drilling formulas mud pump output for sale

Rig pump output, normally in volume per stroke, of mud pumps on the rig is  one of important figures that we really need to know because we will use pump out put figures to calculate many parameters such as bottom up strokes,  wash out depth, tracking drilling fluid, etc. In this post, you will learn how to calculate pump out put for triplex pump and duplex pump in bothOilfield and Metric Unit.

Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.

Oil and Gas drilling process - Pupm output for Triplex and Duplex pumpsTriplex Pump Formula 1 PO, bbl/stk = 0.000243 x ( in) E.xample: Determine the pump output, bbl/stk, at 100% efficiency for a 7" by 12". triplex pump: PO @ 100%,= 0.000243 x 7 x12 PO @ 100% = 0.142884bbl/stk Adjust the pump output for 95% efficiency: Decimal equivalent = 95 + 100 = 0.95 PO @ 95% = 0.142884bbl/stk x 0.95 PO @ 95% = 0.13574bbl/stk Formula 2 PO, gpm = [3(D x 0.7854)S]0.00411 x SPM where D = liner diameter, in. S = stroke length, in. SPM = strokes per minute Determine the pump output, gpm, for a 7" by 12". triplex pump at 80 strokes per minute: PO, gpm = [3(7 x 0.7854) 1210.00411 x 80 PO, gpm = 1385.4456 x 0.00411 x 80 PO = 455.5 gpm

Example:Duplex Pump Formula 1 0.000324 x (liner diameter, in) x ( stroke lengh, in) = ________ bbl/stk -0.000162 x (rod diameter, in) x ( stroke lengh, in) = ________ bbl/stk Pump out put @ 100% eff = ________bbl/stk Example: Determine the output, bbl/stk, of a 5 1/2" by 14" duplex pump at 100% efficiency. Rod diameter = 2.0": 0.000324 x 5.5 x 14 = 0.137214bbl/stk -0.000162 x 2.0 x 14 = 0.009072bbl/stk Pump output @ 100% eff. = 0.128142bbl/stk Adjust pump output for 85% efficiency: Decimal equivalent = 85 100 = 0.85 PO@85%)= 0.128142bbl/stk x 0.85 PO@ 85% = 0.10892bbl/stk Formula 2

PO. bbl/stk = 0.000162 x S[2(D) - d] where S = stroke length, in. D = liner diameter, in. d = rod diameter, in. Example: Determine the output, bbl/stk, of a 5 1/2". by 14". duplex pump @ 100% efficiency. Rod diameter = 2.0in.: PO@100%=0.000162 x 14 x [ 2 (5.5) - 2 ] PO @ 100%)= 0.000162 x 14 x 56.5 PO@ 100%)= 0.128142bbl/stk Adjust pump output for 85% efficiency: PO@85%,= 0.128142bb/stkx 0.85 PO@8.5%= 0.10892bbl/stk Metric calculation Pump output, liter/min = pump output. liter/stk x pump speed, spm. S.I. units calculation Pump output, m/min = pump output, liter/stk x pump speed, spm. Mud Pumps Mud pumps drive the mud around the drilling system. Depending on liner size availability they can be set up to provide high pressure and low flow rate, or low pressure and high flow rate. Analysis of the application and running the Drill Bits hydraulics program will indicate which liners to recommend. Finding the specification of the mud pumps allows flow rate to be calculated from pump stroke rate, SPM. Information requiredo Pump manufacturer o Number of pumps o Liner size and gallons per revolution Weight As a drill bit cutting structure wears more weight will be required to achieve the same RoP in a homogenous formation. PDC wear flats, worn inserts and worn milled tooth teeth will make the bit drill less efficiently. Increase weight in increments of 2,000lbs approx. In general, weight should be applied before excessive rotary speed so that the cutting structure maintains a significant depth of cut to stabilise the bit and prevent whirl. If downhole weight measurements are available they can be used in combination with surface measurements to gain a more accurate representation of what is happening in the well bore.

Mr. Carter has over fifty five years" experience in domestic and international engineering and management positions in the area of drilling, completion and E&P waste management with Conoco, Baroid, and several other drilling contractors. He has conducted seminars and schools on fluids, rig equipment, and drilling engineering related subjects associated with drilling optimization, cost reduction, and well control. Tom has served as Chairman of the API standardization committee (SC 13) on Drilling and Completion Fluid Materials. He was a SPE Distinguished Lecturer in 1993 and served as the Editor of the SPE reprint series book on drilling fluids. Currently, he is a member of the Chevron Clear Leader Center serving as a Technical Learning Advisor in Houston. He coordinates and has teaching participation in several subject areas such as Coiled Tubing Operations, Directional Drilling, Drilling Fluids, Drilling Practices, Fundamentals for Drilling and Completion, HPHT Drilling and Completions, and Solids Control and Waste Management. He is still active in several industry organizations and was President of the Houston chapter of the American Association of Drilling Engineers, Coordinator for the SPE North American Forum Series, Membership Chairman of the editorial committee for the Journal of Petroleum Technology and on the Board of Directors for the Ocean Energy Center Society (Ocean Star rig museum in Galveston). He has published 20 technical publications and holds five U.S. patents. He graduated with a BS in Geology from Centenary College in Shreveport, Louisiana in 1963.

The driller’s method requires two circulations to kill the well. The first circulation is to circulate influx out of the well with original mud weight. The second circulation is to kill the well with kill weight fluid. During the first circulation, the bottom hole pressure remains constant due to maintain drill pipe pressure constant while circulating. For the second circulation, in order to maintain constant bottom hole pressure, casing pressure is held constant while circulating kill mud to the bit. Once the kill mud passes the bit, the drill pipe pressure will be held constant until the kill weight mud is on surface and there is no sign of influx in the annulus.

The Wait and Weight method requires only one circulation. The influx will be circulated out while the kill weight mud is displaced into the well simultaneously. While pumping the kill fluid from surface to the bit, drill pipe pressure schedule must be strictly followed. After that the drill pipe pressure is maintained constant until the kill mud returns back to surface.  Some people call the Wait and Weight method as “Engineer’s Method” because there are more calculations compared to the Driller’s method.

For W&W method, kill weight mud must be prepared prior to circulation therefore the drill string is in static condition with no circulation for a while. There is high chance for wellbore to collapse and pack the drillstring.

Shoe will be exerted the maximum pressure when top of gas kick is at the casing shoe. Once the gas pass the shoe, the shoe pressure will remain constant. The W&W can reduce shoe pressure when the kill weight mud goes into the annulus before the top of gas arrives at shoe. If you have larger drillstring volume than annular volume, you will not be able to lower the shoe pressure using Wait and Weight method. However, if time to prepare the kill weight mud is very long, gas migration will increase shoe pressure. There will be a possibility that using W&W can create more shoe pressure due to gas migration while preparation of drilling mud.

Nowadays, oil-based drilling fluid is widely used for drilling operation. Gas will be soluble in oil based mud and it will not be able to detect at the bottom. Gas may expand when it moves almost to the surface and it is often above the shoe. Hence, W&W will not help reduce shoe pressure.

Around the world, there are a lot of drilling rigs which don’t have great capability to mix drilling fluid effectively, therefore, kill weight mud cannot not be mixed as quickly as the operation required for killing the well using W&W. The Driller’s Method will not have this issue because the circulation can be performed right away. Waiting for preparing kill weight mud for a long time can lead to increasing in shoe and surface pressure due to migration of gas.

If the bit nozzles are plugged during the first circulation of Driller’s method, drill pipe pressure is allowed to increase temporary by maintaining casing pressure constant until the drill pipe pressure stabilizes and then the new circulating pressure. During the second circulation of Driller’s method, if the plugged nozzles are encountered, casing pressure must maintain until the kill mud to the bit and then change to hold drill pipe pressure shown on the gauge.

Well ballooning effect is a natural phenomenon occurring when formations take drilling mud when the pumps are on and the formations give the mud back when the pumps are off. When ballooning is observed, it must be treated as kick. If W&W is utilized to manage this issue at the beginning, the additional mud weight can increase complexity of wellbore ballooning situation. More mud weight can induce more mud losses and the situation will be worse. Since the Driller’s method does not require additional mud weight hence there is no increasing in wellbore pressure. Therefore, the ballooning situation will not become worse.

Deepwater condition is high-pressure and low-temperature conditions which are ideal case for hydrate. Therefore, there is a high chance of hydrate formation in choke/kill lines and BOP when gas influx is taken in a deepwater well. Driller’s method will minimize hydrate issue because the circulation is established as soon as possible. The mud is still warm and the hydrate issue can possibly be mitigated. Conversely, killing the well using wait and weight method requires longer time to shut in because the kill mud must be properly prepared prior to circulating. The static condition will make the mud cool and it is a favorable condition for hydrate formation due to decreasing in temperature of drilling fluid.

Many groundwater professionals prefer using charts and tables to determine these values, and those tabulated references are available in the appendices of many textbooks and in handbooks from cement or drilling fluid suppliers.

This approach works well but relying on a printed reference is not without the risk since the wrong value can still be selected from the fine print of a reference table, or the reference document can be damaged or lost (e.g., dropped in the mud pit) altogether.

So, let’s address the alternative approach of using simple mathematical formulas to determine the same information. Although the reliance on a single sheet of paper to obtain the needed value is avoided with this approach, the potential for human error or miscalculation remains, meaning regardless of the approach, great care in determining such values is prudent.

As we consider the various calculations that enable us to determine the values of length, weight, pressure, volume, flow velocity, etc., we should remain mindful of the units of measure we’re dealing with. The groundwater industry uses units of measure that are somewhat intermingled with other units from associated disciplines such as engineering, surface water hydrology, and the oil and gas drilling industry.

The intermediate casing can be sealed using the pressure grouting technique (Figure 3) to pump cement slurry down through the drill pipe and out to the annulus through a float shoe (a drillable check valve connected to the base of the casing). The inside of the intermediate casing is kept full of water during the cement placement to equilibrate hydraulic pressures inside and outside the casing. After the intermediate casing is sealed with the pressure grouted cement, the float shoe can be drilled out and the borehole advanced for installation of the screen and filter pack in the lower part of the well.

For heavier-walled casing materials or deeper wells, there are situations where the “string weight” of the casing and screen may exceed the safe hang weight of the casing string, or even exceed the mast capacity of the drilling rig. A good rule-of-thumb is to maintain a rig mast capacity that is no less than 1.5 times the string weight.

There are several calculations that are commonly applied by drilling fluid engineers (mud engineers) to determine the time period required for the fluid to move from one location in the borehole to another. Some of the more common equations are described below.

The uphole velocity calculation provides a determination of the speed at which the drilling mud will flow as it moves up the borehole. For direct air rotary or reverse circulation drilling methods, the uphole velocity is high, so this calculation is generally applicable only for the direct mud-rotary drilling method. The formula for uphole velocity is:

Notice the uphole velocity formula is similar to the annular volume formula in that both those calculations use the factor (D2 – d2) to address the cross-sectional area of the annulus. However, the constants in these two formulas are different (0.005454 versus 24.51), which can be confusing. Keep in mind, however, that the constants primarily just provide unit conversions.

Thebottoms-up time calculation enables us to determine the time period for the drilling fluid (and the cuttings it is carrying) to travel from the drill bit up to the land surface. This is illustrated in Figure 6(A).

We can calculate the bottoms-up time by using the uphole velocity formula with the borehole depth and drilling mud flow rate plugged in, but that flow rate is being generated by the mud pump, and positive displacement mud pumps (duplex or triplex) are almost never equipped with a flow meter. To determine the flow coming from the mud pump, we can use the formulas:

Remember the strokes are counted in both the forward and backward directions on a duplex pump, but only in the forward direction on a triplex pump. Drillers often have reference charts that provide oilfield barrels per stroke (bbl/stroke), which can be converted to gpm by timing the strokes per minute and converting barrels to gallons (1 barrel = 42 gallons).

The round-trip time enables us to see the result of drilling fluid additives, as indicated by the return flow of fluids at the land surface, as is illustrated in Figure 6(B). The round-trip time calculation is the same as bottoms-up time, but with the travel time of fluid to displace the drill pipe added in.

A specified volume of drilling fluids (called a pill) can be circulated to a particular depth interval within the borehole (called spotting), so that the additives in the pill of drilling mud can address the borehole problem at a particular depth of the borehole. This is shown in Figure 6(C).

The calculation for time required to spot a pill of drillingfluid involves determining the pumping time (at the calculated flow rate) required to displace the fluid so that the drilling mud additives are located adjacent to the problematic interval. This approach is used by mud engineers to address problems such as lost circulation or stuck drill pipe.

The formulas and calculations provided in this column and elsewhere provide important tools for us to quantify the variables we need for water well design and construction. However, it is important to remember that “doing the math” is not a replacement for applying professional knowledge and consideration to determine whether the mathematical result makes common sense.

Pump Output per Stroke (PO): The calculator returns the pump output per stroke in barrels (bbl).  However this can be automatically converted to other volume units (e.g. gallons or liters) via the pull-down menu.

A triplex mud (or slush) pump has three horizontal plungers (cylinders) driven off of one crankshaft. Triplex mud pumps are often used for oil drilling.

Electronic Pump Stroke Counters are a vital part to any drilling rig operation. When a mud pump is in operation, the driller must know how much mud is flowing down hole in order to keep the operation running at peak efficiency. Pump stroke counters assist the driller by measuring the mud pump’s strokes per minute and total strokes. So, how does a pump stroke counter tally the mud pump’s strokes

Electronic Pump Stroke Counters are a vital part to any drilling rig operation. When a mud pump is in operation, the driller must know how much mud is flowing down hole in order to keep the operation running at peak efficiency. Pump stroke counters assist the driller by measuring the mud pump’s strokes per minute and total strokes. So, how does a pump stroke counter tally the mud pump’s strokes, and why it is important? In order to understand that, you’ll need to know some basic information about mud pumps.

Knowing how a mud pump functions is important in understanding the role a pump stroke counter plays in rig operations. Mud pumps act as the heart of the drilling rig, similar to how our heart works. Just as our heart circulates blood throughout our bodies, a mud pump circulates essential drilling mud down the hole and back up to the surface. Mud tanks house drilling mud, and a mud pump draws the fluid from the mud pump. A piston draws mud in on the backstroke through the open intake valve and pushes mud through the discharge valve and sends it towards the rig. By circulating fluid, the mud pump ensures that the drill bit is cool and lubricated and that cuttings are flushed from the hole. The two main kinds of pumps used are duplex and triplex pumps, where the duplex pump has two pistons and the triplex pump has three. Whether the rig is using a duplex or triplex pump, it is important to know how many strokes per second the pistons are moving. The driller monitors strokes per minute to determine how much costly, yet essential, mud is being pumped into the system with the use of a mud pump stroke counter system. Now, that you know about mud pumps, you’ll need to know what’s in a stroke counter system.

Stroke Counter — The stroke counter stainless steel box is mounted on the driller’s console and is either square or rectangular in shape, depending on the number of pumps it is monitoring. Stroke counters will show strokes per minute and total strokes, and when a particular mud pump is operating the strokes/minute and total strokes will be displayed. Power is supplied by a 3.6 volt lithium battery, and the counter contains a crystal-controlled real time clock with 100 parts per million accuracy or better. Each counter is mounted to the console with 1/4” stainless steel hex head bolts, lock washers and nuts.

Micro Limit Switch — The micro switch is connected to a c clamp near the mud pump piston. The micro switch stainless steel rod (sometimes called a whisker) sticks out in the piston housing near the piston. As the piston passes the rod, it moves the rod and the switch sends an electronic signal back to the counter. The counter increases by one each time the piston moves the rod, counting the mud pump’s strokes. The switch’s signal is then transmitted to the stroke counter. These micro switches are built to stand up to demanding outdoor conditions. They can withstand shock, equipment vibration, extreme temperatures, water and dust.

Cable and Junction Box – A cable is connected to the back of the pump stroke counter and then to the junction box. From the junction box, the cables travel to the limit switches.

Pump Stroke Counters are like a blood pressure machine. Each time our heart pumps, a blood pressure machine reads our systolic and diastolic blood pressure by way of our pulse. A mud pump stroke counter functions in much the same way. Just as a blood pressure machine detects our pulse so too does a limit switch rod detect the movement of the piston. When the stainless steel rod is moved, the micro limit switch detects the movement. The signal is sensed as a contact closure, and it is transmitted to the stroke counter where the contact closure is converted to a logic pulse. The pulse feeds two separate circuits. The total strokes circuit reads and displays the closures one at a time, totaling them up to reveal the total strokes in the LED window. The second pulse is sent along a separate circuit which is a rate circuit. This rate circuit will average the closures against the real time clock. The result is displayed as the total strokes per minute.

Pump stroke counters are essential to drilling rig operations because they measure the efficiency of mud pumps. Knowing strokes per minute and total strokes of the pistons helps the driller to determine if the correct amount of mud is going down hole. Having this information aids in running a drilling rig at peak efficiency, assists in extending drill bit life, and avoids costly overuse of drilling rig mud. Unsure which pump stroke counter is right for your application? Give our friendly, knowledgeable staff a call or email. We’ll keep you turning right.

Mr. Carter has over fifty five years" experience in domestic and international engineering and management positions in the area of drilling, completion and E&P waste management with Conoco, Baroid, and several other drilling contractors. He has conducted seminars and schools on fluids, rig equipment, and drilling engineering related subjects associated with drilling optimization, cost reduction, and well control. Tom has served as Chairman of the API standardization committee (SC 13) on Drilling and Completion Fluid Materials. He was a SPE Distinguished Lecturer in 1993 and served as the Editor of the SPE reprint series book on drilling fluids. Currently, he is a member of the Chevron Clear Leader Center serving as a Technical Learning Advisor in Houston. He coordinates and has teaching participation in several subject areas such as Coiled Tubing Operations, Directional Drilling, Drilling Fluids, Drilling Practices, Fundamentals for Drilling and Completion, HPHT Drilling and Completions, and Solids Control and Waste Management. He is still active in several industry organizations and was President of the Houston chapter of the American Association of Drilling Engineers, Coordinator for the SPE North American Forum Series, Membership Chairman of the editorial committee for the Journal of Petroleum Technology and on the Board of Directors for the Ocean Energy Center Society (Ocean Star rig museum in Galveston). He has published 20 technical publications and holds five U.S. patents. He graduated with a BS in Geology from Centenary College in Shreveport, Louisiana in 1963.

Density of the Kick, ppg = initial mud weight, ppg – (initial stabilized drillpipe pressure, psi – initial stabilized casing pressure, psi)/(0.052 x Length of the kick, ft)

Riser margin is = (drilling fluid gradient to control the formation pressure with riser, psi/ft x depth of the hole (TVD), ft – seawater gradient, psi/ft

Continental Emsco Drilling Products, Inc., which consisted of Emsco drilling machinery and Wilson mobile rigs, was purchased by National-Oilwell, Inc on July 7, 1999. To our knowledge, no pumps have been manufactured and sold under the Emsco brand name since National-Oilwell acquired them.

Fairbanks Morse pumps are currently manufactured in Kansas City, Kansas. Fairbanks Morse is a division of Pentair ever since August, 1997 when Pentair purchased the General Signal Pump Group.

Gaso pumps are manufactured by National Oilwell Varco. Gaso was acquired as "Wheatley Gaso" by National-Oilwell in the year 2000. At the time, Wheatley Gaso was owned by Halliburton.

Skytop Brewster pumps are no longer available as new pumps. Skytop Brewster(Cnsld Gold), a unit of Hansen PLC"s Consolidated Gold Fields subsidiary, was acquired while in bankruptcy by National-Oilwell, Inc. in November, 1999.

parameter Unit Symbol length Feet,inches or Mtr Ft ,inor M Area Square feet, Square inches or square meters Volume Cubic feett, cubic centimeters cubic meters or Cuft. Cu In or Meters cube Capacity US barrels,US gallons, Cubic ft bbl, gal(US), cuft Mass Pounds,Short tons lbs, Sh tn Force (weight) Pounds-force lbf Presure Ppounds –force per square inch psi Density (mudweight) Pounds per gallon, pounds per cubic ft Ppg ,pcf torque Foot pounds ftlbs

The same expression for calculation od hole volumes can also be used for the calculation of mud pump displacements Triplex Pump displacement in bbls/ft = D² x L x e x3 x 12 x100 Where D= liner size in inches L= Stroke length in inches e= Volumetric efficiency in %

Example A drill string weighs lbs in air how much will it weigh in 11.5ppg mud? Buoyed weight = weight in air X buoyancy factor Bouyancy factor= mw 65.44 = = Buoyed weight = 180,000 X = lbs

Example Find the maximum weight on bit if a drill string has 20 drill collars each 8 inch by 2.5 inch and 30ft in length and weight 154 lbs/ft The density of the drilling fluid is 13.4ppg and 90% of the buoyed weight will be utilized

Example Find the maximum weight on bit if a drill string has 30 drill collars each 6.5 inch by 3 inch and 30ft in length and has a nominal wt of pounds per foot The density of the drilling fluid is 12.4 ppg and 80% of the buoyed weight will be utilized

Example Find the maximum weight on bit available if a drill string has 15 drill collars each 9.5 inch by 2.75 inch and 30ft in length The density of the drilling fluid is 13 ppg and 80% of the buoyed weight will be utilized

Tripping Dry The volume of fall is equal to the volume of steel pulled from the hole. The trip tank is then used to fill up the hole. If 1 barrel of steel is removed from the hole, then using the trip tank, we have to add 1 barrel of mud.

Tripping Dry 3- NO FILL UP: If you fail to fill up the hole, the mud level will drop by the volume of steel pulled. It will drop inside the pipe and in the annulus.

The volume of drop is bbls and will drop in a volume of bbl / ft, then the length of drop will be: 0.711 / = feet. If 93 feet are pulled with no fill up, the mud level will drop by feet.

Tripping Wet The volume of fall is equal to the volume of steel pulled from the hole plus the volume of mud inside this pipe. The trip tank is then used to fill up the hole. If 3 barrels of steel and mud are removed from the hole, then using the trip tank, we have to add 3 barrels of mud.

Tripping Wet 2- Calculate the volume of mud pulled: Length x DP Capacity Example: DP Capacity = bbls/ft Length Pulled 93 feet Volume Of Mud Pulled: 93 x = 1.65 bbls

Tripping Wet 5- NO FILL UP: If you fail to fill up the hole, the mud level will drop by the volume of steel and mud pulled. It will drop inside the annulus.

Mud Weight The Mud weight is the density ( mass per unit volume ) of a drilling fluid. Mud Weigth can be expressed in: Pound per Gallon ( ppg ) Pound per Cubic Feet ( pcf ) Specific Gravity ( sg )

Since the pressure is measured in psi and depth is measured in feet, it is convenient to convert mud weights from ppg to a pressure gradient in psi/ft. The conversion factor is 0.052 Pressure gradient (psi/ft) = Fluid Density (ppg) x 0.052 Example: A fluid having a mud weight of 10 ppg will have: 10 x = 0.52 psi ft as a pressure gradient. A 1 foot column of 10 ppg mud will have a pressure of 0.52 psi

Hydrostatic Pressure Hydrostatic Pressure is the pressure exerted by a column of fluid ( at rest )and is calculated by multiplying the gradient of the fluid by the True Vertical Depth at which the pressure is being measured: Hyd Pressure(psi) = Fluid gradient (psi/ft) x TVD Example: What is the hydrostatic pressure at 10,000 ft for a mud gradient of 0.52 psi /ft ? Hyd Pressure(psi) = 0.52 x 10,000 Hyd Pressure = 5,200 psi

Hydrostatic Pressure It is usefull to visualize the well as a U-tube. One column is for the pipe in the well and the other column is for the annulus. If the same fluid is used is both columns, hydrostatic would be equal and the fluid would be static on both sides of the tube. Mud Hydrostatic in the string Mud Hydrostatic in the annulus

Pump pressure increased as pump speed increases P2 =P1x SPM2 2 SPM1 Where: P1=old pump pressure P2=new pump pressure SPM1=Old pump rate SPM2= New pump rate

Pump pressure also increases with fluid density P2= P1 x MW2 MW1 Where P1=old pump pressure P2=new pump pressure MW1= Old mud wdensity MW2 new mud density

Each time the block are raised and lowered during the drilling process a certain amount of work is done by the drilling line Work done = Force X Distance = Ton X Miles Tin mile calculations are used to determine the actual slip and cut off programs for the rig

RTtm = Wp X (Lp+D) +2XDX(2Wb+Wc) 5280 X 2000 Where: RTtm =Round trip Ton Miles Wp= Buoyant weight of drill pipe in mud D=Depth of the hole Lp=average stand length Wb=Weight of travelling block assembly Wc=Buoyant weight of drill collars minus the buoyant weight of the same length of drill pipe

Answer: From Drilling Data Handbook table the buoyancy factor = 0.848 The WP Buoyant weight of drill pipe = 19.5 x = lb/ft. Wc,the Buoyant weight of drill collars = (500 x 147 x 0,848) ‑ (500 x 16,53)= ‑ 8265 = lbs Take average length of 1 stand = 90 ft. RTtm = WP x D x ( LP + D ) + 2 x D x ( 2 Wb + Wc ) 5280 x 2000 and with the numbers entered into the formula - RTt= 16,53 x 7000 x ( ) + 2 x 7000 x ( 2 x x ) x 2000 = 189 TM

Casing Ton Miles Ctm= D xWcx(Lc +D)+4 x D xWb 5280 x2000x2 Where:Ctm= casing ton miles Wc=Submerged wt of casing in mud (lbs/ft) Lc=Average lenght of 1 joint f casing Wb=weight of travelling block assembly

Precharge pressure psi Initial condition with only gas : Pressure x Volume = Constant 1.000 x 10 = The pump system is started and hydraulic fluid is pumped into the accumulator bottle until maximum operating pressure is reached at psi : P1 x V1 = P2 x V  x 10 = x V2 V2= X = gallon gas 3000 Stored hydraulic fluid = = gal

The pump system is isolated and the BOP’s functioned until accumulator pressure reach precharge pressure psi: P1 x V1 = P2 x V  x 10 = x V2 V2= 10 X =8.33 gallons gas 1200 Usable hydraulic fluid = = 5 gal If the minimum operating pressure recommended by the manufacture is psi as for Shaffer Annular Preventer with pipe size smaller than 7” the usable hydraulic fluid would be : P1 x V1 = P2 x V  x 10 = x V2 V2= 10 X =6.66 gallons gas 1500 Usable hydraulic fluid = = gal

Mud Weight The Mud weight is the density ( mass per unit volume ) of a drilling fluid. Mud Weight can be expressed in: Pound per Gallon ( ppg ) Pound per Cubic Feet ( pcf ) Specific Gravity ( sg )

Hydrostatic Pressure It is usefull to visualize the well as a U-tube. One column is for the pipe in the well and the other column is for the annulus. If the same fluid is used is both columns, hydrostatic would be equal and the fluid would be static on both sides of the tube. Mud Hydrostatic in the string Mud Hydrostatic in the annulus

Pumping a Slug It is useful to pump a slug before tripping. The slug weight being heavier than the mud, a length of pipe will be empty. The HP is not reduced because the heavier mud will compensate for the empty pipe.

If 20 bbls of 12 ppg slug are pumped in a 10,000 ft hole containing 10 ppg mud, what will be the height of empty pipe? DP capacity = bbl/ft 1- Calculate the height of the slug: 20 / = 1126 ft

Practical Exercise 3- If 28 bbls of 14 ppg slug are pumped in a 12,000 ft hole containing 11 ppg mud, what will be the height of empty pipe? DP capacity = bbl/ft

MUD WEIGHT CHANGE 2600 psi A well is being drilled using 10 ppg mud. At 80 spm the total circulating system pressure losses are 2600 psi. It is decided to increase the mud weight to 11 ppg. 80 spm Mud wt 10 ppg

It is a good drilling practice to calculate the new circulating pressure before changing the mud weight. The way we calculate this change in pressure is to use the following formula; New Mud ppg Old Mud ppg x Old psi. 11 ppg ppg x 2600 = 2860 psi The new pump pressure would be approximately 2860 psi. 2860 psi 80 spm Mud wt 11 ppg

MUD WEIGHT CHANGE Final Circulating Pressure The formula that was just used to calculate the pressure change due to a change in mud weight, is also the formula used to calculate the Final Circulating Pressure. Kill Mud ppg Old Mud ppg x Slow Pump psi.

PUMP STROKE CHANGE A well is being drilled using 10 ppg mud. At 80 spm the total circulating system pressure losses are 2600 psi. It is decided to increase the pump speed from 80 spm to 100 spm. 2600 psi 80 spm Mud wt 10 ppg

It is a good drilling practice to calculate the new circulating pressure before changing the pump speed. The way we calculate this change in pressure is to use the following formula; New SPM Old psi x Old SPM 2600 x 100 spm spm = 4063 psi The new pump pressure would be approximately 4063 psi. 4063 psi 100 spm Mud wt 10 ppg