Intelligent Running Tool to Provide Real-Time Feedback for Subsea Casing Hanger Landing Operations
Authors: Allen T.J. , Worsley M.T. , Burton J.A. , Elliot K.W. 
Published: October 2008

Abstract
The application of an intelligent running tool (smart tool) for subsea casing hanger-landing operations is presented. The system provides intelligent feedback of critical parameters while landing and cementing the casing and setting and testing the casing hanger seal assembly subsea. Two-way communication is provided between a technician on the rig floor and a Casing Hanger / Seal Assembly Running Tool (CHSART) in the subsea wellhead. The communication provides real time data used to quickly make informed decisions regarding operations related to landing and cementing the casing and setting and testing the casing hanger seal assembly. The information provided reduces drilling costs and running time by providing more positive feedback of casing hanger position and status of the seal assembly. The system thereby reduces the time required to make decisions and diagnostic time required to assess possible problems encountered when landing the casing or setting the seal assembly.

Introduction

Deep water needs better assurance.
Drilling operation activity in deep water results in an increase in the costs associated with drilling and completing a well. This increase comes from many facets of the operations. Additionally, the traditional feedback mechanisms of variations in pipe tally, torque, tension and pressure are significantly reduced in accuracy due to longer running strings, longer drilling risers and larger volumes of fluids in the system. The Camsmart tool is designed to reduce the risks associated with drilling the well and reduce the time and trips required remedying problems encountered in the well program by providing real time information regarding the casing landing and seal assembly setting and testing operations.

Ongoing difficulties running casing.
Casing running operations may have improved in recent years resulting in increased safety and a near perfect record for casing landing and seal setting operations. However, the increase in the use of directional drilling has resulted in casing continuing to get stuck in the hole prior to landing out in the wellhead. One of many recent examples of this is a well West of Shetlands where the casing was run into the hole, the seal assembly set and tested and a completion set above the casing hanger. When the tubing hanger was being tested, the casing hanger settled in the hole, falling approximately 3". The tubing hanger was retrieved and re-run into the wellhead, resulting in a significant amount of non-productive time (NPT). The resultant well was ultimately completed successfully, brought on line and is currently producing. Camsmart is designed to eliminate the risk of an event like this from occurring.

Accurate feedback can reduce NPT.
In many other occasions, the wellhead tools have performed as designed in landing the casing, but the feedback from the tools has been deemed inconclusive or other elements have resulted in operational problems. The proper setting of a seal assembly has been questioned on numerous occasions, particularly when a pressure test fails.