发布时间 : 星期三 文章浜曟帶 - 鐧惧害鏂囧簱更新完毕开始阅读
=10.194at(kgf/cm)≈10.2at
1at=1 kgf/cm2=98066.5 Pa =98.0665 kPa=0.0980665 Mpa 粗略计算时,可认为:
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1MPa=10kgf/cm=10at (误差为2%) 1at=100 kPa=0.1 Mpa
1.3.2 British System-----psi
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psi----pounds/inch(pounds per square inch) 磅/英寸2
1psi=6.895 kPa≈7 kPa=0.007 Mpa 1000psi≈7 Mpa 5000 psi=35 Mpa
井控中很多压力是由液体和气体产生的，但压力的概念是一样的，所不同的是液体和气体在某点的压力在各个方向都相等。
2．静液压力/Hydrostatic Pressure 2.1 定义/Definition
静液压力由静止液体重力产生的压力。 Hydrostatic Pressure is the force exerted
by the weight of static fluid. “hydro”------water or liquid “static”-------at rest
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2.2 公式 /Formula
Ph= gρH= 0.00981ρH Mpa
2.3 钻井液的静液压力/ Hydrostatic Pressure of
Drilling Fluid
在钻井作业中, 钻井液的静液压力是由井中
钻井液重力产生的。
Pm= 0.00981ρm H MPa Where:
ρm----钻井液的密度density of drilling fluid.
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g/cm(kg/l) H------TVD 垂深 m For example:举例
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ρm =1.2 g/cm , H=2000m, 计算Calculate: Pm
答案Answer: Pm=0.00981ρm H
=0.00981*1.2*2000 =23.544(Mpa)
In drilling, hydrostatic pressure is the force
exerted by drilling fluid in the wellbore. When formation pressure is greater than hydrostatic pressure, formation fluid may enter the wellbore. If formation fluid enter the well bore because formation pressure is higher than hydrostatic pressure, a kick has occurred. If prompt action is not taken to control the kick, or kill the well, a
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blowout may occur. To control a well, a proper balance between pressure in the formation and pressure in wellbore must be maintained; Hydrostatic pressure must be equal to or slightly higher than formation pressure.
3. 压力梯度/pressure gradient 3.1 定义/Definition
单位垂直深度压力的变化值。
Pressure gradient is the amount pressure changes with per unit true vertical depth.
TVD&MD: TD
TVD and MD is differ, especially in directionally drilled holes.
TVD is the length of a straight vertical line from the surface to the bottom of the hole. MD or total depth is the length of the well as measured along the actual course of the hole.
3.2 公式/formula
PG??0.00981?(MPa/m)
H
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where:
G-----压力梯度gradient, Mpa/m P-----压力pressure, Mpa H----垂深TVD, m
钻井液的压力梯度：
Gm = Pm/H=0.00981ρm (Mpa/m) 例如For example:
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ρm = 1.24g/cm, H = 3353m. 计算calculate: Gm and Pm
答案answer: Gm = 0.00981ρm
=0.00981*1.24=0.0122(Mpa/m) Pm = Gm H=0.0122*3353=40.8(Mpa) 3.3 英制表示法/Expression Method of British
System 2
g=0.052ft/s
Pm = 0.052ρm H Where:
Pm ------静液柱压力hydrostatic pressure, psi---pounds per square inch.
ρm -------密度density, ppg----pounds per
gallon.磅/加仑
H---------TVD, ft—foot. 换算关系/conversion relation:
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1 g/cm= 8.33ppg 淡水fresh water
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