US3522845A - Method of consolidating and producing a hydrocarbon-bearing formation - Google Patents

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United States Patet Inventor:

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METHOD OF CONSOLIDATIING AND PRODUCING A HYDROCARBON-BEARHNG n 1 mama Primary Examiner- Stephen J. Novosad Attarney- K. E. Kavanagh and Thomas H. Whaley FORMATION 6 Claims, 1 Drawing Fig.

U.S. Cl. 166/272,

166/288, 166/58 ABSTRACT: A method of recovering hydrocarbons from a Int. Cl. ..lE21b 33/13, subterranean formation having an unconsolidated or friable E21b 43/24 structure and traversed by a well bore by heating the forma- Field ofSearch 166/39, 25, tion to a temperature sufficient to cause incipient fusion and consolidation ofthe sand adjacent the well bore.

Patented Aug. 4, 1970 @www Y lHll 1 /00 061)? w I fire/um Er. V

U.S. PATENT 3,522,845 METHOD, OF CONSOLIDATING AND PRODUCING A HYDROCARBON-BEARING FORMATION BACKGROUND OF THE INVENTION This invention relates generally to a method of recovering hydrocarbons from unconsolidated formations. More particularly, this invention pertains to a method of consolidating the formation adjacent a production well bore by thermal means.

In the production of hydrocarbons from a subterranean formation, frequently the formation encountered is composed of loosely cemented or unconsolidated sands. This is particularly true in the fields of California, Louisiana and Southern Texas. If precautionary measures are not taken, once the cap rock is penetrated, large quantities of sand may flow to the surface with the oil and/or gas produced from the formation. The presence of sand during production causes equipment damage, particularly in the form of erosion, and in severe cases, may even cause collapse of the well casing.

Various techniques have been proposed to prevent the production of sand along with the hydrocarbons contained in the formation. Generally, a perforated well casing or a liner having a plurality of holes or slots adjacent the hydrocarbonbearing stratum is provided to allow the fluids to flow through the openings and into the well bore. Screening and/or gravel packing is provided about the holes or slots to filter and protect against sand intrusion into the well bore. This method, although sometimes quite effective, is both expensive and time consuming, particularly due to the extensive preparation and workovers required.

More recent proposals include consolidation of the forma tion sands by thermal means. In this method, the unconsolidated sandadjacent the well bore is consolidated by exposing the formation to a temperature in the range of about 700 F. to about 150 F. A coke-like deposit formed by carbonizing in place crude, provides a means for bonding the particles of sand, resulting in a partially rigid structure. The primary shortcoming of this method is that-the coke-like material is subject to decomposition particularly upon the further application of elevated temperatures. When practicing in situ combustion as a secondary recovery technique, temperatures may be of a sufficient magnitude to cause decomposition of the coke-like bonding means and thereby unconsolidate the formation. By the method of this invention, a formation may be irreversibly consolidated and provide a rigid structural body while maintaining the desired permeability.

SUMMARYOF THE INVENTION The invention herein disclosed provides an improved method for consolidatinga hydrocarbon-bearing formation. Consolidation of the formation is accomplished by exposure to a temperaturesufficiently high to cause incipient fusion of the sand contained therein, thereby creating a rigid and permeable formation.

v the formationis-permanent due to the irreversible process employed. Subsequent exposure of the consolidated formation to elevated temperatures produces no detrimental effects. Further treatment, in accordance with the method of this invention renders a stable formation and maintains adequate permeability therethrough.

' Accordingly, it is a primary object of this invention to provid'e aneffective method for consolidating a hydrocarbonbearin'g formation.

A further object of this invention is to provide a novel methodjfor irreversibly consolidating a formation and maintaining'the permeability thereof.

These and other objects, advantages and features of the invention wiIl-becomemore apparent from the following ..descri'pti on taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The drawing depicts an elevation view, partly in cross sec tion, of a well bore penetrating an unconsolidated hydrocarbon-bearing formation and containing a heat generating means therein.

DESCRIPTION OF THE PREFERRED EMBODIMENT With the method of this invention, unconsolidated hydrocarbon-bearing formations are effectively treated to improve the structural capabilities thereof. Thermal means are utilized to consolidate the formation and thereby eliminate the necessity for screening and/or gravel packing adjacent the well casing. In addition, treatment in accordance with the method of this invention renders the formation capable of producing the hydrocarbons contained therein, since the residual permeability and porosity thereofis maintained or improved.

Referring now to the drawing, which schematically illustrates one embodiment of the practice of this invention, there is shown a well bore 10 penetrating an unconsolidated or loosely packed sand formation indicated at 20. A well casing 11 is positioned within the well bore 10 and is provided with perforations 12 adjacent the unconsolidated hydrocarbonbearing formation 20.

A suitable heating device is lowered into the well bore 10 and positioned adjacent the perforations 12 in the well casing. The perforations 12 provide a means for communication with the formation to be consolidated. Various types of heating devices are suitable for the method of this invention, some of these including downhole heaters, electrical heating devices, chemical compounds or other combustibles placed into the well bore 10. As illustrated in the drawing, an ignition package 30, as disclosed in the copending, coassigned application for patent ofa METHOD AND APPARATUS FOR INITIATING IN SITU COMBUSTION, Serial No. 708,915 filed February 28, 1960, the disclosure of which is incorporated herein on this reference thereto, may be utilized. Therein is disclosed, an apparatus which will generate sufficiently high temperatures to carry out the method of this invention. The lower chamber of the ignition package 30 contains a fuel pack 31 and is placed adjacent the stratum to be treated. Inserted in the fuel pack and positioned in a predetermined relationship are a plu rality of ignitors 32 which are activated by an electrical signal generated at the surface of the well bore. These ignitors initiate combustion of the fuel pack, preferably a kerosene soaked charcoal material, the combustion thereof being sustained by the injection of a combustion supporting gas into the well bore. Further, the upper chamber of the ignition package 30 contains an additional supply of fuel for replenishing that consumed in the lower chamber, thereby insuring generation of temperatures sufficiently high and within a relatively short period of time necessary for consolidation of the formation adjacent the well bore. A stand-off or spacing means 33 on the bottom of the ignition package rests on the bottom of the well bore and provides means for positioning the fuel pack 30 adjacent the formation to be treated. If it is desired, the ignition train disclosed in the above referenced application for patent also may be utilized in the consolidation of the hydrocarbonbearing formation. The injection of a combustible material into the formation, the material preferably having a self-ignition temperature and flash point lower than that of the crude contained in the formation, provides a means for consolidating the formation to a greater extent.

Consolidation of the sand is accomplished by generating sufficiently high temperatures to cause incipient fusion of the sand; thereby creating a solid unitary permeable mass, as shown at 21. In order to fuse the unconsolidated formation, temperatures in excess of about I800 F. but below the temperature at which glazing of the sand occurs, are preferred. Exposure of the formation to temperatures of this magnitude results in a white, consolidated, porous, rock-like material. Further, the formation is irreversibly consolidated and subpose the coke-like bonding material and destroy the consolidation.

Inspection of a previously unconsolidated sand based formation, treated by the method of this invention, reveals that l. A method of recovering hydrocarbons from an unconsolidated hydrocarbon-bearing formation traversed by a well sequently producing hydrocarbons from said formation via said well bore.

one of said well bores and recovering hydrocarbons from the 6. The method of Claim 1 which includes the step ofinlower than that of saidhydrocarbons contained in said formation.

3333 UNITED sTATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3Q522,845 Dated August 97 Inventor-(s) C. L. BAUER It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 36, "15o'F" should read --l500F--.

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