Challenges in High Sour Gas Field Development and Non-Metallics Opportunities in Upstream Processes

Abstract

High sour fields beyond 10% H2S concentration are considered one of the severe environments that require suitable tubular components and accessories in upstream environment to ensure sustainable production. Such environments represent a challenging operating envelop where durability and safety are the top concerns due to higher H2S concentration at a higher partial pressure and higher temperature (HPHT). The risk is amplified for the wells with higher than 10% H2S concentration, namely the High H2S wells, and those exceeding 25% H2S concentration which are typically labeled as Ultra-High H2S wells. Corrosion in gas operations can be aggravated in downhole where high H2S at higher temperatures pose additional challenges. Selection of proper material to ensure a sustainable well condition is one of the important elements for the development of these HPHT gas wells. Various challenges were identified, including the selection of cost-effective material which is capable of withstanding short and long term H2S and CO2 partial pressures as well as control generalized CO2 corrosion, sulfide stress cracking (SSC), and stress-oriented hydrogen induced cracking (SOHIC). With the advancement of Non-Metallics (NM) materials in several applications across the O&G sector, it holds a promise to provide an alternative material solution in lieu of CRA alloy material for the HPHT downhole applications. NM materials are lightweight and they can be designed to withstand higher strength capability in addition to their outstanding corrosion resistance properties in a high H2S environment. Moreover, they can be engineered to fulfill the intended application due to their high design flexibility and durability. In the downhole applications, there is a number of NM products that have been implemented in sour environments, including sealants as well as downhole accessories and tools, where the list of NM technologies is considerably growing. This paper highlights the concept of using NM products such as coiled tubulars, pressure control equipment and elastomers as well as the challenges on the development and deployment of these key components in high sour fields.