地层压力基本知识ppt课件

1、王志战王志战目目 录录前言前言一、孔隙压力术语一、孔隙压力术语二、温压场的划分二、温压场的划分三、国内外研究现状三、国内外研究现状四、异常压力预测的发展趋势四、异常压力预测的发展趋势五、异常高压的成因机制五、异常高压的成因机制斜率斜率(slope) 纯水纯水(1.0g/cm3)：0.433psi/ft 盐水盐水(1.07g/cm3) ：0.465psi/ft 地层水：地层水：0.450.465psi/ft 1g/cm3 = .433 pst/ft开放系统开放系统(open system)a column of water固体固体+流体流体美国海湾盆地水饱和的美国海湾盆地水饱和的沉积岩密度为沉积

2、岩密度为2.3g/cm3，静岩压力梯度静岩压力梯度为：为：.433psi/ft2.3g /cm3=1.0psi/ft异常高压发生在静异常高压发生在静岩压力梯度线和清岩压力梯度线和清水静压梯度线之间水静压梯度线之间的区域的区域固体总量TDS)随深度而增加PressureDepthThe “pore pressure” is the pressure of the fluid in the pore space of the rock.The point at which pore pressures exceed hydrostatic pressures is the “top ofoverp

3、ressures.”In overpressure, fluids are trapped in the pores and bear part of the weight of the overlying solids.Any pressure over the hydrostatic pressure is overpressure超压）. The amount of pore pressure exceeding the hydrostatic line.Effective stress有效应力） is the amount of overburden stress that is su

4、pported by the rock grains.Typical trend curves for resistivity, sonic velocity, and density. Blue curves denote normal compaction trends. Arrows indicate deviations due to overpressure.Cross-section of hypothetical reservoir unit. In the absence of fluid flow, the difference in pore pressure betwee

5、n points A and B is simply the weight of the fluid in the vertical reservoir column.A local pressure gradient defines how pressure varies over small depth ranges. At the smallest scale, it equals the slope of a pressure versus depth curve. The most basic pressure gradient that we use is equivalent m

6、ud weight (EMW).Pressure profile for hypothetical reservoir unitPressure plotted against depth with mud weight scale added1 lb/gal = .0519 psi/ft*气体气体=84.3%C1+14.4%C2+0.5%CO2+0.8%N2Diagram illustrating pore pressure between hydrostatic gradient and fracture gradientUsing mud weight changes pressure

7、axis to gradient axis. This is the view preferred by drillers.Casing points and mud weight profile for hypothetical situationpore pressures are equal. The value of the centroid concept is that it emphasizes the difference between sand and shale pore pressures. Most pore-pressure prediction technique

8、s emphasize shale properties such as velocity and resistivity but do not address this essential mismatch of the shale and sand pore pressures. This concept also points out that sands provide a mechanism for vertical and lateral transfer of pressures. As basins subside and dewater, the sands provide

9、the mechanism for fluid escape including hydrocarbons.Simple illustration of lateral transfer when one side of a basin subsides and fills with shale. Overburden in the subsided portion is higher and, if burial is sufficiently fast that the shale cant dewater quickly enough, it becomes overpressured.

10、 This is known as disequilibrium compaction.0.9Pc1.2)和低压和低压Pc4）、常温区（）、常温区（-4 t4）和低温区（）和低温区（t-4） a. 单一型温单一型温压系统压系统 b.高压型复式温高压型复式温压系统压系统 c.低压型复式温低压型复式温压系统压系统 -4 0 41.21.00.9压力系数地温异常（）济阳坳陷温济阳坳陷温压系统平面分区标准压系统平面分区标准质分为物理的、化学的；或按作用过程分为有效质分为物理的、化学的；或按作用过程分为有效应力成因的和流体扩张成因的。应力成因的和流体扩张成因的。异常低压来源于：异常低压来源于：永冻土退化

11、；永冻土退化；气藏内气的快气藏内气的快速泄露；速泄露；温度降低；温度降低；天然气水合物的形成；天然气水合物的形成；由于剥蚀或冰盖消失导致上覆岩层的压力降低，由于剥蚀或冰盖消失导致上覆岩层的压力降低，从而引起岩石体积的膨胀。从而引起岩石体积的膨胀。少。阿尔伯达盆地、圣胡安盆地和丹少。阿尔伯达盆地、圣胡安盆地和丹佛盆地的白垩系深盆气藏多具异常低佛盆地的白垩系深盆气藏多具异常低压特征，大绿河盆地、皮申斯盆地和压特征，大绿河盆地、皮申斯盆地和尤因塔盆地的白垩系尤因塔盆地的白垩系第三系深盆气第三系深盆气藏多具异常高压特征。藏多具异常高压特征。Science 50，2019)、Pressure Regim

12、es in Sedimentary Basins and Their Prediction（AAPG Memoir 76，2019）、Pore Pressure and Fracture Gradients（SPE Reprint Series No.49，2019等；主要方法有：等处理手段提取层速度；等处理手段提取层速度； 测井声波、密度等与地震联合进测井声波、密度等与地震联合进行异常压力预测。行异常压力预测。异常压力的分布，特别是超压顶界面的分布，异常压力的分布，特别是超压顶界面的分布，来预测油气藏。来预测油气藏。管理将是十分重要的。管理将是十分重要的。Pore structure models used to characterize shale behavior. Pores with aspect ratios