Abstract
Current trends in the oil and gas industry are focusing more heavily on operational efficiency and cost reduction than ever before. Therefore, operators and service companies are investigating any technique that offers possibility for improvement in these areas, and this explains the recently renewed interest in the monobore and slimhole concepts.
The most obvious savings are those that relate to:
the size of the rig required to drill the hole
the amount of well control material used during the drilling of the hole
the quantity of cement required to cement the casing string in place
the size and quantity of tubing and casing required to complete the well
the discharge of drill cuttings would be dramatically reduced.
This paper will review a new equipment design that is ideally suited for use with coiled tubing to perform a cement job in slimhole wells.
This innovative technique is performed with 2-in. coiled tubing. A special device, which is made up with an educated J-slot and a 2.55-in. seal at the end of the coiled tubing, will engage and disengage automatically from a seal bore receptacle that is placed at the end of the 3-½-in. casing string.
This tool is retrieved, easily redressed and re-used. It can be sheared so that the coiled tubing can be pulled in the event a catastrophic event occurs during the cement job.
This tool reduces the contamination of cement. In addition, it offers an economical method for cementing in scenarios in which a standard cement job cannot be performed. For example, when a control-line-activated landing nipple is used in the casing/tubing string, there is risk of depositing cement in the landing nipple bore and plugging the control line when using traditional cementing techniques.
This paper describes the operational procedures, benefits of the system, and a slimhole completion design adopted by ENI-AGIP to take advantage of the benefits of the system.
