Abstract

The loss of circulation is a big problem in drilling operations. This problem is costly, time-consuming and may lead to a well control situation. Much research has investigated the effectiveness of using different chemicals as lost circulation material (LCM) to stop mud and cement slurry losses. However, there remain many limitations for using such LCM types, especially when it comes to field applications. This paper presents a new high strength lost circulation material (HSLCM) that could effectively be used for managing severe lost circulation cases. The HSLCM could easily be pumped into the thief zone where it forms a gel that solidifies after a setting time to provide sealing between the wellbore and the thief zone. With this technique, the material stops the circulation losses, and hence enhances the well bore stability by reducing the well bore stresses. The HSLCM has a high compressive strength and it has a high acid solubility of around 96%. Because the HSLCM has high tolerance towards contamination, it can be utilized with water-based mud or invert emulsion-drilling fluids, hence providing a wide window of applications with the drilling fluids. In this study, laboratory experiments were conducted to evaluate the rheology, thickening time, compressive strength, and acid solubility of the HSLCM. The results showed good performance for the HSLCM as LCM. In addition, a case field study is presented which shows a successful field treatment for severe losses.

Highlights

  • Many challenges are encountered while drilling deep and high-pressure high-temperature (HPHT) wells

  • The performance of the new lost circulation material (LCM) was evaluated through many experiments to test its ability to control the losses; mixing, rheology, thickening or setting time, compressive strength, acid solubility, mud contaminations, and observations on the field case of using this new material will be discussed in this paper

  • The high strength lost circulation material (HSLCM) composition contains water as the base fluid, defoamer, setting control additive for set time design, viscoelastic surfactant (VES) to build the viscosity, acid soluble weighting additive (ASWA) to achieve the required density, monovalent or multivalent salt as ionic strength additive to increase the efficiency of VES, and the dispersant

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Summary

Introduction

Many challenges are encountered while drilling deep and high-pressure high-temperature (HPHT) wells. Samsuri and Phuong [13] introduced a less expensive cement formulation for loss of return issues while drilling in vugular, high permeability, or naturally fractured formations. Savari et al [17] presented a composite LCM solution of an acid-soluble combination with a multimodal particle size distribution to handle severe to total loss of circulation in the naturally fractured formation. The performance of the new LCM was evaluated through many experiments to test its ability to control the losses; mixing, rheology, thickening or setting time, compressive strength, acid solubility, mud contaminations, and observations on the field case of using this new material will be discussed in this paper

Materials Description
Experimental Program Design
Solubility Test
Thickening Time Test
Compressive Strength Teesstt
Compressive Strength Test
Acid Solubility Test
Field Contamination Testing
Findings
Field Application Case Study
Full Text
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