مقدمه عن تنزيل الكيسنج-Casing running
- Good practice when disburdening cement is to blow the first many sacks of cement through the lines in order to help humidity defiled cement from collecting in the tanks. Off- loaded cement should be blown into empty, clean tanks.
- still, avoid storing cement for long ages, If possible. Alternate tank operation totally and check them. Cement will pack when stored for a long ages and it should be aerated for partial hour once a week.
- To help condensation in the cement tanks and lines, pressure should be maintained on the system at all times. This will help breathing which can lead to condensation.
- The Company Drilling and Completion Supervisor is directly responsible for the proper force of cement and complements needed before each job.
- It's necessary to shoot a sample of cement, slush, barite and mixing water to the Company Drilling Office where it shall be tested. Check the drill water for chloride content, calcium and pH.
- Prepare graph, one with containing weight in slush versus depth and the other with sword relegation versus depth. A dupe of these graphs must be given to the Drillmaster and to the slush mastermind.
Installation Patterns( For Mechanical Cementing Aids)
The selection of the proper installation pattern for mechanical cementing aids i.e. centralises, rasp, turbolisers,etc. is essential to optimise covering running and cementing results.Cementing aids and their installation pattern are a function of functional conditions and cementing objects. Because of these variable factors, pattern gospel is different from case to case. The Drilling Programme must specify type, volume and installation pattern of mechanical cementing pieces, with due consideration to eventual variations after caliper log evaluation.
The following cases described below
Case I
The simplest and most practical is the installation of centralisers directly over stop collars. Installation on the racks is judicious as it saves time. This pattern isn't recommended in close- forbearance conditions, i.e. saves 7 ″ carriage covering in an81/2 ″ hole.
Case II
In close- forbearance conditions, the centralisers should be deposited between two stop collars. This pattern may be installed on the rack.
Case III
In this alternate close- forbearance pattern, the centralisers are installed between a stop collar and the covering coupling. This pattern allows limited centraliser trip and requires only one stop collar per centraliser, reducing outfit cost. Installation shouldn't be performed on the rack..webp "مقدمه عن تنزيل الكيسنج-Casing running")
Case IV
Centralisers can be installed over the covering coupling but this reduces annular inflow and the positive stage- off handed by the covering coupling and requires redundant carriage time. Weatherford don't recommend this pattern for close- forbearance conditions or where ST- I and/ or SP- I curvatures are used.
Post Plug Pattern
This pattern( relate to figure 12. b) is recommended throughout the entire cement column to promote bettered cement- to- conformation cling in strings where covering can be recompensed in 30 to 40 ft cycles. Thepost-plug pattern uses at least one centraliser per joint and free- tomove rasp, separated by stop collars installed roughly 10ft( 3m) piecemeal.
The ModifiedPost-Plug pattern requires two centralisers per joint in confluence with multiple rasp and stop collars placed 5ft(1.5 m) piecemeal. Wellbore wipers can replace the rasp for particular operations.
The following canons will be used to describe the number of centralisers per covering
1C one centraliser per joint2C two centralisers per joint
3C three centralisers per joint.
The following canons will be used to indicate the centralisers distance
C1 one centraliser each commonC2 one centraliser every two joints
C3 one centraliser every three joints.
ex.2C3 = two centralizer every three joints.
Consider the following while deciding the installation patterns
1) The use of helical centralizers is recommended in each of the patterns where close forbearance conditions live.2) Alternate left wing/ right handed helical centralizers are used in special operationse.g. covering liner( One of Types Of covering), swerved wells, product strings, enhancement of hydraulic relegation,etc.
3) For open hole intervals, helical arc type centralizers will be used unless else specified. Straight type curvatures will be used for marshland-out sections, loose conformations,etc.
4) Rigid type centralizers( Positive) are noway allowed to enter open hole intervals.
5) In deeper wells, where high- standing covering outfit is used, Positive type centralizers OD for free passage through clamp’s slips should beconsidered.However, spring curvatures are recommended and also in containing to containing intervals, If not applicable.
6) Maximize centralization when special outfit/ tools zone are prognosticated i.e. stage tools, liner hanger, ECIP, GOC, WOC,etc.
7) Special CRC stop collars,( without nails) are essential for CRA( Corrosion Resistant blends) covering.
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