Coiled-Tubing Operations in the Panna Field Offshore Western India

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 100149, "Operability Challenges During Coiled-Tubing (CT) Well Intervention: Panna Field Case Histories From Western India Offshore," by S. Kale, SPE, and R. Proctor, SPE, BJ Services Co., and S. Paliwal, SPE, and S. Nayak, SPE, BG E&P India Ltd., prepared for the 2006 SPE/ICoTA Coiled Tubing and Well Intervention Conference and Exhibition, The Woodlands, Texas, 4-5 April. Coiled tubing (CT) was used in well interventions offshore western India. Well completions are open hole, open hole with tail pipe, and cased hole with swell packers. CT entry was essential to operate sliding sleeves installed in the completions. The full-length paper documents case studies and reviews attempted solutions such as bottomhole-assembly (BHA) excitation tools and contact-friction reducers to extend reach and increase downhole force. Introduction Located off the west coast of India, the target reservoir in the Panna field is a limestone layer. Horizontal wells have been drilled and completed in the field since 1997. The main difference between the wells completed in the late 1990s and current wells is the horizontal-section length. Challenges associated with CT operations can be considered as logistical and technical. The main logistical challenges include limited crane capacity and deck space for CT rig up. Technical challenges include limited CT downhole force. Because of logistical challenges, the preferred CT size cannot be used on most platforms. Logistical Challenges Panna field has two types of platforms, one with nine slots and the other with 15 slots. The nine-slot platforms have limited deck space and crane capacity. Larger CT sizes such as 1 3/4-in.-outside-diameter (OD) pipe cannot be rigged up on nine- slot platforms but can be used on the 15-slot platforms. Two memory-production-logging (PL) campaigns were undertaken on the 15-slot platforms. Because of limited deck space on some platforms, fluid-pumping and nitrogen equipment, tanks, and mixing equipment were offloaded to a dedicated supply boat as required. This presented the logistical challenge of timing the operations to boat availability and tide conditions. Technical Challenges The two most important technical challenges faced by the team were CT-reach prediction and identification of possible solutions to meet well-intervention objectives. The objectives of well interventions in late-1990s completions were acid stimulation and memory PL. Current completions require sliding-sleeve manipulation, acid stimulation, and PL. Accurate CT-entry predictions require use of a CT simulator. In addition, the engineer using the simulator must have a thorough understanding of the modeling parameters and analysis process.