Parameters Affecting Load Recovery and Oil Breakthrough Time after Hydraulic Fracturing in Tight Oil Wells
Bibliographic record
Abstract
Abstract After hydraulic fracture treatment, wells typically produce significant volumes of water, which is primarily recovered fracturing fluid. The amount of fracturing fluid produced back is called load recovery. Single phase water production may continue for several days before oil breakthrough from the formation occurs. A wide range of load recoveries (15%–80%) are reported in the literature, depending on various reservoir, fracture, pumping and operational parameters. This study conducts a comprehensive numerical and statistical analysis to identify the most important parameters affecting load recovery. The sensitivity of oil breakthrough time to these parameters is also investigated. A fit-for-purpose model was created using a commercial coupled reservoir flow/geomechanics simulator to simulate fracturing treatment and flowback operations. Water and oil production trends, and flow regimes observed in the model, are verified using rate-transient analysis (RTA). The effect of twenty parameters including pumping rate, shut-in time, producing bottomhole pressure, production rate constraint, matrix porosity and permeability, matrix and hydraulic fracture compressibility, relative permeability end points and capillary pressure on load recovery and oil breakthrough time is investigated by utilizing Design of Experiment (DOE). The developed model considers non-uniform leak-off during pumping, providing a better understating of water retention, while the application of the DOE method allows the effect of various parameters and their interaction to be studied rigorously. A critical finding is that the majority of total load recovery occurs within the first three months of production. Furthermore, matrix permeability, shut-in time, connate water saturation and fracture compressibility, were found to be the most dominant factors, which can impact the load recovery by up to 22%, 15%, 14%, and 13%, respectively. Matrix permeability, production rate constraint, fracture residual oil saturation and shut-in time are four of the prominent parameters affecting oil breakthrough time. Understanding the impact of operational parameters such as shut-in time and production rate can help industry to implement recycling/disposal options and ultimately optimize load recovery. This can also create significant environmental compliance benefits for operators in addition to benefitting operational efficiency.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".