Delivering Expro landing string assembly technology to Nigeria

Customer’s problem
The customer needed to develop 38 wells, comprising production, water and gas injection wells in Nigeria, in water depths ranging from 4,200 to 5,500 feet, within a two year drilling programme.

The customer needed completion landing strings and surface control equipment to do it and had programmed to start running the strings in late summer 2007.

Expro’s solution
Expro supplied two complete E/H (electro-hydraulic) landing strings and associated surface equipment and the team to run them, in April 2007.

Results
At least 21 wells have now been completed.

Technologies used
The landing string valves were field proven Expro landing String Assembly (ELSA) type, and the riser control module was similar to a system used on the Tahiti project, in the Gulf of Mexico, a high value electro-hydraulic integrated system with dual redundancy throughout.

Providing a safe and environmentally-secure operating system for the commissioning of subsea wells

Customer’s requirements
As exploration and development projects moved into deeper and deeper waters, there was a requirement to improve the valve and control systems on Subsea landing strings during well testing, completion and interventions. This was required to reduce the response times so that an emergency disconnect could be carried out within the time requirements of dynamic positioned drilling units. The customer expressed a need for a safety system to be used in the Gulf of Mexico.

Expro’s solution
Expro’s large bore safety systems became the established method of completion installations with horizontal xmas trees more than 10 years ago. To complement these in deepwater environments, Expro developed the EXPRESS series of Subsea control systems that are capable of working in 10,000ft water depths.

Results
The Expro EXPRESS controls system has been developed and recently successfully deployed, meeting the emerging demands of the deepwater high-pressure subsea Gulf of Mexico market. The Express CI control system has made operational uptime the number one priority. Expro has just completed a deepwater operation in more than 5,000ft of water in the Gulf of Mexico, using its ELSA and Express 7 landing string system. Expro completed more than 720 hours of “in-hole” time in a flowing well condition with no operational issues.

Technologies used
Expro has designed the industry’s first 15,000psi, 250°F-rated, large bore electro-hydraulic system to clean up wells developed with horizontal subsea trees, allowing large-bore subsea completion and interventions to be conducted safely in water depths up to 10,000ft.

Providing a successful clean-out solution for a gas well in Saudi Arabia

Customer’s problem
The HRDH-923 well was drilled and completed as a dual lateral gas well, in the Khuff-C formation, in Saudi Arabia, in January 2007.

A rigless coiled tubing clean-out was conducted to break the upper isolation valve in the completion string, but the well performance was unstable with wellhead flowing pressure declining steadily, from 5,000 to 30 psi.

At the choke manifold, several pieces of cement and formation rocks were recovered. A combined mechanical/chemical clean-out operation was then conducted, but was again unsuccessful as a hard obstruction was encountered at 4,645ft.

The well had been completed and due to a solids plug in tubing, operations were suspended which resulted in lost production and lost revenue to the customer.

Expro’s solution
For this non-routine job, Expro provided its Solids Management System, along with three phase test separators to be tied into the snubbing unit for the tubing clean-out program.

Specific procedures were implemented for the surface separation equipment design including the ability to handle solids slugs, and necessary HAZOP reviews, along with a supply of certified equipment and competent operations personnel for safe handling and disposal of produced well effluents.
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Results
The customer was successful in cleaning out formation solids in the 5-1/2” x 4-1/2” tubing and was able to gain full access to both laterals. The customer was also able to break the ceramic disc at 11,932ft allowing access to the lower lateral.
This eliminated the additional cost of a workover rig to pull the completion had this operation failed.

A total of 1,158 kgs of solids were recovered, some as big as small pebbles. The final FWHP was 1310 psig @ 58/64ths choke with gas rate of 8.0 MMscf/d and condensate rate at 619 bpd. 2170 Expro manhours were spent on this project without any incident or LTI.

Technologies used
The Expro Solids Management System (SMS) was employed for this well’s specific clean-out requirement. SMS removes solids from the well stream at the well head, and prevents erosion of the downstream equipment. This improves the safety during solids removal operations, and reduces the wear and tear on the downstream equipment. SMS consists of two major components; Wellhead Desander unit and Wellhead Filter Unit. The wellhead Desander removes 95-98 % of the wellstream solids and the Wellhead Filter Unit catched any fine solids that carry over from the Wellhead DeSander.

Customer quote
The Aramco foreman said he was under lot of pressure from above and consequently he pushed the testing crews extremely hard and was impressed by their dedication and professionalism.
“Thank you and good work to everyone who has supported this project.”

Providing a solution for testing flow in Algeria

Customer’s problem
To comply with Algerian legislation and to minimise any environmental impact during oil well testing, a “Zero Emission Well Testing” solution was required to test the flowing potential of two oil producing zones and one gas producing zone on the client’s exploration well.
Representative PvT (Pressure, Volume, Temperature) samples were also required from each zone to allowing formation fluids analysis post operations.

Expro’s Solution
Together with the client reservoir engineers, Expro developed a programme to satisfy the objectives of the test using a well clean-up/ fluids injection and pressure fall-off testing technique.

Flowing of the well would be limited to a clean-up phase only during which time PvT samples would be collected at a temporary separator. After the clean-up phase a compatible fluid would be injected to the formation at a stable rate for a predetermined period and post injection pressure fall off rates monitored for analysis after the operation.

The Expro Algeria team proposed an integrated solution to ENI Algeria. A project co-ordinator was identified from within Expro and an outline project plan prepared.

Initially, a fluid compatibility study was performed in the Expro Hassi Messaoud laboratory to ensure diesel was compatible with the expected formation hydrocarbons and could be used as the injection fluid. BJSP was then selected as the pumping sub-contractor to conduct the injection phase of the operation.

To keep flaring emissions to an absolute minimum during the limited clean-up periods, Expro provided a super green burner. Expro also provided a full P&ID and equipment laydown diagram which was submitted to the client together with a risk analysis in respect to the storage of 500m3 of diesel on location during the injection test.

Five tanks sub-contracted from BJSP were mobilised to store the diesel and two pump trucks ensured 100% back-up during the injection phase.

The adapted surface sampling package was also mobilized to location to ensure PVT samples could be taken at the end of the clean-up phase.
During the operation the Expro project test co-ordinator was on location to ensure perfect co-ordination between Expro, BJSP (sub-contractor) and the client ENI.

Results
The two oil zones were cleaned-up through the super green burner and representative PvT samples collected after only a total one hour flow period.

A 12 hour diesel injection test followed by 36 hours fall-off test were both performed without interruption. The Expro surface data monitoring acquisition system EDGE was used to accurately capture all injection and pressure fall off data for post job analysis.

The complete operation was delivered on time and without incident following the strict HSE guidelines for Expro and the client.
Excellence in Operations was achieved on the project to the complete satisfaction of ENI Algeria.

Technologies used

• Expro Project Coordination
• Expro Hassi Messaoud GOLD lab for compatibility study
• Expro Super green burner
• Expro trailer mounted well test equipment
• Expro EDGE surface data acquisition system to ensure real time monitoring during clean-up and injection phase.
• Expro Surface and Bottom hole PVT sampling
• BJSP frac tanks and pump trucks

Customer quote
A spokesman for ENI said : “We have rigged up well testing equipment to perform tests of the reservoirs. The equipment was rigged up well and as required, and all safety tools are in place and tested well.
“The Expro crew did a good job in term of knowledge of the project, equipment, and procedures; and in terms of safety rules they showed very good knowledge. They always use correct PPE and held safety meetings and tool box talks.”