TRNC-WM-001 Wellhead Maintenance Odidi Field
TRNC-WM-001 Wellhead Maintenance Odidi Field
TRNC-WM-001 Wellhead Maintenance Odidi Field
Rev. No: 0
Date: 03-03-15
Page 1 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
TABLE OF CONTENT
Rev. No: 0
Date: 03-03-15
Page 2 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
1.0 INTRODUCTION
At the Royal Niger we pride ourselves on providing Hydraulics, Controls, Drilling and
Production Equipment and services to the Local and International energy and Marine
industries.
At the helm of the Royal Niger is a team of experienced industry professionals who, because
of their understanding of your operational imperatives, strive to deliver quality products and
services ranging from product design and manufacture to complete asset management
support.
When our proven solutions won’t meet the specific requirements of a customer, our
specialist teams will work with that customer to create one that does – technically and
commercially.
Rev. No: 0
Date: 03-03-15
Page 3 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
This Maintenance Manual covers general information on first line maintenance on Odidi field
wellhead systems.
1.2 SAFETY
Safety is paramount. All applicable legal and company safety standards must be adhered to
at all times. Where any procedure gives cause for uncertainty or concern, clarification must
be sought from responsible company representatives before proceeding. The following
categories are examples of these areas of consideration:
Lifting by mechanical or manual means.
Pressure testing and pressure containing equipment where the pressure may
range from compressed air to that required by full working pressure tests.
COSHH the Control of Substances Hazardous to Health. For example
Lubricants and coating materials.
Precautionary statements can be found throughout the manual to highlight special situations.
The statements included describe as many of these special situations as have been
identified, although others may exist. These statements are as follows:
CAUTION: An instruction that must be followed to avoid damage to, or problems with,
equipment.
Wellheads serve as connection points for tubular and surface flow lines and well pressure
control.
The conductor pipe forms the lower section of the wellhead and is fitted with a slip type or
threaded casing head, also known as wellhead flange. The conductor pipe supports the BOP
during drilling or work-over operations.
Annulus port on the wellhead allows communication with the annulus when additional casing
string is run.
Casing-head housings are attached to the upper end of the surface casing.
The casing-head spools are attached to the top connector of housings or other spools. Both
casing-head housings and spools are designed to accommodate hanging and packing
mechanism that can be used to suspend and seal tubing strings.
Tubing-head spools are attached to the top connector of the casing-head housings or
spools. These are designed to accept packing mechanisms which seal casing strings and
hanger and packing mechanism which can be used to suspend and seal tubing strings.
Metal-to-metal seals are used to create leak prove barriers between the wellhead and
multiple tubing spools in severe (sour) service environment.
The upper section of the wellhead, known as Christmas tree is comprised of control (gate)
valves. The tree sits on top of tubing hanger spool and holds the valves for well operation
and control.
Lower and upper master valves are found on the lower section of the tree which are
normally in fully open position during well flow and only closed during emergency
situations.
The lower master valve is manually operated and used for well isolation during well
intervention (wireline, coiled tubing) operations.
The upper master valve is in most cases is hydraulically operated and can be remotely
operated to facilitate well shut-in during emergency. Some trees have manually operated
gate valves as well.
Situated immediately above the upper master valve are the production (flow) wing
valve and kill wing valve.
The flow wing or production wing valve is hydraulically actuated and designed to fail
safe close. The valve closes at the loss of control line pressure.
Situated opposite the production wing valve is the kill wing valve, used for injection of well kill
fluids and chemicals into the well to prevent hydrate formation. The kill wing valve is also
used for the pressure testing of surface equipment and down-hole tools.
The swab valve sits on top of the Christmas tree. The swab valve is normally
manually operated and allows the rig up and pressure testing of surface equipment for
well intervention operations.
Some trees have dual swab valves.
The work scope for the provision of preventive maintenance services for about 20 wellheads
with the following well names; 3S, 3L,15L, 18T, 19S, 19L, 21S, 22S, 23S, 23L, 24L, 28S,
31L, 31S 32T, 34S, 34L, 35S, 35L, 37S, 37L, 38L, 43L, 44S, 44L, 46S, 46L, 48T and 51T in
OML 42, is on call out basis for NPDC wellhead. These among others are:
3.0 RESPONSIBILITIES
It is the duty of the field supervisor to ensure that activities are carried out in safe and control
manners and work procedures and processes are fully implemented and adhered to.
4.2.1.1 Tree valves – inspect flow paths and valves internals for signs of erosion or
corrosion damage
Actuators
Check valves
Chokes
Connectors and fittings
Cross-over connectors (including thickness checks)
Tubing-head adapters
Top connectors
Adapters and spacer spools
Fluid sampling spools
Casing and casing hangers
Mandrel hangers
Slip hangers
Surface and under water safety valves – control panels and control lines
Loose connectors – flanged, threaded and other end connectors:
i Weld neck connectors
ii Blind connectors
iii Threaded connectors
iv Adapter and spacer connectors
v Bull-plugs
vi Valve removal plug
Where applicable, bleed off down-hole safety valve control line pressure to zero to
shut-in well.
Bleed down pressure above down-hole safety valve via production wing valve to 200
psi and monitor well pressure above down-hole safety valve (DHSV) for 15 minutes.
Bleed down pressure above down-hole safety valve to zero after a good leak-off test.
Cycle lower master valve to close position and record valve turns.
Cycle lower master valve to open position, taking note of the number of turns.
If hydraulically operated, function the upper master valve to a close position and
record pump strokes.
If hydraulically operated, function the upper master valve to open position. Record
pump strokes.
Rev. No: 0
Date: 03-03-15
Page 7 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Using the valve handle, close tree kill wing valve. Record valve handle turns.
Using the valve handle, open tree kill wing valve. Record valve handle turns.
Using hydraulic pump, apply 2000 psi pressure to production wing valve actuator to
open the production wing valve. Monitor open line pressure for 15 minutes.
Vent down control line pressure to zero to shut-in production wing valve. Record time
for full valve closure.
Using the gate valve handle, close the swab valve fully and record valve turns.
Using the gate valve handle, open the swab fully and record valve turns.
Repeat the above and grease all valves bodies and bonnets.
Install test caps and needle valves on production wing valve and swab valve.
Close needle valves on production wing valve and swab valve outlets.
Close Lower master valve.
Connect test line via kill wing valve and pressure test against lower master valve
from above to 5000 psi.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open lower master valve.
Close upper master valve Connect test line via kill wing valve and pressure test
against upper master valve from above to 5000 psi.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open upper master valve.
Close production wing valve and open needle valve on the valve outlet.
Pressure test production wing valve from below to 5000 psi via kill wing valve.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open production wing valve.
Close swab valve and open needle valve on the valve outlet.
Pressure test swab valve from below to 5000 psi via kill wing valve.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open swab valve.
Close production wing valve and connect hydraulic test line to valve outlet.
Pressure test production wing valve from above to 5000 psi.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open production wing valve.
Close swab valve and connect hydraulic test line to valve outlet.
Pressure test swab valve from above to 5000 psi.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open swab valve.
Close kill wing valve and open need valve on valve outlet.
Pressure test kill wing valve from below via top of swab valve to 5000 psi.
Monitor test pressure for 15 minutes.
Acceptance criteria: +- 5% of test pressure (API 6A).
Bleed down test pressure to zero and open kill wing valve.
Ensure that all tree valves are in open position and close needle valves on
production wing, kill wing and swab valves outlet.
Confirm the status of SSV/SCSSV. Function SSV/SCSSV open if in close position.
Monitor THP and record stable THP.
Close lower master valve and gradually bleed down pressure above lower master
valve to 100 psi via kill wing valve.
Monitor pressure above lower master valve for 15 minutes.
Acceptance criteria: Pressure increase should exceed 5% of bleed-off pressure (API
6A).
Bleed down pressure above lower master valve to zero and open lower master valve.
Record THP.
Ensure that all tree valves are in open position and close needle valves on production
wing, kill wing and swab valves outlet. Confirm the status of SSV/SCSSV. (Function
SSV/SCSSV open if in close position).
Monitor THP and record stable THP.
Close upper master valve and gradually bleed down pressure above upper master
valve to 100 psi via kill wing valve.
Monitor pressure above upper master valve for 15 minutes.
Acceptance criteria: Pressure increase should not exceed 5% of bleed-off pressure
(API 6A).
Bleed down pressure above lower master valve to zero and open upper master valve.
Record THP.
The purpose of this test is to confirm the integrity and functionality of the SSV/SCSSV,
control lines and actuators.
Record tubing head pressure.
Record control line pressure at the control panel.
Vent down control line pressure to zero on the control panel.
Slowly bleed down SITHP by 20% of recorded THP.
Monitor shut-in pressure for 15 minutes and record final shut-in pressure.
At the control panel pressure and open SSV/SCSSV.
Confirm SSV/SCSSV is fully opened and record pressure.
Monitor line pressure for leaks.
Rev. No: 0
Date: 03-03-15
Page 10 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
APPENDIX
Air Gas
Rev. No: 0
Date: 03-03-15
Page 11 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Rev. No: 0
Date: 03-03-15
Page 12 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Rev. No: 0
Date: 03-03-15
Page 13 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Rev. No: 0
Date: 03-03-15
Page 14 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Rev. No: 0
Date: 03-03-15
Page 15 of 16
This document is uncontrolled when printed or copied from the network
WELLHEAD MAINTENANCE PROCEDURE TRNC-WM-001 Rev 0
Rev. No: 0
Date: 03-03-15
Page 16 of 16
This document is uncontrolled when printed or copied from the network