The information contained within this handbook is believed to be accurate and is based upon run histories and empirical data. However, Andergauge makes no warranties or representations to that effect. All information is furnished in good faith, and the use of this information is entirely at the risk of the user.
Introduction Description How the Anderdrift Works Sur face Test Survey Procedure Trouble Shooting Typical Survey Pressure Profile Specifications (US & Metric)
s t n e t n o c Simplicity in
Action
HHOW OWTHE THEAN ANDERDRIFT DERDRIFT ORKS N o t e sWWORKS
• In t ro d u ct ion •
Monitoring the inclination of vertical hole sections is expensive; either through the time consuming procedure of taking single shot surveys or by the use of expensive MWDsystems and personnel. The Anderdrift Vertical Inclination Indicator is designed to provide a simple, cost effective solution. The mechanical tool is robust and supplies real time survey data pulsed through the drilling fluid. The pulses do not require decoding, and the tool can easily be run by the rig crewafter a short familiarisation period. Surveys are normally taken at connections, with rig time kept to a minimum,and the simplicity of design does not require any surface equipment. In addition to saving time over single shots, and being more cost effective than MWDtools, the Anderdrift has proven itself in ROP optimisation. Real time inclination surveys allow maximumWOB, to optimise ROP, but maintain verticality.
n o i t c u d o r t n i
This handbook is intended to be an aid to the operator and is solely provided for information and illustration purposes. Please contact any of our locations; detailed opposite; for clarification or questions not answered in the following sections.
May 2005 w w w.an d ergau ge.com
H OW THE AN DERDRIFT W ORKS Description
The Anderdrift is a simple mechanical tool, situated within the bottomhole assembly, that allows the driller to rapidly check the angle of the well, to a maximum5˚ of inclination. Inclination data is transmitted to surface as a series of pressure pulses, the number of which correspond to the vertical inclination of the BHAin 0.5˚ increments. The pulses can easily be read on the driller’s pressure gauge and no additional surface equipment is needed. If required, a hard copy of the data can normally be provided by the mud logging company. The survey flask is pre-loaded in a short drill collar, and is located by centralisers top and bottom. It can be easily removed fromthe collar for replacement, should this be required. Ajunk catcher is located above the flask, within the top sub, to prevent debris fromentering the pulse mechanism.
n o i t p i r c s e d
H OW THE DERDRIFT W ORKS How AN t he Anderdrift Work s
At drilling flowrates the survey flask remains in the drilling position with the pulse head down and the pendulumseated (Fig. 1). When a survey is required theflowis stopped, allowing thepulse head to riseuntil it is stopped by thefreehanging pendulum catching on oneof themeasuring rings. Theinclination of the well will determinewhich of themeasuring rings catches the pendulum.(Fig 2. Shows thetool latched at 31/2˚).
Before being stopped, the pulse head will pass a series of pulse rings within the pulsing system. The spacing of which correspond exactly to that of the measuring rings. As an independent action, the survey data is subsequently transmitted to surface when the pumps are started.
Pulse Rings Pulse Head
Bringing up the Pendulum pumps causes the Measuring Rings pulse head to travel down through the pulse rings at a controlled rate. This creates a series of equal pressure pulses within the mud column that can simply be counted Figure 1 Figure 2 Drilling Position Latched at 3 1 /2 ˚ at surface. The number of pulses directly equates to the inclination of the well; see following table; Number of Pulses 11 10
9
Inclination (0-5 tool) 0
1
1 11/2 2 21/2 3 31/2 4 41/2 5+
Inclination(0-2.5 tool) 0
1
°
°
/2 /4
/2
1
8 /4
3
7
6
5
4
3
2
1
1 11/4 11/2 13/4 2 21/4 21/2+
1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
Makeup Anderdrift in BHA Bring up pumps quickly and smoothly to survey flowrate(300-800 gpm/1140-3030 lpm*). Notethetool is pulsing via theSPP gauge. Theseinitial pulses will relateto thesurvey taken wherethepumps werelast stopped. Stop pumps (ensureflowceases**). Pulsehead rises until stopped by pendulum. Wait at least 2 mins. To ensurepulsehead has risen. Bring pumps up quickly and smoothly to survey flowrate. Pulsehead starts moving down through pulsechamber. Maintain constant flowuntil last pulse. Adjusting thepump ratemay corrupt pulses. Count thepressurepulses on theSPP gauge&determineinclination. Tool angleequates to number of pulses counted (seetable). Run in hole.
*Thesurvey flowrateshould beadjusted to giveoptimumpulseheight and frequency. Number of Pulses Inclination (0-5 tool) °
Inclinat ion (0 -2 ,5 tool) °
11 0˚ 0
10 01/2˚ 1/4˚
9 1˚ 1/2˚
8 11/2˚ 3/4˚
**This can beachieved by closingKelly Cock or bleedingSPP.
7 2˚ 1
6 21/2˚ 11/4˚
5 3˚ 11/2˚
4 31/2˚ 13/4˚
Not e: Init ial pulses m ay be separ at ed by a hesit at ion in pr essure r at her t han a d ecrease in pressure.
3 4˚ 2
2 41/2˚ 21/4˚
1 5˚+ 21/2˚+
H O W
T H E A N • D S E u R r D f a R c I e F T e W s t O R • K S
1.0 1.1 1.2 1.3 1.4
Stop rotary and pick off bottom. Set brake. Record survey depth***. Circulate out any sweep/slug/pill. Stop pumps (ensure flowceases**). Wait at least 2 mins.
Ensures clarity of pressure pulses. Pulse head rises until stopped by pendulum. To ensure pulse head has risen.
Connections can bemadeduring2 minutewait provided drill pipeis kept still.
1.5 Bringpumps up quickly &smoothly to survey flowrate (300-800 gpm/1140-303 lpm*). 1.6 Maintain constant flowuntil last pulse. 1.7 Count the pressure pulses on the SPP gauge &determine inclination. 1.8 Record inclination against survey depth***. 1.9 Drill ahead.
Pulse head starts moving down through pulse chamber. Adjusting the pump rate during transmission may corrupt pulses. Hole angle equates to number of pulses counted (see table). Counted pulses relate to survey taken at depth pumps where last cut.
*The survey flowrate should be adjusted to give optimumpulse height and frequency. **This can be achieved by closing Kelly Cock or bleeding SPP. ***Survey position should be taken as midpoint of Anderdrift collar. Note 1: Stoppingthepumps takes thesurvey. Startingthepumps transmits thesurvey. Connections can easily bemadebetween thetwo actions. Pulses relateto thesurvey taken at thedepth where thepumps werelast stopped; i.e. a transmission followinga changein depth between thetwo actions will bea record of thesurvey taken at thefirst depth, wherethepumps werestopped. Note 2: Onepulseindicates 5˚ and abovei.e. thewell boremay bemorethan 5˚.
H O W
T H E A S N u D r v E e R y D P R r I F o T c e W d O u r R e K S
Trouble Shooting H OW THE AN DERDRIFT W ORKS
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of
l e
Notes:
1
2
3
• Pumps are brought up to the survey flowrate (300-800 gpm*).
5 4
1
• The tool starts after a fewseconds. • The interval between pulses is roughly 4 secs. 9 8 7 6 5 4 3 Num ber of Pulses* * 11 10 1˚ 11/2˚ 2˚ 21/2˚ 3˚ 31/2˚ 4˚ • The pulse height is approximately 200 psi. Inclination (0-5 tool) 0˚ 1/2˚ 1 Inclination (0-2.5 tool) 0˚ 1/4˚ /2˚ 3/4˚ 1˚ 11/4˚ 11/2˚ 13/4˚ 2˚ • Nine pulses indicate an inclination of 1˚. ** 1 pulse indicates 5˚ and above i.e. the well bore may be more than 5˚. • After surveying the pressure reduces to the drilling pressure.
6
2
3
4
¡
¡
5
6
This confirms that the final pulses have been received and the tool is in the drilling position. *The survey flowrate should be adjusted to give optimumheight and frequency.
2 1 41/2˚ 5˚+ 21/4˚ 2.5˚+
T y p i c a l S u r v e y P r e s s u r e P r o f i l e