The success of a horizontal drilling campaign depends on the implementation of appropriate technologies and procedures to manage uncertainties and risks that may affect the overall economy of the project. This is the case for most fields in the Orinoco oil belt—the largest reserve of heavy oil in the world—which is mainly developed via horizontal drilling. As with other fields in the area, Junin-6 presents special challenges for horizontal well placement. The friable shallow reservoirs include some of the shallowest currently developed in the Orinoco oil belt. The main target sands range in thickness from 30 ft in the Arenas Basales (Basal sands) to 250 ft in the Oligoceno (Oligocene) reservoir. The lateral sections vary from 3,000 to 4,000 ft. This, combined with a high geological complexity, lack of 3D seismic data, and a limited number of correlation wells, makes the horizontal well placement a real challenge in many cases.
Advanced logging-while-drilling (LWD) technologies had to be implemented in the challenging cases, such as in the Basal sands reservoir. A proactive approach based on bed boundary mapping technologies, combined whenever possible with point-the-bit rotary steerable systems, is being used to improve horizontal well placement in this field.
The main results include net pay increase and cost reduction compared to wells executed with conventional technologies. The risk of unproductive drilling has been considerably reduced, especially in the thinnest formations drilled in this field. The best results were achieved when LWD bed boundary mapping was combined with point-the-bit rotary steerable systems, since this type of technology enabled better well trajectory control, faster execution, longer horizontal sections, and safer completions.
This paper presents the main challenges for horizontal well placement in the giant Junin-6 heavy oil field and how they are being addressed with the use of advanced geosteering technologies.