Existence of Severe Slugging in Toe-Up Horizontal Gas Wells

Abstract

Abstract A systematic experimental study on two-phase air-water was carried out to evaluate the existence of severe slugging in toe-up gas wells. Experiments were conducted in a facility with a 2-in. ID and 62.6-ft. long lateral section and a 41-ft. vertical section. The lateral section was inclined −1° with respect to the horizontal to mimic a toe-up well. In addition, different flow conditions were considered to simulate the well production as the reservoir pressure depletes. The existence of severe slugging was evaluated by measuring pressure fluctuations and visual flow observation. Moreover, transient simulations in OLGA were performed to evaluate the possibility of severe slugging in toe-up gas wells. Experimentally, severe slugging was observed for the toe-up configuration and extremely low gas flow rates. Under this condition, significant fluctuations in pressure, gas and liquid flow rates are observed. However, experimental results did not conclude with certainty whether the severe slugging phenomenon can occur in a real gas well.