Bit/rock interface laws in directional drilling

Perneder, Luc; Detournay, Emmanuel; Downton, Geoff

doi:10.1016/j.ijrmms.2012.01.008

Cited by 51 publications

(26 citation statements)

References 32 publications

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“…Deep boreholes often exhibit spiraling patterns (Gaynor et al 2001;Sugiura and Jones 2008;Dupriest and Sowers 2009). One should avoid this drilling dysfunction, observed in many fields independently of the rock formation, the bit type, the drive system, or the borehole geometry, because it is associated directly with low rates of penetration, increased drag, smaller drift diameters, and damage to components and tools (Gaynor et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Influence of Rotary-Steerable-System Design on Borehole Spiraling

Marck

Detournay

2016

SPE Journal

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The paper investigates the influence of the design of push-the-bit rotary-steerable systems (RSSs) on the tendency to drill spiraled boreholes by analyzing the directional stability of the bit trajectory. In this model, differences in RSS designs are accounted for conceptually by assigning a lateral stiffness to the RSS pads. This simple device, which introduces a dependence of the force on the pads upon the deflection of the bottomhole assembly (BHA) relative to the borehole axis, enables exploration of the influence of the actuation mechanism, with the RSS behaving at the ends of the spectrum either as a soft or as a stiff node of the drilling structure.According to this analysis, low pad stiffness has little consequence on the general behavior of the system. However, as the pad stiffness increases, any perturbation in the borehole geometry sensed by the pads alters the drilling direction of the bit and triggers, under certain conditions, self-excited oscillations in the borehole geometry. By increasing the transverse rigidity of the BHA in the vicinity of the bit, stiff RSS pads thus enhance the propensity of a drilling structure to drill spiraled holes and generate, if the system is directionally unstable, borehole oscillations with pitch that corresponds to the distance between the bit and the pads. In contrast, a directionally unstable BHA equipped with RSS characterized by a low stiffness produces spiraled holes with a wavelength corresponding to the distance between the bit and the first stabilizer.

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Section: Introductionmentioning

confidence: 99%

Influence of Rotary-Steerable-System Design on Borehole Spiraling

Marck

Detournay

2016

SPE Journal

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“…The bit/rock interaction law expresses the relations between the force and the moment acting on the bit and the related kinematic quantities (Ho 1987;Perneder et al 2012), defined as penetration per revolution of the bit. The force and moment are decomposed in an orthonormal reference frame (i 1 , i 2 , i 3 ) attached to the bit.…”

Section: Bit/rock Interaction and Definition Of The Drill Bitmentioning

confidence: 99%

“…Fundamentally, these equations capture the geometric feedback coming from the stabilizers, which has been shown to be the main cause of borehole spiraling. Because of some symmetry in the bit/rock interaction (Perneder et al 2012) and in the BHA model for expressions of lateral force and moment, the coefficients of the propagation equations satisfy the constraints…”

Section: Analytical Equations Of Borehole Propagation and Stabilitymentioning

confidence: 99%

“…The force, and especially the moment, acting on a bit must be computed with respect to an arbitrary point of reference along the bit axis of symmetry. In the case of a cylindrical bit whose reference point is chosen to be at the center of the bit face, the general bit/rock interaction law is given by Perneder et al (2012). However if this point is translated to be at the center of gravity of the bit, defined in such a way that the averaged moment with respect to that point is cancelled when the entire gauge interacts with the rock, the bit/rock interaction reduces to where is O(1), and = and Љ are O(10).…”

Section: Bit/rock Interaction Law For An Ideal Cylindrical Bitmentioning

confidence: 99%

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Spiraled Boreholes: An Expression of 3D Directional Instability of Drilling Systems

Marck

Detournay

2015

SPE/IADC Drilling Conference and Exhibition

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The occurrence of borehole spiraling is predicted by analyzing the delay differential equations that govern the propagation of a borehole. These evolution equations for borehole inclination and azimuth are obtained by considering the following three model components: (i) a bit/rock interaction law that relates the force and moment acting on the bit to its penetration into the rock; (ii) kinematic relationships that describe the local borehole geometry from the bit penetration; and (iii) a beam model for the bottom-hole assembly (BHA) that can be used to express the force and moment at the bit from the external loads applied on the BHA and the geometrical constraints arising from the stabilizers conforming to the borehole geometry.The analytical nature of borehole propagation equations makes it possible to conduct a stability analysis in terms of a key dimensionless group that controls the directional stability of the drilling system. This group depends on the downhole weight on bit (WOB), on properties of the BHA, on the bluntness of the bit, and on parameters characterizing its response. The directional stability of a particular drilling system can be assessed by comparing the magnitude of this group with a critical value that depends only on the BHA configuration and on the bit walk. If this dimensionless group, which depends on the actual drilling conditions, is less than the bifurcation value, the system is deemed to be directionally unstable, and borehole spiraling is likely. Stability curves for an ideal BHA with two stabilizers are shown to depend on the bit walk. An application to a field example is discussed. Borehole simulations, based on solving the equations of propagation, also are presented to illustrate that, for unstable systems, the model reproduces spiraled boreholes with a pitch, comparable to what is observed in the field.

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“…[12][13][14][15][16] In spite of progresses achieved, few of the conducted researches have changed the rock-breaking method of PDC cutters that scrape rocks in certain concentric circles. 17,18 Furthermore, with cutters fixed on the bit body, the configuration of the conventional PDC bit is not able to overcome the disadvantages of continuous scraping of cutters.…”

Section: Introductionmentioning

confidence: 99%

Kinematic and bottom-hole pattern analysis of a composite drill bit of cross-scraping

Yang

Zhang

Lian

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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For improving the drilling efficiency of polycrystalline diamond compact drill bit, a novel polycrystalline diamond compact drill bit is presented with a new rock-breaking method named as cross-scraping. In the novel polycrystalline diamond compact drill bit which is referred to as a composite drill bit, polycrystalline diamond compact cutters are mounted on rotary wheels as major cutting elements, and as a result, mesh-like scraping tracks are formed in the outer radial area of the bottom-hole. Rock-breaking method of the composite drill bit causes both shearing and fracture failure of the bottom-hole rock, which will greatly increase the rock-breaking efficiency and will prolong the bit service life. By analyzing the complex motion of cutters on the composite drill bit, velocity and acceleration models of the cutters, as well as wheel/bit speed ratio model of the bit are established in accordance with the geometric relationship between cutters and bit body in a compound coordinate system. In simulation examples, motion tracks, velocity and acceleration features of the cutter and especially the bottom-hole pattern are analyzed. Further, indoor experiments are conducted to test the mesh-like bottom-hole pattern and rock-breaking features, which have proved the accuracy of the analysis model of the composite drill bit.

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Bit/rock interface laws in directional drilling

Cited by 51 publications

References 32 publications

Influence of Rotary-Steerable-System Design on Borehole Spiraling

Influence of Rotary-Steerable-System Design on Borehole Spiraling

Spiraled Boreholes: An Expression of 3D Directional Instability of Drilling Systems

Kinematic and bottom-hole pattern analysis of a composite drill bit of cross-scraping

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