Enhancing Type Well Profile Accuracy: Key Takeaways from SPEE's Monograph 5

Type Well Profiles (TWPs), often referred to as "type curves," are invaluable in the petroleum industry for predicting the performance of undeveloped wells and those with limited production history. Despite their widespread use, the methods for developing TWPs can vary significantly among engineers, leading to inconsistent and sometimes suboptimal applications. It’s crucial for both technical and non-technical stakeholders to understand the best practices in TWP preparation to ensure accurate predictions and informed decision-making.

Over the last several years, I’ve had the privilege of collaborating with leading petroleum engineers under the auspices of the Society of Petroleum Evaluation Engineers (SPEE). Our goal? To craft the definitive guide on TWPs: "Monograph 5 - A Practical Guide to Type Well Profiles." This comprehensive document, now undergoing peer review, promises to be an important contribution to petroleum engineering practice. In addition to the practicalities of TWP development, the document provides deep insights into fluid flow in horizontal, fractured low-permeability wells, alongside vital statistical considerations. Two of the co-authors presented a short course on the Monograph at SPEE's annual meeting in June, but while we await publication, here's a glimpse at three key topics it addresses.

Analog Selection - A reliable TWP starts with selecting the right analog wells. Analog wells are those that share similar geological, reservoir, and operational characteristics with the wells being evaluated. The accuracy of a TWP is directly linked to how well these analog wells represent the target conditions and behaviors. This process demands a thorough analysis of available data, including production histories, geological surveys, and completion techniques. Engineers must ensure the analog wells are truly representative to avoid significant errors in the resulting TWP. This meticulous process requires a deep understanding of the variables influencing well performance.

Forecasting Before TWP Preparation - Forecasting the performance of analog wells before incorporating them into a TWP is a critical step that often gets overlooked. By predicting future production of these wells, engineers can gain valuable insights into expected performance trends and variability. This approach allows the engineer to understand the distribution of the analog wells' ultimate recovery and examine the reservoir and operational factors that influence performance. TWP's that rely solely on historical data suffer from various biases, most importantly "survivor bias", that reduce their reliability.

Quantifying Uncertainty - Uncertainty is an inherent part of all predictive models, and TWPs are no exception. Quantifying uncertainty involves measuring the various sources of variability that can impact well performance. This includes the estimated ultimate recovery (EUR) variance of analog wells, the standard error of the mean for the EUR distribution, and forecast-related uncertainties. Employing robust statistical methods to quantify these uncertainties allows engineers to present a range of potential outcomes rather than a single deterministic forecast. Instead of relying solely on an average TWP, incorporating these uncertainties provides a nuanced estimate of drilling program outcomes at various confidence levels, as needed in reserves estimation and reporting.

Monograph 5 will run several hundred pages, so it's impossible to do it justice here. However, we'll let readers know when it's available and delve deeper into some of the topics in future newsletters.