Eagle Ford Lateral Wellbore Analysis Using Drill Cuttings

Abstract

Thanks to advances in technology and expertise, shale well drilling times continue to drop and the total drilling cost per well continues to decline. Enhancing this trend of improved drilling efficiency, operators are also developing methods and procedures for improving well stimulation based on local rock characteristics. These “engineered completions” require rock quality data along the lateral in order to be effective. Since open-hole well logs (MWD/LWD) and conventional coring is seldom practical along laterals and there can be a great deal of variability, it is becoming more critical to obtain high quality geologic data from drill cuttings. We will show results of drill cuttings analysis from several hundred samples along both the vertical and horizontal tracts from an Eagle Ford well (EF1). Data collected from drill cuttings samples includes elemental composition and scanning electron microscopy to allow detailed visualization and quantification of pore types and organic material abundance throughout the section. Utilizing cuttings can assist in adjusting the landing (target) zone, adjusting geologic spacing of fracturing zones for well completions, predicting Estimated Ultimate Recovery (EUR), and comparing results between multiple wells. Well EF1 has data from both a vertical pilot-hole (10 foot intervals) and from the lateral wellbore (30 foot intervals). In all more than 350 sample intervals were analyzed. Specialized sample collection and handling procedures were developed for this project. These procedures helped ensure that adequate and useable samples were collected and that the depth registration was reliable. Analytical results show that lithology variation along the lateral wellbore can be determined from shale cuttings samples. The drill cuttings data has been compared to other data from well logs and whole core and the results are consistent. The data shows that some zones along the lateral were in the targeted strata and others were not.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015