Occurrence, Prediction, and Prevention of Zinc Sulfide Scale Within Gulf Coast and North Sea High-Temperature and High-Salinity Fields
Bibliographic record
Abstract
Summary In oil and gas production operations, precipitation of mineral scales causes many problems, such as formation damage, production losses, increased workovers in both producers and injectors, poor injection-water quality, and equipment failures caused by underdeposit corrosion. The most common mineral scales are sulfate- and carbonate-based minerals. However, scale problems are not limited to these minerals, and there recently have been reports of unusual scale types, such as zinc and lead sulfide. This paper focuses on zinc sulfide scale that has been found in several fields along the Gulf Coast of the U.S.A. and in fields within the North Sea Basin. Scale deposition has caused significant pressure and rate reductions in high-temperature and high-rate gas, condensate, and black oil wells. After acid washes to remove zinc sulfide scale (and other acid-soluble solids), production rates and flowing tubing pressures returned to previous levels, but new scale deposits formed in many wells and retreatments were required. Topside process equipment, most noticeably low-pressure separators and hydrocyclones, were observed to suffer reductions in performance owing to zinc sulfide scale deposition. In addition, there are significant risks associated with acid treatments in high-temperature, high-pressure (HT/HP) gas wells in corrosivity of the acid at high temperatures (general corrosion, sulfide stress cracking, and chloride stress cracking) and in safety (hydrogen sulfide generation by acid dissolution of zinc sulfide plus high-pressure pumping). One possible method for preventing production declines and reducing the need for HT/HP acid jobs is to use scale inhibitors or chelating agents to prevent the formation of zinc sulfide scale. The relative effectiveness of eight scale-inhibitor chemistries and two chelating agents in preventing formation of zinc sulfide scale has been determined. The required scale-inhibitor concentrations are significantly higher than those needed for common sulfate and carbonate scales. For chelating agents, it is possible to prevent the formation of zinc sulfide scale when the required concentrations are proportional to the zinc ion concentration in the scaling brine. This paper outlines the testing methods used for chemical screening and prediction so that assessment of the potential problem within fields can be assessed during appraisal, before production commences, making a method of managing the risk available.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".