Optimum Fluid and Proppant Selection for Hydraulic Fracturing in Shale Gas Reservoirs: a Parametric Study Based on Fracturing-to-Production Simulations.

Abstract

Production from shale gas reservoirs depends greatly on the efficiency of hydraulic fracturing treatments. The cumulated experience in the industry has led to several best practices in treatment design which have improved productivity in these reservoirs. However, further advances in treatment design require a deeper understanding of the complex physics involved in both hydraulic fracturing and production, such as stress shadow, proppant placement and interaction with natural fractures. This paper investigates the non-linear physics involved in the production of shale gas reservoirs by improving the understanding of the complex relation between gas production, the reservoir properties, and several treatment design parameters, with a focus on proppant and fluid selection. A fracturing-to-production simulation workflow integrating the Unconventional Fracture Model, with the Unconventional Production Model is presented. This workflow has shown qualitative consistency with real production data. In this paper we applied the workflow on a realistic reservoir with characteristics from the Marcellus play, and then studied the relation between production and treatment design parameters such as proppant size, proppant concentration, the treatment volume of the treatment, fracturing fluid viscosity, pumping rate and proppant injection sequence. Since this paper focuses on fluid and proppant selection, our methodology was to run 28 simulations to cover the 2D parametric space of proppant size and fluid viscosity for every parameter. More than four hundred simulations were run in this parametric study and the results provide guidelines for optimized treatment design. The behaviors observed confirm several best practices in treatment design for shale. For example, combination of different sizes of proppant optimizes production by maximizing initial production and slowing down production decline. Simulations also confirm the best practice of injecting the smallest proppant first. Another key finding is that the optimum fluid viscosity increases with treatment volume, and decreases when pumping rate increases.

Impact of Low Prices on Shale Gas Production Strategies

“…3). Less widely reported is that proppant usage also fell, owing to a positive correlation with water usage in commonly accepted best practices (Phatak et al, 2013). Reduced water (and proppant) usage translates to lower completion costs.…”

Numerical Simulation of Proppant Transport in Transverse Fractures of Horizontal Wells

“…In recent years, a series of breakthroughs have been made in the exploration and development of unconventional oil and gas worldwide, and the production of unconventional oil and gas is growing rapidly and becoming increasingly prominent in the global energy supply. The application of the hydraulic fracturing technique on horizontal wells has been successfully applied in the unlocking of unconventional reservoirs, and the final hydraulic fracturing effectiveness has a close relationship with the proppant distributions [1][2][3][4]. Due to the fact that horizontal wells are usually drilled along the direction of the minimum horizontal principal stress, multiple transverse fractures can be generally created.…”

Modeling the Risk of Commercial Failure for Hydraulic Fracturing Projects Due to Reservoir Heterogeneity

“…However, with the production decline of conventional reserves, the petroleum industry has shifted more towards the development and production of unconventional hydrocarbon resources. In this sense, improving gas recovery from unconventional gas resources such as shale gas [1][2][3][4] and tight gas [5][6][7] reservoirs using the hydraulic fracturing technology has proved to be effective in supplying a part of the increasing global energy demand. Some examples of hydraulic fracturing applications have been reported all around the world [8][9][10][11][12].…”