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目前注水开发油田矿场确定单井控制的平均地层压力真值不仅关井时间较长（长于２ｄ），而且误差较大。提出改进方法：以压力导数异常变化起始点的压力值作为单井控制的平均地层压力真值；未测到压力导数后期异常变化的井，沿用原有方法确定。推导出计算注水开发井地层压力的港Ⅰ法（利用半对数直线段或外推直线段求取，包括３种计算式）和港Ⅱ法（压力恢复速度法）。在此基础上，考虑现场条件，统计大港油田３５口井实测资料，提出关井时间可由流动系数确定：流动系数大于１μｍ２·ｍ／（ｍＰａ·ｓ）为５～８ｈ；流动系数为０．１～１μｍ２·ｍ／（ｍＰａ·ｓ）为１ｄ；流动系数小于０．１μｍ２·ｍ／（ｍＰａ·ｓ）为２ｄ。应用２组各３口井的实测资料进行验证，港Ⅰ法、港Ⅱ法计算的平均地层压力与实测地层压力的误差都小于３％，且平均关井时间可比目前通用方法缩短约２ｄ。港Ⅱ法精度高、计算简单，可优先采用。提出的地层压力计算方法可普遍应用于注水开发井，并可扩展应用于注水井。图２表３参３（陈志宏摘）
At present, the true value of average formation pressure for single-well control of oilfield development in the field of oilfield waterflooding is not only longer (longer than 2 days) but also larger error. The improved method is as follows: the pressure at the starting point of the abnormal change of pressure derivative is taken as the average formation pressure true value of single-well control; the well that has not been measured abnormally in the late stage of pressure derivative is determined according to the original method. The method of Port I (calculated by semi-logarithmic straight line or extrapolated straight line, including three kinds of calculation formulas) and Port II method (pressure recovery rate method) is deduced to calculate the formation pressure of water injection development well. On the basis of this, considering the on-site conditions, the data of 35 wells in Dagang Oilfield are calculated. It is suggested that the shut-in time can be determined by the flow coefficient: the flow coefficient is more than 1μm2 · m / (mPa · s) for 5 ~ 8h and the flow coefficient is 0.1 ~ 1μm2 · m / (mPa · s) for 1d; the flow coefficient is less than 0.1μm2 · m / (mPa · s) for 2d. The test data from 3 wells in 2 groups were used for verification. The average formation pressure measured by Port I method and Port II method is less than 3% of the measured formation pressure error, and the average shut-in time can be shortened by about 2 days compared with the current common method. Port Ⅱ method high precision, simple calculation, can be used first. The proposed calculation method of formation pressure can be widely applied to water injection development wells and can be expanded and applied to water injection wells. Figure 2 Table 3 Senate 3 (Chen Zhihong pick)