Hydrogen Sulfide In The Drilling Industry
Authors: Carter D.R. , Adams N.J. 
Published: December 2007

Carter, D.R., and Adams, N.J., Prentice and Records Enterprises, Inc. Prentice and Records Enterprises, Inc. Copyright 1979, American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Petroleum Engineers, Inc. This paper was presented at the 1979 Society of Petroleum Engineers of AIME Deep Drilling and Production Symposium held in Amarillo, Texas, April 1–3, 1979. The material is subject to correction by the author. Permission to copy is restricted to an abstract of not more than 300 words.

When a well is to be drilled in a known or suspected sour gas area a number of precautions must be taken. These measures can be separated into the three general categories of (1) methods of protecting the rig and site personnel, (2) safeguards to protect the general public, and (3) precautions to safeguard all equipment from exposure to hydrogen sulfide.

Introduction

Hydrogen sulfide (H2S) has become an important topic in recent years due to the increasing demand for hydrocarbon products. To meet these demands, operators are now increasing drilling activities in known sour gas areas. In addition, sour gas has been reported in old fields where the presence of hydrogen sulfide had not been previously reported. To drill and complete a sour gas well safely and at minimum costs, operators need a basic understanding of the effects of encountering hydrogen sulfide. Hydrogen sulfide is a toxic gas that can cause sudden death from exposure to low concentrations of the substance. In addition to the toxicity, hydrogen sulfide is very corrosive. H2S corrosion adds tremendous costs to an already expensive endeavor if the operator has not taken proper precautions to prevent such damage. prevent such damage. This state-of-the-art paper presents pertinent topics relative to hydrogen sulfide drilling such as the responsibilities imposed by federal and state regulations. Emphasis is placed on OSHA and NIOSH rules and state regulations. The effects of hydrogen sulfide on the rig site worker and equipment also will be presented as well as methods for preparing and protecting workers and equipment for exposure to an H2S environment.

RULES AND REGULATIONS

The operator is faced with many rules, regulations, and standards when attempting to drill and produce hydrocarbon products containing hydrogen produce hydrocarbon products containing hydrogen sulfide components. The regulatory agencies are found both on the state and federal level. The primary regulations will be presented in the following primary regulations will be presented in the following section while details of these regulations can be found in the referenced sources. Occupational Safety and Health Administration (OSHA). Although a particular drilling area may be void of state regulations relative to hydrogen sulfide drilling, many federal regulations and standards must be followed anytime a toxic environment is encounterd. The Office of Occupational Safety and Health Administration (OSHA) in its 29 CFR 1910, Subpart I 1910.134 states that "(1) In the control of those occupational diseases caused by breathing air contaminated with harmful dusts, fogs, fumes, mists, gases, smokes, sprays, or vapors, the primary objective shall be to prevent atmospheric contamination. When effective engineering controls are not feasible, or while they are being installed, appropriate respirators shall be worn pursuant to the following requirements. (2) Respirators shall be provided by the employer when such equipment is necessary to protect the health of the employee. The employer shall provide the respirators which are applicable and suitable for the purpose intended. The employer shall be responsible for the establishment and maintenance of a respiratory program."In this same publication, guidelines are presented for the selection of respiratory equipment presented for the selection of respiratory equipment on the basis of exposure. The standard from which the information is obtained is ANSI Z88.2. This standard classifies H2S as an extremely toxic gas and is immediately dangerous to health. Those respirators which are acceptable must be of the positive pressure type which maintains a constant positive pressure type which maintains a constant pressure within the facepiece at all times. This pressure within the facepiece at all times. This classification is further defined by 29 CFR 11 which specifically states the types of respirators that are approved in an H2S environment. (See Table 1)American National Standards Institute (ANSI). Another national standard which has a great impact upon respiratory equipment is American National Standards Institute Z37.2-1972.