Tubing and Casing Connections

This article descirbes the Tubing and Casing Connections Functional and Operational requirements.

Functional requirements:

- strength -sealing properties, -resistance to damage, corrosion or erosion.…

Sand Control

The sand production philosophy for a particular field and production system must be formulated after careful evaluation of a number of interacting factors which range from the well and surface…

Wellhead Valves Design

When specifying or designing valves, reference should be made to the information contained in the Operating Envelope for that particular well.

All valves purchased by must at least meet the standards…

Tubing movement, forces and stresses

Tubing movement and stress behaviour are a function of the well temperatures and pressures: The changes in temperature will cause the tubing to expand and contract.

For example, 10,000 ft of tubing…

Pressure Testing Wellheads

Examples of programs for Pressure Testing Wellheads.

1. Onshore

20in Casing

After installing the 20in casing and 20.3/4in -3 000 psi CHH, pressure test CHH and BOP’s to 500 psi against the bag…


Corrosion generally involves carbon dioxide (CO2), sweet corrosion, or hydrogen sulphide (H2S), sour corrosion. In both cases, water must be present for corrosion to occur.

The problems can be…

ESP - Retrieving Electrical Sumbersible Pumps

ESP - Retrieving Electrical Sumbersible Pumps

Retrieval of an Electrical Submersible Pump (ESP) requires similar precautions to those taken during installation and some additional points should also be considered when retrieving ESPs.

Analysis of…

ESP - Preparation of the Well

ESP - Preparation of the Well

Electrical Submersible Pump (ESP) completions are not as tolerant to changes in downhole conditions as other forms of artificial lift. Care must be taken to minimize the well PI impairment.


Completion Operations Reporting Requirement

This article describes the reports required to be submitted by the contractor to the Company Completion Supervisor.

Well Completion Equipment Report

Contractor shall submit to the Company Completion…

Completion Operations - Gravel Packing

The objective of all sand exclusion techniques is to arrest the movement of formation sand into the well. Sand production can cause erosion of well equipment, well restrictions, and sand deposits in…

Sub-assembly preparation and make up

The length and composition of sub-assemblies is usually dictated by the space and handling equipment considerations. They will ideally be made up and tested (both functionally and hydraulically) in a…

General completion design considerations

The well completion typically includes the perforations, sand exclusion system, (liner), tubing, wellhead, tubing accessories, packers, associated safety equipment and Xmas tree.

The perforations,…

Xmas tree installation

this article presents the main operational and safety precautions to be taken when installing a xmas tree.

1. General Precautions

There are many methods of landing the tubing and leading control…

Wellhead selection guidelines summary

The wellhead is simply a crossover between the various casings and the Christmas tree or -temporarily - the BOP.

Unitized wellheads

The evolution from spool type wellheads to compact, or uniheads has…

Sub-surface safety valves (SSSV)

Sub-surface safety valves (SSSV)

Subsurface safety valves (SSSVs) are installed in the wellbore of hydrocarbon producing wells to shut off the production flow to the surface in case of an emergency. The importance of the correct…

Safety Valves

The purpose of the Safety valves is to protect people, environment and property from uncontrolled production.

  • SSV: Surface Safety Valves: an automatic fail-safe closed valve fitted at the wellhead.
  • SSSV:…

Selection guidelines for wellhead equipment

Selection guidelines for wellhead equipment

This article describe the design and selection criteria necessary in the construction of safe and cost effective Wellheads and Christmas trees.

Standardized wellhead design

The objective of…

Completion Packers

Completion Packers

This article describe the completion packer selection, specifications, classification, setting mechanism, etc.

Packer selection/specification


Tubing storage, handling and transport

Guidelines for storing, handling and transporting completion tubing

1 Storage

The design of pipe racks depends on local conditions (load capacity, degree of permanency, etc). Racks can be made with…

Workshop and support services

This article describe the requirements and specifications for workshop intended to support well services operations.

The work undertaken by a typical workshop may include:

  • quality assurance checking…

Completion Operations - Buying tubulars

When buying tubulars, reference should be made on purchase orders to relevant international standards, such as API Specification 5CT and API Standard 5B on specifications for casing, tubing and…

Wellhead Chokes

The designer must ensure that there is critical flow through the choke in order to eliminate the effects of downstream pressure variations on the formation. This is achieved when the FTHP is…

Wellhead Procurement Strategy

This article describes the key items to address to develop a Wellhead Procurement Strategy.

Vendor selection

To qualify as an acceptable equipment supplier of Wellheads and Christmas trees, the…

Wellhead Specifications, Operating Perating Envelope & Philosophy

This article describes the wellhead technical specifications, Operating Envelope  and Operating Philosophy.

The operating envelope

When defining the type of equipment and service for a project…

Christmas tree design

This article describes the preferred approach to various aspects of Christmas tree design, with regard to pressures, types of well, equipment, experience, operability and safety. All wellhead valves…

Tubing running and testing

The following installation considerations apply to all threaded connections if mishaps are to be avoided:

  • drift check and inspect connections before running;
  • properly apply correct thread dope;
  • backout…

Responsibilities during Completion Operations

It is advised that onshore meetings will be held between equipment vendor, Company, wireline contractor and drilling contractor at least 6 weeks prior to the start of operations.


Completion Operations - Wellsite Inspection and Testing

All inspection and testing shall be performed by contractor's personnel and witnessed by Company's completion supervisor.

The drilling programme shall contain all the necessary information, including…

Procedures for Completion Assembly Preparation

This procedure identifies the assembly and test method for all completion sub assemblies.

All assembly and testing shall be performed by persons, who have, as a minimum, undergone indoctrination and…

ESP - Transport

ESP - Transport

The transport and handling of Electrical Submersible Pump (ESP) components should reflect the high cost and fragile nature of the equipment.

Flexing resulting in permanent distortion of the equipment…

ESP - Safety

ESP - Safety

Close co-operation is required between the designer, drilling personnel, production personnel, engineering staff, and the representative of the  Electrical Submersible Pump supplier.


ESP - Testing

ESP - Testing

Prior to leaving location it is recommended that a well test is carried out to the Electrical Submersible Pump using a dedicated test separator with the rig on site.

This will ensure that any…

ESP - Assembly pump / motor

ESP - Assembly pump / motor

The assembly of the Electrical Submersible Pump unit and cable connection must be carried out by the Electrical Submersible Pump (ESP) supplier's field engineer. In order to comply with the…

ESP - handling practices

ESP -  handling practices

The following procedures on handling of equipment and cables are recommended to properly install or pull an Electrical Submersible Pump unit:

  • The Electrical Submersible Pump, motor, and cable must be…

ESP - Cable handling

ESP - Cable handling

Proper handling and running procedures are essential to ensure cable reliability. The majority of cable failures are caused by damage resulting from improper handling.

The ESP cable is often the most…

Starting up and operating an Electrical Submersible Pump (ESP)

Guidelines for starting and operating an Electrical Submersible Pump (ESP) system.

1 Personnel

A field engineer from the pump supplier should be present whenever an Electrical Submersible Pump is to…

Completion design considerations

This article describes the Completion design considerations.

Reservoir considerations

Reservoir drive mechanism may determine whether or not the completion interval will have to be adjusted as gas-oil…

Standard Completion Designs

This article describes the Standard Completion Designs.

Monobore completion

Completion with fullbore access across the payzone, without diameter restrictions (but not necessarily with a constant…

Packer Accessories and tailpipe assembly

The Purpose of the Packer Accessories and tailpipe assembly is described in this article.

  1. the ability to isolate the well below the packer;
  2. the ability to land off downhole pressure and temperature…

Causes of Packer seal failure

Causes of Packer seal failure

The article identifies the most common factors which can play a role in premature failures of packer seals:

1. Installation procedures

  • Storage damage: ageing (heat, sunlight or radiation); distortion…

Christmas Tree (xmas tree) Design

The Christmas tree is the cross-over between the wellhead casing and the flowline. The wellhead is the cross-over between the Christmas tree and the various casings.

  • controls the wellhead pressure…

Completion Seals

This article describe the categories and types of seals used for completion equipment.

2 categories of seals:

  • static seals where the sealing surfaces do not move relative to one another,
  • dynamic…

Seal Assemblies (Locator, Anchor, Latch)

Seal Assemblies (Locator, Anchor, Latch)

Used with permanent type packers to provide isolation between the producing zone and the annular space above the packer when the tubing is located into the packer.

The seal assemblies are designed…

Completion Design – Artificial Lift

Early planning of artificial lift is essential for long-term profitability of the wells. Decisions on the artificial lift method to be used may not be available at the field development planning…

Valve Design

Valve Design

When specifying or designing valves, reference should be made to the Operating parameters for that particular well. All valves purchased must at least meet the standards set in API 6A PSL 1, 2, 3 or 4…

Completion Operations - Perforating

Perforating is a service provided by specialist companies, however, it is common for Production Operations to be involved in the operation to facilitate well production after perforation in completed…

Completion Operations - Gravel Packing Procedures

Perforation prepacking refers to the methods that can be used to pack the perforation tunnels with gravel prior to filling the screen/casing annulus. The main objective of prepacking is to maximise…

Completion Operations - Packer (introduction)

Completion Operations - Packer (introduction)

A packer is defined as a sub-surface tool used to provide a seal between the tubing and casing (or wall) of a well, thus preventing the vertical movement of fluids past this sealing point. Packers…

Completion operations - Setting packers

Completion operations - Setting packers

Whatever type of packer is installed, the manufacturer's instruction for setting and the completion programme on setting depth and running must be followed if satisfactory results are to be obtained.…

Packers retrievability

Packers retrievability

The following provides information based on past experience of the retrievability of packers, which provides general trends and guidelines for the execution of such activities. However, every well is…

Packer Setting Mechanism

Packer Setting Mechanism

The following 5 Packer setting mechanisms are discussed in this article:

  1. Compression set anchor packer
  2. Mechanically set compression packers
  3. Mechanically set tension packer
  4. Hydraulic set…

Preparation for running tubing

Proper preparation of tubing before running serves two purposes. Firstly to ensure that the pipe body and threads are adequately protected from possible damage when being moved to the drill floor.…

Completion Chokes

The designer must ensure that there is critical flow through the choke in order to eliminate the effects of downstream pressure variations on the formation. This is achieved when the FTHP is…

Completion Tubing - Material Selection

Material selection is determined by the abrasion and corrosion properties of the fluid, the pressures and the mechanical and hydraulic loadings on the completion string under operating conditions,…

Equalisation of christmas trees

In the design process for all wells, consideration should be given to the repressurisation of the Christmas tree after it has been closed in. Several approaches may be taken depending on the…