Gulf of Mexico Frac-Pack with a 10% Loading of an Intermediate Strength, Chemical-Infused Proppant-Sized Particle Designed to Provide Long Term Inhibition for Barium Sulfate Scale

Abstract

A new substrate, based on nanotechnology, that has strength greater than an intermediate strength proppant and a high surface area for chemical adsorption has been introduced and applied in deep water well in order to inhibit barium scale deposition for a prolonged period of time and/or a desired cumulative water production.The subsea oil well in 1700 feet of water in the Gulf of Mexico was completed with a frac-pack using a total of 14,881 pounds of proppant. This includes a 10% (1,488 pounds) loading of the solid scale inhibitor product. The well was put on production following the completion. The field design calls for a sea water flood (containing sulfate). The scale inhibitor is designed to desorb into the connate water (containing barium) and to inhibit the formation of barium sulfate scale.The solid product placement with the proppant was monitored to assure a homogeneous distribution of solid chemical particle in the proppant bed. Upon the onset of water production samples were analyzed for the presence of residual scale inhibitor. A residual indicates there is still sufficient chemical in the formation to inhibit scale. When the scale inhibitor residual falls below the minimum inhibitor concentration, and if the water still shows a scaling tendency, the operator has two choices. At that point he can initiate surface treatment through a chemical injection mandrel or perform a scale inhibitor squeeze. A squeeze onto this chemical-laden proppant substrate will last longer than a conventional squeeze that is placed onto the native formation rock.The cost of a well intervention for a deep water sub-sea well can exceed ten million dollars. The cost for an intervention in a deep water dry tree will be less but still significant. By placing a long lasting scale inhibitor into the propped zone, the operator will realize an economic benefit far in excess of the cost of the application. By extending or possibly eliminating the need for a future intervention, the application of this technology can have a significant impact on the well economics.