Your SlideShare is downloading. ×
Q921 de2 lec6 uc v1
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Q921 de2 lec6 uc v1

245
views

Published on

Published in: Business

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
245
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
73
Comments
0
Likes
1
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Drilling Engineering 2 Course (1st Ed.)
  • 2. 1. 2. 3. 4. 5. 6. Laminar Flow in Pipes and Annuli Turbulent Flow in Pipes and Annuli Pressure Drop Across Surface Connections Pressure Drop Across Bit Optimization of Bit Hydraulics Particle Slip Velocity
  • 3. Casing functions Casing costs compromise one of the largest cost items of the drilling project. Therefore proper planning of casing setting depths and casing selection is vital to realize a cost effective and safe well. The casings themselves fulfill multiple functions that can be summarized as: Isolate porous formations with different fluid-pressure regimes from contaminating the pay zone, Prevent near surface fresh water zones from contamination with drilling mud, Protect the hole from caving in, Provide a connection and support of the wellhead equipment, Provide exact dimensions for running testing, completion and production subsurface equipment. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 3
  • 4. Casing Types According to the different functions, the total casing program consists of different casings strings. Conductor Casing Surface Casing Intermediate Casing Production Casing Liners Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 4
  • 5. Conductor Casing The function of the conductor is to enable circulation of the drilling fluid to the shale shakers without eroding the surface sediments directly below the rig foundation. The conductor prevents the subsequent casings from corrosion and may partly support the wellhead weight. Commonly a diverter is installed on top of the conductor casing to divert an unexpected inflow of formation fluids into the wellbore away from the rig-site and the personal. Conductor setting depths are in the range of 150 to 600 [ft] (46-183 m), their seizes range from 36 to 20 [in] (0.91-0.5 m). Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 5
  • 6. Surface Casing The function of the surface casing is  to prevent cave in of unconsolidated, weak near-surface formations as well as protect the shallow, freshwater sands from contamination with drilling mud.  As the conductors, surface casing protects the subsequent casings from corrosion. Before the surface casing is set,  no blow out preventers (BOP) are installed.  After setting the surface casing and installing the wellhead, a BOP is available to handle kicks when drilling the intermediate hole section. Surface casing setting depths are in the range from 300 to 5,000 [ft] (91-1524 m), their diameters range from 24 to 17-1/2 [in].  the surface casing setting depth is often determined by government or company policy and not selected due to technical reasoning. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 6
  • 7. Intermediate Casing The intermediate casing string is a purely technical casing. One or more may be necessary to handle abnormal formation pressures, unstable shale formations, lost circulation or cave-in zones. An intermediate casing may also be necessary to realize the planned mud weight profile. When for example an abnormally pressured formation is encountered, it may have to be protected by an intermediate casing so when formation pressure of the formations below is normal, a lower mud weight can be applied. Intermediate casing diameters range from 17-1/2 to 9- 5/8 [in]. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 7
  • 8. Production Casing The production casing is set through the prospective production zone(s). This casing string protects the environment in case of production tubing failure and permits the tubing string to be maintained or replaced during the production life. Commonly production casing and production liners have gas-tight connections, their diameters range from 9-5/8 to 5 [in]. A production casing diameter of 7 [in] is encountered often. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 8
  • 9. Liners To save cost, the casing installed sometimes doesn’t reach until the surface but finishes within the previous string. Such a casing configuration is called liner. A liner is mounted on a so called “liner hanger” to the previous casing string. Commonly the liner head is several hundred feet into the previous casing to enable a good cement seal. Liner Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 9
  • 10. Various typical casing programs Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 10
  • 11. develop a casing program To develop a casing program, first the various casing setting depths have to be determined. Since the primary reason to drill a well is to produce hydrocarbons out of a reservoir, the final casing inside diameters have to be large enough to allow for the forecasted completion and production schemes. Factors like completion type (open hole, cased hole, monobore production, etc.), expected amount of production (production tubing seize), expected production forecast (e.g. need of gas-lift, etc.) and seize of evaluation tools to be run have to be considered. In general, for production purposes the well diameters shall be as large as possible. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 11
  • 12. Advantages of small hole sizes On the other hand, as small as possible hole seizes reduces the total cost of the well since: drilling times are faster, less mud has to be used (purchase and disposal of mud), smaller mud equipment can be used (cleaning, pumps, etc.), smaller casings can be used (cheaper, higher strength at same grade), smaller rig can be applied (lighter casings, smaller mud volume), rig site can be smaller (especially important offshore and platform types like TLP where weights are limited). Out of this reason a technology called slim-hole drilling was developed. Fall 13 H. AlamiNia Drilling Engineering 2 Course (1st Ed.) 12

×