Study On Prediction And Control Of Water Coning In Fractured-Vuggy Carbonate Reservoir

Fractured-vuggy carbonate reservoirs exist widely in the world with massive geological reserve. Tahe 4th District belongs to extremely heterogeneous fractured-vuggy reservoir which develops many large vugs and fractures. These characteristics cause uncertainty of production performance and complexity of water cut change during the development of Tahe oilfield. According to the practical geological data and production performance, this thesis studies the corresponding relationships between three main water cut change types existed in Tahe oilfield and their particular storage patterns. On this basis, both analytical and numerical simulation methods are used to study the coning prediction and control for all kinds of storage patterns. As for the water coning prediction, in view of the difficulty in determining the reservoir parameters, a dynamic method is proposed to calculate net thickness and permeability. With these calculated parameters, critical production rate and breakthrough time of typical wells are calculated and regressed using analytical method, and finally a program of water coning prediction for fractured-vuggy carbonate reservoir is attained. Furthermore, with the analysis of geological and flow characteristics in all kinds of reservoirs, suitable numerical models are selected to forecast the water coning of typical wells. As for the water coning control, a mathematical model is established to simulate the cone change during the water coning control using analytical method and the impacts of various coning controls measures and their corresponding parameters on coning control effects are analyzed. Then using numerical simulation methods, optimal parameters combinations of various coning control measures for all kinds of wells are studied. These optimal operations are used in the production of wells and proved to be effective. Through a series of studies, both theoretical basis and technical support can be provided to forecast and control water coining in fractured-vuggy reservoirs in future.