MC305 Aconcagua SCSSV Control Hydraulics Problems Uncommanded and SCSSV Closure Problems
Bibliographic record
Abstract
Abstract The Aconcagua field, operated by TotalFinaElf, is located in 7000’ of water in MC305, and is part of the Canyon Express development. Aconcagua is a dry gas field, comprising four subsea wells. The Canyon Express project involves a commingled tieback of three dry gas fields, owned and operated by different companies, through a jointly owned twin 12" flowline tieback to a third party host platform at 56 miles distance. Two problems have been experienced in the operation of the SCSSVs, initially during the flow-back testing, and later in the production phase. The first problem was the rapid rise in hydraulic pressure in the control lines during well start-up; this is related to a problem with the design of the pod hydraulics, and is found on all four wells in the Aconcagua field. The second problem is related to uncommanded closures of the SCSSV; this problem has been experienced on three out of the four Aconcagua wells, to varying degrees of severity. Although procedural mitigation methods have enabled the MC305-1 and MC305-2 wells to operate correctly, the uncommanded closures have continued in the MC305-4 well during the first four months of field life. The MC305-4 well is located in 7,055 feet of water; top of reservoir is located at around 12,500 feet TVD below MSL, and the SCSSV is set at 9,400 feet below MSL. The TR SCSSV is a Schlumberger TRC-DH type; it has dual redundant pistons with a gas spring system to counter balance the hydrostatic pressure of the Transaqua HT control fluid (4,300 psi at the SCSSV depth). This paper describes the hydraulic design of the control pods, the reasons for the increase in hydraulic supply pressures in the control lines, and the procedural steps taken to mitigate over-pressurisation of the SCSSV hydraulics. Also described are the system modes associated with the uncommanded SCSSV closures, and the diagnostic testing carried out to establish the reasons for the closures. The detail of the steps taken to avoid the closures is offered, both with procedural and hardware modifications noted.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".