Hydraulic fracturing method employing special sand control technique

• US 4,549,608 A
• Filed: 07/12/1984
• Issued: 10/29/1985
• Est. Priority Date: 07/12/1984
• Status: Expired due to Fees

• Current Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Stowe, Lawrence R., Strubhar, Malcolm K.
• Primary Examiner(s): Suchfield, George A.
• Application Number:
  US06/630,177
• Time in Patent Office: 474 Days
• Field of Search: 166/280, 166/281, 166/278, 166/308
• US Class Current: 166/280.1
• CPC Class Codes: E21B 43/025 Consolidation of loose sand or the like round the wells without excessively decreasing the permeability thereof
• CPC Class Codes: E21B 43/04 Gravelling of wells
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping

Abstract

A subsurface oil or gas reservoir is hydraulically fractured by injecting a fracturing fluid through perforations in the casing of a well penetrating into such subsurface reservoir. The fracturing fluid contains a clay stabilizing agent for stabilizing clay particles or fines along the face of the resulting formation fracture. A proppant comprising a gravel packing sand is injected into the fracture. Oil or gas is then produced from the reservoir through the fracture into the well.

Claims

1. A sand control method for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which is otherwise likely to introduce substantial amounts of sand into the borehole, comprising:

(a) providing a borehole casing through said unconsolidated or loosely consolidated oil or gas reservoir,

(b) perforating said casing at preselected intervals therealong to form at least one set of longitudinal, in-line perforations,

(c) hydraulically fracturing said reservoir by injecting a fracturing fluid containing a fine grain sand and a clay stabilizing agent through said perforations at a volume and rate to allow said stabilizing agent to penetrate the fracture face along its entire length at a depth sufficient to overcome the effects of fluid velocity increases in oil or gas production flow on the movement of clay particles or fines located near the fracture face into the fracture as such production flow linearly approaches said fracture face,

(d) injecting a proppant comprising a gravel packing sand into said fracture so that said gravel packing sand pushes said fine grain sand up against the face of the fractured reservoir, whereby a first layer of fine grain sand is held in place along the entire face of said fracture by a second layer of gravel packing sand also extending along the entire length of said fracture to prevent the migration of clay particles or fines from said reservoir into said fracture, and

(e) producing oil or gas from said reservoir through said fracture into said borehole casing.

2. The method of claim 1 wherein said fine grain sand is no larger than 100 mesh.

3. The method of claim 2 wherein said gravel packing sand is 40-60 mesh.

4. The method of claim 1 wherein said fine grain sand is a mixture of particles, the largest being 40-60 mesh.

5. A sand control method for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which otherwise likely to introduce substantial amounts of sand into the borehole, comprising:

(a) providing a borehole casing through said unconsolidated or loosely consolidated oil or gas reservoir,

(b) perforating said casing at preselected intervals therealong to form at least one set of longitudinal, in-line perforations,

(c) hydraulically fracturing said reservoir by injecting a fracturing fluid through said perforations,

(d) injecting a clay stabilizing agent into the face of the resulting reservoir fracture along the entire length of the fracture at a rate to penetrate the fracture face along its entire length to minimize the movement of clay particles or fines from the reservoir into the fracture under the influence of oil or gas fluid velocity increase as such fluid linearly approaches the fracture along its entire length during production,

(e) injecting a fine grain sand no larger than about 100 mesh into said fracture and forcing said fine grain sand up against the face of the fractured reservoir to form a first filter layer along the entire length of the fracture,

(f) injecting a gravel packing sand into said fracture to form a second filter layer for holding said first filter layer in place along the face of the fracture, the combination of said first filter layer of fine grain sand up against the face of the fracture and said second filter layer of gravel packing sand up against the fine grain sand provides a two-layer gravel filter that prevents both clay particles or fines and formation sands from migrating from said reservoir during oil or gas production from said reservoir,

(g) reducing the rate of injection of said gravel packing sand after the propagation of the fracture has been completed and continuing such reduced rate of injection until screen out has occurred, and

(h) producing oil or gas from said reservoir.

6. A sand control method for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which is otherwise likely to introduce substantial amounts of sand into the borehole, comprising:

(a) providing a borehole casing through said unconsolidated or loosely consolidated oil or gas reservoir,

(b) perforating said casing at preselected intervals therealong to form at least one set of longitudinal, in-line perforations,

(c) hydraulically fracturing said reservoir by injecting a fracturing fluid containing a clay stabilizing agent through said perforations, said clay stabilizing agent penetrates the reservoir to minimize the movement of clay particles or fines from the reservoir into the resulting fracture under the influence of oil or gas fluid flow during production,

(d) injecting a proppant comprising a gravel packing sand into said fracture,

(e) forming a first gravel layer up against the face of the resulting formation fracture along its entire length,

(f) forming a second gravel layer up against said first gravel layer along the entire length of the face of said fracture and completely filling said fracture up to said well casing with said second gravel layer, the grain size of said first gravel layer being much finer than the grain size of said second gravel layer to prevent the plugging of said second gravel layer with clay particles or fines which would otherwise move from said reservoir into said fracture and plug up said second gravel layer under the sweeping influence of oil or gas flow from said reservoir into said fracture during production, and

(g) producing said reservoir through said well casing.

7. The method of claim 6 further comprising the step of providing an inside the casing gravel pack prior to the step of producing said reservoir, such a gravel packing step assures the extension of the packing material into the fracture since the fracturing step has brought the fracture right up to the well casing perforations.