Hydraulic Fracturing: A Marcellus Case Study of an Engineered Staging Completion Based on Rock Properties

Abstract

In multi-fractured horizontal wells, the wellbore is segmented into stages that are stimulated separately. This segmentation is traditionally geometrically based on a specific stage length ("geometric staging"); which is usually determined by trial and error including cost and production history considerations. However, this approach does not take geological and geomechanical properties into account. An alternative method for staging ("engineered staging") uses these properties to determine the wellbore segmentation by grouping intervals with similar rock properties together; theoretically promoting a higher percentage of stimulated clusters and subsequently better production. This alternative method is not commonly used as data acquisition can be costly for a large group of wells. In Pennsylvania, two pairs of wells were completed in order to understand the added value of engineered staging design. In one of them, a comprehensive suite of openhole logs was run in the horizontal leg of a dry gas well. The staging was then designed according to the measured rock properties and the well was stimulated using slickwater with plug and perf. Finally, a production log was run in the well after a year in order to determine the downhole contribution of each stage and cluster. After 400 days of production, the well cumulative production outperforms its offset with geometric staging by around 5 to 7%, potentially attributable to the engineered design but still within the expected statistical regional deviation between wells. Long term impact is yet to be determined. In the other pair, no openhole log other than MWD Gamma-ray was run. However properties were projected from a nearby vertical pilot hole with logs onto the horizontal section of a well which was then completed using the engineered staging method. Here again production figures after a year are showing a potential benefit; but this time without the cost of data acquisition in the lateral. This paper describes the process that was applied to achieve the engineered staging of these wells. It details the initial geological and geomechanical data acquisition or projection; then describes the design of the hydraulic fracturing engineered staging and finally discusses the performance of the wells.

Four critical issues for successful hydraulic fracturing applications

“…Slocombe et al (2013) do not, however, report the impact on productivity of the wells. On the other hand, Lim et al (2014) report production impacts relative to a control group for 4 wells in the Marcellus Shale. The log-driven placement cases produced over 20% more gas over their first 400 days than the control group.…”

Multi-Fracture Propagation Considering Perforation Erosion with Respect to Multi-Stage Fracturing in Shale Reservoirs

“…Therefore, the effect of stress shadow should be weakened, or the increased resistance caused by stress shadow should be balanced, to promote a uniform flow distribution between fractures. Quite a few technologies have been proposed to promote uniform fracture propagation, such as limited-entry fracturing, temporary plugging fracturing, and fracture optimization [19][20][21]. Wu et al [22] investigated multi-fracture propagation and found that reducing the perforation number and adjusting non-uniform cluster spacing could effectively improve the unevenness of the fracture propagation using the displacement discontinuity method (DDM).…”

Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

“…Owing to the low porosity and permeability of shale gas reservoirs, hydraulic fracturing is regarded as a prominent technology for industrial gas production [1]. It has been proven by practice that multi-cluster fracturing of horizontal wells is the key technology for the successful development of shale gas reservoirs [2,3]. In the multi-cluster fracturing of a horizontal well, the fracturing fluid is pumped into the horizontal wellbore at high speed.…”