Bibliographic record
Abstract
This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 112476, "Multiple- Layer Completions for Efficient Treatment of Multilayer Reservoirs," by Gary Rytlewski, SPE, Schlumberger, originally prepared for the 2008 IADC/SPE Drilling Conference, Orlando, Florida, 4-6 March. The paper has not been peer reviewed. A new method of completing multiple-layer formations has been tested successfully. This new method places sliding-sleeve valves in the casing that are opened one at a time to fracture layers independently without perforating. Completions using these casing valves have a unique design feature that allows a theoretically unlimited number of valves to be placed in a single well without incremental reductions to the inside diameter (ID). This near fullbore feature allows normal cementing operations to be performed with a special cement wiper plug. Introduction The US and Canadian tight-gas market is deploying new methods to stimulate multiple-layer reservoirs efficiently. The treat-and-produce (TAP) completion system has been developed to allow efficient treatment of individual layers in cemented cased-hole completions. TAP completions use special casing valves that isolate individual layers. The TAP valves are near full bore and do not require incremental ID reductions, thus allowing normal cementing operations. The TAP valves also have unique helical ports that align to any preferential fracture plane, regardless of the orientation of the valve in the casing string. These ports ensure that a single bi-wing fracture plane is initiated from the wellbore. Fracture-initiation pressures with TAP valves are expected to be comparable to openhole fracture-initiation pressure or be lower. The Main TAP Valve The main TAP valve is a sliding-sleeve valve with several unique features that enable it to open selectively one valve at a time and isolate previously treated layers. There is a C-ring in the main TAP valve that, when squeezed by a piston, reduces in size. The C-ring originally has the same ID as the valve, but when reduced in size, the C-ring becomes a seat on which the next ball or dart can seal. Fig. 1 shows a cross section of the main TAP valve and the C-ring in the run-in-hole position. The piston that squeezes the C-ring (the magenta-colored component in Fig. 1) is controlled by the pressure in a control line connected to the TAP valve below it. When the lower TAP valve is opened, the port to the control line is opened to the ID fluid. The control line, which was at atmospheric pressure, now has bore pressure. The upper TAP valve receives the bore pressure through the control line and ports it to the C-ring piston. The C-ring piston has two atmospheric chambers. When the bore pressure floods one of these atmospheric chambers, the C-ring piston moves and squeezes the C-ring and is able to catch the next ball or dart pumped down. When the dart lands on the C-ring seat, it creates a seal, and pump pressure pushes the sleeve open.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".