Comparison of Single-Entry Coiled Tubing-Activated Frac Sleeves vs. Multi-Cluster Plug-and-Perf Completion in the Permian and Anadarko Basin: A Case Study
Authors: Algadi Otman A. , Castro Luis , Mittal Rohit 
Published: September 2015

Maximizing ultimate recovery in unconventional wells presents many completion challenges. Among the most relevant, is consistently initiating multiple dominant fractures in close proximity to each other along the lateral. The most common fracturing method, Plug-and-Perf (PnP), relies on stimulating multiple clusters at once, leaving much of the pay zone unstimulated due to fractures initiating at the path of least resistance instead. These unstimulated sections create gaps in the fracture networks, which result in lower well profitability by hindering production and reducing estimate ultimate recovery (EUR). An alternative completion system, coiled tubing-activated frac sleeves (CTFS), is a method that provides accurate fracture placement and greater efficiency. This paper evaluates the production performance of this single-entry fracturing technique compared to the traditional multi-entry PnP method in the Granite Wash and Bone Spring formations.

In this study, production analysis was done to compare performance CTFS vs PnP wells. Monthly well production data was derived from public sources. Decline curve analysis was used to appraise the estimated ultimate reserves for each well compared to the other wells in the immediate surrounding area.

To complement the decline curve analysis study, a single stage reservoir simulation study is also included in order to compare the performance of the two completion methods. Three and six clusters for PnP stage and 3 entries for the single-entry completion were first simulated in hydraulic fracturing software. The estimated fracture geometry and conductivities were then used to generate a single stage reservoir simulation model. The properties of the reservoir were based on Wolfcamp formation. The simulation estimated cumulated recovery in 30 years.

The results of the study show that the use of the single-entry fracturing technique has improved production in comparison to offset wells that were completed conventionally. In the Bone Spring formation, a well completed with CTFS outperformed top 20% producers in the same formation. In addition, results from fracture modelling and reservoir simulation show that more efficient and evenly distributed fracture networks were achieved by using the single-entry technique. Consequently, production has improved by 12% over the multi-entry technique. Also, long-term performance analysis of the Granite Wash study confirms that the use of CTFS as an alternative to PnP has tripled the estimate ultimate recovery. Hence, the CTFS method improved overall fracture placement and proved to be a more efficient alternative to PnP method.

The paper presents novel information by evaluating long-term production data and benefits of single-entry stimulations compared to multiple entry fracturing treatments. Additionally, analysis of actual field data through the use of fracture modeling, reservoir simulation and type well analysis provides new technical insights when comparing fracture geometry, hydrocarbon recovery, and production performance between single and multiple-entry wells.