Multiphase flow occurs in almost all producing oil wells and nearly every flowing well has some sort of choke to regulate the flowing rate, for the following reasons:to maintain sufficient back pressure to prevent sand entry,to protect surface equipment from high pressure,to prevent gas or water coning andto produce the reservoir at the optimum flow rate. Present choke correlations are best used for the area where same conditions met with the data used to generate the correlations. Inaccurate flow rate predictions could lead to gas/water coning, sand entry, and excessive pressures at the separator which can be a major factor of killing the producer well. In this paper, actual data production tests from vertical wells from Sabriyah Fields in Kuwait, were utilized to establish a new generalized multiphase flow choke correlation that predicts liquid flow rates as a function of flowing wellhead pressure, gas-liquid ratio, and surface wellhead choke size. The primary proposed correlation exhibits more accuracy (only 4% average error) than the existent correlations. The multiphase correlation coefficient was determined as 89%. These results will undoubtedly encourage the production engineer to utilize the proposed correlation for future practical answers when a lack of available information, time, and calculation capabilities arises. Introduction In a producing well, choke is controlling the production, as well as valves installed for safety purposes. One of the reasons for using choke is to prevent water and gas coning. Much research has been conducted to describe the relationship between the flow rates through wellhead and choke size. There are two surface conditions under which a flowing well is produced, either using a choke or using no restrictions at all. The majority of flowing wells are produced against chokes. Chokes are used to control flow rates, and thus to produce reservoirs at optimum rates. This also prevents water and/or gas coning and sand problems. Another use of well head chokes is to monitor production rates by operating in the sub critical-flow region, especially when oil and gas are produced from offshore or hostile environments. Flow through the choke can be described as either critical or sub-critical. In a critical flow region, the mass flow rate reaches a maximum value that is independent of a pressure drop applied across the choke. Therefore, once critical flow is reached, any disturbance introduced downstream of the choke will have no effect on upstream conditions. Therefore, chokes are commonly operated on upstream conditions. Hence, chokes are commonly operated under critical-flow conditions to isolate the reservoir from pressure fluctuations introduced by surface equipment.

New procedures are proposed to help estimate the distance to the discontinuity under certain conditions with good accuracy. These procedures can be applied using the derivative of the pressure buildup test data if the mobility ratio is less than unity. A 3-D numerical model is used to generate pressure transient data from synthetic data for a vertical well. The reservoir is considered as a composite reservoir where the inner zone contains the oil phase, and the outer zone contains the water phase. Some of the parameters that control the accuracy of the proposed analysis procedure are the producing time and the external reservoir radius. The procedures are useful in monitoring the position of the edge water front for future planning development purposes.[porous media including shale oil, shale gas and coalbed methane reservoirs. He, with his graduate students, works in the implementation of advanced simulation, well testing and artificial intelligence technologies to the 2 M. Alrumah and T. Ertekin aforementioned reservoir systems. His research efforts with his graduate students have produced more than 100 PhD and MS theses. He is the author and co-author more than 250 publications including four books and has given more than 250 lectures and seminars, workshops and short courses throughout the world.

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This study is concerned with the water coning phenomenon that takes place around production wells of hydrocarbon reservoirs. In this paper, the development of artificial neural networks to predict the water saturation buildup around vertical and horizontal wells with a good level of accuracy is described. In the development of expert systems, it is assumed that water encroachment originates from an active aquifer which is located under the hydrocarbon reservoir (reservoir with bottom water drive). A highfidelity numerical model is utilized in generating training data sets that are used in structuring and training the artificial neural networks. The artificial expert systems that are developed in this paper are universal and are capable of predicting the change of water saturation around the wellbore as a function of time and the prediction process is faster than a reservoir simulator and requires less data, which saves time and effort. With the help of these models, it will be possible to predict the position of high water saturation zones around the wellbore ahead of time so that remedial actions such as closing the perforations that produce the water can be implemented on a timely basis.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMultiphase flow occurs in almost all producing oil wells and nearly every flowing well has some sort of choke to regulate the flowing rate, for the following reasons: (1) to maintain sufficient back pressure to prevent sand entry, (2) to protect surface equipment from high pressure, (3) to prevent gas or water coning and (4) to produce the reservoir at the optimum flow rate.Present choke correlations are best used for the area where same conditions met with the data used to generate the correlations.Inaccurate flow rate predictions could lead to gas/water coning, sand entry, and excessive pressures at the separator which can be a major factor of killing the producer well.In this paper, actual data production tests from vertical wells from Sabriyah Fields in Kuwait, were utilized to establish a new generalized multiphase flow choke correlation that predicts liquid flow rates as a function of flowing wellhead pressure, gas-liquid ratio, and surface wellhead choke size.The primary proposed correlation exhibits more accuracy (only 4% average error) than the existent correlations. The multiphase correlation coefficient was determined as 89%.These results will undoubtedly encourage the production engineer to utilize the proposed correlation for future practical answers when a lack of available information, time, and calculation capabilities arises.