Economic initiatives are usually the drivers of new technologies. and with the significant decline in the oilfield climate during the last decade, it is not surprising that no era has been as momentous in providing stimuli for operational change. Unfortunately, however, operators who seek new methods usually look to new technologies as the potential problem solvers, and in so doing, overlook enhancements to the older technologies that could provide the cost efficient alternatives they are seeking.
This has been true of slickline. Until the resurgence of investigation into new strategies to meet the oilfield cost constraints of the last decade, slickline service had only been considered for routine mechanical workovers. This paper will discuss new developments in this technology that economically provide alternatives to services traditionally reserved for other, more costly options. The discussion will include in-depth descriptions of the new scope of services, an overview of the equipment that combines to make the new options possible, and case histories that illustrate how the equipment combines to efficiently provide low cost solutions for a broad scope of well interventions. These service alternatives now provide accurate locating of downhole tubular goods/profiles; high-speed data retrieval and transmission for production of quality logs from downhole memory surveys; accurate correlation of tubing or casing collars; setting bridge plugs, packers and other downhole equipment without explosives; shifting downhole tubular sleeves; setting monobore tools; and other well interventions that are dependent upon measurement accuracy. Slickline now can provide the efficient, low cost well servicing alternatives to traditional methods that the industry needs to comply with current cost constraints.
The comparison of today's slickline capabilities with its early usage for routine remedial workovers and maintenance best illustrates the significant advances that have occurred within this technology. Today, for example, slickline can be used to 1) set and retrieve slickline-retrievable safety valves or plugs, 2) open and close downhole circulating devices, 3) retrieve and transmit high-speed data for production of quality logs from downhole memory surveys, 4) provide accurate correlation of tubing casing collars, and 5) pull and run multiple flow controls.
The capabilities that have changed the profile of slickline service from one of routine mechanical well workovers to a multi-faceted service technology are derived from the new slickline tools that can be used independently or combined to further enhance the scope of services. The equipment includes an electronic triggering device (ETD) that enables safe detonation of explosive devices, a battery-operated, electro-mechanical tool that sets wellbore devices on slickline and braided line without explosives, an electronic measurement system that automatically corrects measurement inaccuracies resulting from line stretch and environmental stress factors, a slickline collar locator (SLCL) that accurately verifies collar locations in a tubing string, and data/job loggers or acquisition software systems that connect to the electronic measurement system to graphically record dynamic wireline information.
Traditionally, slickline servicing has been able to provide an effective means for performing well maintenance by high speed mechanical deployment, manipulation. and retrieval of downhole service tools in all types of wells, including those with high pressure and flowing well conditions. Its portability has allowed it to be cost efficient for performing these services in remote locations and on satellite platforms. Although slickline service capabilities, completion equipment, and wire have continually been improved over the last fifty years, a significant increase in the use of slickline to replace the traditional service options has only recently been noted. Several factors have been instrumental in effecting this change: