摘要
地层压力影响页岩储层的弹性。在深层高压下,裂缝结构是影响页岩储层弹性的一个重要因素。目前,考虑压力影响的深部页岩储层地震岩石物理建模方法较少。为此,首先,根据Toksöz的包体理论,考虑有效压力对裂缝纵横比的影响,建立有效压力与裂缝纵横比的定量关系,将有效压力的影响引入Eshelby‑Cheng模型并进行压力修正;其次,利用修正后的Eshelby‑Cheng模型,将受有效压力影响的水平裂缝以包含物的形式耦合到背景介质中,构建一种考虑压力影响的深部页岩储层地震岩石物理模型;最后,将构建的地震岩石物理模型应用于实际工区,并与非压力修正Eshelby‑Cheng模型进行纵、横波速度估算对比。通过分析有效压力对裂缝纵横比、Thomsen各向异性参数及储层纵、横波速度的影响,可以得出:在有效压力变化初期,裂缝纵横比、Thomsen各向异性参数随有效压力增大而减小;储层纵、横波速度随有效压力增大而增大;当有效压力增大到一定限度时,上述三者都趋于稳定,即有效压力变化不再对储层产生影响。该方法对深部页岩储层的纵、横波速度预测结果与实际数据吻合度较高,证明了该模型对深部页岩储层的适用性。
Formation pressure affects the elasticity of shale reservoirs,and in deep high‑pressure conditions,fracture structure is an important factor influencing the elasticity of shale reservoirs.At present,few seismic rock physical modeling methods for deep shale reservoirs consider the influence of pressure.Firstly,based on Toksöz inclusion theory,this paper considers the influence of effective pressure on the aspect ratio of cracks,establishes a quantitative relationship between effective pressure and the aspect ratio of cracks,and introduces the influence of effective pressure into the Eshelby Cheng model for pressure correction.Secondly,the corrected Eshelby Cheng model is em‑ployed to couple the horizontal fractures affected by effective pressure into the background medium in the form of inclusions and build a seismic rock physics model of deep shale reservoirs considering pressure effects.Finally,the built seismic rock physics model is applied to the actual work area and compared with the non‑pressure corrected Eshelby‑Cheng model for estimating the P‑wave and S‑wave velocities.By analyzing the effects of effective pressure on the aspect ratio of fractures,Thomsen anisotropy parameters,and P‑wave and S‑wave velocities in the reservoir,the results show that in the early stages of effective pressure changes,the aspect ratio of fractures and Thomsen anisotropy parameters decrease with the increasing effective pressure.The P‑wave and S‑wave velocities of reservoirs increase with the rising effective pressure,and when the effective pressure increases to a certain limit,all three of the above tend to stabilize,which means that changes in effective pressure no longer affect the reservoir.The P‑wave velocity and S‑wave velocity prediction in deep shale reservoirs through this method is highly consistent with actual data,thus proving the applicability of this model for deep shale reservoirs.
作者
武陈月
印兴耀
印林杰
李坤
WU Chenyue;YIN Xingyao;YIN Linjie;LI Kun(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2023年第4期893-901,共9页
Oil Geophysical Prospecting
基金
国家自然科学基金青年项目“多重孔隙储层物性参数多链交叉概率化AVO反演方法研究”(42004092)
国家自然科学基金项目“裂缝型储层五维地震解释理论及方法研究”(42030103)
“含一组倾斜裂缝储层多参数概率化宽方位AVO反演方法研究”(42274157)
中国科协青年人才托举工程项目(2021QNRC001)联合资助。
关键词
深部页岩
有效压力
地震岩石物理模型
储层速度预测
deep shale
effective pressure
seismic rock physics model
reservoir velocity prediction
