Small, Lightweight CTU Helps Enhance Production from Limited-Space Offshore Platform

Abstract

Over the past several years the coiled tubing industry has seen significant coiled tubing-related technology advancements that have supported new applications for smaller coiled tubing (CT) services, from basic onshore capillary chemical injection installations to more complex offshore CT applications 1-8 . New and older well completion and location challenges continuously redefine the boundaries of conventional CT well intervention methods especially for offshore situations which can often be difficult to economically justify. These challenges require solutions that yield better economics. Small CT technologies have recently been developed and deployed on challenging projects in Asia Pacific to provide operators with cost effective methods to maintain wellbore integrity and enhance production.A lightweight, small-footprint coiled tubing unit (CTU) has been developed in Asia allowing for the use of Small CT technology on a broad spectrum of well service applicationsThis OTC paper will cover the specifics of an application of Small CT technology in Malaysia. Numerous challenges will be reviewed including using small (1-in. OD) CT pipe, small CT motors and working inside a restricted completion with high dogleg severity and a 70 degree hole angle. A total of 23 CT runs, inclusive of 14 CT perforation runs, were performed and the entire job was completed safely, without any major operational issues and delivered a gas rate of 15 MMscfpd.The Small CT equipment package is very comparable to a more conventional, larger CTU spread. A Small CT package can consist of a lightweight and small-footprint CT unit, a small nitrogen unit, reduced-size nitrogen tanks and compact pressure pumping equipment. As an example, for a gaslift type job using Small CT versus conventional CT equipment, the equipment footprint is reduced by 40% and the equipment weight is reduced by 46%. The small footprint and light weight of the Small CTU is especially beneficial where crane or deck space limitations are challenges. Small CT equipment can be customdesigned to suit most land or offshore applications, and the CT pipe can be installed on a semi-permanent basis (such as small capillary installations) or deployed as a work-string for well intervention programs.Application of this technology has the potential to substantially reduce operating costs, logistical support and risk exposure and can be applied to both onshore and offshore environments worldwide. Wells that were once considered plug and abandon candidates due to economic, technical challenges or accessibility may now be candidates for Small CT technology solutions. CT Run 4Perforation #1 The objective for this run was to perform an equalization shot from depth 2225-2235m MD-RKB. Start RIH with an equalizing shot at 15m/min and stop at 2261m MD-RKB (actual TD 2272m MD-RKB). CT Run 5 Perforation #2 The objective for this run was to perforate the interval 2220.7-2229.5m MD-RKB. RIH gun BHA with THP=550psi and stop CT at depth 2259.6m MDRKB to correlate depth. CT picked-up to top of the de...

Smaller Coiled Tubing Diameter Achievable by the Use of Lubricants

“…Many older or depleted fields have logistical challenges such as onshore road access or offshore crane lifting/deck loading limitations that restrict the size of CT units Terry et al, 2013; Sundramurthy et al, 2014). These challenges translate in difficulties to economically justify deploying larger CT units.…”

“…These challenges translate in difficulties to economically justify deploying larger CT units. In some cases, it was reported that wells were abandoned before reaching their potential producing maturity because they were not economically viable to be serviced by large CT units (Terry et al, 2014).…”

“…It was reported recently that small CT units have been utilized in Southeast Asia Terry et al, 2013;Sundramurthy et al, 2014). These units are capable of deploying a wide range of small CT sizes, from 3/8-, 5/8-, 3/4-, to 1-in.…”

“…3. As an example of the logistical implications for a gas lift job using a small CT unit versus a large CT unit, i.e., a unit for large CT sizes, the CT unit weight is reduced by 46% and the footprint is reduced by 39% , Sundramurthy et al, 2014.…”

“…Using additional technologies such as CT modeling software for more accurate job planning and highly performant lubricants such as Lubricant 3 (new lubricant) reported above for increasing the reach and overpull now allows for many other applications, both onshore and offshore, to be evaluated for operations with smaller CT units and/or string sizes. These potential applications include hydrate removal, production logging, fishing, remedial cementing, spotting chemicals, acid wash, fiber optic logging, and thru-tubing inflatable packer deployment (Terry et al, 2014).…”