Study Of Connectivity And Water Control Strategy In The Early Development Of Carbonate Gas Reservoir

Carbonate gas reservoir is strong of heterogeneity. In the early development , because production time is short, gas field faces the problems,such as connected units are not clear, relationship of gas and water is not clear. Because of these problems, when producing well produces water, ways to control water could not be took correctly. It perhaps seriously affect production, even closed in production.Sichuan LG gas field is carbonate gas reservoir, and the formations of interest are T1f and P2ch. To overcome water coning, in this gas field all the wells in which gas bearing formations connected water bearing formation, the water bearing formations were perforated. Both gas and water are producted. When gas produces, it also carries as much more water as they can. This way could overcome water coning. Because water bearing formations were perforated, the wells connect water produce much water at early stage, even high capacity well LG2 was submerged by water. Different well has diferent situation. As the connectivity among the wells is not clear, the producing water types are not known. As a result, it is not sure to know that wether produce with avoiding perforating water bearing formation is better or perforating water bearing formation. The facts show that make sure the connected units and mechanism of water are important for study perforating water bearing formation.Files such as drilling, logging, pressure, MDT, water chemistry and producing etc. are used in the article to classify the connected units, and their drive types, and studied the water mechanisms and features of each producing well. According to the WGR and its changes, three types of water are summed up, typeA(strong water invasion),typeB(weak water invasion),typeC(steady water invasion).The reservoir features and water types of each connected units are coMPared. It shows that stype A was caused by the fractures forming high permeability zone. There are no fractures in the units met stype B and stype C with low permeability.By concept numerical simulation, the true parameters of the gas field were adopted, reservior with fractures and reservior without fractures were separately simulated to produce by avoiding perforating water bearing formations and perforating water bearing formations. CoMParing the results, the way of avoiding perforating water bearing formations and controling production should be used to the unit LG2 with fractures, because it caused to higher recovery and longer period of stabilized production. For the units without fractures such as unit LG001-3, unit LG001-1, unit LG001-18 and unit LG001-2, the simulated result shows that perforating water bearing formations has higher recovery and longer period of stabilized production. So this method was suggested.Through study, the connected units among each well are more clearly. Avoiding perforating water bearing formations and controling production was suggested in unit with fractures, and perforating water bearing formations was suggested in unit without fractures. This study supplies reliable basis for large-scale successful development.