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AssigneeHalliburton Energy Services, Inc.
InventorsB. Raghava Reddy, Larry S. Eoff, Donald L. Whitfill, J. Michael Wilson, Denise Berryhill, Russel M. Fitzgerald, Thomas E. Becker, Jimmie D. Weaver
Estimating the term…
Methods of consolidating unconsolidated weak zones or formations and forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and that comprises water, a polymeric cationic catalyst which is adsorbed on the mineral surfaces in the weak zone, a particulate curable solid thermoset resin and a delay acid catalyst for curing the solid resin, and forming a filter cake on the walls of the well bore. The filter cake is then contacted with a treating fluid comprising a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin, whereby the treating fluid components deposit on the filter cake and the thermoset resin cures into a hard and tough cross-linked chemical casing thereon.
A method of consolidating unconsolidated weak zones or formations containing unconsolidated rocks and minerals to prevent sloughing and forming a chemical casing comprising the steps of:
A method of consolidating unconsolidated weak zones or formations containing unconsolidated minerals and rocks to prevent sloughing and forming a chemical casing in a well bore penetrating the weak zones or formations to improve the mechanical strength of the well bore while drilling the well bore comprising the steps of:
A method of consolidating unconsolidated weak zones or formations formed of unconsolidated minerals and rocks to prevent sloughing and forming a chemical casing in a well bore penetrating the weak zones or formations to improve the mechanical strength of the well bore or to provide zonal isolation, or both, while drilling the well bore comprising the steps of:
A method of consolidating unconsolidated weak zones or formations formed of clays, shale and sandstone to prevent sloughing and forming a chemical casing in a well bore penetrating the weak zones or formations to improve the mechanical strength of the well bore while drilling the well bore comprising the steps of:
A method of consolidating unconsolidated weak zones or formations formed of clays, shales and sandstone to prevent sloughing and forming a chemical casing in a well bore penetrating the weak zones or formations to improve the mechanical strength of the well bore or to provide zonal isolation, or both, while drilling the well bore comprising the steps of:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Clay-free compositions: containing synthetic organic macromolecular compounds or their precursors
Synthetic organic compounds: polymers
Containing organic compounds: macromolecular compounds
Macromolecular compounds: containing cross-linking agents
Term ended 13 Jun 2022 (estimated)
1. Field of the Invention
The present invention relates to methods of consolidating unconsolidated weak zones or formations formed of clays, shales, sand stone and the like and forming a chemical casing in a well bore penetrating the weak zones or formations.
2. Description of the Prior Art
The present invention provides methods of consolidating unconsolidated weak zones or formations formed of clays, shales, sand stone and the like while drilling a well bore penetrating the zones or formations to prevent sloughing, methods of forming a hard and tough cross-linked chemical casing in a well bore while drilling the well bore which increases the mechanical strength of the well bore and provides zonal isolation and methods of both consolidating unconsolidated weak zones or formations penetrated by a well bore and forming a hard and tough cross-linked chemical casing in the well bore while drilling the well bore.
Unstable materials such as clays, shales, sand stone and the like make up a high percentage of the formations in which wells are drilled, and a majority of well bore problems are a result of the instability of such materials, particularly shale instability. Shales are sedimentary rocks that contain a variety of clays. Shales containing montmorillonite, often referred to as smectite clays, swell and disperse when contacted by water. Shales which swell upon contacting water are often referred to as heaving or sloughing shales. Such shales upon contact with aqueous drilling fluids swell and fracture rendering the well bore wall unstable. In such cases, the well bore wall sloughs into the well bore. Sloughing of shale and other similar unstable materials into the well bore can cause the drill string to become stuck and can enlarge the well bore resulting in large subterranean cavities. Additionally, when sloughing occurs while the drill bit is being changed at the surface, the well bore fills up and must be cleared before drilling can proceed. Furthermore, the heaving unstable material suspended in the drilling fluid increases its solid content, and as a result, the viscosity of the drilling fluid increases to the point where the drilling fluid must be chemically treated to reduce its viscosity or it must be diluted followed by the addition of weighting material to maintain its mud weight. The instability of clays, shales, sand stone and the like is also caused by hydraulic pressure differential leading to fluid transport and by pressure changes near the well bore as the drilling fluid compresses pore fluid and diffuses a pressure front into the formation. The chemicals and other materials used in accordance with the present invention prevent swelling and dispersion of unstable materials, reduce pressure transmission from the well bore fluids and prevent drilling fluid penetration into the unstable materials by building an impenetrable lining at the unstable material/well bore interface.
Consolidating unconsolidated weak zones or formations formed of clays, shales, sand stone and the like while drilling a well bore prevents sloughing of the clays, shales, sand stone and the like into the well bore and prevents the need for implementing time consuming and costly remedial steps. The formation of a hard and tough chemical casing in a well bore while the well bore is being drilled increases the mechanical strength of the well bore whereby hydrostatic pressure exerted on the well bore by the drilling fluid does not cause fractures or the like to occur in the well bore. Such fractures cause drilling fluid to be lost and also require stoppage of the drilling operation and costly remedial steps to be taken. Another significant advantage of increasing the mechanical strength of the well bore by forming a hard and tough chemical casing thereon is the reduction or elimination of casing points at which casing or liners are cemented in the well bore which reduces or eliminates the overall time and cost of cementing the well. An additional advantage is that the well bore has a larger diameter in the production zone due to fewer casing points which increases productivity.