Directional Challenges and Planning of Relief Well to Resolve an HP/HT Well Blowout

Abstract

A blowout in an HPHT deep well posed a major challenge while designing the relief well which was required to bring the well under control. For the relief well it was necessary to carry out a comprehensive well design and operational planning, identification and mobilization of necessary equipment in a short time. This paper will describe the preparations made for this type of relief well in the region. An existing deep J-shape directional well, suffered a blow out while drilling a deep Salt/Anhydrite formation where formation pressures were extremely high. The blowout well was surrounded with many other producing facilities, drilling activities and inhabited areas. The main challenge was to choose a suitable location as close as safely possible, in such a congested mature oil field, taking into consideration all the safety aspects such as wind direction, surrounded wells, flame and heat created from blowout well, etc. The other main well challenges concerned; well placement, intercept with blowing well and dynamic kill. This paper will concentrate on the aspects of relief well design and planning. It will cover all related topics, such as; number of relief wells planned, surface location choice, potential drilling problems, directional design, detection of the blowout well, and placement philosophy. It will include a discussion on the specialized directional and ranging equipment and techniques needed to perform the critical operations of locating, following, and intersecting the blowing well. All aspects concerning HSE will be discussed in detail. The paper will present these in a case history format covering the design process, operational planning, and a description of well operations.