Vertical tree solutions
ELSA OW (Open water)
Open water valves are used when running subsea production trees/intervention systems on tubing or drill pipe in open water, i.e. no marine riser. Positioned between the tree/intervention running tool and the rig floor, the valves enable safe deployment and retrieval of intervention tools into and out of the well. This provides a safety barrier during ‘live well’ operations and enables cutting of coiled tubing and or wireline in event of emergency.
ELSA DB (Dual bore)
The ELSA DB is designed to be run with the ELSA HD retainer valve and lubricator valve. The Subsea Test Tree (SSTT) forms an integral part of the subsea landing string for well test or intervention operations. The ELSA DB is a unique landing string system that is used in conjunction with vertical production tree systems. This innovative ‘mono-bore’ design landing string system enables well clean up/completion deployment from a modu prior to installing the vertical xmas tree. The ELSA DB incorporates the orientation sleeve/helix as required allowing correct orientation of the tubing hanger into the wellhead at all times.
ELSA Non Flow Back
The ELSA Non Flow Back landing string provides the customer a system to interface with either a mono bore or dual bore production tree depending on the client’s individual requirements. Providing an internal bore suitable for through bore operations in a non-flow back scenario whilst still accommodating the required BOP stack ram interfaces required by the industry today. The ELSA Non Flow Back landing string system also enables tubing hangar running tool and other down hole functions to be controlled or monitored with the option to accommodate an electric line(s) dependent on the customer’s needs.
ELSA BS (Bore selector)
The Bore Selector is designed to interface with dualbore production trees and allows deployment of a dual bore system on a mono-bore riser. In this application the bore selector is normally run between the emergency disconnect package and the riser stress joint retainer valve. The system is also sufficiently flexible that it can be interfaced easily with workover control systems. It offers the advantages of simplification and economy both of equipment and operational sequences.
Exploration and appraisal Completion and intervention High pressure
Expro’s EXPRESS systems control landing and testing string functions during well testing, appraisal, completion and intervention operations. Electro-hydraulic control improves response times, enables ‘real time’ data feedback, reduces the physical umbilical size on deep water applications and addresses the disconnect philosophy from dynamically positioned mobile drilling units.
EXPRESS employs electrical communication as the primary control method, rapidly improving response times and eliminating the response constraints of conventional hydraulic systems due to water depth. The system comfortably achieves the present industry requirements for the disconnect protocol, achieving system shut-in or well closure and disconnect, within a 15-second time period.
The designs are fully adaptable from 3” to 7” landing strings and provide hydraulic control to the subsea landing string and completion equipment where applicable. It provides a fully integrated control system for full functionality.
Case studies and testimonials:BP Block 31
Angola is Sub-Saharan Africa’s largest oil producer and, since 2008, has been a member of the Organisation of Petroleum Exporting Countries (OPEC). Located in the ultra-deep waters off Angola lies Block 31 PVSM, comprising four oil fields; Platao, Saturno, Venus and Marta. Block 31 PVSM was discovered in 2002 and covers an area of some 5,349 square kilometers.
Expro was first hired in 2009 to deliver electro hydraulically controlled completion landing string technology for conventional Xmas trees, which uses a safe, reliable, innovative and novel design to aid completion installation. This was extended in 2012 to provide additional landing string equipment and personnel support alongside the original scope of supply.
Expro was the preferred vendor for BP’s PSVM project due to its field proven technology and track record for subsea operations with BP in Angola. Expro has a track record of more than 30 successful completions with BP on its Block 18 project.
Expro’s subsea safety systems allow for the safe deployment and control of tree vendor running tools, as well as the hydraulic and electrical feed-through for downhole functions and subsea well operations to be conducted under controlled conditions without having to use the BOP.
The benefits of using Expro’s ELSA dual bore landing string means mono bore landing strings can be utilized while still providing functionality for vertical xmas trees.
These successful completions led to BP extending Expro’s contract scope of supply in 2012, covering the second phase of PSVM. The additional equipment comprises of two ELSA dual bore landing string assemblies, two EXPRESS control systems and one set of topside control equipment.
The system has been designed to provide the ability to accommodate an emergency disconnection of the riser system from the wellhead / Xmas tree in the event of a well control situation. The inclusion of the EXPRESS controls system offers a rapid disconnect time which is depth independent.
Its dual ball valve subsea test tree enables the well to be isolated in a controlled manner when any disconnect is required, while at the same time providing the ability to cut coil tubing and wireline. In addition to this the retainer valve allows for the fluid inventory of the riser to be contained during any disconnect.