A Battery-Operated, Electro-Mechanical Setting Tool for Use with Bridge Plugs and Similar Wellbore Tools. (1995)

ABSTRACT Traditionally, the method of choice for setting packers, bridge plugs, and similar wellbore tools has consisted of running an electrically-activated explosive-charge setting tool to the required setting depth on electric line and activating the tool by an explosive charge. Although this method requires an electric line truck and an operator who is licensed to handle the explosives, it is more cost efficient and faster than other mechanical or hydraulic alternatives. Recently, however, new completion technologies with wellbore configurations in which the explosive-type setting method is not desirable have been introduced to the oil field. This paper will discuss the design and operational advantages of a new slickline service tool, the downhole power unit (DPU), which has the capability to set wellbore devices without the use of explosives, and thus, can comply with the needs of the new completion technologies. Its gradual setting motion allows the slipsnd sealing elements of packer and bridge plugs to expand and conform uniformly against the tubing/casing wall, thus decreasing chance of a misrun. The gradual setting motion also eliminates the high impact stresses that are imposed upon downhole devices when using an explosive-charge setting tool. The DPU utilizes an electric gear motor and linear drive mechanism to generate forces of up to 60,000 lbf, and the design is inherently safer than equipment requiring an explosive charge since the power to operate the tool is provided by standard alkaline batteries. Its specially developed circuitry also increases assurance that the tool will be activated at the proper depth. The tool can be redressed quickly at the wellsite, and routine maintenance involves only lubrication and battery replacement. The combination of simple maintenance, safety-enhanced operation through elimination of explosives, deployment with slickline, and capability to reduce high impact stresses and misruns has provided the service industry with a cost-efficiency state of- the-art setting tool that can be used in applications for which traditional methods have not been satisfactory. INTRODUCTION Using the conventional wireline method for setting packers, the setting tool is deployed via electric line to the proper setting depth, at which point an electrical impulse in, diced at the surfaced, etonates the explosive charge, and thereby, activates the tool. The resulting setting stroke is of high force and velocity. The traditional methods have been satisfactory for conventional service needs, but with the increasing impetus on economic constraints in the oilfield, new, nmre cost-efficient operational strategies in drilling and completion technologies have been introduced. Of particular significance in the new developments have been the monobore and slimhole concepts and the feeling that greater use of these technologies, both individually and in combination, could provide thesought-after economic advantages. These beliefs are based on the assumption that if restrictions such as landing nipples can be eliminated from well geometry, and wellbore diameters can be reduced; then, enhanced production, improved reservoir management and simplified work over procedures can be achieved as well as reductions in the initial completion costs. In response, newly-developed concepts of slimhole drilling and monobore completions have emerged.