A New Nozzle System To Achieve High ROP Drilling

Abstract

This paper waa selected for presemalion by an SPE Program Commiltee following review of information contained in an abslract submitted by the author(s), Contents of the oaper, os presented, have not been reviewed by the SOcietyof Petroldum Engineers and are subject to correc~'?nby the author(a). The material, as presented, doea not necessarily reflect any posilionof the %ciely of Petroleum Engineers, ita officers, or membw Papers presented at SPE meetings are subject to publication reviaw by Editorial Committees of !he Society of Petroleum Engineers. Permission LOcopy is restricted to an abstract of not more tf%, JO words. Illustrationsmay not ba copied. The af=tract should contain conspicuousacknowledgmentof where and by whom Ihe paper is presented, Write Public:.tionsManager, SPE, ABSTRACTGiven the various controllabledrilling parameters, hydraulic power is perhaps the most versatile, and yet least understood effect. The primary usage of hydraulic energy and t?,edrilling fluid as applied by rock bits is to clean the wellbore botto~and the teeth of the bit. For decades, hydraulic energy had been determined according to first order approximations of jet effects, such as impact force andfor hydraulic horsepower. These factors were useful to the drilling personnel but did not provide enough informationfor the engineer to intentionallydesign the hydraulic system to clean the bit and wellbore. In order to achieve the cleaning objectives, one needed to knc,wnot only the jet velocity but also its interacticz with the bit body and the rock formation. The challenge to find the stagnation zones, the erosion rate on the different parts of the bit, and the movement of the rock chips became apparent.The paper discusses a computer simulation study of the fluid characteristicsat each point of importance on the bit, which has been utilized to design a new nozzle system. This study consists of uiniextended nozzles, stabilizer pads, and a center nozzle. The means of designing an optimized hydraulic system, including laborc;ory work and the statisticalanalysis of field run data for correlation between theory and practice is presented. This integrated nozzle configuration increased the overall rate of penetration an average of 18 percent based upon 134 mini-extended nozzle bit runs. The drilling costs were cut inherently due to the penetrationrate increase.

Shoe Track Drillout Analysis: Factors Affecting Drilling Efficiency

“…It" can" be" expressed"the"same"way"as"in"equation"above. "The"difference"is"that"in"this"case" instead"of"total"pressure"loss,"we"use"pressure"loss"at"the"bit" [14]. " Bourgoyne" et$ al."…”

Improved Hydraulics for Rock Bits With Extended Slant Nozzles

“…Due to turbulence, the emerging fluid jet from a nozzle becomes partly mixed with the surrounding fluid, which leads to a rapid dissipation of the f 1 u i d • s k i net i c energy [ 1 ] . Part i c 1 e s of fl u i d from the surroundings are entrained in the jet, resulting in an increased mass-flow in a downstream direction.…”

“…To simulate the experiments, a computer flow code was used to model the fluid flow for a roller cone bit [ 1]. This solved the three-dimensional Navier-Stokes equations including the viscous effects for bit flo-w at high R~ynolds Number.…”

“…-Reducing the distance between the nozzle and the bottom of the hole [1] -Creating a forced circulation with two slant nozzles directed to the tooth/rock contact line and a center jet.…”

Performance Comparison of Rolling-Cutter Bits With Alternative Nozzle Designs

“…These are typically made by placing an extended-length tungsten carbide nozzle in the traditional nozzle socket. 8 This usually extends the nozzle 1 to 3 in. [25.4 to 76.2 mm] closer to the formation.…”