Chemical Sand Consolidation - Developing a Strategic Capability Across a Wide Portfolio

Abstract

Mechanical sand control completions are often used to optimise hydrocarbon production from weak formations. In a few wells this primary sand control method has sub-optimal performance. There is substantial value in remediating some of these wells, but developing this capability is not a quick and simple task. Recompleting a well could be feasible, but is often cost prohibitive. Mechanical solutions could be applied to stem sand production if the sand producing interval is known; however, in some cases chemical sand consolidation is the most effective approach. Chemical sand consolidation works by pumping chemicals downhole to strengthen the formation and stop sanding. In most cases reported in the industry, chemical consolidation has been used in short production intervals (<100m). Our approach was to develop a laboratory programme to test various industry chemicals and to achieve a good understanding of how these can be applied. Candidate wells were matched to chemicals to identify which systems (may be more than one) would be the best fit. The strategy was to initially trial the technology in low-rate onshore wells (typically <1 mmscf/d), before moving progressively to more challenging wells (up to 2,500 bopd). The wells were split into 3 groups based on their complexity: (1) proppant flow back remediation, (2) <100m producing interval and (3) >100m intervals. Each has unique challenges, but this approach facilitated a progressive learning curve. In proppant flow back remediation 7 field applications were conducted with 100% success rate. Longer intervals were successfully treated over time. Matrix consolidation presented a bigger challenge - 10 field trials have been carried out with a mix of successes and failures. A key learning is that adequate placement of the chemicals is critical. Chemical sand consolidation would fulfil its potential only when the chemicals can be reliably delivered to the target sand-producing zone – (often unknown), and remain static to allow sufficient curing time. Some treatments have been bullheaded (i.e pumped down the production tubing); others have been placed with coiled tubing. Operator has successfully developed an organisational capability whereby this technology can be part of the toolkit and - where appropriate - can be applied with a reasonably high chance of success to add value. Wells have been treated in the Lower 48 states in the USA, Canada, Alaska, Azerbaijan and Egypt and other wells are constantly being evaluated. Well types include oil and gas producers, onshore and offshore, with reservoir temperatures from 29 °C to 135°C. This technology is therefore being used across a wide well portfolio.

Evaluation of Chemical for Sand Consolidation in Laboratory Scale

“…The strategy to remedy the sand problem were to tested several types of chemical sand consolidation and choose the best fi t and performance for matrix consolidation. A key learning is that adequate placement of the chemical is critical (Aytkhozhina, et al, 2015). Epoxy resin sealant also had been used to improve well integrity (Alkhamis, et al, 2019).…”