Bibliographic record
Abstract
This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 137821, ’New Approach To Improve the Horizontal-Drilling Reach,’ by O.M. Vestavik, SPE, H. Syse, O. Hole, SPE, and J. Aleksandersen, Reelwell, prepared for the 2010 CSUG/ SPE Canadian Unconventional Resources & International Petroleum Conference, Calgary, 19-21 October. The paper has not been peer reviewed. A drilling method was developed to enhance extended-reach managed-pressure drilling. A conventional drillstring with a special inner string forms a dual concentric drillstring (DCD). The inner string is used to remove drill cuttings from the bottom of the well. A separate hydraulic-fluid system is used to push the drilling assembly forward using fluid pressure from the surface. Development began in 2004, and the system has been through several full-scale operations in Norway. In 2009, the DCD method was used to directionally drill the 81/2-in. section of an onshore well. Introduction As targets for new petroleum resources become increasingly challenging, there is a need for new technology to keep exploration and production costs at an acceptable level. Development of the DCD method was supported by the Research Council of Norway, Statoil, and Shell. DCD method The DCD method, shown in Fig. 1, is based on conventional drilling, with the following components added to the system. The dual drillstring (DDS) facilitates closed-loop circulation of the drilling fluid. The cuttings are trans-ported to the surface by the drilling fluid through the center pipe, leaving the wellbore annulus free of cuttings. The top-drive adapter (TDA) is a dual-conduit swivel that facilitates rotation of the drillstring and accommodates the discharge and return conduits and a slip ring for power and data transmission. The dual-float valve (DFV) enables downhole pressure isolation of the well and facilitates controlled-pressure drilling and nonpressured pipe connections. The sliding piston is used to pump the bottomhole assembly (BHA) into the horizontal section of the well. The piston provides hydraulic weight on bit (WOB) and provides the ability to push the limits of extended-reach-drilling. The flow-control unit is a control valve for the active drilling fluid to ensure constant downhole pressure during drilling and pipe connections. The unit is equipped with pressure and flow sensors on both the drilling-fluid inlet and the return lines. A computer monitors and controls the status of the well. An annulus-control unit is used to keep a constant pressure in the annulus behind the piston. A main difference between this method and conventional drilling is the circulation path of the drilling fluid. In conventional drilling, the fluid returns through the wellbore annulus. The DCD method pumps the drilling fluid into the DDS annulus through the TDA. The drilling fluid flows down the DDS annulus to the DFV, which terminates the DDS at the top of a conventional BHA.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".