Frictional Pressure vs. Rheological Models

Abstract

When the drilling fluid leaves the mud pump, it circulates through the stand pipe, rotary hose, swivel, Kelly, drill pipe, drill collar, bit and the annulus between the drill string and the open hole or the casing.

During drilling fluid circulation, frictional pressure drop occurs in the hydraulic circuit consisting of the elements mentioned earlier. The total pressure drop in the hydraulic circuit is known as the stand pipe pressure, abbreviated as SPP. Calculation of the SPP is strongly depended on the rheological models and the assumption of their rheological constants.

A number of the rheological models are available. Among them, three most widely used in petroleum industry as Bingham Plastic model, Power low model and the Herschel-Bulkely model have been chosen.

For predication of SPP we have to consider the rheological constants of drilling fluid because SPP predication is strongly depends on rheological constants. There are two suggestions to determine these rheological constants named as two point regression or field approach and six points’ regression approaches. Most theoretical principles have been reviewed in the earlier chapter of this work. Then our suggestion based on predication of SPP using two and six points regression have been presented at the rest of the chapters. At the end it has been presented weaknesses and conclusions of this work.

This project includes 9 main chapters and a large numbers of tables and figures which have been calculated by hydraulic programming in Excel. All these tables and figures have been putted in Appendixes.