3) primary cementing overview

8/3/2019 3) Primary Cementing Overview

1/21

Primary Cementing

Overview


2/21

2

Primary Cementing

The introduction of a cementacious material into

the annulus between casing and open hole to :

Provide zonal isolation

Support axial load of casing strings and strings to be run

later

Provide casing support and protection

Support the borehole


3/21

3

Types of Casings

Conductor

Surface

Intermediate

Production

Liner


4/21

4

Conductor

Purpose

Prevents washing out under the rig

Provides elevation for flow nipple

Common sizes and depths:

30 - 20 Welded

20 - 16Threaded

30 - 200 (< 100 common)


5/21

5

Conductor

Other Remarks:

Plugs not used

Careful pumping practices

Large excess required

Thru-drill pipe cementing common

BOPs not unusually connected

Common Cements

Accelerated Neat


6/21

6

Thru-Drill Pipe Cementing

Key Points:

Cement contamination

Channelling

Displacement

Pump until cement to surface


7/21

7

Outside Cementing

Purpose

Bring cement to surface

Macaroni tubing used

Max. depth 250-300 ft

High friction pressures

Non-standard connections

Tubing movedduring job


8/21

8

Surface

Purposes:

Protects surface fresh water formations

Cases off unconsolidated or lost circulation areas

Supports subsequent casing strings

Provides primary pressure control (BOP support)


20 - 9 5/8 threaded

100 - 3000 (or more)


9/21

9

Surface Cementing

Excess of 100% plus not uncommon

Recommend thru-drill pipe method to save

Cement

Rig time

Common cements:

Lead light weight slurries with high yields

Neat tail slurries with good compressive strength

Reduce WOC to a minimum with accelerators


10/21

10

BOP

Rotary tableRig Floor

Choke Line

Mud Outlet

Annular Preventor

BLIND RAMS

SHEARRAMS

PIPE RAMS

Conductor pipe

Cement

Surface Casing Head

Surface Casing


11/21

11

Intermediate (Also called Protection)

Purposes:

Separates hole into workable sections

Lost Circulation

Salt Section

Overpressured Zones

Heaving Shales


133/8, 103/4, 9 5/8

3000 to 10,000


12/21

12

Intermediate Casings

Cemented to surface or to previous casing shoe

Two stage jobs common

Plugs, casing equipment, casing accessories usual

Good cementing practices are required

Large cement volumes

Common Cements:

Typically filler slurries followed by high compressive tail

Specialised (light, heavy, salt - saturated, etc)


13/21

13

Two Stage Cementing

Key Points: Separation and

isolation of zones

Reduces hydrostatic Can leave zone in

the annulus

uncemented (cement

at TD and surface) 1st Stage

Stage

Collar

2ndStage


14/21

14

Production

Purposes: Isolates the pay zone from other formations and the fluids

in them.

Protective housing for production equipment.

Subsurface artificial lift

Multiple zone completion

Screens for sand control

Covers worn or damaged intermediate string.

Common sizes:

4 1/2,5,7, & 9 5/8


15/21

15

Liners

Liner Wiper

Plug

Drill pipe

Wiper Plug

Liner

HangerRunning

Tool

Shear

Pin

Key Points:

Requires less casing

Deeper wells

Small annular clearance

Specialized equipment


16/21

16

Casing API Casing Specs

OD 9 5/8

Weight 53.5 lbs/ft (determines ID)

Grade C75 (yield point allowable tension)

Burst pressure 7430 PSI

Collapse pressure 6380 PSI Thread Buttress

Tapered string used to minimize well cost.

Casing program for well based on :

Burst Pressure

Collapse Pressure

Tensile Load


17/21

17

Thread Types 8 Round

Seals on threads

Use of couplings

Buttress Seals on threads

Use of couplings

VAM Seals on threads &

shoulder

Use of couplings

Hydrill Seals on threads &

shoulder

Integral

2 sets of threads


18/21

18

Running Casing

Inspection of Casing Tuboscope

Pipe tally

Hole Preparation

Mud condition Clearance

Running

Casing crews

Too fast

Landing Casing

Nippling up


19/21

19

Job Procedures

Pre Job: Check calculations with co-man

Rig up

Stem 1 on equipment

Check materials

Safety and organisation meeting

Prepare mix fluids, spacers and washes


20/21

20

Job Procedures

The Job: Test lines

Load plugs

Pump Washes / Spacers

Drop bottom plug

Mix and pump cement

Drop top plug

Displace Bump plug and check returns


21/21

21

Job Procedures

Post Job: Wash up

Rig down

Stem equipment Paper work

3) primary cementing overview

Documents