BD Gas Field Near-HPHT and Critical Sour Development: A Journey to Maintain Well Integrity
Bibliographic record
Abstract
Abstract BD Gas Field is located in offshore in the Madura Strait, Indonesia, and has a total of four producing wells - one vertical (Well Y1) and three horizontal (Well Y2, Well Y3, and Well Y4) from an unmanned platform. Its reservoir was considered near HPHT and critical sour with 8,100 psi bottom hole pressure, 300°F bottom hole temperature, 5.5% CO2 and 5,000 ppm H2S. This paper highlights on the Company journey to maintain well integrity during well design phase, well construction phase, and production phase of BD Gas Field. During well design phase, material selection and design for 9-5/8 in. intermediate casing, 7 in. production casing, and 4-1/2 in. tubing were based on the expected life of the well and reservoir properties in accordance to the requirements of NACE. Cementing design for 7 in. production casing cement was tested and analyzed in the laboratory for 60 days in the HPHT chamber simulating reservoir properties. Top of cement was designed to the mud line to minimize wellhead growth. Completion design was monobore type and divided into lower, intermediate, and upper completion strings. All packers were V-0 (zero bubble) rating. Maintaining well integrity during well construction phase was challenging. Batch drilling and completion was applied, and at all times, the wells were required to be suspended with proper and adequate barriers. During drilling and well clean-up phase, inter-casing pressure management (i.e., annulus pressure, wellhead growth monitoring, bleed off program, etc.) was implemented to maintain the casing and tubing integrity. During production phase, routine wellhead growth measurement, constant monitoring and bleed off program were developed and communicated with related departments. Pressure control valves and alarm system were installed and tested to the annulus. In additional to the wellhead growth, transverse wellhead movement was observed in one of the wells especially during rough sea conditions. In order to reduce the tranverse wellhead movement which may induce more stress on the surface pipings and connections, it was planned to install under water shims in between the conductor pipe and platform jacket guide funnel. Some surface piping and platform modification were also considered because wellhead growth leads to limitations on gas production to prevent safety issues.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".