Fracturing Process to Enhance Propping Agent Distribution to Maximize Connectivity Between the Formation and the Wellbore

Abstract

A method of treating a subterranean formation may include placing a first treatment fluid into a subterranean formation through an access conduit connecting the subterranean formation to a wellbore at a pressure sufficient to form at least a portion of a fracture network; pumping a second treatment fluid comprising a propping agent into the fracture network such that the propping agent forms a proppant pack in at least a portion of the fracture network; placing a third treatment fluid comprising a secondary diverting agent into the fracture network so as to substantially inhibit fluid flow through at least a portion of the fracture network without substantially inhibiting fluid flow through the access conduit; and placing a fourth treatment fluid comprising a primary diverting agent into the wellbore such that the primary diverting agent substantially inhibits fluid flow through the access conduit.

Description

BACKGROUND[0001]The present invention relates generally to enhancing propping agent distribution in order to maximize connectivity between a subterranean formation and a wellbore so as to improve production from a subterranean formation.[0002]After a wellbore is drilled, it may often be necessary to fracture the subterranean formation to enhance hydrocarbon production, especially in shale formations that typically have high closure stresses. Access to the subterranean formation can be achieved by first creating an access conduit from the wellbore to the subterranean formation. Then, a fracturing fluid, called a pad, is introduced at pressures exceeding those required to maintain matrix flow in the formation permeability to create or enhance at least one fracture that propagates from at least one access conduit. The pad fluid is followed by a fluid comprising a propping agent to prop the fracture open after pressure is reduced. In some formations like shales, fractures can further br...

AI Technical Summary

Benefits of technology

The present invention helps improve production from a subterranean formation by enhancing the distribution of a propping agent to maximize connectivity between the formation and a wellbore.

Problems solved by technology

Heterogeneous distribution of propping agents within a fracture network often yields a production curve with shorter steady state production and steep production decline, shown in FIG. 1a, i.e., the formation produces hydrocarbon for a shorter amount of time and production decline is very rapid.

Recovering a well after production decline typically involves refracturing, which can be costly and time consuming.

Such techniques may be only partially successful towards uniform distribution of propping agents, especially in dendritic and shattered fracture networks, because they only address the distribution issues at the wellbore, i.e., at the access conduit, not within the highly interconnected, multi-branched fracture network.

One of many problems in the use of some or all of the above described procedures may be that the means of diverting the treatment fluid requires an additional step of removing it from the wellbore to allow the maximum flow of produced hydrocarbon from the subterranean zone into the wellbore.

Similarly, sand plugs or bridges are cleaned out for production; sealing balls are often recovered for production, both of which incur additional time and expenses.

Particulate diverting agents may be difficult to remove completely from the subterranean formation, which may cause a residue to remain in the wellbore area following the fracturing operation, which may permanently reduce the permeability of the formation.

In some cases, difficulty in removing conventional diverting agents from the formation may permanently reduce the permeability of the formation by between 5% to 40%, and may even cause a 100% permanent reduction in permeability in some instances.

Additionally, when the wellbore to be treated is a highly deviated wellbore, traditional sand plugs are thought to be ineffective at isolating zones along the highly deviated wellbore because they may fail to fully plug the diameter of the wellbore.

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