Assessment of relationships between drilling rate index and mechanical properties of rocks

2013 ◽  
Vol 33 ◽  
pp. 46-53 ◽  
Author(s):  
Olgay Yarali ◽  
Eren Soyer
Keyword(s):  
Mechanical Properties ◽  
Drilling Rate ◽  
Drilling Rate Index

Evaluation of physical and mechanical properties of rock for drilling condition classification

2013 ◽  
Vol 10 (4) ◽  
pp. 359-366 ◽  
Author(s):  
B. Adebayo ◽  
B. Adetula
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Point System ◽  
Drilling Rate ◽  
Quartz Content ◽  
Drilling Condition ◽  
Drilling Rate Index

This work deals with the investigation of physical and mechanical properties of selected rocks for condition of drilling categorization. Rock samples collected from five drilling locations were tested in the laboratory for uniaxial compressive strength, tensile strength, and Drilling Rate Index (DRI) using 1,100 kN compression machine, point load tester and miniature drill. Similarly, hardness, brittleness, Rock Abrasivity Index (RAI), penetration rate and bit wear rate were determined. The results showed that uniaxial compressive strength, tensile strength and Drilling Rate Index varied from 47.78 - 111.11 MPa, 8.09 - 19.44 MPa, and 20 - 52 respectively. The Nast point system chart was used to classify the rocks into drilling conditions. The drilling classification shows that the drilling condition of the rocks varied from slow to fast. The drillability characteristics of the rocks vary from extremely low to medium as specified by the Drilling rate Index (DRI). It was concluded that uniaxial compressive strength, texture and grain size, drilling rate index and Equivalent Quartz Content (EQC) are important parameters affecting drilling condition of the rocks.

A Theoretical Description of Rotary Drilling for Idealized Down-Hole Bit/Rock Conditions

1969 ◽  
Vol 9 (04) ◽  
pp. 443-450 ◽  
Author(s):  
Paul F. Gnirk ◽  
J.B. Cheatham
Keyword(s):  
Mechanical Properties ◽  
Rate Equation ◽  
Chip Formation ◽  
Confining Pressure ◽  
Drill Hole ◽  
Differential Pressure ◽  
Drilling Rate ◽  
Rotary Drilling ◽  
Rock Interaction ◽  
Rock Bit

Abstract The results of combined analytical and experimental studies involving simulated multiple bit-tooth penetration into rock are incorporated into a drilling rate equation for roller-cone bits assuming rather idealized downhole conditions. In particular, it is assumed That the rock behaves statically in a ductile fashion during bit-tooth penetration and that the rock chips are instantaneously removed from the bottom of the drill hole. The general analysis demonstrates an application of plasticity theory for the rock/bit-tooth interaction to The formulation of an upper limit on rotary drilling rate. Introduction Extensive experimentation involving single and indexed bit-tooth penetration into rock in a confining pressure environment has demonstrated that the pressure environment has demonstrated that the chip formation process is of a ductile, or pseudoplastic, nature at sufficiently low differential pseudoplastic, nature at sufficiently low differential pressures so as to be of interest in rotary drilling. pressures so as to be of interest in rotary drilling. Coincident with the experimentation, analytical consideration has been given to the theoretical problems of single and indexed bit-tooth penetration problems of single and indexed bit-tooth penetration into rock. In general, the analyses have assumed that the rock behaves statically in a rigid-plastic fashion and obeys the Mohr-Coulomb yield criterion. The quantitative comparison between experimental and calculated values of bit-tooth load required for chip formation has been remarkably good for a variety of rocks commonly encountered in drilling and at simulated differential pressures as low as 500 to 1,000 psi. Results obtained recently for indexed bit-tooth penetration indicate that the work (or energy) penetration indicate that the work (or energy) required to produce a unit volume of rock chip can be minimized by a proper combination of bit-tooth spacing and bit-tooth load for a given rock type and differential pressure. By utilizing this information, it is possible co formulate a drilling rate equation, at least in a preliminary fashion, for a roller-cone bit performing under rather idealized downhole conditions. In particular, through the use of characteristic dimensionless quantities pertinent to a roller-cone bit and to indexed bit-tooth penetration, interrelationships among bit weight, rotary speed, rotary power, bit diameter, rock strength and bit-tooth shape and spacing can be explicitly expressed. In the formulation of the equations, however, it is assumed that the rock chips are instantaneously removed from the bottom of the drill hole and that the rock behaves in a ductile manner during bit-tooth penetration. In addition, the effects of bit-tooth load application And penetration by a yawed tooth at an oblique angle are neglected. Although the analysis is presented in the light of some rather restrictive conditions, it does demonstrate a method of applying fundamental rock/bit-tooth interaction data, obtained by combining the results of analysis and experiment to the formulation of a drilling rate equation for rotary drilling. INDEXED BIT-TOOTH/ROCK INTERACTION PREVIOUS RESULTS PREVIOUS RESULTS The mechanics of bit-tooth/rock interaction under simulated conditions of borehole environment have been extensively described in a number of papers. In particular, the effects of differential papers. In particular, the effects of differential pressure, mechanical properties of rock, pore fluid, pressure, mechanical properties of rock, pore fluid, bit-tooth shape and spacing, rate of bit-tooth load application and dynamic filtration below the bit-tooth have been investigated experimentally. From a sequence of experiments, it was demonstrated that, for dry rock at atmospheric pore pressure, the mode of chip formation exhibits a transition, with increasing confining pressure, from predominantly brittle to predominantly ductile. SPEJ P. 443

Cuttability assessment using the Drilling Rate Index (DRI)

2015 ◽  
Vol 74 (4) ◽  
pp. 1349-1361 ◽  
Author(s):  
Serdar Yasar ◽  
Mehmet Capik ◽  
Ali Osman Yilmaz
Keyword(s):  
Drilling Rate ◽  
Drilling Rate Index

scholarly journals Variation of Drilling Rate Index (DRI) with temperature and its relationship with thermal damage on ‘Prada’ limestone

2021 ◽  
Vol 833 (1) ◽  
pp. 012053
Author(s):  
V Martínez-Ibáñez ◽  
A Basco ◽  
M E Garrido ◽  
C Hidalgo Signes ◽  
R Tomás ◽  
...  
Keyword(s):  
Thermal Damage ◽  
Drilling Rate ◽  
Drilling Rate Index

A sampling study on rock properties affecting drilling rate index (DRI)

2018 ◽  
Vol 141 ◽  
pp. 1-8 ◽  
Author(s):  
Hayati Yenice ◽  
Mehmet V. Özdoğan ◽  
M. Kemal Özfırat
Keyword(s):  
Rock Properties ◽  
Drilling Rate ◽  
Drilling Rate Index
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