Sunday, July 17, 2011

20. KICK OFF PROCEDURE FOR DIRECTIONAL WELLS

Dedicated to : Mr. APS Gill, Mr. Munir Alam, Mr. S Suman & Mr. Chandrashekhar Mallik , Directional Drilling Team, ONGC Limited, Mehsana Asset, INDIA                       
----------------------------------------------------------------------------------------------

In directional wells we usually drill vertically upto the kick-off point (KOP).
From the KOP the well is deflected towards the target.
While planning a directional well we determine an angle and a direction in which the well is to be kicked off.

I hereby furnish my experience of kick off operation gained at a Horizontal directional well at Location No. :SNHK, drilled at Santhal Oil Field, Cambay Basin of Western Onshore, India.

Operator: Oil and Natural Gas Corporation Ltd., India
Directional Drilling Service Provider: M/s Weatherford Oil Tool Middle East Ltd.

Fig 20.1 General Well Data
 Note: The Excel sheet has been manually developed by Deepak Choudhary for Academic Purpose.

Fig 20.2 Kick off String Assembly
Note: The Excel sheet has been manually developed by Deepak Choudhary for Project Report Purpose.
 
Operation Report :

M/Arrangement & R/I with above BHA along with MWD tool assembly upto 661.50 m against planned 687.00 m. 
Circulated to condition mud at 661.5 m. 
Stopped circulation and conducted survey at bottom keeping the string in satic condition. 
The survey reading gives us the value of inclination, azimuth and toolface.
It should be noted that for angle less than 3 or 5 degree, the tool gives us MAGNETIC TOOL FACE.
These survey readings are displayed on the MWD Rig Floor Display Unit and looks like shown in figure below:


Fig 20.3 MTF indication at MWD Rig Floor Display Unit

Now after the survey is conducted, we observed that that MTF is 40 degree.
It is to be noted at the MTF and Azimuth are same, i.e. wrt true North. So by adjusting the MTF we can kick of the well at our required azimuth which is 189 degree.
So in order to bring MTF to 189 degree, the scribe line of the motor should be rotated by an angle of 149 degree (= 189 - 40)  towards right (clock-wise).

Once the required toolface setting has been determined (i.e. 149 degree), the effect of reactive torque must be considered.

Reactive torque is the twisting effect caused by the stator of the downhole motor turning anticlockwise in response to the rotor turning clockwise.

The amount of twisting depends on the physical properties of the motor, the length of the drill string and the formation characteristics. 

Motor manufacturers provide estimates of how much left-hand turn can be expected under certain situations. From these tables, or from experience of drilling with similar tools in similar formations, the directional driller must compensate for reactive torque by deliberately pointing the tool face to the right of the calculated heading.

As soon as the bit begins to drill, the scribe line will turn to the left to bring it
back to the calculated heading. The amount of WOB will also affect the reactive torque. As the bit drills off, the reactive torque will reduce.

In our case, the result of reactive torque was estimated to be about 20 degree.

So, net right turn to be provided = MTF Correction (149)+Reactive torque (20) 

Thus to make a 149 degree incriment in MTF, we need to rotate the whole system by 169 degree right (i.e. clockwise).

Now we take into consideration the Bit walk. Bit walk is the tendency of the bit to wander off course by following the direction of rotation (usually to the right). 
Let us consider 10 degree as a correction factor to maintain the deviation tendency due to bit walk.
So now from 169 degree we have to reduce 10 degree to adjust the bit walk tendency.

Finally, we are left with 159 degree.

To do so, we make a reference marking on rotary table and other marking which is 159 degree to right of rotory table marking on the floor using chalk.
Note: the two markings should be visible to the driller as he is the one who is going to rotate the rotary table.

The marking made on the rotary table is as shown in the picture below :

Fig 20.4 Tool face Correction
 Now, by rotating the rotary table in clock wise fashion, we will coincide the two markings so that the whole system rotates by 159 degree right.
After the two markings coincide, it looks something like as shown in the figure below :
Fig 20.5 Tool face Correction
 After the markings coincide, we look at the MWD Rig Floor Display unit which keeps updating the tool face every 30 seconds.

Now the situation is that, the string is stationary and we are waiting for the tool face to be updated on Rig floor display unit.

We want the rig floor display unit to show the MTF to be equal to 179 degree exact wrt North (N). 
It is to be noted that the reactive torque may vary. The data provided my Mud motor manufacturers and the estimate made by the directional driller are not always an exact data. It's an estimated one. So there might be some positive or negative error in the MTF reading which we are waiting for.

So the wait is over ... Here comes the updated tool face reading :

Fig 20.6 MWD Rig Floor Display Unit showing the corrected MTF
The actual reading of 175 degree is practically obtained which is 4 degree less than the desired 179 degree.

We have a scope to correct this 4 degree difference in azimuth over the remaining course length. Therefore this difference of azimuth is not a harmful issue. It is suggested that there is no harm if kick off is performed at 175 degree azimuth and later correction may suitably be made for the said 4 degree.

KICK OFF TECHNIQUE

Now to kick off the well with azimuth = 175 degree, we lock the rotary table so that there is no rotational movement provided to the drill string which may disturb its tool face orientation.
The drilling is now performed by the mud motor, not by the kelly. At the derrick floor the whole system is stationary and the mud motor performs its drilling job at the bottom.
From the surface we continuously keep maintaining the desired WOB so that the further drilling by mud motor is continued. This process of drilling using mud motor by keeping the rotary table in locked condition is called SLIDING.

During kick off, our main motive is to initially provide a guided path to the BHA. Now what length to slide will depend on the type of formation being drilled.
In prevailing practice, slide in one stretch is done for 10-12m of MD. The decision of the length to be slided depends upon the consolidation of the formation being drilled. 
In loose formation there is more risk of deviation, so the slide length is taken more than 2 drill pipe length. 
In hard formation the deviation tendency is less, so even a single drill pipe length of slide is sufficient to guide the bit in a particular path.

The kick off operation is now over.

Based on his experience, the Directional Driller will decide to take further sliding or to switch over to rotary drilling. 

Fig 20.7 Sliding using Mud Motor (Left) and Rotary Drilling (Right)
Now our next objective is to check the result of our slide. It is to be noted that the MWD tool lies at about 20 m above the bit. This distance b/w the MWD tool and the Bit is called the tool offset. After we have slided for say 12 m, the drilled depth is 661.5+12 =673.5 m. The position of bit is now at 673.5 m and the MWD tool is 20 m above the bit, i.e. at 653.5 m.
When the drilled depth will be 673.5+20=693.5 m, the position of MWD tool will be at the end of slide, i.e., at 673.5 m.

Now we can take survey to check the result of our sliding action.

Survey Procedure :
- Stop Rotary.
- Bring String 3-4 m off bottom.
- Circulate out cuttings.
- Shut off pump and confirm that Pump Down Time at MWD Rig Floor Display  unit declines to zero. It indicates that the pump discharge is zero.
- Now concentrate at Pump Up Time at MWD Rig Floor Display unit. It keeps on increasing which indicates the time for which the pump had been kept shut off (no discharge observed). 
- It is worth mentioning that it takes about 2 -3 minutes for the display of survey data at MWD Rig Floor Display unit.
- Record the Survey data.

The case data is furnished as below :
Fig 20.6 Survey Sheet
Note: The Excel sheet has been manually developed by Deepak Choudhary for Project Report Purpose.

In the table, the survey readings at 693.15 m MD is the result of 12 m slide. This also indicates that the slide was properly performed and has given the desired result.


END OF THE BLOG





46 comments:

  1. Thank you Ami. Please go through the other posts too. Hope you'll love them too.

    ReplyDelete
    Replies
    1. . I do not agree with your explanation of reactive torque. Newton’s Law, reactive torque is simply the opposing force of the bit in action. How much reactive torque is due to many different factors. Drill pipe size, grade and length as well as weight on bit (WOB). The Stator (Nitrile Rubber in the power section) does NOT move. The rotor only moves within the stator in an eccentric motion which a drive shaft setup converts to concentric motion. This section needs revision asap.

      Delete
  2. The reactive torque is 10-20 deg for every 1000 feet 10 for the low torque motors and 20 for high torque motor. Can you add some more material on how to obtain desired tool face?

    ReplyDelete
  3. May I just say what а геlief to
    fіnd ѕomebody that genuinely knows what they're talking about over the internet. You actually understand how to bring an issue to light and make it important. A lot more people must read this and understand this side of your story. It'ѕ surpriѕing
    уοu're not more popular because you definitely have the gift.

    Feel free to visit my web-site :: what is a nootropic
    my webpage > how do nootropics help cognitive function

    ReplyDelete
  4. I’m not that muсh of а internet reader tо be honest
    but your sitеs гeally nice, keep
    it up! I'll go ahead and bookmark your website to come back later on. Many thanks

    http://www.dfw-taxicab.com/2011/07/taxi-service-in-hurst-tx/
    Feel free to visit my website limo service irving tx

    ReplyDelete
  5. Thank you for the goοd writeuρ. It aсtually
    used to be a lеiѕure account it. Look сompleх tο faг brought agrееable
    from you! Hoωeveг, hоw сould ωe communicаtе?


    Feel fгeе to surf to my ωeb-ѕite
    - www.dallasautoinsurance1.com
    My web page - auto insurance

    ReplyDelete
  6. How you decided Kick off point...??

    ReplyDelete
  7. Sir,
    How do we select that what kind of well profile we gonna use. ie.- how to decide that drilling should be using S/J/any other profile...??

    ReplyDelete
  8. Εxcellent ωeblog here! Additiоnally your site quitе a bіt uρ very fast!
    What ωеb host are yоu using? Can ӏ
    am getting your associate link іn уour hoѕt?
    Ι desiгe my webѕite loaded up аs fast
    as yοurѕ lol

    Hеre is my wеbpage; tens machine

    ReplyDelete
  9. After I initially left a comment I seem to have clicked
    the -Notify me when new comments are added- checkbox and now each time a comment is added I get 4
    emails with the same comment. Perhaps there is a way you can remove me from that service?
    Thanks!

    Also visit my homepage ... bmi for women chart

    ReplyDelete
  10. It's a shame you don't have a donatе button! I'd definitely donate to this brilliant blog! I suppose for now i'll settle for booκ-mаrking and aԁding your RSЅ feeԁ to
    my Gоogle acсоunt. І lоok forward to fresh
    upԁates and will talk about this blog with mу Facеbook grοup.
    Chat soon!

    Alѕo νisіt my homepage ... hcg extreme

    ReplyDelete
  11. I like the helpful information you provide in your articles.
    I'll bookmark your blog and check again here frequently. I'm quite certain I'll learn plenty of new stuff right here! Best of luck for the next!

    My web blog :: Storage Dayton

    ReplyDelete
  12. That іs reallу intегestіng, You're an overly skilled blogger. I'νe joined your
    feed and look ahead to seaгching for еxtra оf youг fantastic pοst.
    Also, I have ѕharеd yοur site in mу social networks

    Ηerе is my ωeb ѕite - buy and sell cars for profit

    ReplyDelete
  13. When you аre looκіng at music, Brussels can
    be quite diverѕe, with many diffeгent
    styles and genrеs being showcaѕeԁ throughout the
    city. Therе are ѕοme univerѕities that οffeг this ρrogгam.
    This feаr ωill act bеing a pгevеntive for
    dгug use.

    my site - junior mechanical engineer salary canada

    ReplyDelete
  14. With Localroulette, you can certainly find your regular telefonsex calls here but we are oblivious in our own center that we don't. Either way, you allow her to do. But I thought we could keep a secret as he's been keeping it for
    almost 19 years now.

    Take a look at my web page Telefon Sex

    ReplyDelete
  15. Havе уou ever thоught abοut creating аn ebook or gueѕt authoring on
    other sites? I have а blog based on the same subjectѕ you
    dіscuss and wοuld гeallу like to have you shaге
    some storіeѕ/information. I know my
    audiеncе would enјoy your work. If yоu're even remotely interested, feel free to shoot me an e-mail.

    Feel free to visit my web page ... allen homes for rent

    ReplyDelete
  16. If some one wants expert view about blogging afterward i advise him/her
    to pay a visit this website, Keep up the nice job.


    My webpage - free nudes live

    ReplyDelete
  17. When some one searches for his essential thing, therefore
    he/she wants to be available that in detail, thus that thing is maintained over here.


    Also visit my web page: Free Web Cams

    ReplyDelete
  18. excellent points altogether, you simply received a new reader.
    What would you recommend about your put up that you made a few days
    ago? Any certain?

    My web blog; sexy live cam free

    ReplyDelete
  19. Unquestionably believe that which you said. Your
    favorite justification appeared to be on the internet the easiest thing to be aware of.

    I say to you, I definitely get annoyed while people consider worries that they just don't know about. You managed to hit the nail upon the top and defined out the whole thing without having side-effects , people can take a signal. Will probably be back to get more. Thanks

    Feel free to surf to my homepage ... free live sex Webcam

    ReplyDelete
  20. Superb, what a weblog it is! This website presents
    helpful information to us, keep it up.

    my page ... live web sex cams

    ReplyDelete
  21. What's up, after reading this amazing article i am also delighted to share my experience here with colleagues.

    Have a look at my page: Flavorchem.com

    ReplyDelete
  22. Hi! Do you know if they make any plugins to protect against hackers?
    I'm kinda paranoid about losing everything I've worked hard on.

    Any recommendations?

    my weblog - free Video chat live

    ReplyDelete
  23. Does your blog have a contact page? I'm having a tough time locating it but, I'd
    like to shoot you an e-mail. I've got some creative ideas for your blog you might be interested in hearing. Either way, great site and I look forward to seeing it improve over time.

    Feel free to surf to my web blog; Bench Craft Company advertising for good

    ReplyDelete
  24. What a information of un-ambiguity and preserveness of ѵaluable κnowledge regarԁing unpгediсted feelings.


    Review mу homepage houston Real Estate virtual assistant

    ReplyDelete
  25. I am really happy to read this webpage posts which consists of plenty of valuable data, thanks for providing these kinds of information.


    Here is my webpage - online sex cams free

    ReplyDelete
  26. Hi Dear, are you in fact visiting this web site daily, if so afterward you will definitely obtain fastidious knowledge.


    Also visit my website: anonse katowice

    ReplyDelete
  27. An impressive share! I've just forwarded this onto a co-worker who has been conducting a little research on this. And he in fact bought me dinner due to the fact that I stumbled upon it for him... lol. So let me reword this.... Thank YOU for the meal!! But yeah, thanks for spending the time to discuss this issue here on your site.

    Here is my weblog :: socialgrapes.com

    ReplyDelete
  28. Hello there, You have done a fantastic job. I'll definitely digg it and personally suggest to my friends. I am confident they'll be benefited from this site.



    Look into my webpage; http://anonsesex.net.pl

    ReplyDelete
  29. First off I would like to say great blog! I had a quick question which I'd like to ask if you don't mind.
    I was interested to know how you center yourself and
    clear your mind before writing. I've had difficulty clearing my mind in getting my thoughts out. I truly do enjoy writing but it just seems like the first 10 to 15 minutes are generally wasted simply just trying to figure out how to begin. Any suggestions or tips? Cheers!

    Stop by my web-site ... http://erotyczne-oferty.org.pl

    ReplyDelete
  30. I am sure this piece of writing has touched all the internet people, its really really pleasant
    article on building up new blog.

    Also visit my homepage: http://oferty-prywatne.org.pl

    ReplyDelete
  31. Woah! I'm really digging the template/theme of this site. It's simple, yet effective.
    A lot of times it's tough to get that "perfect balance" between usability and visual appearance. I must say you've done a excellent
    job with this. Additionally, the blog loads very fast for me on Chrome.
    Superb Blog!

    Feel free to surf to my page - real webcam Sex

    ReplyDelete
  32. Wow, this article is fastidious, my younger sister is analyzing these
    kinds of things, thus I am going to convey her.

    Also visit my weblog :: inexpensive web site hosting

    ReplyDelete
  33. I every time spent my half an hour to read this web site's articles or reviews all the time along with a cup of coffee.

    Also visit my blog; czeskie tabletki Na Odchudzanie

    ReplyDelete
  34. Have you ever thought about adding a little bit more
    than just your articles? I mean, what you say is important and everything.
    However think of if you added some great visuals or
    videos to give your posts more, "pop"! Your content is excellent but with images and clips, this site could certainly be one of
    the best in its field. Terrific blog!

    Feel free to surf to my web blog detox

    ReplyDelete
  35. Thanks for sharing such a nice thought, post is good, thats why i
    have read it fully

    My web site ... http://medlandiya.com/

    ReplyDelete
  36. Pretty nice post. I simply stumbled upon
    your blog and wished to say that I have truly loved
    surfing around your blog posts. After all I will be subscribing for your
    rss feed and I hope you write again soon!

    Visit my web-site ... sex Live

    ReplyDelete
  37. You can certainly see your enthusiasm within the work you write.
    The world hopes for more passionate writers such as you who are not afraid to say how
    they believe. Always go after your heart.

    My page: sex

    ReplyDelete
  38. Write more, thats all I have to say. Literally, it seems as though you relied on the video to make your point.
    You obviously know what youre talking about, why waste your intelligence on just posting videos to
    your blog when you could be giving us something informative to read?



    Here is my website: online chat site

    ReplyDelete
  39. I think the admin of this web site is truly working hard in favor of his site, for the reason that here every material is quality based data.


    Feel free to surf to my site: sex

    ReplyDelete
  40. I think the admin of this site is truly working hard
    in support of his web site, since here every stuff is quality based material.


    Visit my blog post :: live cams animals (http://www.linkvis.com/profile/Arnoldo58)

    ReplyDelete
  41. I'm gone to tell my little brother, that he should also go to see this website on regular basis to get updated from latest reports.

    Feel free to surf to my webpage ... online sex webcams ()

    ReplyDelete
  42. Wow, incredible blog layout! How lengthy have you been blogging for?
    you make running a blog look easy. The entire look of your website is magnificent, let
    alone the content!

    My web page - live cams sexy

    ReplyDelete
  43. Thank you for the good writeup. It in truth used to be a amusement account it.
    Glance advanced to more introduced agreeable from
    you! However, how can we keep in touch?

    Here is my web page: live sex free online

    ReplyDelete
  44. Howdy would you mind stating which blog platform you're working with? I'm looking
    to start my own blog in the near future but I'm having a hard time deciding between BlogEngine/Wordpress/B2evolution and Drupal. The reason I ask is because your design seems different then most blogs and I'm looking for something unique.
    P.S Apologies for getting off-topic but I had to ask!

    Also visit my webpage sex Cam com free

    ReplyDelete