Date of Award
Doctor of Philosophy (PhD)
A dynamic water control, dubbed Downhole Water Sink (DWS) technology, is a well completion technique for production of hydrocarbons from reservoirs with bottom aquifer causing water coning. Typically, a DWS well is dually completed with top completion designated mostly for hydrocarbon production and bottom completion used for water drainage and coning control. Positions and flow rates of the completions are the DWS performance parameters to be determined by a process designer. This dissertation presents a theoretical and experimental study of DWS performance for various reservoir conditions and production schedules. A new mathematical model, developed in this work calculates steady state pressure distribution around DWS well under two-phase inflow conditions, i.e. producing oil and water at the top and bottom completions. Based upon the model, computational techniques have been developed for prediction of production rates of water and oil, calculation of water cone profile, and performance comparison of DWS with conventional single completions. The theoretical results show how to find a unique relationship between three performance variables of DWS: liquid rates at the top and bottom completions, and the total water production. The results also show DWS performance limit resulting from pressure interference between the two completions. Experimental part of the work has been performed with a tabletop Hele-Shaw model. The model was calibrated and theoretically scaled-up so that the results from this model could be transformed to the radial flow systems. Preliminary experiments provided qualitative insight of the water coning reversal mechanism for conventional and DWS completions. Also, more detailed studies demonstrated the similarity in water production control with DWS in the linear and radial flow systems. Also demonstrated in this study was a minimum 30% increase in oil recovery with DWS in comparison to conventional completions. Also presented in this work is a mathematical model of DWS well at early time of production when oil and water is in transient and time-dependent. The new Moving Spherical Sink Transient Model (MSSTM) and the MSSTM computer program was qualitatively validated by comparing with results from a numerical simulator software of DWS system.
Shirman, Ephim I., "Experimental and Theoretical Study of Dynamic Water Control in Oil Wells." (1998). LSU Historical Dissertations and Theses. 6709.