Compatibility: A Key To An Efficient Matrix Acidizing Fluid Design

Dankwa Ok,Appah D

doi:10.4172/2157-7463.1000274

Abstract

In this work four acidizing treatment systems have been formulated to treat various degrees of wellbore damages due to organic and inorganic materials, fines, mud-cake and other particles that block perforations and pore spaces around the wellbore. The treatment fluids are: clay stabilisation system, matrix stimulation system, non retarded mud acid system and oil-based dispersant fluid system. Emulsion break tests were conducted at test temperatures of 80°F, 150°F and 190°F. Clay stabilisation and matrix stimulation systems separated out of solution within the acceptable time of 10 minutes at all the test temperatures and showed no incompatibility. The rest of the treatment fluid systems separated after ten minutes. It was observed that, the higher the temperature, the faster the separation in most of the tests. It can be concluded that, different formation fluids react and behave differently with matrix acidizing treatment fluids and thus every treatment fluid would have to be tested for compatibility with formation fluid to ensure a successful stimulation.

Highlights

Wellbore damage describes any restriction to flow from near-well reductions in flow capacity
The compatibility issues addressed in this study pertains to that between the reservoir fluids and stimulation fluids due to the tendency of these combinations to causing damage to the wellbore if their compatibility is not ensured
The aim of the study is to ascertain the behaviour of the matrix acidizing fluid upon contact with formation fluids; as to whether there will be sludge or sediments formation or whether it will it cause increment in the fluids viscosity?

Summary

Introduction

Wellbore damage describes any restriction to flow from near-well reductions in flow capacity. These damages are as a result of reductions in near-well permeability caused by perforating debris or from the solids or mud filtrate invasion caused by the drilling process as well as certain production operation practices including well stimulation. The compatibility issues addressed in this study pertains to that between the reservoir fluids and stimulation fluids due to the tendency of these combinations to causing damage to the wellbore if their compatibility is not ensured. The sludge and sediments which may form can end up blocking pores around the near wellbore and impeding flow of reservoir fluid. Increase in viscosity will make it difficult for the fluid to be pumped out of the wellbore after the acidizing operation, increasing pumping pressure

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