Annular velocity

<h2 id="scope">Scope</h2>
<p>For this article, annular velocity is described, as used in drilling fluid applications in the <a href="/facts/Oil_industry/xCKs0yQJ">oil exploration industry</a>. There may be other applications in other fields of study such as <a href="/facts/Fluid_mechanics/NIy4tRfE">fluid mechanics</a> (the study of the movement of fluid) or <a href="/facts/Fluid_dynamics/y7uzSCfg">fluid dynamics</a> (the study of the flow of fluid).
</p>
<h2 id="determination">Determination</h2>
<p>The annular velocity can be calculated using one of the following <i>formulas</i>.
</p>

A
        V
        =
        
          
            
              1029.4
              (
              P
              
                O
                
                  b
                  p
                  m
                
              
              )
            
            
              I
              
                D
                
                  2
                
              
              −
              O
              
                D
                
                  2
                
              
            
          
        
        
      
    
    {\displaystyle AV={\frac {1029.4(PO_{bpm})}{ID^{2}-OD^{2}}}\,}

A
        V
        =
        
          
            
              24.5
              (
              P
              
                O
                
                  g
                  p
                  m
                
              
              )
            
            
              I
              
                D
                
                  2
                
              
              −
              O
              
                D
                
                  2
                
              
            
          
        
        
      
    
    {\displaystyle AV={\frac {24.5(PO_{gpm})}{ID^{2}-OD^{2}}}\,}

<p>Where:
</p>
<ul><li>AV = annular velocity in Ft/min (feet per minute)</li>
<li>PObpm = pump output in bpm (barrels per minute) 1 barrel = 42 gallons</li>
<li>POgpm = pump output in gpm (gallons per minute) 1 gallon = 0.0238095238 barrels</li>
<li>ID2 = inside diameter of the wellbore or casing, squared</li>
<li>OD2 = outside diameter of the drill pipe or tubing, squared</li>
<li>1029.4 = A conversion factor constant used to calculate the volume between the outside of a tube within  the inside of another tube, using barrels.</li>
<li>24.5 = A conversion factor constant used to calculate the volume between the outside of a tube within  the inside of another tube, using gallons.</li>
<li>Pump Output = Refers to the measurement of the quantity of a fluid (to put that fluid in motion).</li></ul>
<h2 id="application">Application</h2>
<p>The annular velocity is one of two major variables in the process of cleaning
solids (<a href="/facts/Drill_cuttings/mBYoJqXW">drill cuttings</a>) from the wellbore. By maintaining the annular velocity at certain rates (speeds) in conjunction with the rheological properties of the <a href="/facts/Drilling_fluid/B8fWCc74">drilling fluid</a>, the wellbore is kept clean of the <a href="/facts/Drill_cuttings/mBYoJqXW">drill cuttings</a> to prevent them  from settling back down to the bottom and causing drilling problems.
</p><p>The other major variable is the <a href="/facts/Rheology/KexaBNCS">rheology</a> of the drilling fluid. Rheology is sometimes thought of as <a href="/facts/Viscosity/QLVfrdCz">viscosity</a> to the uninitiated, though improperly. Viscosity (sometimes thought of as its thickness) is a very basic measurement of the fluids resistance to change in movement or flow. The viscosity of a fluid can be measured with a <a href="/facts/Marsh_funnel/oWGdJbUo">Marsh Funnel</a>. Rheology is the study of viscosity and requires more precise and complicated procedures and <a href="/facts/Rheometer/tn2DmtEo">equipment</a> for its determination. For drilling fluid applications a rheometer is used.
</p>
<h2 id="see-also">See also</h2>
<ul>
<li>Energy portal</li></ul>
<ul><li><a href="/facts/Petroleum_Engineering/owk07hr2">Petroleum Engineering</a></li>
<li><a href="/facts/Drilling_rig/o4esL5fh">Drilling rig</a></li>
<li><a href="/facts/Oilfield/wYoSQmGN">Oilfield</a></li>
<li><a href="/facts/Oil_well/mNNRJmuE">Oil well</a></li>
<li><a href="/facts/List_of_acronyms_in_oil_and_gas_exploration_and_production/u27wC2Hb">List of acronyms in oil and gas exploration and production</a></li>
<li><a href="/facts/List_of_oilfield_service_companies/0JVHQuxc">List of oilfield service companies</a></li>
<li><a href="/facts/List_of_oil_fields/KuDYRGhy">List of oil fields</a></li>
<li><a href="/facts/Natural_gas_field/wYoSQmGN">Natural gas field</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Annulus (mathematics) <a href="/wiki/Annulus_(mathematics)" target="_blank">/wiki/Annulus_(mathematics)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
</ol>

Annular velocity open-in-new

Annular velocity