Simulating Proppant Flowback for Conventional, Screenless and Multizonal Fracpack Using Novel Resin Coated Proppant

Abstract Brown fields with unconsolidated reservoirs often produce high amount of sand and fines. Typical conventional screened Multizone Single Trip (MZST) completion technique is cost-intensive and erodes project economics. Screenless fracpack via frac sleeves offers a solution to significantly reduce well cost while at the same time achieving downhole sand control. Proppant flowback in a screenless fracpack application is a major concern that can curtail production and hence, negatively affects the overall project economics. Mathematical models and laboratory tests to simulate flowback of a novel resin-coated proppant (RCP) are performed to ascertain production boundaries and avoid proppant flowback. The engineering-based proppant flowback studies have enabled the project team to potentially reduce up to 25% of wells cost by performing screenless fracpack via frac sleeves. Recent literatures on proppant flowback studies have shown that frac width, proppant size, proppant pack permeability, proppant friction coefficient, confining stress and producing fluid viscosity are relevant parameters that determine the critical velocity for proppant flowback. Proppant 40/70 RCP pack is sandwiched between sandpaper, polymer-layered metal plates to mimic the closure stress acting on the RCP pack. Mixture of heated water and glycerol is pumped through the flowback cell with increasing flowrate and measured differential pressure. The free proppant is collected on a fine mesh metal sieve. From the laboratory test, the critical velocity for RCP flowback required for mathematical model and simulations is obtained. The model is then compared with an actual screenless fracpack via frac sleeves job in Field B Different levels of curing strength of the RCP are prepared with the "least curing strength" (65 C and 4-hour curing time) whereby the "strongest curing strength" (85 C and 24-hour curing time), which these parameters is based on the parameters of each targeted reservoir zone of each well. The least curing strength's RCP pack shows instability with low critical velocity while the strongest curing strength's RCP pack shows high critical velocity beyond 63 cm/s and high pressure drop at failure. The associated critical velocities are incorporated into the flowback simulator and modelled with specific geomechanical properties of the reservoir. The results show that the longer RCP curing time of beyond 48 hours, with longer drawdown duration of at least 6 hours and maximum drawdown of 300 psi can prevent proppant flowback and ensure near wellbore area is maintained to be propped. The recommendations of the laboratory and simulation studies were performed in Field B where very limited proppant flowback was observed. The success of the RCP flowback simulation backed by actual field results paves the way for more screenless fracpack application which significantly improves project economics This is the first RCP laboratory test conducted whereby the results were incorporated into the flowback simulator. Previous studies only involved standard non resin coated ceramic proppants.