Improve Rheological Properties of Palygorskite Water-Based Drilling Fluid by Caustic Soda and Soda Ash

Nada M Suliman,Nada Sabah Al-Zubaidi

doi:10.31026/j.eng.2020.06.01

Abstract

In drilling fluid program, selecting the drilling fluid that will reduce the lost time is the first objective, and will be economical regardless of its cost. The amount and type of solids in drilling fluid is the primary control of the rheological and filtration properties. Palygorskite clay (attapulgite) is an active solid that has the ability to reactive with its environment and form a gel structure within a fluid and due to its stability in the presence of brines and electrolytes this type of clay is preferred for use. The aim of this study is to improve properties of Iraqi palygorskite (PAL) by adding different chemical additives such as caustic soda NaOH and soda ash Na2CO3 with a different concentration in both fresh and salt water-based drilling fluid to satisfy the API specification and to compete with imported palygorskite. The palygorskite claystone of Late Cretaceous age is present in the Western Desert of Iraq within the Digma Formation. In this study, two areas in Western Desert palygorskite were obtained, Bahr Al-Najaf and Trefawi. The results of rheological properties showed that the performance of Bahr Al-Najaf PAL was more affected by caustic soda than Trefawi PAL. In contrast, Trefawi PAL performance was more affected with low concentrations of soda ash than Bahr Al-Najaf PAL in both fresh and salt water-based drilling fluid. Also, these additives lead to improve the value of pH in both fresh and salt drilling fluid that increases the ability of clay to be more dispersed in drilling fluid. Besides that, enhancement of drilling fluid prepared with Iraqi palygorskite stability to 85 and 80 in fresh and saltwater, respectively, was observed with soda ash additions.

Highlights

Different additives such as polymers, chemicals, and nanoparticles with various concentrations were added to enhance the properties of palygorskite water-based drilling fluids. (AlBaidari, 1997) studied the effect of aging time, chemicals, and polymers on the rheological properties of drilling fluids prepared with Iraqi claystones from Injana formation/Najaf-Karbala region and showed that when added Iraqi bentonite to palygorskite reached the required viscosity according to API specification. (Al-Ajeel et al, 2008) studied the beneficiation of attapulgite – montmorillonite claystone with dispersion sedimentation technique using polyionic salts as dispersant
This study aims to improve the performance of Iraqi palygorskite in fresh and salt water-based drilling fluid by adding chemical additives such as caustic soda and soda ash with various concentrations
Due to montmorillonite (MMT) in Bahr Al-Najaf PAL (XRD analysis showed the presence of montmorillonite, palygorskite kaolinite, feldspar, quartz, and calcite), low concentration of caustic soda caused a decrease in PV, YP, and AV

Summary

Introduction

‫الخلاصة‬ ‫اختيار مائع الحفر الذي يقلل من الوقت الضائع في عمليات الحفر‪ ,‬هو الهدف الاول في تصميم برنامج مائع الحفر‪ .‬كمية و نوو‬ ‫المواد الصلبة في مائع الحفر هي السيطرة الاوليوة للاووار الريولوجيوة والترشوي ‪ .‬تعتبور نطيوال الباليورسويايت مون الموواد‬ ‫الصلبة الفعالة والتي لها القابلية على التفاعل مع المحيط وتيوول تركيوه هيموي داخول الموائع و نتيسوة الوى اسوتقطابها بوجوود‬ ‫الاميح يفضل استادام هذا النو من الاطيال‪ .‬الهدف من هذه الدراسة‪ ,‬هو تحسين خوار و ادائية الباليورسيايت العراقي عن‬ ‫طريق اضافة مواد كيميائية ماتلفة مثل الصودا الياوية و بييربونات الصوديوم بتراكيز ماتلفة في الماء العذب والمال لغرض‬ ‫الوصول الى معيار (‪ )API‬ومنافسة الاطيال المستوردة التسارية‪ .‬ثم استادام الباليورسيايت العراقي المتواجد في بحر النسو‬ ‫و طريفواوي فوي الصوحراء الغربيوة فوي العوراو‪ .‬نتوائج الاووار الريولوجيوة بينوت تحسون فوي اداء الاطيوال المحضورة مون‬ ‫الباليورسيايت‪ /‬بحر النس باضافة الصودا الياوية (هيدروكسيد الصوديوم) اكثر من الاطيوال المحضورة مون الباليورسويايت‬ ‫‪/‬طريفاوي‪ ,‬بينما اداء الاطيال المحضرة مون الباليورسويايت ‪/‬طريفواوي تحسون باضوافة قليلوة مون رمواد الصوودا (بييربونوات‬ ‫الصوديوم) اكثر من الاطيال المحضرة من الباليورسيايت‪ /‬بحر النس ‪ .‬كذلك قيم ‪ pH‬تحسنت باضافة كل من الصودا الياويوة‬ ‫و رماد الصودا والذي بدورة يزيد من تشتت اطيال الباليورسيايت‪ .‬الى جانه هذا‪ ,‬هنالك تحسن باسوتقرارية موائوع الحفرحيو‬. ‫‪Drilling fluid is one of the essential factors to success rotary drilling operation, which consists of‬‬ ‫‪liquids and different active solids, inert solids, and chemical additives to enhance its properties.‬‬ ‫‪The principal functions of drilling fluid are removing cuttings from beneath the bit and carry out‬‬ ‫‪from the borehole, lubricate and cooling the bit, and maintain the stability of borehole by‬‬ ‫‪controlling the hydrostatic pressure to prevent blowouts and formation damage (Caenn, et al.,‬‬ ‫‪2017).‬‬ ‫‪Palygorskite is 2:1 layer silicates, where the tetrahedral sheets are linked infinitely in two‬‬ ‫‪dimensions It is structurally different from other clay minerals in that the octahedral sheets are‬‬ ‫‪continuous in only one dimension, and the tetrahedral sheets are divided into ribbons by the‬‬ ‫‪periodic inversion of rows of tetrahedrons. Several studies have been conducted to improve the performance of palygorskite Different additives such as polymers, chemicals, and nanoparticles with various concentrations were added to enhance the properties of palygorskite water-based drilling fluids (fresh and saltwater).

Objectives

Methods

Results