Abstract: A procedure is proposed to study dual cresting of horizontal wells in gas cap and bottom oil reservoir by water drive process. The seepage flow panel that is perpendicular to the lateral is divided into many bidirectional plane-parallel flow models in which gas displaces oil from above and water displaces oil from below. By dynamically allocating flow rate into each flow region, the advancing process of gas-oil contact and oil-water contact in each region is calculated in each time step. Using this method can get a whole picture of gas crest and water crest at any time before they arrive at bottomhole and calculate gas and water breakthrough time when horizontal well has different standoffs to oil-water contact. Both crest shapes and breakthrough times of gas and water are comparable with results from commercial simulator-Eclipse. It is indicated that this method can used to predict the performance of horizontal wells in reservoirs with gas cap and bottom water.

Key words: gas cap, bottom water, horizontal well, water cresting, reservoir numerical simulation