Is While-Drilling True Vertical Depth True?

ElGizawy, Mahmoud; Androsovich, Natalia; Rachi, Hakim; Abbas, Nashat; Katheeri, Y. Al; Koakkadan, Saleel; Noukhatha, Jamal Al; Hargreaves, Brad

doi:10.2118/188921-ms

Cited by 5 publications

References 3 publications

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Step Change in Wellbore Positioning Accuracy

ElGizawy

Aklestad

Lowdon

2018

Day 2 Tue, January 30, 2018

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A survey program is designed for every well drilled to meet the well objective of penetrating the target reservoir and to avoid colliding with other offset wells. The selection of the wellbore survey tools within the survey program are limited to the current accuracy available to the industry. A newly developed wellbore survey technique has proven to have superior accuracy compared to the current standard measurement-while-drilling (MWD) surveys with in-field referencing and multi-station analysis (MSA). In almost every drilling bottom hole assembly (BHA), there is an MWD survey tool to survey the wellbore while drilling. Accuracy of the MWD surveys has been improved over the years by correcting potential error sources such as misalignment of the survey package from the borehole, drillstring magnetic interference, limited global geomagnetic reference, and gravity model accuracy. This new positioning technique takes the accuracy of MWD surveys to the next level by combining surveys from two independent survey packages. The second survey package is installed inside the rotary steerable system (RSS). Surveys from both packages are retrieved while drilling. Results have been obtained from multiple runs worldwide, enabling comparisons between the new technique and standard MWD surveys from both an enhanced accuracy and true wellbore placement point of view. A proposed error model is based on both the theoretical improvements in accuracy and the empirical proof from the data analyzed. The improved accuracy while drilling assures higher confidence that the well placement will maximize reservoir production and avoid collision with nearby offset wells. In reservoir sections, the wellbore survey accuracy limits the lateral spacing, and this constrains the reservoir production. In top and intermediate sections, wellbore survey accuracy limits the well plan, and this affects how close the well can be drilled in proximity to other offset wells. This directly impacts the complexity of the directional work and the cost per drilled foot. The new technique unlocks the potential to significantly improve the wellbore positioning accuracy.

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Step Change in Wellbore Positioning Accuracy

ElGizawy

Aklestad

Lowdon

2018

Day 2 Tue, January 30, 2018

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Operators' Group, Rig Contractors, and OEM/Service Company Work to Solve Rig Data Quality Issues

Behounek

Nguyen

Halloran³

et al. 2018

IADC/SPE Drilling Conference and Exhibition

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In the current economic climate Operators must reduce drilling costs, so they are turning to well data analytics, real-time advisory, and automation systems to make sustainable improvements (Behounek et al. 2017). Rig surface sensor data is critical to improvement; however, documented issues with consistent, reliable, quality data complicates and delays the value from these systems. The Operators Group for Data Quality (OGDQ) seeks to accelerate the adoption of standardized key measurement specifications, data storage, transmission, transformation, and integration by working with Rig Contractors, Original Equipment Manufacturers (OEMs), and Service Companies. The OGDQ effort focuses on key measurements used for important drilling process decision making. For this paper, the OGDQ worked with Rig Contractors and an OEM/Service Company to advance recommended data quality components in work processes and commercial agreements. By bringing transparency to the process, the authors hope to contribute to the efforts to address operational data quality issues and to drive alignment and improvements among Operators, Rig Contractors, OEMs, and Service Companies. This paper outlines an approach to putting data quality into practice, including initially identifying the problem, field verification, developing key measurement specifications, constructing framework components, and anticipating management of change issues. Quality drilling data is essential to both rig and office personnel who are tasked with decision making for fast-paced well programs. Quality drilling data is also essential for the data-driven systems developed to assist in managing well delivery. Rig studies show several cases where Operators independently uncovered systematic errors for 10 key measurements used for drilling process decision making (Zenero 2014; Zenero et al. 2016). The 10 key measurements are listed as follows: Rotary/Top Drive TorqueJoint Makeup/Breakout TorqueHookloadRotary/Top Drive Rotational SpeedStand Pipe PressureDrilling Fluid Pump RateDrilling Fluid Tank/Pit VolumeDrilling Fluid DensityDrilling Fluid ViscosityBlock Position Widespread agreement on data quality practices among Operators, Rig Contractors, OEMs, and Service Companies is crucial for their quick adoption, and an industry-wide approach has a profound effect on drilling operations. Widely adopted practices will support and drive requirements for sensor quality, calibration, field verification, and maintenance. This standardization will, in turn, significantly enable improved drilling operations, drilling analysis, and big data processing by correcting many errors resulting from poor data quality. This paper outlines the methodology used to develop a guide for commercial drilling components, and illustrates the application of this guide with selected drilling data use cases.

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Combining Best-in-Class Surveying Measurements to Provide the Most Accurate Wellbore Position

ElGizawy

Lowdon²,

Aklestad³

et al. 2023

SPE/IADC International Drilling Conference and Exhibition

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A survey program is designed for every well drilled to meet the well objective of penetrating the target reservoir and avoiding colliding with other offset wells. The selection of the wellbore survey tools within the survey program is limited in number and accuracy by the current surveying technologies available in the industry. This article demonstrates how a higher level of accuracy can be achieved to meet challenging well objectives when the accuracy of the most accurate wellbore surveying technology individually is not sufficient. This highest level of wellbore positioning accuracy to date is achieved by combing two wellbore positions of the same wellbore trajectory. The first wellbore position is calculated using the latest technology of magnetic Measurement-While-Drilling (MWD) Definitive Dynamic Surveys (DDS). The accuracy of the MWD DDS has been enhanced by correcting potential error sources such as misalignment of the survey package from the borehole, drill-string magnetic interference and limited global geomagnetic reference and accelerometer sensor accuracy. Further, the MWD DDS inclination accuracy is improved using an independent inclination measurement from the Rotary Steerable System (RSS). Hence the first position is derived from magnetic MWD DDS after applying In-Field Referencing (IFR), Multi-Station Analysis (MSA), Bottom Hole Assembly (BHA) sag correction (SAG), and Dual-Inclination (DI) corrections. A Second wellbore position is calculated using the latest technology in Gyro-measurement-While-Drilling (GWD). The results and comparisons of multiple runs are presented. The highest accuracy of wellbore positioning had been proven in successful case studies by penetrating a very small reservoir target on an extended reach well that was unfeasible using either the most accurate enhanced MWD DDS or the latest GWD technology. The presented case study shows how the wellbore objectives of penetrating the tight target reservoir had been confirmed by Logging-While-Drilling (LWD) images and interpretation of the subsurface team. This gave the highest accuracy of the wellbore position accuracy to date while drilling assured placing the well with higher confidence to maximize reservoir production without colliding with nearby offset wells. In reservoir sections, the wellbore survey accuracy limits boreholes' lateral and true vertical depth spacing, constraining reservoir production. In the top and intermediate sections, wellbore survey accuracy limits how close the well can be drilled in the proximity of other offset wells. This directly impacts the complexity of the directional work and the cost per drilled foot. This technique unlocks the potential to improve the wellbore positioning accuracy significantly. It demonstrates the highest wellbore positioning accuracy achieved to date when compared to the latest magnetic MWD surveys after correcting all known errors compared to the GWD.

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Is While-Drilling True Vertical Depth True?

Cited by 5 publications

References 3 publications

Step Change in Wellbore Positioning Accuracy

Step Change in Wellbore Positioning Accuracy

Operators' Group, Rig Contractors, and OEM/Service Company Work to Solve Rig Data Quality Issues

Combining Best-in-Class Surveying Measurements to Provide the Most Accurate Wellbore Position

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