井控常见计算

FORMULAS AND CALCULATION 公式和计算

1. Hydrostatic Pressure(HP) 静液柱压力

Hydrostatic pressure using ppg and feet as the units of measure HP（psi）=mud weight,ppg?0.052?true vertical depth(TVD),ft 举例：

Example: mud weight =13.5ppg（泥浆密度） True vertical depth =12,000ft（垂深）

HP=13.5ppg?0.052?12,000ft =8424psi （静液柱压力）

2．Annular Velocity(AV) 环空返速 AV,ft/min=

24.5?Q

Dh2?Dp2Where Q =circulation rate , gpm 排量

Dh=inside diameter of casing or hole size ,in. 套管内径或井眼尺寸 Dp=outside diameter of pipe,tubing or collars,in. 钻具或油管的外径 举例：

Example: pump output=530gpm Hole size=12-1/4 in. Pipe OD=4-1/2 in AV=

12.985=100ft/min

129.8125

3．Pump output,gpm,required for a desired annular velocity,ft/min 给定所需环空返速后如何确定泥浆排量

AV,ft/min(Dh2?DP2)Pump output,gpm=

24.5Where AV =desired annular velocity,ft/min 所需要的环空返速

Dh =inside diameter of casing or hole size ,in 套管内径或井眼尺寸 Dp=outside diameter of pipe ,tubing or collars,in. 钻具或油管的外径 举例：

Example:desired annular velocity=120ft/min Hole size =12-1/4 in Pipe OD =4-1/2 in

120(12.252?4.52)PO=

24.5

4．Buoyancy Factor(BF) 浮力系数 Buoyancy factor using mud weight,ppg

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BF=

65.5?mud?weight,ppg

65.5举例：

Example:Determine the buoyancy factor for a 15.0ppg fluid : 确定泥浆密度为15.0ppg的浮力系数 BF =

65.5?15.0 BF=0.77099

65.5

5．Pump Pressure/Pump Stroke Relationship 泵压和泵冲的简单换算关系 (Also Called the Roughneck’s Formula) Basic formula

?newpumprate,spm?New circulating Pressure,psi= present circulating Pressure ? ??

?oldpumprate,spm?举例：

Example : Determine the new circulating pressure,psi using the following data:

确定新的循环泵压

Present circulating pressure =1800psi 现在的循环泵压 Old pump rate =60spm 现在的排量 New pump rate =30spm 新的排量

2?30spm?New circulating Pressure,psi = present circulating? ?? =450psi 新的循环泵压

60spm??

6．Temperature Conversion Formulas 摄氏和华氏温度的转化公式 Convert temperature,?Fahrenheit(F)to?Centigrade or Celsius(C)

2?C=

??F?32?5OR?C??F?32?0.5556

9举例：

example: Convert 95?F to ?C: 将95?F转换成?C:

?C=

?95?32?5OR?C?95?32?0.5556=35 ?C:

9

7．Slug Calculations 压钻杆重泥浆的计算

1）Barrels of slug required for a desired length of dry pipe

设定期望的不倒返泥浆的钻具高度后，如何计算重泥浆的体积量 Step 1

Hydrostatic pressure repuired to give desired drop inside drill pipe: Hp,psi=mud wt,ppg?0.052?ft of dry pipe Step 2

Difference in pressure gradient between slug weight and mud weight: Psi/ft=(slug wt,ppg-mud wt,ppg) ?0.052

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Step 3

Length of slugin drill pipe:

Slug length,ft=pressure,psi?difference in pressure gradient,psi/ft Step 4

Volume of slug,barrels:

Slug vol,bbl=slug lenth,ft?drill pipe capacity,bbl/ft 举例：

Example:determine the barrels of slug required for the following:

确定所需要的重泥浆体积量

Desired length of dry pipe(2 stands)=184 ft 期望的不倒返泥浆的钻具高度（两柱） Mud weight =12.2 ppg 在用泥浆密度 Slug weight =13.2 ppg 重泥浆密度 Drill pipe capacity =0.01422bbl/ft 钻具的内容积 4-1/2 in.—16.6 1b/ft

Step 1 第一步计算

Hydrostatic pressure required: 需要的液柱压力降 Hp,psi=12.2 ppg?0.052?184 ft =117 psi

Step 2 第二步计算 Difference in pressure gradient,psi/ft: 压力的不同 Psi/ft=(13.2ppg-12.2ppg) ?0.052 =0.052 Psi/ft

Step 3 第三步计算

Length of slug in drill pipe,ft: 重泥浆在钻具内的长度 Slug length,ft=117psi?0.052 =2250 ft

Step 4 第四步计算 Volume of slug,bbl:

Slug vol,bbl=2250ft?0.01422 bbt/ft=32.0bbl 需要的重泥浆的体积量

2）Weight of slug required for a desired length of dry pipe with a set volume of slug

设定期望的不倒返泥浆的钻具高度和重泥浆的体积量后，如何计算重泥浆密度 Step 1

Length of slug in drill pipe,ft:

Slug length,ft=slug vol,bbl?drill pipe capacity,bbl/ft Step 2

Hydrostatic pressure required to give desired drop inside drill pipe: Hp,psi=mud wt,ppg?0.052?ft of dry pipe Step 3

Weight of slug,ppg:

Slug wt,ppg=HP,psi?0.052?slug length,ft+mud wt,ppg 举例：

Example:determine the weight of slug required for the following: 确定重泥浆密度

Desired length of dry pipe(2 stands)=184 ft 期望的不倒返泥浆的钻具高度（两柱） Mud weight =12.2 ppg 泥浆密度 Slug volume =25 bbl 重泥浆体积 Drill pipe capacity =0.01422bbl/ft 钻具的内容积

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4-1/2 in.—16.6 1b/ft

Step 1 第一步计算

Length of slug in drill pipe,ft: 重泥浆在钻具内的长度 Slug length,ft=25 bbl?0.01422 bbl/ft=1758 ft

Step 2 第二步计算

Hydrostatic pressure required: 需要的液柱压力 HP,psi=12.2 ppg?0.052?184 ft=117psi

Step 3 第三步计算

Weight of slug,ppg: 重泥浆密度 Slug wt,ppg=117 psi?0.052?1758 ft+12.2 ppg=13.5 ppg

3）Volume,height,and pressure gained because of slug:

因为重泥浆造成的泥浆体积、高度和压力的变化

a)Volume gained in mud pits after slug is pumped,due to U-tubing:

Vol,bbl =ft of dry pipe?drill pipe capacity,bbl/ft b)Height,ft,that the slug would occupy in annulus:

Height,ft=annulus vol,ft/bbl?slug vol,bbl

c)hydrostatic pressure gained in annulus because of slug:

HP,psi=height of slug in annulus,ft?difference in gradient,psi/ft between slug wt and mud wt 举例：

Example:Feet of dry pipe(2 stands) =184 ft 干钻杆的长度（不倒返泥浆） Slug volume =32.4 bbl 加重泥浆的体积量 Slug weight =13.2 ppg 加重泥浆的密度 Mud weight =12.2 ppg 在用泥浆的密度 Drill pipe capacity =0.01422bbl/ft 钻具的内容积 4-1/2 in.—16.6 1b/ft

Annulus volume(8-1/2 in.by 4-1/2 in.)=19.8 ft/bbl

环空容积（例如：8-1/2 in.钻头和 4-1/2 in钻杆）

a) Volume gained in mud pits after slug is pumped,due to U-tubing:

因为U型管效应，加重泥浆泵入井内后，泥浆罐增加的泥浆体积量： Vol,bbl =184 ft?0.01422 bbl/ft =2.62bbl

b)Height,ft,that the slug would occupy in the annulus: 加重泥浆在环空所占的高度：

Height,ft=19.8 ft/bbl?32.4 bbl =641.5 ft

c)hydrostatic pressure gained in annulus because of slug:

加重泥浆造成的液柱压力的增加值：

HP,psi=641.5 ft(13.2-12.2)?0.052 =33.4psi

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