cryogenic flow metering technology using laser Doppler velocimetry (LDV) as an alternative to ultrasonic and Coriolis flow metering. Cesame–Exadebit is trying to develop this technique as a primary standard for cryogenic flow meters. Currently, cryogenic flow meters are calibrated at ambient temperatures with water. Results are then extrapolated to be in the Reynolds number range of real applications. The LDV standard offers a unique capability to perform online calibration of cryogenic flow meters in real conditions (temperature, pressure, piping and real flow disturbances). The primary reference has been tested on an industrial process in a LNG terminal during truck refuelling. The reference can calibrate Coriolis flow meters being used daily with all the real environmental constraints, and its utilisation is transparent for LNG terminal operators. The standard is traceable to Standard International units and the combined extended uncertainties have been determined and estimated to be lower than 0.6% (an ongoing improvement to reducing the correlation function uncertainty, which has a major impact in the uncertainty estimation).

A comprehensive dynamic wellbore/reservoir flow model is successfully built by implicitly coupling a wellbore flow model with a near-wellbore reservoir model. The integrated model can be used to simulate various well flow transients that are subject to wellbore/reservoir dynamic interactions. In order to evaluate its performance, several hypothetical cases, such as well shut-in/start-up, heading, coning, and crossflow, are simulated. Comparison is made between the integrated approach and the conventional IPR approach, and the advantage of using the integrated model is justified. With given completion details and early-time reservoir data, the integrated model is then used to simulate a pressure buildup and drawdown test of an appraisal gas well. The simulation results show that the model can easily and accurately match the well testing data only by tuning the skin factor, which indicates the integrated model is suitable for optimizing well testing design, assisting well testing interpretation, and estimating the BHP where downhole measurements are not cost-effective and reliable. Introduction Conventional dynamic well flow models use steady-state IPRs to describe the influx of oil and gas from the reservoir, which ignore the flow transients in the near-wellbore area. On the other hand, reservoir models use steady-state lift curves to represent the TPRs, which ignore the flow dynamics in the wellbore. Neither the well models nor the reservoir models can account for the dynamic wellbore/reservoir interactions. For example, Gaspari[1]et al. verified the performance of an advanced transient multiphase flow model with the field data from an offshore well in Brazil. Even though the simulation matched the steady-state production perfectly, the model failed to simulate the shut-in/start-up operation by a big deviation in the downhole shut-in pressure prediction. This was attributed to the strong pressure transient in the tight reservoir, which was not considered in the modeling. To bridge this modeling gap, many efforts[2~15] have been made in developing integrated transient wellbore/reservoir models. These modeling efforts were related to the simulation of well testing[2,4,6,7,8,10,11,15], heavy oil thermal recovery[5], long horizontal well performance[3,9], and unstable well flows[12,13,14]. Despite most of the models have been very successful in simulating the special cases that they were developed for, they are lack of the general applicability for being used in a much wider scope due to either a poor wellbore flow model was used, or a simple reservoir description was adopted, or the numerical coupling between the wellbore and reservoir models was not properly handled. For example, one of the latest efforts from Ballard[14]et al. was intended to couple a comprehensive well flow model with a comprehensive reservoir model for investigating formation heading and liquid loading in a gas well that produces from a fractured tight reservoir. The coupled system is really advanced in terms of the modeling capabilities of the wellbore and reservoir models. However, the simulation speed had to be kept very slow in order to assure the coupling numerical stability, which was based on an explicit procedure. Some previous modeling efforts tried to solve the whole wellbore/reservoir system in one unified numerical scheme that could skip the coupling issues between the two models. This can only be achieved by sacrificing the modeling details of either the wellbore or the reservoir, e.g. by attaching an analytical solution of the reservoir model to the wellbore flow model, or by attaching a simple wellbore model to the reservoir model. However, this approach is not practical when the models on both sides of the sandface need to be comprehensive, particularly, when they are made to deal with the complexity of the modern advanced wells. The multiphase flow in wellbore and in porous medium is fundamentally different in nature, which requires separate modeling formulations and different numerical solution schemes. This paper is concerned with the development and testing of a novel integrated wellbore/reservoir model, which is achieved by implicitly coupling an existing transient wellbore flow model with an existing near-wellbore reservoir model. As both the two models are already comprehensive and powerful in their functionalities, the main focus of this work is on the numerical coupling between the two models and testing the usability of the integrated simulator. The detailed introduction of the models and their integration are given below.

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