Optimising Sand Control and Production Strategies in a Low Permeability Sandstone Oil Field

Abstract

This paper presents how the sand control and management strategies of an oil field were optimised after multiple well failures between 2014 and 2016. It describes the impact of the new strategies on oil production and net present value. Field E is a sandstone field with oil and gas-cap gas at initial conditions, and has been developed with 5 production wells, 2 water injection wells, and 2 gas injection wells. The first nine wells were drilled from an offshore platform and completed with sand screens between 2012 and 2013. Production commenced in late 2013, and by the end of 2016, multiple sanding events had been reported and four of the five production wells had died. The asset team was tasked with diagnosing the cause of the well failures and developing solutions. Pressure data suggested that three of the failed wells had tubing restrictions, and the fourth failed well had a blockage upstream of the BHP gauge. The sand count data suggested significant sand production prior to well failures, and sand was also recovered from the separators. Pressure transient analysis suggested that the field had a lower permeability than the pre-development estimate, and higher pressure drawdowns were needed to produce economic oil rates from the field. It was concluded that the well failures were most likely caused by the high pressure drawdowns, which pulled sand from the reservoirs, and led to screen breakage in at least two wells and screen plugging in one well. A decision was made to re-drill the failed wells in 2016, and complete them with frac-pack sand control solutions. The drilling and production performance of the first two new wells are presented in this paper. The asset team also implemented a new and improved sand management strategy in Field E. This paper presents the lessons learnt from a new oil field impacted by sand production. It also outlines practical well diagnosis and sand management strategies, and presents simple methods of preserving well integrity and cash flow in oil fields struggling to manage sand production in a 40 USD/barrel oil price environment.

A review of experimental studies on sand screen selection for unconsolidated sandstone reservoirs

“…The decision was made based on a thorough analysis of the formation sand, the design of the screen as well as the completion fluid during SAS installation. • Daramola and Alinnor (2018) present remedial sand control for a low-permeability sandstone reservoir. The field was an oil field located offshore Nigeria.…”