Optimizing Well Engineering for Permian Geology/Fluid Using Model-Based Analytics

Abstract

Description:

A comprehensive interpretation of nearly 2 million geologic tops is used to build a structural framework spanning the: Delaware Basin, Central Basin Platform and Midland Basin. Digital well logs are extracted over mapped Leonardian and Wolfcampian geologic zones and are gridded into regional trends. Fluid information, gathered during production testing and historical production, are similarly gridded for corresponding well target zones – to create maps of: GOR, water-cut, gas-cut, and more. Full 3D models are constructed for key petrophysical and fluid properties, which in turn are extracted to average values along intersecting horizontal wellbores.

Model-based analytics are then used to correlate extracted properties and engineering data (horizontal length, etc.) to build a well production prediction model. Finally, the analytics model is normalized for engineering variability (i.e. engineering parameters are set to nominal values) and is applied to the 3D property models of gamma-ray, porosity, pressure, water-cut, etc. – creating a 3D sweetspot volume. Incorporating vertical and horizontal well spacing data into the analytics model updates provides a way to estimate well production depletion effects on the sweetspot model

Application:

The original and depleted Permian 3D sweetspot models provide insight into existing well pattern effectiveness and metrics for design of future multi-bench development. Well-to-well frac interference and production contention effects are highlighted, providing guidance into not just horizontal well placement – but also timing of infill and extension development. The analytics model can also be used to predict planned well performance, through specification of intended target location, well length, frac intensity and stage spacing.

Results and Conclusions:

Contrary to previous published studies that focus on the importance of high-energy fracs, we find that frac intensity, and other engineering parameters, need to by tuned to rock and fluid properties of targeted reservoirs. Specifically for the Permian: water-cut, reservoir pressure, potential frac barriers and relative lithology and porosity need to be factored into any engineering optimization workflow.

Technical Contributions:

Regional 3D property models of the Permian Basin. Creation of corresponding original and production-depleted 3D sweetspot models. Evergreen model of optimizing engineering designs for specific target reservoirs.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018