Years ago, when I asked my mentor what the key to a successful well test was, he said, “Clear objectives, the right equipment, attentive operations, and comprehensive analysis.” I joked that it sounded quite simple and obvious, to which he responded, “Simple and obvious doesn’t mean easy to achieve.”
So, here we go, years later, with my contemplation of the simple and the obvious of a successful well test.
First, establish clear and specific objectives using a systematic approach and align them with all stakeholders. From design and implementation to data collection and analysis, test objectives should remain the go-to framework for decision-making.
The Right Equipment
Advances in equipment enable us to gather data beyond the capabilities of what was previously feasible: high-resolution gauges, wireless telemetry, distributed temperature sensing, real-time flow-control devices, advanced bottomhole and surface sampling techniques, and multiphase flowmeters, to name but a few. We understand that hardware dictates the quality of the data. We should also consider equipment fit for purpose with value of information in mind while remaining committed to safety and tolerant of uncertainty. A deepwater exploration test will require a different set of equipment than a diagnostic fracture injection test (DFIT) or a production-allocation test.
Procedures should be in place to achieve success, such as basis of design, risk assessment, well tests on paper, detailed operation procedures, and meetings (e.g., prejob safety, pretour). But, as Murphy’s Law tells us, what can go wrong will go wrong: Equipment may fail, people may make mistakes. Complacency is the enemy, so operational personnel should always remain alert and keep uncertainty and contingency in mind. As always, safety is the No. 1 objective and the most critical consideration.
Analytical capabilities have progressed since the days of the semilog plot, with, for example, various type curves and near-wellbore/boundary models, carbonate and fracture models, deconvolution, nonlinear modeling, interference tests, horizontal wells, and DFITs. While the new digital era will provide insights from machine learning and automation from massive amounts of information, foundational data still should be collected and quality checked. Subsurface remains inherently a nonunique problem to solve, so, rather than mindlessly fitting the data, the engineer still will need to consider what makes sense with uncertainty in mind.
The papers selected for this issue focus on key factors in achieving a successful well test. They also apply reservoir fundamentals as well as sound engineering judgment, with examples from conventional and unconventional assets.
This Month's Technical Papers
Recommended Additional Reading
SPE 189826 DFIT Analysis in Low-Leakoff Formations: A Duvernay Case Study by Behnam Zanganeh, University of Calgary, et al.
SPE 189840 Reinterpretation of Flow Patterns During DFITs on the Basis of Dynamic Fracture Geometry, Leakoff, and Afterflow by Behnam Zanganeh, University of Calgary, et al.
SPE 189844 Estimating Unpropped-Fracture Conductivity and Compliance From Diagnostic Fracture Injection Tests by Han Yi Wang, The University of Texas at Austin, et al.
|Heejae Lee, SPE, is a senior engineer with ExxonMobil Production Company. He has 18 years of experience in the oil and gas sector, including in simulation research, worldwide exploration/development well testing, and various projects in ventures/development/production as a reservoir engineer. Lee is currently the supervisor for the upstream reservoir engineering integration team, which is home to the well-testing team. He holds a PhD degree in petroleum engineering from The University of Texas at Austin. Lee is a member of the JPT Editorial Committee and can be reached at firstname.lastname@example.org.|
Heejae Lee, SPE, Senior Engineer, ExxonMobil Production Company
01 February 2019
Artificial Intelligence Transforms Offshore Analog Fields Into Digital Fields
This paper details how artificial intelligence was used to capture analog field-gauge data with a dramatic reduction of cost and an increase in reliability.
Field Trial of Cloud-Connected Wireless Completion System
This paper describes the development and field trials of a cloud-connected, wireless intelligent completion system that enables long-term monitoring and interval control to enhance production management by connecting the user wirelessly from the desktop to downhole inflow-control valves.
Liquid-Loading-Mitigation Strategies Maximize Recovery From Gas Reservoirs
To predict liquid-loading tendencies and to identify opportunities for production enhancement, the performance of 150 gas wells was analyzed in two gas fields in India.
No editorial available
Don't miss out on the latest technology delivered to your email weekly. Sign up for the JPT newsletter. If you are not logged in, you will receive a confirmation email that you will need to click on to confirm you want to receive the newsletter.
13 January 2020
16 January 2020
14 January 2020
No editorial available