Abstract
Hydraulic fractures created during completion operations are assumed to produce back to the original well. While multi-well pad completions increase efficiencies, it complicates fracture connectivity between wells. The proximity of newly completed wells to a pre-existing producing well suggests a depleted zone that can "steal" fracture surface area. Correlations between real-time shear fracture measurements and post-stage Pressure Transient Analysis (PTA) can shed light on the fracture surface area connected to the original well vs. fracture surface area "stolen" by offset wells.
During hydraulic fracturing operations, shear fractures per slurry barrel are measured on the active stage. The connected fracture surface area is then calculated using the end of stage fall-off pressure data via PTA. This allows for the correlation of the fracture surface area created and the fracture surface area connected back to the original stage. Variations off a straight-line correlation suggest interactions with offset wells. For example, when fracture interaction with an offset depleted zone is present, PTA will calculate an extremely high fracture surface area when compared to the number of fractures created during the active stage. This reduces the effective production as the area created is not able to produce back to the original well.
This paper presents a new real-time method to estimate the stage-to-stage interference and well-to-well interference and their implications on completions efficiency. This paper also presents a solution to minimize frac hits between parent and child well based on generated fracture surface area to improve a pad's Estimated Ultimate Recovery (EUR). This is supported by a case history which shows a positive correlation between the created fracture surface area and its connectivity back to the wellbore. The new method does not require any well surveillance compared with existing methods and does not incur extra cost to operator.
