Multistage Hydraulic Fracturing in an Openhole Ultratight Sandstone Formation in China—Design Considerations and Execution Results
Bibliographic record
Abstract
Abstract In the winter of 2005, the first multistage completion in an openhole, ultratight sandstone reservoir of the Dot Three field, China, was successfully completed using hydrajet-fracturing technique. Six propped hydraulic fractures were placed individually at strategically selected locations along two horizontal wellbores. Many horizontal wells with openhole completions have been drilled in low-permeability sandstone formations. The Dot-Three reservoir is one such case. Many of these wells perform below predicted rates with uneconomical oil production. Until recently, no method existed to effectively fracture-stimulate this type of horizontal, openhole wellbore to optimize production. Successful proppant placement in the Dot Three field (this field has adopted early-c waterflood pattern) has proved to be extremely difficult in the past. Propped fracture treatments pumped within the past 10 years were not successful and their post-frac production only averaged 1 ton oil/day. Proppant placement problems occurred, and were believed to be caused by simultaneous propagation of very narrow multiple hydraulic fractures. Past propped fracture treatments were performed on vertical wells and a few multiple fracture treatments on horizontal wellbores. These were only possible inside a cased hole using conventional methods (i.e. perforate, frac, set mechanical/chemical zone isolation, repeat cycle). The resulting treatment efficiency was low and results were not satisfactory. Because successful development of this reservoir would significantly impact Chinese oil production, another method for fracturing cased, horizontal wellbores and a new method of propped fracture stimulation in horizontal, openhole wellbores was justified. This paper discusses a hydrajet-fracturing technique that uses dynamic fluid energy (instead of mechanical methods) to isolate treatment fluid flow to a specific fracture point along the wellbore. Final results compared to past fractures using conventional methods and post-fracture production responses of the two experiment wells are also discussed.
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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".