A Comprehensive Investigation of Factors Controlling Edge Water Intrusion Behaviors in Naturally Fractured Gas Reservoirs Using EDFM
摘要
Assessment for water control management is critical to economically develop naturally fractured gas reservoirs, of which the profitability is heavily influenced by the water invasion. Water intrusion can occur through several mechanisms such as water coning/fingering/channeling through fractures that connect the water zone to the wellbore. Therefore, understanding water intrusion mechanisms plays a vital role in maximizing such reservoirs’ recovery and avoid workover costs. This study starts by establishing a base case reservoir with a water zone and non-producing zone, in which the well is located. Natural fracture (NF) paths are generated to connect the wellbore and the water zone and are numerically simulated by embedded discrete fracture model (EDFM). In order to fully apprehend variables that affect the shape and magnitude of water flow rates, 7 parameters. These include number of NF paths, lengths of NF paths, conductivity of NF paths, relative permeability of NF paths, number of natural fractures within water zone, production pressure drawdown, and water zone permeability. The simulated results of water flow rates are compared & summarized between different scenarios of each sensitivity parameter. The following major observations are found. First, the more or the longer the NF paths, the more water intrusion time is delayed. The conductivity of NF paths affects water break through time and its magnitude. Lastly, the production pressure drawdown also affects both the intrusion time and the amount of intrusion. This investigation adds crucial information to field modeling and vastly helps guide the decision-making process of wells operation by anticipating water intrusion behaviors through NF paths.