Offshore reservoirs are subjected to pressure loading from the ocean tide. The resulting pressure fluctuation, notably its amplitude and phase, provides valuable information regarding the formation compressibility and heterogeneity. The purpose of the present study is twofold: First, to propose a method for calculating tidal efficiency from harmonic analysis of regional tide stations and detrended bottomhole pressure (BHP), and second, to compare the compressibility from tidal analysis with that obtained from rock-mechanics measurements and material balance. This case study is on a fractured oil field for which matrix laboratory measurements alone cannot capture the large-scale formation compressibility that is driven by the fracture distribution.

This paper will show how, in the absence of seabed-pressure measurements, a synthetic diurnal tide can be simulated by interpolating the harmonic constituents of neighboring tide stations. The validity of this method was confirmed on two offshore fields. A new procedure that combines a Savitzky and Golay (1964) (SG) filter and cubic splines gave satisfactory results to filter out the tidal signal residual from the reservoir-transient response for both buildup and interference tests. In addition, this paper found that wells in fractured areas of the field have higher rock compressibility and exhibit a higher tidal efficiency. The same effect is observed in flank wells with higher water saturation. Conversely, the tidal efficiency is dramatically reduced in wells experiencing gas breakthrough.

海上储层承受来自海潮的压力载荷。由此产生的压力波动，特别是其幅度和相位，提供了有关地层可压缩性和非均质性的有价值的信息。本研究的目的是双重的：首先，提出一种通过区域潮汐台站的谐波分析和去趋势井底压力（BHP）计算潮汐效率的方法，其次，比较潮汐分析的可压缩性与岩石分析获得的可压缩性力学测量和材料平衡。此案例研究是在一个裂缝性油田上，仅凭矩阵实验室的测量就无法捕获由裂缝分布驱动的大规模地层可压缩性。

本文将展示在没有海床压力测量的情况下，如何通过对邻近潮汐台站的谐波成分进行插值来模拟合成的日潮。该方法的有效性已在两个海上油田得到证实。结合了Savitzky和Golay（1964）（SG）滤波器和三次样条的新程序给出了令人满意的结果，可以从储层瞬态响应中滤除潮汐信号残留，以进行积聚和干扰测试。此外，本文发现，该油田裂隙区的油井具有较高的岩石可压缩性，并具有较高的潮汐效率。在水饱和度较高的侧井中观察到相同的效果。相反，在遇到天然气突破的井中，潮汐效率大大降低。