Openhole Cleanup of Deep, High-Temperature Horizontal Wells With a Chelant-Based Acid System—Case Histories From Indonesia
Bibliographic record
Abstract
Abstract ConocoPhillips Indonesia Inc. Ltd. is producing oil and gas in various locations in Indonesia, both on and offshore. This paper covers work performed in the Belanak field offshore Indonesia. The field is located in Natuna Sea, north of Indonesia, near the border between Indonesia and Malaysia. The gas produced by the Belanak field is transported to Singapore and Malaysia. Belanak wells which are drilled in the Gabus Massive reservoir have a bottom hole static temperature of 315°F (157°C). The wells are typically long horizontals (2,300–3,400 ft) with openhole completions utilizing stand-alone screens through the producing interval. The reservoir section is drilled with a water-based Drill-in-Fluid (DIF) consisting of polymer and CaCO3 particles and displaced to a solids-free, DIF prior to running the screens. Typically, acid is used to degrade water-based DIF filtercake and remove CaCO3 contained in the filtercake. The use of a common acid was not an option for this development because of the high reservoir temperature (>300°F). The combination of high reservoir temperature and long shut-in times after acid treatment lead to a high probability of severe corrosion of the sand control screens. In addition to the corrosion concerns with common acids, the rapid removal of the filtercake with acid could create localized, high leak-off of the treating fluid resulting in an uneven distribution of acid across the horizontal open-hole section. To overcome these problems, a slow reacting alternative chemical solution was required allowing the stimulation fluid to be placed across the entire horizontal open-hole section before the CaCO3 filter cake was dissolved and before major losses started to occur. The solution was found in the application of a Chelant Based Acid System. This paper details the application of the Chelant Based Acid System as a means to remove CaCO3 filter cakes in 10 Belanak wells, post treatment well performance, best practices, and lessons learned.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".