Application of Micro-Proppant to Enhance Well Production in Unconventional Reservoirs: Laboratory and Field Results

Abstract

As more wells are drilled and completed in tight, brittle formations, operators rely more on small-sized proppants to help ensure the created complex fractures are propped, and to maintain conductive flow paths for production. Most microfractures generated in the far-field away from the primary fracture branches are believed to return to a closed state soon after the release of hydraulic pressure, unless propping agent has been successfully placed inside such fractures. This paper presents the results of laboratory study, numerical modeling, and field trials, to demonstrate and quantify the effectiveness of a new treatment method for enhancing conductivity of microfractures and primary fractures formed in tight formations, thus helping improve well production.The approach involves using a micro-proppant (MP) and an aqueous-based surface modification agent (ASMA) as part of the pad fluid stage to treat fracture faces of microfractures and leakoff induced fractures before placement of larger-sized proppant into the primary fractures. This coating causes the proppant particulates to adhere to the created fracture faces by forming partial monolayer, thus mitigating settling and enhancing vertical distribution in the fractures. During experimental testing, various shale core samples were split along the core length to create artificial fracture faces. These fracture faces were then exposed to MP or proppant slurry treated with an ASMA, and were then reassembled for core flow testing under closure stress. An effective permeability comparison of the fractured cores, with and without ASMA treated MP or proppant, demonstrated a dramatic effective permeability increase in fractures of the treated cores.Field treatments involved injection of pad fluid containing a low concentration of MP, with and without treating with ASMA in offset wells, to treat the microfractures formed in the far-field regions. Proppant slurry of larger size particulates (100-mesh and larger) then followed to prop the primary fractures and their branches. Production from wells treated with MP have shown to provide significant improvement in terms of liquids production compared to the production of control wells. Reservoir simulation performed in this complex retrograde condensate reservoir supports this result, with sensitivity testing showing that increasing the connected fracture area enables the production of more hydrocarbon liquids at higher sustained production rates.

Porosity‐Permeability Relationships in Mudstone from Pore‐Scale Fluid Flow Simulations using the Lattice Boltzmann Method

“…Our models suggest that upon fluid injection in low porosity mudstones, the growth of a distributed microfracture network yields a greater vertical mudstone permeability compared to propagation of a macrofracture. This is consistent with several experimental, numerical, and field‐scale studies that record greater increase in mudstone permeability upon distributed fracture growth compared to a wide macrofracture (Backeberg et al, ; Dahl et al, ; Matthäi & Belayneh, ). Recent studies show that productivity of shale gas wells increases with the use of microproppants (1–50 μm) compared to typical proppants (100–300 μm) due to greater permeability enhancement provided by microfractures of smaller width (Calvin et al, ).…”

Research on the transport behavior of microparticle proppants inside natural fractures

“…Ultra-low permeability tight reservoirs are economically viable if proppant can reach these natural fractures and prevent them from closing (Apaydin et al, 2012;Cipolla et al, 2009). Therefore, Microparticle proppants (referred to as MPs) are introduced to increase the stimulation area (Dahl et al, 2015a;Kim et al, 2018;Dharmendra et al, 2019). Several studies have successfully applied MPs to the field (Nguyen et al, 2013;Bose et al, 2015;Dahl et al, 2015a;Dahl et al, 2015b;Calvin et al, 2017).…”

“…Therefore, Microparticle proppants (referred to as MPs) are introduced to increase the stimulation area (Dahl et al, 2015a;Kim et al, 2018;Dharmendra et al, 2019). Several studies have successfully applied MPs to the field (Nguyen et al, 2013;Bose et al, 2015;Dahl et al, 2015a;Dahl et al, 2015b;Calvin et al, 2017). Bedrikovetsky et al and Khanna et al proposed a staged proppant injection method (small proppants are injected first, and then large proppants are injected) (Bedrikovetsky et al, 2012;Khanna et al, 2013).…”

Effects of Well Placement Timing and Conductivity Loss on Hydrocarbon Production in Multiple Hydraulically Fractured Horizontal Wells in a Liquids-Rich Shale Play

“…Incorporating realistic induced hydraulic fractures in a reservoir model is easier if unstructured grids are used. In recent years, substantial progress has been made in the use of unstructured grid-based reservoir simulation models for describing flow in unconventional reservoirs for both single-well and multiwell cases (Siddiqui et al 2015;Dahl et al 2015aDahl et al , 2015bSchechter 2015a, 2015b;Ejofodomi et al 2015;Pankaj et al 2015).…”