Technology Trail Review: Selective Coiled Tubing Reentry of Two Open Hole Multilateral Wells Using Intelligent Electromechanical Arm

摘要

A maximum reservoir contact (MRC) well, by definition, is a single or a multilateral horizontal well with more than 5 km of total contact with the reservoir rock. Planning of these wells requires extensive modeling studies to optimize the well's total length, well placement, and the configuration of its branches. The main objective behind the MRC well concept was to improve individual well productivity, and thereby reduce the unit development costs and better develop a field's hydrocarbon assets. In fact, oil fields developed using MRC wells show significant improvements in those wells' performance in terms of increased productivity index, lower drawdown, and delay of water and gas conning. A major challenge that faces production engineers in their daily operations is identifying and accessing lateral windows in those MRC multilateral wells; this is typically done to perform rigless downhole sensing and intervention jobs - logging, stimulation, etc. This challenge varies in difficulty based on the technology advancement of multilateral (TAML) levels. For example, in TAML Level 2 wells - cased mainbore (MO) - metal logging tools such as the casing collar locator can be used to identify and confirm the access of laterals. This, of course, is not an option in TAML Level 1 multilateral wells -open hole MO and lateralfs). Another reason selective reentry involving TAML Level 1 wells is considered very difficult is the shape and quality of the wellbore near the junction (window) post-drilling and after distortion of hydrocarbon flow. This article describes an intelligent electromechanical (EM) tool, jointly developed to address this issue. The tool consists of a sensing package that can identify and locate the depth and orientation of the lateral window using an ultrasonic scanner and EM sensor, and an EM arm that can be easily rotated and actuated, with a wide range of angles, to lead and steer the bottom-hole assembly into the required lateral. This article also discusses the discoveries, challenges, and results of testing this intelligent tool in two TAML Level 1 multilateral oil producers: one a fishbone well with a MO and six open hole laterals branching from it (accessed under shut-in conditions), and the other an open hole well with a MO and a lateral branching from it (accessed under both shut-in and flowing conditions). In both trials, the tool was successfully used to guide a production logging tool (PLT) into different well laterals.