This paper presents a case study of field trials completed by Saudi Aramco to evaluate use of the Wireline Engineering Company's Roller BogieTM tool to improve wireline (both Slick and Electric Line) intervention in highly deviated cased-hole wells. Conventional wireline intervention tool operations are normally limited to a maximum of 65° inclination due to frictional resistance between the wireline toolstring components and well tubulars. The Roller BogieTM tool was used to overcome well inclination limitations and complete necessary wireline interventions without the utilization of costly and complex coiled tubing or wireline tractor operations.
Conceptually, the Roller BogieTM tool drastically reduces frictional contact between the wireline toolstring and the wellbore tubulars by lifting the entire wireline assembly off the well tubulars on low-friction rollers. Moreover, the Roller BogiesTM uses a self-orienting body profile to ensure that the rollers are always located on the low side of the tubing and also have integral swivels that allow the rollers to be oriented independently to the rest of the toolstring.
The use of this tool in Saudi Aramco wells has enabled conventional wireline operations to be conducted at well deviations in excess of 82°. The Roller BogieTM tool was used in tandem with a cement bond log (CBL) tool in an offshore highly deviated (maximum of 87°) cased hole oil well at a depth of 9,154 ft (2,790 m). This CBL log was recorded successfully at a maximum of 82° of inclination and to a depth of 8,406 ft (2,526 m) without any significant wear out or damage to the Roller Bogie™ tool or attached wireline assemblies.
After the success of the trial test operation and the resultant cost avoidance of the coil tubing or wireline tractor utilization, additional operations were completed, such as bridge plug installation, perforating and ceramic disc rupturing.
The ability to perform conventional wireline operations in an increasingly deviated cased hole wells has always been limited by the cumulative frictional resistance between the wireline with associated toolstring components and the tubing through which these are being run. Such frictional drag increases as wellbore deviation becomes greater and effectively limits the practical deployment of wireline equipment, both in terms of maximum well deviation and the depth to which the wireline can gain efficient access at any given deviation. In addition, it has been widely recognized that wellbore tortuosity can also increase frictional resistance and, in severe cases, this can inhibit wireline operations even at moderate wellbore inclinations.
To overcome this constraint and perform reliable intervention activities in more deviated cased hole wells, some operators have resorted to use either coiled tubing or wireline tractors instead of conventional wireline, with consequent implications for cost and operational complexity. In many cases, well productivity can be intentionally compromised in order to limit maximum well deviation to that which is accessible by wireline systems.