Abstract: The major beds in upper Ahdeb oilfield are developed with success through an early stage horizontal well flooding-production method.However in the current stage,the observed high water cut in many producers has affected the stable production seriously.Therefore,it is urgent to study the water control of horizontal wells.In observing that the horizontal well water breakthrough is caused by active edge or injected water in high-permeability layers or fault fissures,we set up a serious of completion schemes to achieve water control of horizontal wells based on an integrated analysis of encountered reservoirs in drilling,and an newly established numerical model of integrated wellbore-reservoir coupling suitable for simulating screen,central tube,and ICD water control completion.In the modeling,the variable mass flows in horizontal wellbores under multiple forces have been considered to increase the match between the single-well simulation results and the real water cut performance.The results show that the ICD and central tube completion measures are more effective in water control when the water breaks through in the heel section,with the water cut decreasing from 49.8% to 37.8% and 35.0% respectively.In order to achieve efficient water control,the flow-limiting range of the water control completion devices should be slightly longer than that of water breakthrough section.The application of water control devices before water breakthrough of horizontal wells will lower the cumulative water cut during the whole production life to the maximal degree,and in turn this will increase the cumulative production for single wells.

Key words: water control, water control completion, numerical modeling, horizontal well, carbonate rock, heteroge-neous reservoir, Ahdeb oilfield