On 04 September 2024 a SPWLA Hydrocarbon Resources Special Interest
Three-Dimensional Subsurface Positioning and Positional Uncertainty
Improved subsurface well positional accuracy using way-point method
3D Way-point is a subsurface three-dimensional well positional calculation method that includes positional uncertainty. 3D Way-point makes use of a "balanced" approach to well depth, inclination, and azimuth measurement accuracies. Well depth accuracy is achieved using the Driller's Way-point Depth (DwpD) method. This makes use of accurately measured drill pipe length and then application of thermal and elastic stretch corrections based on the actual well temperature and POOH SSM travelling block pipe tension profiles. This results in significant improvements in well depth length determination and uncertainty, and so provides the balanced input to the 3D Way-point positional calculation. These measurements can be made as part of the drilling workflow, so while drilling. The result is a significant improvement in well depth, and thereby 3D well positional accuracy, plus the definition of specific markers downhole that can be used as subsurface reference points. This improves the well placement description, the confidence in the reliability of mapping of downhole structures, and increases reservoir reserves volumes.
Specification Title | Specification Description |
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Accuracy
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3D positional uncertainty by design. The operator gets horizons to a defined positional uncertainty.
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Areas of Application
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Well placement engineering | Geological modelling | Reservoir description | Asset value determination
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Capabilities
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Repeatability of well depth and well position determination, confirmation of measurement result, and uncertainty determination.
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CAPEX
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Negligible.
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Certifications / licences
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Driller's Way Point Depth (DwpD) and 3D Way-point (patent pending) are patented methods owned by DwpD Ltd., requiring license to operate.
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Compliance
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ISO measurement, API RP-78
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Cost
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Operating costs include drill pipe length determination to specified accuracy, unless this is already done. Otherwise, costs are limited to license use of the patent (pending) processes. Training and assistance is offered for implementation of the methods. Turn-around calcualtion service is also offered.
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Methodology
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Logical and justified well depth measurement and correction method based on way-points using drill pipe. Well depth is defined using POOH SSM rig-state. Important to note is that the same approach can be adopted to wireline.
The method and background is detailed in the book "3D Subsurface Positioning and Positional Uncertainty, Rev 7.0" available on www.lulu.com. |
Services
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DwpD and 3D Way-point calcualtion services are offered, but ideally the process is internalized. Other DwpD Ltd. services include well depth measurment consulting, audit, and training. Adaptation and/or writing of necessary work-flows is also offered. Ad-hoc consulting for well depth discrepency issues is also available.
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Usability
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DwpD can be applied any time drill pipe is run in the well: new drill through to work-over and P&A. 3D Way-point can be applied to any 3D well survey data set (also wireline), but is optimized with balanced well depth, inclination, and azimuth measurment accuracies.
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Reviews
Latest Updates
At the Apil 2024 ISCWSA #59 conference held in Glasgow
Subsurface 3D Positioning and Positional Uncertainty is a major rewrite
The Technology Readiness Level (TRL) indicates the maturity level of novel technologies. Learn more about the TRL scale used by us.
[9/9]
Relative Business Impact

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