There are several different technologies available for completing and stimulating multi-stage horizontal wells. By far the most common of these is to use a cemented liner with multiple perforation clusters treated simultaneously in a single stage (plug-and-perf). One alternative method gaining popularity also employs the use of a cemented liner but with sliding sleeves allowing for single point entry into the formation (pinpoint). The objective of this paper is to compare the expected and observed reservoir performance resulting from each of these approaches.
To accomplish the objectives, two methods are appliedtheoretical and experimental. The theoretical approach uses a hydraulic fracture simulator to predict fracture geometry for both plug-and-perf and pinpoint completion techniques for a predefined set of treatment parameters. A reservoir simulator is then used to predict production and ultimate recovery for each case. The experimental approach involves choosing a drilling spacing unit (DSU) where these two completion techniques have been applied (in close proximity) while controlling, or normalizing for, as many other reservoir and completion variables as possible. The well performance data is analyzed using rate transient analysis (RTA), and the results compared to the predictions made by the theoretical models.
Theoretical modeling predicts that slightly better reservoir performance ought to be obtained in pinpoint completions, over plug-and-perf. Experimental (empirical) analysis of actual well performance data supports the theoretical predictions directionally, but significantly exceeds the uplift predicted by the theoretical models. Ideally, the experimental data should be collected under controlled conditions. In reality, this is not the case as operations on a typical well pad (as is the case in this study) are continuously subjected to disturbances, unconstrained variables and incomplete and/or inaccurate measurements. Thus, results from RTA are somewhat subjective and error prone. The confidence of these results improve dramatically as the sample data set increases.
To our knowledge, this work represents the first objective comparison of different completion types using rate transient analysis as an evaluation tool. The experimental benchmarking procedure introduced in this work is novel and represents a significant improvement over existing industry standards for understanding how completion technology can impact well performance.