Entering multilateral wells using coiled tubing

Using a lateral-entry tool with coiled tubing enhanced production and injection, saving time and adding pay zone offshore Qatar.

Robert Proctor and Ryan Grant, BJ Services; Andrew Marron and Danny Cubas, Occidental Petroleum of Qatar

Openhole, horizontal multilaterals have proven cost-effective to drill, delivering high-rate wells in the short term. However, longer term, as production declines and the watercut increases in the well, intervention operations are required including water conformance, stimulation, production logging and water shutoff. Openhole, horizontal multilaterals are not designed for interventions into the laterals. The intervention method requires a drilling or workover rig to pull the completion and then use jointed pipe to guide the tools into the desired lateral. High rig rates, long workover times, limited rig availability, operational risks and the high potential for formation damage make workovers costly. Alternatively, well interventions could be done using Coiled Tubing (CT), a cheaper method than jointed pipe. For CT to enter all the laterals, a lateral entry guidance system is required, since CT has no inherent steering capability.

LATERAL-ENTRY GUIDANCE SYSTEM

Entering openhole multilateral wells is not simple. The problem was considered with respect to tool string complexity. A fluid-activated guidance system was designed to allow entry into a lateral without an electronic telemetry system.

The tool was designed to be thru-tubing capable, acid compatible, solvent compatible, and able to run on multiple CT sizes, with no telemetry system or fluid-activated electrics and positive surface indications for lateral entry.

The tool is made of three components: a control valve, a kickoff section and a sweep section. The upper part contains the control valve section, which has two operational modes: circulation and navigation. Circulation mode is activated while Running In Hole (RIH) and circulating fluids. While circulating fluids, the BHA remains in a straight position.