Abstract

Microseismic event density heat maps at sequential time intervals during the treatment of individual completion stages have been developed to better understand fracture behavior on a stage level. Animating these heat maps through time on a single stage provides fascinating visual insights into the dynamic sequencing of populations of events, event timing and their likely genesis, providing a new way of visualizing and interpreting microseismic data sets. This technique leverages heat-map benefits from URTEC 2674376, excluding microseismic event clusters that may obscure or skew statistical analysis of the event densities, thus allowing for more accurate assessment of geologic features, stimulated rock volume, near-field concentration of events due to varying cluster spacing, fracture efficiency and stress shadowing. Far-field microseismic events prior to ramp up of treatment pressure are clearly indicated from this technique that cannot be observed with standard heat maps with certain completion designs. Unambiguous changes in microseismic event character from these far-field pre-ramp up events to those near-field events occurring at the onset of pressure are also observed. Applying a stage by stage approach on packages of wells and different locations provides robust statistical conclusions pertaining to reservoir behavior during well completion.

Introduction

The objective of drilling and completion design is to produce the maximum volume of hydrocarbons per dollar invested. During the course of well placement and completion design, engineers have a number of basic questions that require evaluating hydraulic fracture stimulations or treatment (Maxwell S., 2014). These include: What is the primary fracture orientation? How far away from the well will the fracture grow? How much upward and downward height growth will occur? What are the best injection volume, rate, and pressure? How many fracture stages should be used and where? How many fracture initiation points (i.e., casing perforations) per stage will be required and where? Are there preexisting fracture zones of faults that can influence the fracture? What is the best spacing between wells?

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