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 standardizing wellhead design is to obtain a cost effective completion of the well and ease of well maintenance. Wellheads have traditionally been of the individual spool type. … Selection guidelines for wellhead equipment

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 and components should comply with the current edition of API Specification 6A. Definition of a christmas tree A Christmas tree is the cross-over between the wellhead casing … Christmas tree design

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 potential supplier’s technical ability, quality assurance plan, and commercial viability should conform to internationally acceptable standards and be auditable. Tendering Before issuing requests for proposals it … Wellhead Procurement Strategy

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 the information given should cover virtually all areas of concern. Therefore the production envelope must cover the total lifespan of the project. If, for example, there was a need … Wellhead Specifications, Operating Perating Envelope & Philosophy

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 set in API 6A PSL 1, 2, 3 or 4 and in several areas it must exceed those standards Cases where the standards are … Wellhead Valves Design

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 approximately 1.7 times the downstream flowline pressure. There are additional factors to be considered in choke selection. 1 Actuated chokes By its very … Wellhead Chokes

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 circumstances and the design of the well. In the case of the well being shut in and depressurised with full pressure below the … Equalisation of christmas trees

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 occurred over a number of years. This evolution has generated a wellhead which is technically superior, offers enhanced safety and rig time saving, … Wellhead selection guidelines summary

Close co-operation is required between the designer, drilling personnel, production personnel, engineering staff, and the representative of the  Electrical Submersible Pump supplier. An integrated discipline approach during the installation phase is important to ensure that the installation is of the required standard, and results in minimum deferral of production. The quality of work and the … ESP – Safety

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 assembled and handled during installation or removal according to the manufacturer’s instructions. The Electrical Submersible Pump (ESP) supplier’s field engineer should be present whenever a … ESP – handling practices