How do I remove chapter number at the start of each chapter without affecting the subchapters?

Question

How can I Remove the "Chapter 9" text and number in front on the chapters. see "chapter 9" below in the picture. I want to keep the numbering for the sections and subsections in the text and in the table of content.

I have seen methods to remove chapter number, however the section count will then continue from the past chapter. For instance 9.1 Chapter overview will be changed to "8.12 Chapter overview"

\documentclass[12pt,twoside]{report}
%\documentclass[draft]{article}
\usepackage{graphicx}
\graphicspath{{images/}}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{textcomp}
\usepackage{gensymb}
\usepackage[utf8]{inputenc}
\usepackage{nomencl}
\makenomenclature

\begin{document}

\addcontentsline{toc}{chapter}{List of Tables}

\chapter{Results section overview \& Reservoir Characteristic}
\input{chapters/Reservoir_Characteristic.tex}

Answer 1

This kind of formatting can be done with the titlesec package. Using this package, the standard formatting for a chapter title is defined with the command

\titleformat{\chapter}[display]
    {\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge}

The argument {\chaptertitlename\ \thechapter} is the one which asks to write the huge "Chapter 9" text that you want to be removed, so you can just leave that argument blank and nothing will appear. For more details, see the package documentation.

The following code should work.

\documentclass[12pt,twoside]{report}
\usepackage{titlesec}
\titleformat{\chapter}[display]
    {\normalfont\huge\bfseries}{}{20pt}{\Huge}

\begin{document}

\setcounter{chapter}{8}
\chapter{Results section overview \& Reservoir Characteristic}
\section{Chapter overview}

This chapter present...

\section{Results Static and Dynamic Model Characteristic}
\subsection{Permeability and Porosity L14 \& L25}

\end{document}