Coupling of Downhole Dynamics Recorder Enhances System-Matched Approach to Drill-Bit Design and Application With a Specific Rotary-Steerable System

Barton, Steven Paul; Lockley, John Russell; Stroud, Daryl; Peach, Simon

doi:10.2118/102182-ms

Cited by 20 publications

(6 citation statements)

References 9 publications

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“…An alternative to the 4" gauge length would be the use of a partial ring gauge geometry 8 which has proven beneficial for both stability, borehole quality, and directional response in prior tests and in the field. This is documented in detail in a prior paper 5 . The final option, and one less desired, is the coupling of a short gauge length with a passive extended gauge sub.…”

Section: Field Testing (Motorized Rss)mentioning

confidence: 99%

Changing Selection Concepts: True Optimization of Drill Bits with Latest Generation Rotary Steerable Systems

Barton¹,

Pierce²,

Stroud

2009

SPE Annual Technical Conference and Exhibition

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Use of Rotary Steerable Systems (RSS) has steadily increased since their introduction in the mid-1990's. Improvements in durability, reliability, and operator familiarity, have moved these systems further into mainstream drilling use around the globe. However, the large majority of footage drilled with RSS is with side force (Push) tools. These tend to require some degree of sidecutting, thus utilize drill bits that have specifically engineered cutting structure, profile, and gauge design to achieve this. Due to common availability of this type of bit design, plus extensive experience with operators, they are often also utilized on the growing number of Point RSS. Due to the significant difference in operating mechanism, these bit designs can be poorly suited, resulting in sub-optimal drilling performance. This paper describes a joint engineering approach in developing specific drill bits for the latest generation of RSS that utilizes point-the-bit technology. The project has included systematic testing at a purpose-built, full-size drilling test facility. This has enabled a direct comparison of the directional response, hole quality, and drill string vibration to be made for the various combinations of drill bit and RSS configurations tested. The testing and subsequent field performance has led to development of specified characteristics of the drill bit for optimal performance. To ensure consistent and accurate matching of the bit to this specific RSS, an interactive, intranet tool was developed. This software incorporates logic regarding tool operation and assesses these against key characteristics of the bit including length, profile, gauge geometry, cutting structure, and sidecutting capability. This allows the ideal design to be rapidly identified, particularly as some characteristics are not visible within the visual geometry of the bit. Several case studies are documented that clearly demonstrate that the correct matching of drill bits to this specific Point RSS has delivered improved drilling efficiency with excellent directional control. Introduction The paper focuses on the development and testing of one of the latest generation point-the-bit RSS. The tool comprises three main elements; downhole electronic control module, mechanical bias unit and pivot stabilizer (Figure 1). The bias unit is a hydraulic/mechanical mechanism that develops power from differential rotation between the rotating drill-string and a nonrotating steering sleeve. This hydraulic power is used to deflect the drill-string (eccentrically to the borehole) in the required direction for steering. The system employs a pivot (fulcrum) stabilizer such that the driveshaft is deflected in the opposite direction to required hole deviation (Figure 2). Sprung anti-rotation guides prevent the steering sleeve from rotating, but if the sleeve begins to roll, the system automatically redirects hydraulics to maintain desired orientation. The electronic control module applies algorithms to provide closed loop control of the position of the bias unit, giving tight toolface control and proportional deflection control; enabling fine adjustment of wellbore deviation rates.

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Section: Field Testing (Motorized Rss)mentioning

confidence: 99%

Changing Selection Concepts: True Optimization of Drill Bits with Latest Generation Rotary Steerable Systems

Barton¹,

Pierce²,

Stroud

2009

SPE Annual Technical Conference and Exhibition

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“…In point-the-bit mode, a fullgauge near-bit stabilizer is used as the fulcrum point, allowing the bit to tilt in the steered direction. In addition to providing a pivoting point, the use of a full-gauge near-bit stabilizer can dampen lateral shocks that may originate from the drill bit 10 .…”

Section: Non-rotating Steering Unitmentioning

confidence: 99%

The Use of the Industry's First 3-D Mechanical Caliper Image While Drilling Leads to Optimized Rotary-Steerable Assemblies in Push- and Point-the-Bit Configurations

Sugiura

Jones

2008

SPE Annual Technical Conference and Exhibition

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It has been widely recognized that poor hole quality causes tight borehole, packing off, high torque/drag, stick-slip, degraded logging-while-drilling (LWD) and wireline log quality, unpredictable directional performance, and consequently problematic casing runs. Conventionally, borehole quality is monitored with LWD standoff caliper logs and caliper images. In wireline application, multi-arm mechanical calipers are used to create such logs. Until today, it is believed that the use of such equipment is the only way to detect 3-D borehole problems, such as borehole oscillation. This paper presents the industry's first 2-D and 3-D mechanical caliper image while drilling and back-reaming with rotarysteerable systems (RSS). The near-bit mechanical caliper integrated into the specific RSS 1,2,3 takes measurements 4 ft from the bit in push-the-bit configuration and 7 ft from the bit in point-the-bit configuration. This pad-contact mechanical caliper provides both real-time and memory-based caliper images.The advantage of this new type of near-bit caliper measurement is that the sensor measures borehole geometry right at the bit as compared to 50-100 feet behind the bit with conventional LWD sensors. Borehole washout, for example, does not necessarily occur at the bit, but could be caused by string stabilizers far away from the bit. The ability to detect borehole washout in real-time helps the operator take immediate corrective action while drilling to maintain borehole integrity since near-bit washout often affects the steerability of RSS.In this paper, 2-D and 3-D near-bit caliper logs are extensively examined from different RSS assemblies and bits. The downhole data were gathered through controlled non-commercial field tests, as well as commercial runs. Frequency analysis using the discrete Fourier transform is also applied to the depth-based caliper images to identify the BHA and borehole oscillation issues. The effect of bit selection, stabilizer size/profile/geometry, and spacing on borehole quality is analyzed using the 2-D and 3-D near-bit caliper logs. As a result, this new sensor information helped to improve the RSS assembly performance and resulted in optimized BHAs in both push-and point-the-bit configurations for superior steerability, stability and borehole quality.

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“…In point-the-bit mode, a full-gauge nearbit stabilizer is used as the fulcrum point, allowing the bit to tilt in the steered direction. In addition to providing a pivoting point, the use of a full-gauge near-bit stabilizer dampens some of the vibrations from the drill bit [1].…”

Section: Non-rotating Steering Unitmentioning

confidence: 99%

Integrated Approach to Rotary-Steerable Drilling Optimization Using Concurrent Real-time Measurement of Near-bit Borehole Caliper and Near-bit Vibration

Sugiura

Jones

2008

All Days

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A novel sensor system, integrated into a rotary steerable system (RSS), has led to a new level of drilling optimization by providing the concurrent real-time measurement of near-bit borehole caliper and near-bit vibration. This new sensor system gathers all the information 2 to 3 meters above the drill bit, whereas conventional MWD/LWD sensor measurements are made 20 to 40 meters away from the bit.Integration of these sensors with an RSS resulted in consistent measurements of borehole caliper and the three principal types of downhole vibration (torsional, lateral, and axial), which has helped facilitate comparative analysis of drill bit and BHA performance for different BHAs and wells. Additionally the real-time drilling data was available to a multi-disciplinary drilling optimization team consisting of engineers and researchers. Remote satellite communication and Internet technologies enabled the team to monitor the downhole drilling conditions around the clock and to provide critical feedback to rig site engineers for minimizing vibration-related failures and for improving drilling efficiencies. This paper will discuss the application of real-time near-bit caliper and vibration measurements while drilling with various hole-size RSS. One unique feature of this particular RSS is a shop-configurable point-the-bit or push-the-bit mode, depending upon the application. This paper also shows a comparison of borehole conditions and vibration between point-thebit and push-the-bit modes using an identical RSS, having consistency in stiffness, weight, force applying capability and control system.Through the integrated sensor and team approach, the ability to detect borehole washout conditions and/or BHA instability due to vibration allows RSS operators to take timely remedial action before the occurrence of downhole RSS failure. As a result, the performance and survivability of the RSS has been remarkably improved.

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Coupling of Downhole Dynamics Recorder Enhances System-Matched Approach to Drill-Bit Design and Application With a Specific Rotary-Steerable System

Cited by 20 publications

References 9 publications

Changing Selection Concepts: True Optimization of Drill Bits with Latest Generation Rotary Steerable Systems

Changing Selection Concepts: True Optimization of Drill Bits with Latest Generation Rotary Steerable Systems

The Use of the Industry's First 3-D Mechanical Caliper Image While Drilling Leads to Optimized Rotary-Steerable Assemblies in Push- and Point-the-Bit Configurations

Integrated Approach to Rotary-Steerable Drilling Optimization Using Concurrent Real-time Measurement of Near-bit Borehole Caliper and Near-bit Vibration

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