Enzymatic and Oxidizing Agents for the Decomposition of Polymers Used in the Composition of Drilling Muds

Małgorzata Uliasz,Sławomir Błaż,Bartłomiej Jasiński,Grzegorz Zima

doi:10.3390/en14165032

Małgorzata Uliasz, Sławomir Błaż + Show 2 more

Open Access

https://doi.org/10.3390/en14165032

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Journal: Energies	Publication Date: Aug 16, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: Oil and Gas Institute - National Research Institute

Abstract

The article presents the results of research on the influence of enzymatic and oxidizing agents on polymers used in drilling mud technology. The research used calcium hypochlorite, urea peroxide, sodium persulfate, amylase and cellulase. This allowed us to determine the optimal concentrations of these agents in order to reduce the rheological parameters of drilling muds. The ability of enzymes and oxidants to decompose colloids used in the composition of drilling muds was determined on the basis of measurements of their rheological parameters and the influence of oxidants and enzymes on the properties of filter cakes. The final effect of the presented research was the development of a drilling mud treatment method before the cementing procedure and the development of washer fluids containing enzymatic or oxidizing agents to be used to prepare the borehole for the cementing procedure. The drilling muds selected for the research contained starch and cellulose polymer colloids, which allowed for the selection of appropriate agents depending on the type of polymer set used in the drilling mud. Positive results were obtained regarding the possibility of thinning the drilling mud immediately before cementing, as well as the possibility of using oxidants and enzymes in the composition of washer fluids.

Highlights

In order to improve the quality of cementing of casing, the drilling mud is treated to lower its rheological parameters
The obtained results of laboratory tests indicate the possibility of selecting, depending on the borehole conditions, the appropriate type of agents that cause the decomposition of agents that impart viscosity to drilling muds
The effectiveness of selected enzymes and oxidants has been confirmed in the conducted tests, both in polymer solutions and drilling muds prepared according to the compositions used by the drilling services

Summary

Introduction

In order to improve the quality of cementing of casing, the drilling mud is treated to lower its rheological parameters. Obtaining low rheological parameters of the drilling mud facilitates displacement of the drilling mud solidified at the wall of the borehole and partial leaching of the clay cake that hinders the contact of the cement grout with the rock. The filter cake on the borehole wall is formed by filtering the water phase from the drilling mud. It is a mixture of a polymer solution, weighting agent and finely drilled solid phase. The filter cake produced during drilling increases the stability of the borehole walls and reduces the permeability of the porous layers, there are no major losses of the water phase from the drilling mud, which can significantly reduce the strength of the rocks. The filter cake protects the borehole wall against the erosive impact of the drilling mud stream and ensures a good technological process until the casing is inserted into the borehole [3,4,5,6]

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Results

Conclusion