Investigation of in-situ low-temperature oxidation as a viable sand consolidation technique

Abstract

This paper presents the results of the laboratory development phase of a major project to develop a novel sand control technique that could overcome the technical and economic limitations associated with existing methods of sand control. The novel technique is based on in-situ sand consolidation by low-temperature oxidation of a hydrocarbon material that saturates the sand around the wellbore. Laboratory development consisted of two stages. In the first stage, the various process-controlling parameters were optimized to yield consolidated sand with the highest possible compressive strength, minimum loss of permeability, and high stability against typical formation and workover fluids. Under the optimum consolidation conditions, it was possible to produce consolidated sand, from originally loose sand, that is completely stable against flow of crude oil, water and mud acid; has a compressive strength between 1800 and 2300 psi; and with permeability retention between 86.4% and 95.5%. In the second stage, the feasibility of field application of the process was demonstrated on a full-scale physical model resembling an 8-ft section of a 7-in. cased well. The model was packed with loose sand and saturated with crude oil and residual brine. The resulting consolidated sand around the casing was tested by flowing back at a rate of 44 bpd/ft (the maximum available pump capacity) without any sand production. Plans are underway for the first field implementation of the process.