How to Utilize Hydraulic Fracture Interference to Improve Unconventional Development

Abstract

As unconventional reservoir development progresses, tighter well spacing improves recovery at the risk of an increase in well-to-well hydraulic fracture interference. During stimulation, fractures dilate along preferential planes of weakness that extend into an existing offset well"s producing volume. This can result in water penetration and stress reorientation. The objective is to show how to analyze pressure and rate responses from fracture interference data to impact operations, adjust field development, and identify future upside potential. The methodology starts with identifying whether fracture interference during hydraulic stimulation is beneficial (positive frac interference) or detrimental (negative frac interference) to offset producers. The impact of hydraulic fracture interference is then quantified by performing multi-phase production data analysis. The system alteration is measured by calculating the changes in well productivity and estimating incremental loss or gained volume for the pre-existing producer due to a frac interference event. This information is utilized to build full field development scenarios by modifying the drilling and completion schedule and well spacing so that the most profitable strategy is obtained. We identify that the drivers of fracture interference consists of (1) areal variation of reservoir properties, (2) pressure depletion due to the initial generation of wells, and (3) distance between producer and infill wells. The first development scenario evaluates the impact of deferred or gained production due to a frac interference event for different geological areas. The following case high-grades acreage based on areal variation of reservoir properties by delaying the development of deferred or lost production areas due to a negative frac interference event. The last scenario captures the opportunity for a tighter well spacing in areas with positive frac interference event. Based on the learnings derived from each scenario, the most profitable development strategy is presented for a typical unconventional reservoir. Furthermore, a new re-stimulation selection criteria is proposed to capitalize on the benefits of fracture interference. Conclusions are drawn from analyzing multiple multi-stage horizontal wells from the South Texas Eagle Ford and North Dakota and Montana Bakken reservoirs. In this paper, our results extend beyond retrospective studies by quantifying reservoir changes using a multi-phase approach and utilizing these results to impact development. Prior studies limited the classification of fracture interference as negative consequences of development. However, our investigation indicates that with improved understanding, we relate the impact of these events to development scheduling, confirmation of well spacing, and high-grading acreage to mitigate risks and harness the benefits of fracture interference as a mechanism of passive re-stimulation.

Numerical Investigation of Major Impact Factors Influencing Fracture-Driven Interactions in Tight Oil Reservoirs: A Case Study of Mahu Sug, Xinjiang, China

“…Second, the oil production rate sharply decreased in the fracture phase of the adjacent active wells. This behavior has been reported in Woodford, Eagle Ford, Bakken, and Horn River [4,26,27], but this is the first time it has been abundantly observed in Mahu. Finally, these production data showed evident, simultaneous variations in the passive wells in response to interference from active wells.…”

Physical Models for Inter-Well Interference in Shale Reservoirs: Relative Impacts of Fracture Hits and Matrix Permeability

“…Ideally, the infill wells should have the minimum well interference with the existing wells (Ajani and Kelkar 2012). When the well spacing is much closer, the well interference is more frequent (Ajani and Kelkar 2012;Malpani et al 2015; Kurtoglu and Salman 2015). The fracture hits can negatively affect well performance when damaging a well (Yaich et al 2014;Malpani et al 2015).…”

“…The degree of well interference can be observed and quantified through the change of parent wells' performance when drilling offset wells (Ajani and Kelkar 2012;Yaich et al 2014). The wells might show an increase in water production and an increase or decrease in oil or gas production (Lawal et al 2013;Kurtoglu and Salman 2015). In addition, pressure testing on pad wells is often utilized to identify the well interference (Portis et al 2013;Sardinha et al 2014;Sani et al 2015;Scott et al 2015).…”

CO2, Water and N2 Injection for Enhanced Oil Recovery with Spatial Arrangement of Fractures in Tight-Oil Reservoirs Using Huff-‘n-puff

“…This requires the rock to be water-wet. To alter the rock wettability, surfactants can be used [36][37][38].…”