ABSTRACT:

Novel drilling and completion techniques have substantially increased production of unconventional reservoirs around the world. Hydraulic fracturing has proven as an efficient method to enhance productivity of unconventional resources including shale oil and gas, geothermal reservoirs, and for in-situ recovery mining systems, and to increase the safety and efficiency of block cave and longwall mining. However, undesirable propagation extent of hydraulic fractures has always been considered a shortcoming and a potential risk associated with this technique.

In this study, a set of laboratory experiments are carefully designed to benchmark the potential of utilizing small-diameter Radial Jet Drilled (RJD) laterals in directing hydraulic fractures. Numerical simulation of the experiments is performed to predict the geometry of the induced fracture as well as examining the experiment procedure and fracturing fluid properties.

1. Introduction

Hydraulic fracturing has proven as an efficient method to enhance productivity of unconventional resources including shale oil and gas (Economides and Nolte 2000), geothermal reservoirs (McClure and Horne 2014), and for in-situ recovery mining systems (Silva and Ranjith 2019), and to increase the safety and efficiency of block cave and longwall mining (Jeffrey and Mills 2000).

A hydraulic fracture initiates from the wellbore and is expected to grow along the minimum in-situ stress plane. Other factors including layering, stress contrast, weak bedding planes, natural fractures, and anisotropy may affect the direction of the hydraulic fracture. Thus, other than the initiation point in the wellbore, the operator has little control on the direction of induced fracture, arising the need for methods to control the direction of hydraulic fractures.

Radial jet drilling (RJD) is a cost-effective drilling technology that uses a high-pressure fluid jet to drill small-diameters holes to bypass the near-well damaged zone. The technology has been successfully applied in the USA, Canada, Bolivia, Argentina, and China (Huang and Huang 2019). The RJD technology has been recently revisited for developing of shale gas and geothermal resources, and as an alternative to hydraulic fracturing in places where the hydraulic fracturing is not allowed (Reinsch et al. 2018).

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