塔河油田4区块奥陶系油藏原始地层压力的确定

Determining Initial Reservoir Pressure of Ordovician System in 4 Block of Tehe Oilfield

塔河油田4区块奥陶系油藏在投产初期由于地质、施工等主观、客观上的因素,未获得油藏的原始地层压力。从实测地层压力的第一手资料甄别入手,分析了压力的可靠性和压力梯度,结合油藏的地质特征,对地层压力及其变化规律进行了研究,确定了油藏的连通系统。在此基础上,根据碳酸盐岩缝洞性油藏连通的特点及油藏压力整体均衡下降原理,利用生产动态资料,用物质平衡法反推油藏的原始地层压力,确定了该油藏原始地层压力的合理范围。

At the beginning of reservoir initial production stage in Ordovician System in 4 Block of Tehe Oilfield,because of the subjective and objective factors,such as geology and construction so on,initial reservoir pressure can not be obtained.From distinguishing firsthand data about formation pressure being actually gained,reliability of pressure and pressure gradient are analyzed.Combining with geology characteristic of reservoir,formation pressure and its changing law are studied,so the connection system of reservoir is determined.Basing on this,by the characteristic of connection in carbonate rock reservoir with fracture and cavern and principle which reservoir pressure entirely and equally draw down,using the data of production performance,initial reservoir pressure is derived reversely by material balance method,and the reasonable range of initial reservoir pressure is determined in this reservoir.