Study On The Secondary Development Of Well Pattern Reconfiguration In Middle West Of Sa-zhong Development Area

Based on findings of fine geology in Sa-Zhong Development Area, three-dimensional seismic technique, highly accurate dynamic monitoring techniques, fine reservoir description techniques, and fine reservoir structure description techniques, the paper aims at studying the secondary development of well pattern reconfiguration in Middle West of Sa-Zhong Development Area, in order to reveal remaining oil distribution and to reconstruct reservoir cognition.The paper not only gives a basic overview of the Midwest, such as structure and fault structure, reservoir characteristics, fluid properties, reservoir pressure and temperature, reservoir type and geolograph reserves, etc., it also sums up the exploitation course, the condition of research in each mine field, and the problems in the exploitation. Furthermore, the paper describes the sedimentary feature of the Midwest, the reservoir development, and oil heterogeneity.The paper introduces the producing condition of well pattern and the features and types of remaining oil distribution. Remaining oil distribution in class II reservoir: non-perforated well pattern; reservoir injection-production faultiness; the top of thick oil pay. Remaining oil distribution in class III reservoir: thin and poor reservoir in edging and bridging state with channel sand; non-perforated well pattern; reservoir injection-production faultiness. Remaining oil distribution in Gaotaizi oil layer: in poor layer; interlayer interference; non-perforated well pattern. Besides, some remaining oil exists because of the pinch-out sealing reservoir injection-production faultiness, but with loose scatter.On the basis of fine geology and numerical simulation, the paper provides the secondary development object, development order and regulating methods. After close selection of some proper deployment schemes, the paper gives three schemes of the development of well pattern: Sapu class II reservoir tertiary recovery well pattern, class III reservoir"the combination of class II and class III"well pattern, and Gaotaizi oil layer infilling adjustment well pattern. Each uses the present well pattern but optimizes and reorganizes it, and subdivides the straticulate exploration. The paper makes an adaptability study of well pattern, establishes standard for the secondary development of well pattern and well spacing: for ASP flooding in Sapu class II reservoir, producer-injector spacing is 125m; for"the combination of class II and class III"well pattern in Sapu class III reservoir, producer-injector spacing is about 100m; for Gaotaizi oil layer infilled well pattern, producer-injector spacing is about 100m. Since Gaotaizi oil layer infilled well pattern should be adaptable to old well pattern, its producer-injector spacing is set as 106m approximately.The paper also involves the study of development potential and index forecast: forecast for the potential in increasing the storage, predesign for injection-production pressure system and proper pressure, index preliminary forecasting.The focus of the secondary development is to improve the extraction ratio of old field. Through geological modeling and numerical simulation, the paper plans to make history matching and index forecast, in order to improve recoverable reserves and extraction ratio. The paper concludes that the secondary development of well pattern reconfiguration is practicable and can be spread in Sa-Zhong area because of its obvious economic benefit.