Real-Time Load Measurement Improves Coiled Tubing Downhole Tools Performance on Horizontal Wells

By Fernando Baez, Victor Lyashkov, Richard Morrison, March 27, 2014

some instances, the tools show unexpected failures when used in extended reach (ER) wells. When utilizing traditional CT tools the actual downhole forces acting on the bottomhole assembly (BHA) remain unknown and job objectives often cannot be met due to the inability to reach required TD or because of downhole tool damage caused by constantly variable downhole conditions.

Global industry shows an increasing trend towards exploiting highly deviated and horizontal wells to recover hydrocarbons from marginal reservoirs and sustain cost-efficient production. Figure represents activity in the United States, which is similar to global trends, with large volumes of wells designed with deviated trajectories. 

A real-time downhole data acquisition solution for interventions beyond production logging without the negative impact of a heavy cable includes the implementation of a fiber-optic (FO) cable to establish the communication link between surface equipment and tool to provide real-time downhole measurements. The ACTive* family of live downhole coiled tubing services was first field-tested in 2007 with a 2-1/8 inch outside diameter (OD) (photo). The first generation system is deployed with a FO cable that is unaffected by common wellbore pressure and pumped fluids. It is also significantly smaller and lighter than mono and hepta-cable alternatives, with an OD of 1.8 mm and an approximate weight of 10 kg/1,000 m. The first generation downhole sensors included strain gauges as pressure sensors, temperature sensors, and a casing collar locator (CCL), initially acquiring data at a rate of 38.4 kb/s. Pressure measurements for the system had a range of 12,500 psi, with a resolution of 0.3 psi, and an accuracy of +/-30 psi. The temperature measurement had resolution of 0.03 deg F and accuracy of +/-1 deg F. The included CCL was able to operate in up to 7 inch casing. 

In 2011 improved electronics were introduced for the ACTive family of live downhole coiled tubing services. The improved electronics allowed for higher acquisition bandwidth of 460.8 kb/s, more accurate pressure and temperature measurement using micro-electromechanical systems (MEMS) sensors with resolution of 0.075 psi and accuracy of +/-5 psi, and an architecture that provided increased modular expandability. Leveraging this architecture, a new modular Gamma Ray detector, as well as a force and torque sensing module were successfully field-tested on a number of wells. The ACTive TC live CT tension and compression tool is a load cell with axial force sensing capability of -10,000 to +45,000 lbf, with a usable resolution of around 2 lbf and an accuracy of +/- 2 percent of BHA-applied load for most applications. 

Case Studies

The following case studies illustrate how surface measurements alone are not sufficient enough to describe changing downhole conditions – especially in horizontal or highly deviated wellbores – and how the availability of downhole force measurements can improve the success of well intervention applications. 

Example 1: False Overpull

During a recent inflatable packer operation in a long horizontal well in the Middle East, real-time downhole force measurements helped to avoid unnecessary delays due to corrective action to prevent premature disconnect. Figure