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Operations Manual
DOC #: OPS-FIELD-001 REV: H | PAGES: 61
REV ECR AMENDMENT DETAIL
ORIGINATOR APPROVAL
DATE
A B C
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Draft Version & Initial Release
SB TH TH
RH RH RH
09/21/16 11/28/16 02/19/17
Release to Field
Addition on Flow Restrictor, Bit Break Out Instructions, Update of Field Download Links, and 675 Curve RST Fishing Diagram RST Specification Table Update Updated Pictures for RST Software and WITS Hardware.
D
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TH TH
RH
12/12/17 05/29/18
E
HM
Updated RST Specification
F
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TH
HM HM
11/29/18 04/16/20
Specifications, pictures, hydraulics, formatting, best practices, added RST650 fishing diagram Added the following sections: Real-Time, Low angle steering, TFA Calculator, coming to bottom before downlinking Updated the following sections: Flow Restrictor, RST Components, WITS Decoder, Troubleshooting, Best Practices, Software links, Tool Specifications General updates throughout to reflect current tool specifications and procedures Removed Fishing diagrams
G -
NB, KR
H -
AC
KR
07/01/24
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Confidentiality Statement This document contains
confidential information about D-Tech Rotary Steerable and is intended solely for use by the party to whom it has been issued. Any unauthorized use or the disclosure of information contained in this document to any third party without the prior written permission of D-Tech Rotary Steerable is strictly prohibited.
CONTENTS TABLE OF
Introduction to Rotary Steerable System ...............................................................10
RST BHA Design Theory.......................................................................................10 D-Tech Functionality.............................................................................................10 D-Tech TFA ..........................................................................................................11 D-Tech RST Components ...................................................................................11 Collar ...................................................................................................................12 Stabilizer ..............................................................................................................12 Steering Body ......................................................................................................12 Control Unit (CU) .................................................................................................12 Control Unit Chassis.............................................................................................12 Turbine & Generator Assembly.............................................................................13 Motor & Valve Assembly.......................................................................................13 Pre-Run Information Required .............................................................................13 Motor Setup..........................................................................................................14 Software ..............................................................................................................14 Bit Setup...............................................................................................................15 TFA (Total Flow Area) ...........................................................................................16 TFA Calculator .....................................................................................................17 Using the TFA Calculator......................................................................................17 Using the TFA Calculator Input Data (Excel) .......................................................18 Using the TFA Calculator Output Data (Excel) ....................................................19 Flow Restrictors....................................................................................................20 WITS Decoder .....................................................................................................21
CONTENTS TABLE OF
WITS Cable and Setup ........................................................................................22 WITS Decoder Software Setup ............................................................................22 Smart Phone App ................................................................................................25 RST Operation............................................................................................................27 Picking up / Laying Down of the RST...................................................................27 Make-up Torque Specs........................................................................................27 Breaking the Drill Bit ............................................................................................28 Tool Operations ...................................................................................................29 RST Downlinking Procedure................................................................................29 Downlinking Steps................................................................................................30 RST Operation .....................................................................................................31 Downlinking Steps................................................................................................31 Coming To Bottom Before Downlinking...............................................................33 Steering Modes ........................................................................................................ 34 Open Loop Modes ...............................................................................................34 Magnetic Toolface (MTF) .....................................................................................34 Gravity Toolface (GTF) .........................................................................................34 Demand Percentage.............................................................................................34 Closed Loop Modes ............................................................................................34 Inclination Hold (IH) .............................................................................................35 Inclination Hold R/L (IHR/IHL) ..............................................................................35 Inclination Hold RR/LL (IHRR/IHLL) .....................................................................35
CONTENTS TABLE OF
Inclination Hold 2 (IH2) ........................................................................................35 Vertical Hold (VHOLD) .........................................................................................36 Neutral Mode (NTRL) ...........................................................................................36 Steering Modes - Visual representation of INC Modes .......................................37 Steering Modes (Specifications) ..........................................................................38 Well Section Recommended Steering Modes ....................................................... 39 Vertical & Low Inclination Tangents .....................................................................39 Curve Building/Maximum Yield ...........................................................................39 Horizontal / Lateral Section .................................................................................40 Low Angle Steering .............................................................................................41 Controlling Azimuth at Low Angles ......................................................................41 Controlling Inclination at Low Angles ..................................................................42 Reaming and Circulating .....................................................................................43 Relogging for MWD .............................................................................................44 Off Bottom Circulating .........................................................................................44 Clean up Cycles ...................................................................................................44 Pump or Rig Repair .............................................................................................44 Drill Out of Casing Shoe ......................................................................................45 Appendix A: Suggested Minimum Flow Rate for Tool Sizes ...............................45 Flow Range Operations .......................................................................................45 RPM - D-TECH RST RPM Limitations ......................................................................46
Stick-Slip Vibration Identification ........................................................................46
CONTENTS TABLE OF
Lateral Vibration Identification .............................................................................46 Axial Vibration Identification ................................................................................46 H 2 S Exposure........................................................................................................47 On Location Tool Storage & Maintenance ...........................................................47 Re-Running the D-Tech System ..........................................................................48 Real-Time RST Operations...................................................................................48 RST Message ......................................................................................................49 Inclination ............................................................................................................51 Delta Azimuth ......................................................................................................51 Generator Voltage ................................................................................................51 Collar RPM ...........................................................................................................51 Delta Max Collar RPM .........................................................................................52 Toolface Position Error ........................................................................................52 Mean Motor Current ............................................................................................52 Max Motor Current ..............................................................................................52 Diagnostic Message ............................................................................................53 Downlink Counter ................................................................................................53 Last Downlink ......................................................................................................53 Best practices: Troubleshooting..............................................................................54 Software Troubleshooting ...................................................................................54 Downlinking Troubleshooting ..............................................................................55 Drilling / Steering Troubleshooting ......................................................................56 Lost Circulation Material (LCM) ...........................................................................58
CONTENTS TABLE OF
Appendix A: LCM Recommendations .....................................................................58
Appendix B: Software Download Links ..................................................................59
Appendix C: Tool Specifications ..............................................................................60
Operations Team Contact Information ...................................................................61
Operations Manual
Introduction to the D-Tech Rotary Steerable System Founded in 2007,D-Tech set out to deliver an economical rotary steerable solution to operators and Directional Companies. In late 2014, The D-Tech Rotary Steerable System commercially entered the US Land market and as of 2024, is currently on its fifth iteration, with over 100 design improvements. The current tool fleet comprises 5 7/8 in. (149.225mm) to 18 1/8 in.(460.375mm). D-Tech’s low-risk, high-return rotary steerable tool was engineered to meet and overcome drilling challenges, with an emphasis on reliably reaching total depth quickly, accurately, and with reduced financial risk. RST BHA Design Theory The three points are the bit, the steering body, and the top stabilizer, which must always be to a minimum of 1/8 under hole gauge and spiral wrapped for wellbore contact. The variability in steering geometry comes from the steering body which is constantly rotating at the same speed as the total bit RPM. If running separate string stabilizers above the RST tool, it is best practice to choose non-magnetic spiral stabilizers with the shortest tong end possible. Overly long tong ends affect the geometry and have a negative impact on steering efficiency. D-Tech has run many BHA combinations over the years and will work with the client to recommend the best BHA design for the application. D-Tech Functionality The D-Tech Rotary Steerable Tool operates as a push-the-bit system. The tool utilizes six hydraulically activated pistons in pairs, 120 degrees apart, to push against the wellbore and drive the BHA in the desired direction. The pistons achieve force by diverting a percentage of the drilling fluid into the pistons. A bit pressure drop is calculated to generate the force at pistons by creating a difference in pressure from inside the D-Tech tool and the annulus. The tool is powered by a turbine generator with no additional batteries required. The tool is fully rotated at bit RPM, and there are no slow rotation components in the tool.
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Operations Manual
D-Tech Total Flow Area (TFA) The D-Tech Rotary Steerable tool is designed to operate at a predefined pressure drop dependent on tool size. This is a vital part of the functionality of the D-Tech tool and a 10% change in TFA can have as much as a 25% change in the force of the pistons. The pressure drop is achieved by setting the bit TFA to a calculated value. Depending on tool size, the target TFA pressure drop will be 500 or 600 psi. This allows the steering body pistons to generate the necessary force to steer the well path, alternatively an internal flow restrictor may be added to provide an additional internal pressure drop. D-Tech RST Components The D-Tech Rotary Steerable tool has three main external components (collar, stabilizer, and steering body) and three main internal components (control unit chassis, turbine/generator assembly, and motor valve assembly) see Figure 1.
Figure 1
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Collar – All D-Tech RST tool sizes use a proprietary collar to house the internal electronics of the tool. The collar is made of Non-Magnetic Alloy, similar with that used on most MWD tools. The collars meet all BSR (Bending Strength Ratio) guidelines recommended by the American Petroleum Institute and TH Hill and Associates. Stabilizer – The D-Tech Rotary Steerable utilizes a stabilizer to complete the 3-point geometry, using either a stabilizer sleeve incorporated into the collar or a separate stabilizer sub above the control collar, dependent upon tool size and configuration. A 1/8 in. under hole gauge spiral non-mag stabilizer is recommended to ensure the RST remains centralized in the wellbore. Steering Body – All D-Tech tools share a common push-the-bit style steering body with six pistons. The pistons receive 5 to 11% of the drilling fluid which is bypassed and diverted to each bank of pistons by the motor valve assembly. The steering body pistons are arranged 120 degrees radially allowing for 360-degree directional control. The steering body is a purely mechanical unit, no electronics are housed in the assembly. Control Unit – The D-Tech control unit (CU) consists of the chassis, turbine, generator assembly, and motor valve assembly, housed inside a pressure case and installed inside the RST collar. The CU is utilized across all tool size and only changes to the turbine, internal stabilization anchors, and motor are required for tool size configuration. Control Unit Chassis – The CU chassis houses a full directional package with 3 tri-axial accelerometers and magnetometers, a processing unit, and power supply unit. The tool measures and records relevant information such as turbine speed, inclination, shock, vibration, and other tool specific data. The CU chassis has a single 1.5v lithium battery to record a time stamp to memory and has no impact on tool function or service delivery.
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Turbine and Generator Assembly – This assembly supplies power to the RST, it uses the energy of the drilling fluid to spin the turbine at an engineered speed to generate the required power to the RST system. Each RST size has a range of turbine impeller designs to cater to the appropriate flow range for the tool. It is recommended to run a downhole filter sub to limit debris from damaging the turbine/generator assembly. Motor Valve Assembly (MVA) – The MVA attaches directly onto the steering body and directs 5 to11% of the drilling fluid depending on tool configuration into the flow galleries to achieve force at the pistons. The assembly contains a brushless DC motor which orients the valve to the required position as calculated by the CU chassis. Pre-Run Information Required 1. Hole Size – in inches or milometers 2. Mud Weight – TFA calculations require the planned mud weight for the well. It is recommended to run all calculations off the maximum mud weight for the well. If mud weight changes, flow rate will need to be adjusted to maintain maximum force at the pistons. 3. Flow Rate – minimum and maximum planned flow rates. What will be the flow rate at the beginning of the run and at the end of the run? It may be necessary to reduce starting flow rate to allow for reduced flow at the end of the run or during lost circulation operations. 4. Motor Bypass – If the run is motor assisted, an anticipated motor bypass must be accounted for. It is important to verify whether the motor is mud lubed or seal bearing. Work with the motor provider to get an accurate motor bypass. 5. Bit Information – Certain information about the bit is needed as well for calculating the bit TFA, the number of jets as well as any fixed ports.
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Motor Setup The D-Tech tool does not require a downhole motor for the RST to function; however, it is recommended that mud motors are used in all applications. Mud motors are powerful, efficient tools to aid the drilling of wells and are continually increasing in reliability. D-Tech recommends the use of mud motors for three main reasons. 1. Minimize the effects of vibrations and stick-slip which is dangerous and challenging for RST tools. 2. Increase the energy at the bit; thus, increasing the ROP and improving the economics of the system. 3. Drill bits are generally designed for higher RPM and many drilling contractors will not operate their top drive or rigs at speeds over 180 RPM.
D-Tech has a general set of guidelines for mud motor configuration.
1. Fixed straight housing. 2. Slow speed / high torque power section. 3. Pin down extended mandrel (the use of pin x pin crossovers is also acceptable) Software D-Tech has developed a suite of user-friendly software solutions for both the field staff on location, and office-based personnel. The software is designed to be simple and effective to use and can be installed on almost any user’s smart phone, tablet, or PC. When beginning a new job, be sure to re-download the latest versions of the D-Tech software and apps. See Appendix C for software links.
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Bit Setup Push-the-bit RST systems require a certain style of drill bit in order to steer the well effectively. We continue to work with all the major bit providers to offer a drill bit best suited for application with the system. Our standard guidelines for PDC bit selection are: 1. Short gauge length – 2 in. for RST 475/500, 3 in. for RST 650/675, 4 in. for RST 800/900. 2. Passive cutting structure. Active gauge bits are not recommended with the D-Tech tool. 3. No vertical seeking features. 4. Medium size cutters. 5. 5, 6, or 7 blades – More blades = less susceptible to stick-slip, however ROP may be compromised. 6. Bits with depth of cut control/torque arresters have been proven to help alleviate stick-slip in RST applications. The use of these is recommended. 7. Preferred cone angle – low/med, avoid bits with a deep cone angle. 8. Avoid bits with “High force”/high back rake gauge cutters.
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TFA The TFA of the drill bit is critical for the operation of the D-Tech RST system. The tool operates with a specific pressure drop across the BHA. If this pressure drop is not achieved, then the RST system will be underpowered and will produce unpredictable and erratic steering results. All of D-Tech's runs to date have been with PDC technology bits. Rock bits have shown to work well with push-the-bit rotary steerable systems and we see no issue running with a tri-cone style rock bit.
Steps to ensure proper TFA.
1. Select the correct bit for the application, identify the nozzles and fixed ports. 2. Determine the mud weight that you will be drilling with (careful consideration needs to be taken if the mud weight is expected to increase greatly throughout the section). 3. Determine the flow rate required during the run. 4. Use the D-Tech TFA Calculator software to calculate the TFA and the usable flow range for the run. Each RST tool size has an optimal required pressure drop, see table below, staying in the upper range will produce increased steering force. In order to achieve the recommended pressure drop, the tool requires a smaller TFA than typical directional drilling without an RST system. Taking time to understand the application and limitations of the drilling rigs hydraulic delivery system are crucial in setting a correct TFA for the operation.
Tool Size
Pressure Drop Required
RST 475/500 RST 675/650 RST 800/900
520 to 640 psi 500 to 620 psi 430 to 520 psi
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TFA Calculator For the D-Tech Rotary Steerable to generate the required piston force, a bit pressure drop is needed. This is achieved by adjusting the Bit TFA. There is a difference in pressure from the inside of the RST piston to the outside of the pad/piston in the annulus and, depending on which RST size you are utilizing, the required pressure drop will vary. Using the TFA Calculator – Figure 2 The simple to use D-Tech TFA Calculator software is used to calculate the correct bit TFA for the run and provides the RST usable flow range for the run. Hydraulic data can be easily recalculated to suit any operational scenario that may arise throughout the run. 1. Select the hole size in inches – This automatically populates the correct RST tool size as well as the target pressure drop. 2. Complete the operations panel – If a range in flow rate or mud weight is expected to be used during the job, input the highest likely values. 3. Input the number of nozzles in the bit, and click on the Find TFA button. 4. The recommended TFA will be shown, to get as close to but not exceed the target pressure drop. 5. The usable flow range is shown in the right panel, with a graph showing the expected pressure drop throughout the range. The usable flow range is calculated with a pressure drop tolerance of 20% - Be aware that steering performance may be affected as the pressure drop decreases.
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Figure 2
If adjustments to the TFA or any other parameters need to be made, click on the Calculate button to see the impact that this has on the pressure drop and usable flow range without recalculating the TFA.
Using the TFA Calculator Input Data (Excel) – Figure 3
Figure 3
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As with the TFA Calculator, the excel version will have specific criteria that will need to be filled out.
1. Tool Size 2. Hole Size
3. Motor Bypass – 8% is recommended for most applications to allow for parasitic losses seen in the mud system on most rigs (pump inefficiency or motor wear over the entirety of the run.) 4. Flow Restrictor – If a restrictor is not utilized put 0. 5. Viscosity – Enter funnel viscosity time and cP will auto calculate. 6. Mud Weight – Recommended to use highest mud weight anticipated. 7. Flow Rate – Recommended to target a flow rate near the anticipated flow rates seen at the end of the well/section.
PLEASE CONTACT D-TECH OPERATIONS TO REVIEW TFA BEFORE OPERATING THE TOOL
Using the TFA Calculator Output Data (Excel) – Figure 4
Figure 4
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1. Tool information – Minimum and maximum flow rate, fluid velocity, HSI. 2. Flow Rate Range – The graph of operational range for flow rates. 3. GPM Range – Mud weight changes and the corresponding flow rate changes. 4. Max Pressure/Target Pressure – Max pressure recommended, and the target or calculated pressure drop. It is recommended that target pressure does not exceed 5% of max pressure drop. Flow Restrictors The combination of lower-than-normal flow rates with lighter mud weights make it difficult to generate the required pressure drop from the bit nozzles, in this instance D-Tech can provide flow restrictors which can be inserted into the bit box end of D-Tech Tool. The flow restrictor will lower the pressure drop requirement across the bit which in turn will allow the bit TFA to be increased. The use of flow restrictor is dependent upon the well hydraulics and drilling program. The D-Tech Operations team will determine whether a flow restrictor is required, and which size is appropriate. Below are the steps for inserting the flow restrictor. If it is likely that a flow restrictor is required, it must be requested as early as possible to ensure availability for the run. Note – Currently D-Tech provides flow restrictors for all tool sizes. Careful consideration to downlinking flow rates should be taken when running in lo flow situations. 1. Select appropriate flow restrictor kit, each tool size has a designated flow restrictor sleeve and various sized carbide inserts, see Figure 10 2. Make up the flow restrictor using the required O-rings, ensure the carbide insert is secured using spiral clip. 3. Insert the narrow side of the flow restrictor into the steering body box end. 4. Use the handle of a mallet or hammer to tap the flow restrictor securely into place.
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5. Once the flow restrictor is in place, re-insert the thread protector. 6. Note - Some NOV drill bits have a larger ID on the pin which may make it possible for the flow restrictor to fall into the drill bit while drilling. Make sure when on the rig floor that the thread protector is not removed until well hole is covered.
Figure 5
WITS Decoder The WITS decoder monitors live rig data and is used to confirm that a downlink sequence was carried out correctly. It is also used to transmit RST information via the internet to off-site operations personnel. The WITS decoder can be installed on any windows-based PC and requires a WITS feed containing live drilling data. While the WITS decoder is not required to operate the D-TECH tool, however it is highly recommended. The WITS decoder has the same algorithms that the downhole RST tool has in its Control Unit and is always looking for a possible downlink sequence and displays the most recent downlink sent to the tool.
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WITS Cable and Setup D-Tech has developed a custom WITS cable ( Figure 6 ) to transmit data from the WITS feed source to the WITS decoder, see image below, this can be used to also split/share the WITS feed with another PC. If the WITS feed is to be shared, then the red switch on the splitter box should be in the ON position.
Figure 6
WITS Decoder Software Setup 1. Open the WITS decoder on the Windows PC. 2. Select the communication tab and verify that the USB port is connected to the WITS feed on location. 3. Select the appropriate com port number and click ‘Open’ under step 1 on the screen. 4. Select the ‘write frequency’ to 10 seconds. This will not affect the operation of the program at the rig site. 5. On the right side of the window check the box ‘Show Wits Feed‘ a. Data will begin to scroll in the open area on the right. IF DATA IS NOT DISPLAYED CONTACT D-TECH SUPPORT BEFORE MOVING FORWARD.
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6. Enter the 6-digit run code provided by the D-Tech operations team, and click connect, if successful “connected” will be displayed. If it does not, check that the run code is correct and verify that the computer is connected to the internet. Some Wi-Fi networks have firewalls which block the connection, try a different network if available. 7. You should now see the status under the WITS data feed displaying ‘Success’ and a data process time. 8. Under the hydraulics section, enter the tool size from the drop-down menu. 9. Add the TFA, mud weight in ppg, flow restrictor if used (0 if no restrictor is used), and the motor bearing loss. (Refer to Figure 7) 10. In the Misc section, click "Enable Pump 3." If three pumps are being used, click handshake if the WITS feed is from a source that requires a handshake to remain open, for example Pason EDR. 11. If running without an MWD system, the button on the top of the wits box will need to be moved to the ‘On’ position and the ‘Handshake’ box in the bottom left needs to be checked. 12. If the rig is configured with 3 pumps ‘Enable Pump 3’ by checking the box. IF THIS IS NOT CHECKED DOWNLINK DECODING WILL NOT WORK CORRECTLY 13. Move to the WITS Decoder Tab. For the data to populate, you will need to fill in all the grey boxes on the screen with data. 14. Under ‘Operation’ from the pull-down menu select the current operation 15. Now fill in the run number, BHA number and the motor rev/gallon, put 0 if not running a motor. Once these are selected the logging box should change from Off to On (Refer to Figure 8)
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Figure 7
Once you begin pumping across the tool, the other status boxes will change from red to green indicating the WITS decoder is looking for downlinks. The WITS software will calculate the RST pressure drop and the piston force of the tool you have in the hole. If the piston force is green, you are producing the necessary force on the pads to steer the well, if the piston force is yellow or red you are below the recommended pressure and flow required to effectively steer the well. This does not mean the tool will not steer, just that the tool is not operating as efficiently as it was set up for. While performing a down link, the WITS Decoder will calculate the safety factor for the down link. The safety factor is the percentage of flow rate above the point at which the tool will be powered down. The safety factor uses the tool type/size, the lowest flow rate during the down link, and the motor bearing loss. THE SAFETY FACTOR SHOULD REMAIN ABOVE 10% FOR ALL DOWN LINKS TO ENSURE THE DOWN LINK WAS RECEIVED BY THE TOOL.
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Figure 8
Smart Phone App The D-Tech smart phone app is available for Android and Apple products. This app is the primary software application users of the D-Tech tool will need. The app is available for download at the link in Appendix C and works with all modern smart phones. To use the app, complete the following instructions:
1. Download the app to your phone and open the application.
2. Select your drilling flow rate at the top of the page, then your steering mode, and complete the boxes relevant to the desired mode and press the calculate button. THIS WILL TAKE YOU TO THE DOWNLINK INSTRUCTIONS PAGE WHERE YOU CAN SEE THE SEQUENCE AND TIMING REQUIRED TO SEND THE DOWNLINK TO THE TOOL.
3. Click the ‘Auto Down-Link’ button and it will take you to the timing sequence page.
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4. When ready, and after the pumps have been on and pressure has stabilized for 90 seconds, press the Start button and follow the procedure to send a downlink to the tool. For best downlink practices See Appendix E for Best Practices Note – Remember to check your WITS decoder to verify that the downlink was transmitted properly. Note – If it is required to lower the flow rate for any reason outside of down linking, it is best practice to shut down the pumps and then bring the pumps up to the new flow rate.
Figure 9
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RST Operation Picking up / Laying Down of the RST
The D-Tech tool requires no formal rig up or on-site testing prior to running the tool. The rig operations team should verify the TFA in the bit matches the recommendations, that the WITS decoder is up and running, and that there are no issues with the rig equipment that could interfere with the operation of the D-Tech tool. Make-up Torque Specs The D-Tech tools uses standard API connections on the top and bottom of the tool. The tool should be made up just as any other tool on the rig but paying attention to keep the tong jaws away from the steering body. (Refer to Figure 10).
Connection
Description
Recommended Torque
7 – 9 klb (9.5 – 12.2 kNm) 9 – 11 klb (12.2 –14.9 kNm) 16 – 18 klb (21.7 – 24.4kNm) 28 – 32 klb (37.9 – 43.4kNm) 28 – 32 klb (37.9 – 43.4kNm) 54 – 58 klb (73.2 – 78.6kNm)
1 3 ½ Reg
D-Tech RST 475/500 Bit Box Connection
2 3 ½ IF
D-Tech RST 475/500 Top Connection
3 4 ½ Reg
D-Tech RST 650/675 Bit Box Connection
4 4 ½ IF
D-Tech RST 650/675 Top Connection
5 6 5/8 Reg
D-Tech RST 800/900 Bit Box Connection
6 6 5/8 Reg
D-Tech RST 800/900 Top Connection
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Place rig tongs above connection
Figure 10
Breaking the Drill Bit Place the tongs above the steering body to collar connection and attempt to break the drill. If the drill bit will not break, the tongs can be placed on the steering body if the RST is not being reran. Before attempting to break the bit using the tongs on the steering body, make a mark across the collar to steering body connection to ensure it is not being un-torqued. Refer to Figure 11.
Figure 11
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Tool Operations Standard operation of the D-Tech tool will consist of setting a desired flow rate and RPM range and drilling ahead while monitoring surveys being taken by the MWD tool. As deviation occurs or is required, the operator will send an appropriate steering mode to the RST tool via a downlink. Different steering modes are available to achieve directional goals as the well is drilled, however it is important to establish a baseline performance for the tool early in the well. Rotary Steerable tools respond differently to many different factors. Bit selection, BHA design wellbore lithology, ROP, WOB, flowrate, and vibration (stick-slip) all have impact on the performance of the tool. It is important to monitor these parameters to ensure consistent and repeatable performance. Appendix X will have more detailed best practices to review for most applications. If you have any concerns about tool functionality, please contact D-Tech Remote support at +1 832-409-4711. They can also be reached on WhatsApp. RST Downlinking Procedure All D-Tech tools will arrive on location pre-programmed with all steering modes available. The RST uses a simple and robust system to change steering modes, commands are sent by reducing the flowrate by 15-25% and returning to the drilling flowrate in a timed sequence to create a series of pulses. All personnel involved in the downlinking process, the DD, driller etc, should be made aware of the process to ensure the downlink is carried out correctly. There are two types of downlink, circulating downlink and drilling downlink, they are both identically performed the only difference being a circulating downlink is off-bottom, and a drilling downlink is on-bottom. IT IS RECOMMENDED TO PERFORM DOWNLINKS ON BOTTOM AS MUCH AS POSSIBLE TO REDUCE SHOCK AND VIBRATION ACROSS THE BHA.
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Downlinking Steps 1. The full downlink sequence will be shown, including the timing required between each change of flowrate. 2. Press Auto Down-link to display a list of downlink instructions. 3. To ensure the downlink is received by the RST the instructions displayed must be followed. Downlinks are commonly sent after a survey has been taken, therefore the pumps would have been cycled and been up for 2 minutes. If there is any doubt that the instructions have not been followed, recycle the pumps and wait 2 minutes before downlinking. 4. Press continue when ready to begin the downlink. 5. The current total time for the downlink is shown at the top of the page as well as the current flowrate. Each downlink requires 8 alternations between the two flowrates creating 4 reductions in flow rate, the pulse number shows the current stage of the downlink. The time until the next change in flowrate is shown, when there is 15 seconds remaining a notification will sound on the phone. 6. Press start when ready to begin the downlink and follow the sequence alternating between flowrates when directed. Before starting the downlink process put the smartphone into Airplane mode if possible, to avoid the process being inte rrupted. 7. If the downlink needs to be restarted press stop, the app will remind you to shut the pumps down for 30 seconds before restarting. 8. After each downlink look at the EDR data there should be 4 uniform pulses dropping 25% from the drilling flowrate. 9. Use WITS decoder/viewer to confirm that the correct downlink sequence was performed. 10. Once weight on bit begins to increase indicating bottom has been tagged, increase drilling parameters to desired levels. 11. Check differential pressure on EDR chart, if a large increase is seen when going to bottom, it is likely that the flow to the turbine has been disrupted.
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RST Operation
1. Open the D-Tech Smartphone app, the first page displayed is titled Steering. Input the drilling flowrate, the app will then display the downlink flowrate required. The app will only calculate a 25% drop in flow. If a lower drop in flow is required manually calculate the flowrate to be used. 2. Input the type of RST that is downhole, and the desired steering mode details. 3. Press Calculate to be taken to the downlink sequence page.
Downlinking Steps 4. The full downlink sequence will be shown, including the timing required between each change of flowrate. 5. Press Auto Down-link to display a list of downlink instructions.
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6. To ensure the downlink is received by the RST the instructions displayed must be followed. Downlinks are commonly sent after a survey has been taken, therefore the pumps would have been cycled and been up for 2 minutes. If there is any doubt that the instructions have not been followed, recycle the pumps and wait 2 minutes before downlinking. 7. Press continue when ready to begin the downlink. 8. The current total time for the downlink is shown at the top of the page as well as the current flowrate. Each downlink requires 8 alternations between the two flowrates creating 4 reductions in flow rate, the pulse number shows the current stage of the downlink. The time until the next change in flowrate is shown, when there is 15 seconds remaining a notification will sound on the phone. 9. Press start when ready to begin the downlink and follow the sequence alternating between flowrates when directed. Before starting the downlink process put the smartphone into Airplane mode if possible, to avoid the process being interrupted.
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10. If the downlink needs to be restarted press stop, the app will remind you to shut the pumps down for 30 seconds before restarting. 11. After each downlink look at the EDR data there should be 4 uniform pulses dropping 25% from the drilling flowrate. 12. Use WITS decoder/viewer to confirm that the correct downlink sequence was performed.
If any unexpected fluctuations in standpipe pressure, differential pressure, or flowrate are observed before or during the downlink, this may result in the downlink being missed or an incorrect steering mode interpreted. If there is any doubt regarding the downlink sequence sent, recycle the pumps and return to drilling flowrate for 90 seconds before resending the downlink. Coming To Bottom Before Downlinking Tagging bottom after a connection at a rate greater than 150 ft/hr can cause disruption to the flow rate seen at the generator impeller prematurely inducing a downlink command. If a downlink is to be carried out the following guidelines should be followed. 1. Bring BHA 1-2 ft from bottom, engage rotary to desired RPM, and set ROP limiter on auto driller to a maximum of 150 ft/hr (45 m/hr). Zero weight on bit as required. 2. Once weight on bit begins to increase indicating bottom has been tagged, increase drilling parameters to desired levels.
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3. Check differential pressure on EDR chart, if a large increase is seen when going to bottom, it is likely that the flow to the turbine has been disrupted.
Steering Modes
Below is a detailed description of all D-Tech steering modes available.
Open Loop Modes – Open loop steering modes are used to define where the user determines how much input is required to achieve desired steering. This is done by setting a steering percentage and targeted toolface. The D-Tech tool has 2 open loop modes for the user. In the open loop modes, the user will determine a steering percentage required to meet the directional requirement. Magnetic Toolface (MTF) – In MTF mode the user will select a desired toolface target from 0-345 degrees in 15-degree increments and a command percentage from 20-100% in 20% increments. This is the recommended mode to kick off from vertical. However, the tool is not internally corrected for magnetic declination; this should be noted when working in high declination areas and the targeted toolface will need to be accounted for. Gravity Toolface (GTF) – In GTF mode the user will select a targeted toolface from 0 to +/- 180 degree in 15-degree and a command percentage from 20-100% in 20% increments. This is the recommended mode when steering above 20 degrees inclinations and MTF should be used up to 20 degrees inclination. Demand Percentage – Demand percentage is used to tell the tool how often it should steer not the force of the pads. Demand is based on a 5-minute drilling cycle, if you set the tool for 40% demand the tool will steer for 2 minutes out of the 5-minute cycle and the rest of the time the tool will function in neutral. Closed Loop Modes – A closed loop mode operates independent of user input, this is best described as goal seeking . The user will set a targeted goal for the tool to achieve where the tool will determine toolface placement and steering percentage to achieve the set target/goal. These modes are your inclination and azimuth seeking modes.
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Inclination Hold (IH) – In IH mode the user will select an inclination target mode and the tool will steer in gravity at 0 or 180 (up/down) to reach that inclination and stay within 0.5 degree of the target inclination. When the tool is within 0.5 degrees of the targeted inclination the tool will operate in Neutral until deviation of target is greater than 0.5 degrees. Inclination Hold R/L (IHR/IHL) – In IHR / IHL mode the user will select an inclination target and the tool will steer at tool -30 and -150 or 30 and 150 to hold inclination and turn the BHA left or right. For example, when in IHR the tool will steer constantly to achieve the inclination target but at a toolface of 30 right or 150 Right. Effectively, the tool is working to steer right and maintain a targeted inclination. The same holds for IHL where the toolface will be 30 left and 150 left. Inclination Hold RR/LL (IHRR/IHLL) – In IHRR / IHLL mode, the user will select an inclination target, and the tool will steer at toolface -60 and -120 or 60 and 120 to hold inclination and turn the BHA left or right. For example, when in IHRR the tool will steer constantly to achieve the inclination target but at a toolface of 60 right or 120 Right. Effectively, the tool is working to steer right and maintain a targeted inclination. The same holds for IHL where the toolface will be 60 left and 120 left. Inclination Hold 2 (IH2) – In IH2 mode the RST will steer to hold the current azimuth as well as a targeted inclination. Like the other INC Hold modes, the user sets an inclination, but at the completion of the downlink the tool will record its current azimuth. As the BHA deviates from targeted inclination and azimuth the tool will determine the optimal toolface at 1 degree resolution to steer back to target. The tool will target prioritizing the greater deviation between inclination and azimuth. IH2 works better at close to horizontal or lateral sections but has been shown to also work in high angle tangents.
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Vertical Hold (VHOLD) – In VHOLD mode, the tool will actively steer the wellbore to a vertical inclination when the inclination the tool records is over 0.5 degree. The tool continuously steers to vertical but does not seek out a specific coordinate, if the desired goal is to stay directly under the surface location, magnetic steering may be required to bring the well back under the well head in highly deviated formations. Neutral Mode (NTRL) – In NTRL mode the tools valve turns freely, not allowing the pistons to extend with the necessary force or at a target toolface to deviate the BHA. NTRL mode is used for tool transport and for drilling the shoe, tripping, and extended reaming operations.
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Steering Modes - Visual representation of INC Modes
INC HOLD
HS
INC HOLD R
INC HOLD L
30L
30R
INC HOLD LL
INC HOLD RR
60L
60R
60R
90L
90R
120L
120R
INC HOLD RR
INC HOLD LL
150L
150R
INC HOLD L
INC HOLD R
LS
INC HOLD
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Steering Modes (Specifications)
Level of Degree
Steering Percentage
Loop System
Steering Mode Toolfaces
0 to 100% in 20% increments
Magnetic Steering
0 to 20°
Open Loop
0 to 345° in 15° increments
Gravity Steering
0 to +/- 180° in 15° increments
20 to 120°
0 to 100% in 20% increments
Open Loop
High side or 180° Gravity TF
20 to 120° in 1° increments.
Internally Determined by the RST
Closed Loop
Inclination Hold
30° or 150° Gravity TF if steering Right. -30° or - 150° Gravity TF if Steering Left 60° or 120° Gravity TF if steering Right. -60° or - 120° Gravity TF if Steering Left Determined Internally by the RST based upon the formation walk rate and build rate
20 to 120° in 1° increments.
Internally Determined by the RST
Closed Loop
Inclination Hold L/R
Inclination Hold LL/ RR
20 to 120° in 1° increments.
Internally Determined by the RST
Closed Loop
20° to 100° in Increments of 1°
Internally Determined by the RST
Closed Loop
Inclination Hold 2
High side or 180° Gravity TF
Maintains an Inclination of less than 1°
Internally Determined by the RST
Closed Loop
Vertical Hold
Closed Loop
Neutral
Non-Applicable
Non-Applicable
Non-Applicable
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