Recently, a lot of discussion has revolved around the benefits of multilaterals in unconventional reservoirs. But is this truly the next breakthrough for the industry, or is it all hype?
No doubt enormous need exists for a technology such as this to improve reservoir recovery and reduce well cost.
The current modus operandi in many plays is to drill horizontal hydraulically fractured wells. The results, however, continue to show that these well types are not effective at draining the reservoir. This is a result of complex hydraulic-fracture geometries with very short propped heights and lengths. Fracture complexity is a natural phenomenon now proved by coring and is likely caused by reservoir stratigraphy and geomechanics. Completion engineers typically counteract this, to some degree, by pumping more fracture treatments in the horizontals. This ineffective drainage points to the benefits of greater reservoir contact with a multilateral.
As well as improved drainage, multilateral technology also can reduce well cost by avoiding the necessity to drill top hole for the second (or third) lateral and requiring only one completion and one set of surface equipment.
Multilateral technology has been around for many years; however, what has changed in recent times is the reliability of these systems, with more than 98% reliability quoted in a recent publication. Hydraulically fracturing the laterals is now possible as well.
Companies such as Occidental, BP, and ConocoPhillips are evaluating the potential of this technology in onshore unconventional plays. In fact, in the fourth quarter of 2017, Occidental successfully performed its first pilot.
Enormous need for this technology exists, and time will tell whether it is the next major step in subsurface technology to improve the unit cost of production.
This Month's Technical Papers
Coalbed Methane Prospects in Indonesia
Unlocking Egypt’s Unconventional-Resource Potential
Coalbed Methane Development in China: Challenges and Opportunities
Recommended Additional Reading
SPE 188231 Modeling Early-Time Rate Decline in Unconventional Reservoirs Using Machine Learning Techniques by Aditya Vyas, Texas A&M University, et al.
SPE 186107 Optimization of Spacing and Penetration Ratio for Infinite-Conductivity Fractures in Unconventional Reservoirs: A Section-Based Approach by S. Liu, Texas A&M University, et al.
SPE 186092 Rate Dependence of Bilinear Flow in Unconventional Gas Reservoirs by M.S. Kanfar, University of Calgary, et al.
