Fracturing Design Optimization through Dimensionless Productivity in the South Sulige Field

Abstract

Abstract A field development project in the central part of the Ordos Basin began in 2011 with the intent to develop commercial production from the two main gas producing intervals. The gas layers within the Shihezi and Shanxi Formation within the South Sulige field are low permeability (0.1 mD) with moderate volumes of gas in place that require hydraulic fracturing to be commercially viable. The early application of technology to minimize development costs and surface impact included multiwell pad-drilling to enhance drilling, completion, and operational efficiency. Fracturing cycle times were reduced by the implementation of multiwell hydraulic fracturing processes, while not compromising well productivity. To date, 33 well pads have been completed which represents more than 280 vertical wells and 13 horizontal with more than 600 hydraulic fracturing stages being done within the previous three years. The wells completed have encountered a largely heterogeneous field that has resulted in a sizable amount of data being collected. To improve on this phase of the project, a fieldwide study of fracturing performance has been performed and includes the quantification of dimensionless productivity index (JD), dimensionless fracture conductivity (CfD), and dimensionless proppant number (Np). This analysis was performed on various well types, completions types, and fracturing design approach to benchmark performance. Analysis shows some improvements were made since the initial years of the project with designs starting to approach an optimum, but more significant advances can be made. Subsequent design adjustments and well optimization were done with improved understanding of postfracture performance derived from fracturing performance type curves. This paper will discuss the optimization of the fracturing design through use of JD. The discussion will mainly focus on the use of the JD type curves and accumulated production performance to determine optimal proppant and half-length for improvements in future fracturing designs.