This paper correlates selected properties of limestone with tri-cone bit performance variables for developing LIMROCKWARE2010. In order to achieve these objectives rock samples were collected and uniaxial compressive strength, tensile strength and chemical composition tests were carried out on these samples. The length of the insert buttons on the surface of the drill bits were measured using digital vernier caliper at regular interval. Also, the tooth and bearing wear rate as well as the penetration rate were determined on the field. The results of the uniaxial compressive strength varied from 86.5 MPa to 112 MPa. Hence, the strength characteristic of these rocks varied from medium to high strength limestone. The Equivalent Quartz Content (EQC) of the rock samples also varied from 17.37% to 36.676% while the Rock Abrasivity Index (RAI) varied from 15.03 to 43.317. The results of statistical correlation matrix revealed that uniaxial compressive strength, tensile strength, silica content, Equivalent quartz content and rock abrasivity index are dominant rock properties affecting performance variables, having high coefficient of correlation. The developed regression equation for predicting penetration rate, tooth wear rate and bearing wear rate for limestone are given as Pr = 4.583- 1.052T + 0.029EQC + 0.046SiO2, WG = -8.127 + 2.7T- 1.29EQC – 0.024SiO2 and WB = -10.296 + 3.453T – 0.203EQC – 0.027SiO2 respectively. The regression models formulated were used for the development of LIMROCKWARE2010 which will compute the penetration rate, tooth and bearing wear rate, depth drilled per metre, estimate number of bits required and cost of drilling per metre when necessary rock input are supplied.

Author Name: Adebayo Bayo, V.O. Akeju

URL: View PDF

Keywords: Limestone; Quartz; Correlation; Bit; Variables; Strength

ISSN: 2169-642X

EISSN: 2169-6438

EOI/DOI:

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