Much of the credit for the recent rapid growth in the Coiled Tubing Industry can be attributed to the development of larger diameter and higher strength spoolable steel tubular products allowing for an expansion of the operating limits and the applications that can be performed such as drilling, completions and horizontal well servicing. The development of an advanced composite, high performance spoolable tubular product will help fuel this market expansion even further by creating additional enabling capabilities for the Coiled Tubing well servicing industry.
Conoco, Inc. initiated the development project for high-performance, composite spoolable tubular products in 1988. The initial focus was on corrosion resistant water injection lines and later evolved to a 1.5" OD composite coiled tubing. The development effort lead to a composite tube design formed by taking a thermoplastic liner and surrounding it by a carbon fiber and epoxy matrix structure. The matrix includes an external KevlarR fiber layer to provide wear and impact resistance. The advantage of a composite spoolable pipe over steel pipe is that it can be "engineered" for particular applications to take advantage of the composite's enabling attributes. These attributes include corrosion resistance, high strength to weight ratios, high working pressure capability and low material density. In fact, the current composite tubing designs weigh in at 1/3–1/4 the weight of a like OD steel tube in air and are 1/7th the weight of steel in water. This obvious advantage allows longer and larger strings of composite tubing to be handled by lower pull capacity coiled tubing units or lifted onto offshore platforms with smaller crane capacities.
This paper will review the development efforts and operational issues addressed to qualify the advanced composite spoolable tubing for several enabling applications. The first full scale field trials are scheduled to be performed in the 2nd quarter of 1997.
