Drilling Vibration Monitoring and Control System

Project Number

DE-FC26-02NT41664

Goal

Improve the rate of penetration and reduce the incidence of premature equipment failures in deep hard rock drilling environments by reducing harmful drillstring vibration.

Performer(s)

APS Technology, Inc., Cromwell, CT 06492

Background

Drilling through the hard rock formations encountered in deep wells can often lead to severe and potentially damaging vibration of the drillstring. Vibration can be axial (up and down), lateral or torsional (where the drillstring momentarily stops and then spins free, called stick-slip or bit whirl). Vibration that causes the bit to bounce against the sides or bottom of the hole can cause premature bit or drillstring failure and low rates of penetration. One way to control this vibration is to adjust the rotary speed and weight on bit (WOB), but this can also have a negative effect on drilling efficiency. Shock subs (downhole shock absorbers run as part of the drillstring’s bottomhole assembly) can help, but these are designed for one set of conditions and can be ineffective or even counterproductive when conditions change.

The Drilling Vibration Monitoring and Control System (DVMCS) design is composed of two elements. The monitoring element is a real-time system to monitor three-axis drillstring vibration, and related parameters including weight- and torque on-bit and temperature. This monitor will determine the vibration environment and adjust the vibration damper component accordingly. The shock attenuation system is a multi-axis active vibration damper that incorporates a spring and a magnetorheological (MR) fluid that allows continuous adjustment of the damper’s hydraulic impedance (hardness). The DVMCS, when completed, will sense the magnitude and character of drillstring vibration and adjust the damper response by varying the MR fluid viscosity. The damper will be able to react to variations in drillstring vibration magnitude and character in real time, optimizing its ability to maintain bit contact with the bottom of the hole and minimize damaging vibration effects.

Results
To date, this project has produced the following results:

Carried out a review of the major sources of vibration likely to influence the bottom hole assembly (BHA) and in particular the bit, and characterized them by their anticipated frequency and amplitude;
Developed a software model to analyze drillstring axial vibration and determine optimal damping action;
Developed a method to directly quantify the various vibration modes using a system of four accelerometers and a magnetometer mounted in a sensor sub of the damper component;
Completed overall tool design and prepared the specifications for manufacture of the mechanical components, circuit boards, software and test bench;
Tested a prototype damper assembly and demonstrated that it can provide the required range of damping coefficients with acceptable power levels;
Calculated the damping coefficient over a range of operating values;
Designed, assembled and laboratory tested field prototype;
Tested laboratory prototype in commercial drilling laboratory and analyzed data. The tests were deemed successful and show significant promise for the development of a pre-commercial DVMCS prototype in Phase III;
Completed Phase II final report;
Designed and built three pre-commercial protoypes. These prototypes are currently undergoing field testing;
Signed development-distribution contract with major oilfield supply company;

Benefits
The DVMCS will significantly reduce the vibration at the bit and through the entire BHA. This, in turn, will provide significant improvements in the efficiency of the drilling process through several mechanisms: By keeping the bit from bouncing, the drilling process can proceed 100% of the time, rather than intermittently.

By adjusting the stiffness of the damper, the weight actually applied to the bit (WOB) can be maintained in the optimal range, enhancing the efficiency of drilling, and increasing the rate of penetration (ROP).

By reducing the harmful effects of shock and vibration in the drillstring, the attenuation and velocity dispersion (AVD) will reduce the likelihood of costly failures of components including drill bits, motors, and expensive measurement-while-drilling (MWD) systems.

All of the current means of intervention are essentially passive systems or require operator intervention. These include a number of means to measure bit bounce and downhole vibration, and some even include systems to transmit the data to the surface. There are also downhole systems to dampen shock in known, specific environments (shock subs.) Finally, there is the traditional recourse of the driller’s skill at detecting adverse conditions through the feel of the brake and making intuitive changes to the perceived conditions. All of these methods provide some level of relief in particular environments; none works everywhere and none is universally applicable. The DVMCS offers the first approach that will monitor downhole vibration and act to reduce it in an autonomous closed-loop system without intervention from the surface.

Drilling laboratory tests have shown that the use of the DVMCS can provide significant increases in ROP, particularly in hard rock drilling where the vibrations are most severe. The most attractive area for use of this system is in deep drilling, since the benefits of improved penetration rates and longer bit runs increase significantly when round trip times become very large. Once proven, however, the benefits of the DVMCS will more than justify its use over a wide range of drilling operations.

Overall, by reducing the costs and time required to drill deep wells, the DVMCS will make the economics of deep drilling more attractive. This will enable the exploitation of deep reserves that may not be feasible today.

Summary
Significant accomplishments under Phases I and II were carried forward into Phase III: Characterization and modeling of the major sources of vibration at the bit led to the determination of an optimal damping action and development of a method to directly quantify the vibration modes and provide a dampening action. A tool to accomplish this was designed and a prototype damper assembly tested and successfully demonstrated. In Phase III, three pre-commercial protoypes were built and are undergoing field testing. In addition, APS has signed a development-distribution contract with a major oilfield supply company;

Current Status

(December 2008)
The project has been completed. The final report is available below under "Additional Information".

Project Start

Tue, 10/01/2002 - 12:00