A Geomechanical Analysis of Shale Hydraulic Fracturing Containment

Author(s):  
Amirhossein Kamali ◽  
Ahmad Ghassemi
2014 ◽  
Vol 2 (3) ◽  
pp. SG25-SG39 ◽  
Author(s):  
Yi Yang ◽  
Mark D. Zoback

We performed an integrated study of multistage hydraulic fracture stimulation of two parallel horizontal wells in the Bakken Formation in the Williston Basin, North Dakota. There are three distinct parts of this study: development of a geomechanical model for the study area, interpretation of multiarray downhole recordings of microseismic events, and interpretation of hydraulic fracturing data in a geomechanical context. We estimated the current stress state to be characterized by an NF/SS regime, with [Formula: see text] oriented approximately [Formula: see text]. The microseismic events were recorded in six vertical observation wells during hydraulic fracturing of parallel wells X and Z with three unusual aspects. First, rather than occurring in proximity to the stages being pressurized, many of the events occurred along the length of well Y, a parallel well located between wells X and Z that had been in production for approximately [Formula: see text] years at the time X and Z were stimulated. Second, relatively few fracturing stages were associated with an elongated cloud of events trending in the direction of [Formula: see text] as was commonly observed during hydraulic fracturing. Instead, the microseismic events in a few stages appeared to trend approximately [Formula: see text], approximately 30° from the direction of [Formula: see text]. Earthquake focal plane mechanisms confirmed slip on faults with this orientation. Finally, the microseismic events were clustered at two distinct depths: one near the depth of the well being pressurized in the Middle Bakken Formation and the other approximately [Formula: see text] above in the Mission Canyon Formation. We proposed that steeply dipping N75°E striking faults with a combination of normal and strike-slip movement were being stimulated during hydraulic fracturing and provided conduits for pore pressure to be transmitted to the overlaying formations. We tested a simple geomechanical analysis to illustrate how this occurred in the context of the stress field, pore pressure, and depletion in the vicinity of well Y.


2020 ◽  
Vol 1 (2) ◽  
pp. 50
Author(s):  
Aris Buntoro ◽  
Muhammad Nurcholis ◽  
Basuki Rahmad ◽  
Allen Haryanto Lukmana ◽  
Ristiyan Ragil Putradianto

In general, the South Sumatra Regional Stratigraphy of the Baturaja Limestone Formation facies is deposited on the Buildup Carbonate (Reef) and the Limestone Clastic Carbonate of the Baturaja Formation which grows as a buildup reef on the platform in the Basement High (Horst) underneath is the Lemat Formation volcanic deposits. Referring to the facies model in general, the Baturaja Limestone Formation, the depositional environment starts from Shelf Lagoon Open Circulation - Winnowed Edge Sand - Organic Buildup - Fore Slope - Deep Shelf Margin - Open Sea Shelf - Basin, meaning that carbonate is formed starting from pure organic Cabonate Buildup Reef without / a little sludge / mud to the Carbonate Basin where more muddy / mud is present, this condition causes clay minerals to also more and more mix with Terigenous Clastics (Quartz, feldpar). The complexity of the Baturaja Limestone Formation requires fracture barrier analysis associated with well stimulation planning in order to increase oil productivity with the appropriate method.   Fracture barrier fracture analysis is an approach method to determine the depth interval that becomes a barrier in hydraulic fracturing by correlating the results of geomechanical analysis from well log data and mineralogical analysis from drill cuttings data, so that a commonly used well stimulation method can be selected, namely hydraulic fracturing, acidizing, and acid-fracturing.From the ternary diagram plot the XRD (bulk) analysis results show that the distribution of the main minerals (Quartz, Clay, Calcite) is more dominant in the ductile zone, hard to frac category. This shows that all the depth intervals in the OBF-01 and OBF-04 wells are more ductile, and are not recommended for hydraulic fracturing. From the XRD (bulk) analysis, Calcite mineral is more dominant, so for well stimulation work it is recommended to use acidizing or acid-fracturing.


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