Controlled optimization is true optimization

To truly optimize a multistage completion design for a given field and formation, you need a systematic completion approach that allows you to make well-to-well comparisons with confidence. You need consistent, repeatable frac delivery plus measured downhole data that helps you better understand the formation, the well, and the stimulation.

Watch Optimization: Plug & Perf vs NCS Multistage Unlimited Pinpoint Fracturing.

That means you can’t truly optimize conventional plug-and-perf completions and open-hole-packer/ball-drop-sleeve completions, because you don’t know how many fracs are created, where they are, and how much proppant goes into each one. Even if you did know, you couldn’t reproduce the completion because, with highly variable formation breakdown pressures, you have little or no control over where the fracs and proppant actually go. And you don’t get any downhole data unless you deploy a costly monitoring system.

A conceptual sketch of a field frac network using an older completion method.

A conceptual sketch of a field frac network using an older completion method, showing unstimulated reservoir resulting from uncontrolled frac spacing and frac dimensions. Technical References: URTeC 1571745; SPE 144326; SPE 163820; SPE 169574; SPE 174943

The goal of optimization is a field frac network that has the maximum number of stages without interzone communication.

The goal of optimization is a field frac network that has the maximum number of stages without interzone communication and the maximum frac dimensions without bashing other wells or unintentionally poaching other formations. The only way to achieve this is pinpoint fracturing.

With the Multistage Unlimited®pinpoint-frac system, you know where fracs initiate and exactly how much proppant you put in each one. No matter what else you adjust—frac spacing, frac dimensions, proppant type, frac fluid, injection rates, proppant concentration—frac placement remains predictable and repeatable from well to well, so you can evaluate the effects of any design changes you make. 

Recorded downhole data describes every frac

At every stage, the Multistage Unlimited frac-isolation assembly records actual pressures and temperatures at the frac zone and in the wellbore below (see chart below). Two proprietary, high-resolution gauge/recorders—one above the bridge plug and one below—measure and record pressure, temperature, and forces acting on the tool string during a completion. Stage-by-stage details give you insights you don’t get with older completion technologies. Use recorded pressures to optimize stage spacing

Use recorded pressures to optimize stage spacing

Post-completion analysis of the data reveals both the presence and type of any interzone communication (natural fractures, cement failure, longitudinal frac), so you can establish minimum frac spacing in a given formation. The data also identifies the presence and source of near-wellbore restrictions as well as proppant bridging when it occurs.

Actual pressure and temperature data from a single Multistage Unlimited frac stage.

Actual pressure and temperature data from a single Multistage Unlimited frac stage. The pressure readings confirm isolation from the stage below. Temperature readings show the cooling effect of the frac fluid.

 

Use recorded pressures to improve frac modeling

Recorded pressures at the frac zone (no pipe friction guesswork) permit better pressure history matching for calibrating rock properties, enabling more accurate frac modeling and reservoir simulation.

Use actual bottom-hole temperatures to optimize crosslinkers and breakers

As a bonus, recorded temperatures in and below the frac zone enable better crosslinker and breaker design and testing, using actual downhole warm-up and cool-down measurements instead of guesstimates.

Use deadleg pressure to optimize fracs from stage-to-stage

You can start optimizing during the completion by watching bottom-hole pressure in real time via the coiled tubing deadleg and adjusting pad size, sand concentration and ramp, and pump rates from stage to stage as you move up the wellbore, based on actual formation response. You can also be very aggressive without fear of screening out, because circulation will remove excess proppant very quickly so you can get right back to work.

Contact an NCS Multistage representative for more information on controlled optimization using the Multistage Unlimited frac-isolation system.

Download Controlled Optimization brochure.