Int. J. of Oil, Gas and Coal Technology   »   2016 Vol.11, No.4

 

 

Title: Experimental investigation into rate of penetration in carbonated rocks

 

Authors: Emadoddin Shaabani; Milad Rezaeian; Mohammad Javad Afshari Moein; Parviz Maarefvand

 

Addresses:
Department of Petroleum Engineering, Amirkabir University of Technology, 424 Hafez, Tehran, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, 424 Hafez, Tehran, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, 424 Hafez, Tehran, Iran
Department of Petroleum Engineering, Amirkabir University of Technology, 424 Hafez, Tehran, Iran

 

Abstract: Rate of penetration (ROP) in drilling processes is dependent on various operational variables (bit weight, rotary speed etc.), in addition to rock drillability. Drillability of rock depends on physical, mechanical and micro-structural properties of rock. Evaluation of rock drillability is not a trivial task and different methods have been proposed to measure it. In this study we measure the drillability of several carbonate rocks and evaluate them with ROP experiments. Using a laboratory drilling setup, ROP was measured at different weights on bit (WOB) and rotary speeds for ten different carbonate rocks (other operational variables were constant). Experiments showed that unconfined compressive strength (UCS) is not applicable for characterising the drillability, while drilling rate index (DRI) leads to more reliable evaluations of drillability of carbonate rocks. The experiments demonstrated that there is a relationship between WOB exponent, rotary speed exponent in ROP equation and DRI. Using DRI as the indicator of drillability, we performed 500 tests to correlate ROP as a function of WOB, rotary speed and drillability for carbonate rocks. [Received: February 1, 2014; Accepted: September 17 2014]

 

Keywords: drilling; rock drillability; rate of penetration; ROP; drilling rate index; DRI; carbonated rocks; bit weight; rotary speed; compressive strength.

 

DOI: 10.1504/IJOGCT.2016.075086

 

Int. J. of Oil, Gas and Coal Technology, 2016 Vol.11, No.4, pp.339 - 349

 

Available online: 03 Mar 2016

 

 

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