Limited entry perforation configurations effect on proppant transport and distribution in fresh water

Proppant transport in horizontal wellbores has received significant industry focus over the past decade. One of the most challenging tasks in the hydraulic fracturing of a horizontal well is to predict the proppantconcentration that enters each perforation cluster within the same stage. The main objective of this researchis to investigate the effect of different limited-entry perforation configurations on proppant transport,settling, and distribution across different perforation clusters in multistage horizontal wells. To simulate afracturing stage in a horizontal wellbore, a laboratory-based 30-foot horizontal clear apparatus with threeperforation clusters is used. Fresh water (∼1 cp) is utilized as the carrier fluid to transport the proppant. This research incorporates the effect of testing three different injection rates each at four different proppantconcentrations on proppant transport. Different limited-entry perforation configurations are also used to testthe perforation effect on proppant transport using similar injection rates and proppant concentrations for thesame proppant size. The proppant is mixed with fresh water in a 200-gallon tank for at least 10 minutesto ensure the consistency of the slurry mixture. The mixture is then injected into the transparent horizontalwellbore through a slurry pump. This laboratory apparatus also includes a variable frequency drive, a flowmeter, and two pressure transducers located right before the first two perforation clusters. Sieve analysisis conducted to understand the ability of fresh water to carry bigger particles of the mixture at differentinjection rates, proppant concentrations, and perforation configurations. The results show different fluid and proppant distributions occur when altering the perforationconfigurations, injection rates, and proppant concentrations. The effect of gravity is extreme when usinga limited entry configuration at each cluster (1 SPF) located at the bottom of the pipe, especially at lowinjection rates, resulting in uneven proppant distribution with a heal-biased distribution. However, evenproppant distribution is observed by changing the limited entry perforation configuration to the top of the horizontal pipe at similar injection rates and low proppant concentration. Increasing the proppant concentration reduces the void spaces between the particles and pushes them away toward the toe cluster. Even proppant distribution is also observed across the three perforation clusters when using high flow ratesand a 2 SPF perforation configuration located at both the top and the bottom of the pipe. The results ofthe sieve analyses show different size distributions of the settled and exited proppant through different perforations and clusters. This illustrates the ability of fresh water to transport different percentages ofdifferent proppant sizes to different perforations and clusters within a single stage. Frequently, the injectedproppant is assumed to be distributed evenly across the perforation clusters and that the distribution offluid and proppant is identical. However, this research adds data to the portfolio that this assumption isgenerally not valid. Additionally, the distribution of the transported proppant is observed to be different across individual clusters and different perforations within each cluster. Such information is beneficial to understanding transport in horizontal, multi-stage completions and how such impacts the overall treatment efficiency, especially when employing limited-entry perforation techniques.