Laboratory Studies of Chemicals for Sand Consolidation (Scon) in the Niger Delta Fields

Abstract

Sanding during oil production causes severe operational problems in the oil and gas industry. Several techniques have been used for sand production control in sandstone reservoirs. Consolidating materials, such as, crude oil coke and nickel plating have been used in the past by researchers. At present, the chemical binders, such as; phenol resin, phenol-formaldehyde, epoxy, and furan or phenol-furfural provides cementation. This work is centered on the laboratory studies of selected sand consolidating resins that would be suitable for application in the Niger Delta (ND) oil fields. Considering the available resins for consolidation process, six types of chemical resins namely; Epoxy (A&B), Novalak Phenol-Formaldehyde, Furan Phenol Acrylic, Furan and Phenol resins were selected for studies. Three other locally made resins: Rubber Latex, Evo Stik and Polystyrene gum were reviewed alongside for comparison and test for their applicability. Different core samples were made by mixing these resins and their hardening agents with sand sample obtained from a sand producing oil field in the Western Niger Delta. The core samples made were subjected to laboratory qualitative and quantitative analysis in order to obtain individual permeability and porosity under different overburden pressures from 500psi through 3500psi. Results from experimental data show that Epoxy A&B resins ranked best followed by Furan resin and then, the local resins. This was adjudged based on minimal variation in the permeability and porosity of the core samples retained in acceptable values after curing and by analytical result from measurements at various overburden pressures.

A Review on Chemical Sand Production Control Techniques in Oil Reservoirs

“…Different resins can be divided into categories, including alkyd resins, unsaturated polyester resins, epoxy resins, phenol-formaldehyde resins, urea-formaldehyde resins, acrylic resins, and vinyl ester resins. , …”

“…Research in this field deals with three categories due to the sharp decrease in the formation permeabilityin some cases, up to 60%: (1) maximizing the formation permeability, (2) minimizing sand production, and (3) proper placement of injectable resins in the reservoir . The most widely used resins to strengthen the formation are epoxy resins, furan resins, polyester resins, urea, and phenol–formaldehyde resins. , The selection of these resins is dependent on financial parameters, simplicity of production, the degree of effect on the strength and permeability of the formation, and the density during the injection. Resins must have an insoluble three-dimensional structure to strengthen formation and be placed on the surface of the sands inside the formation to prevent their flow, while, at the time of injection, must have a low viscosity .…”

“…Chemical treatment has been considered since 1940 to control fine migration and sand production in oil and gas wells . In this type of treatment, efforts have been made to stop or mitigate the production of sand, rather than collecting the produced sand at the surface .…”

“…Note that using chemical methods may face challenges such as determining some operational parameters, e.g., the injection rate and the optimal concentration of the injectants . Side issues should also be meticulously considered, such as the reduction of formation permeability due to clogging the porous media, improper distribution of chemicals under downhole conditions, low diffusion depth of the chemicals into the wellbore, temperature sensitivity and stability of chemicals, and the so-called chemical–rock and chemical–formation fluid interactions. , However, despite all these technical problems, chemical methods have attracted significant attention to tackle sand production, particularly in narrow hydrocarbon wells, multiple completion wells, and formations composed of extra fine sand. , …”

“…Chemical treatment has been considered since 1940 to control fine migration and sand production in oil and gas wells. 33 In this type of treatment, efforts have been made to stop or mitigate the production of sand, rather than collecting the produced sand at the surface. 34 Sand production mainly occurs in unconsolidated or semiconsolidated formations, because of the stress forces inflicted upon the formation during the drilling or production operations and the drag forces imposed due to the fluid flow inside the formation.…”