Squeeze Related Well Productivity Impairment Mechanisms & Preventative/Remedial Measures Utilised: Norwegian Continental Shelf

Abstract

Squeezing is routinely employed by Statoil as a means of maintaining well productivity and avoiding safety issues related to downhole safety valve scaling. In the majority of cases, squeezing maintains well production through minimisation of scale related downtime. However, it has been observed occasionally by Statoil that the benefits of scale prevention by squeezing can be outweighed by the detrimental impact on well productivity. While there have been several articles covering specific elements of a squeeze operation that have affected well productivity, little has been published that attempts to completely describe squeeze related, production impairment mechanisms. This paper will aim to address this gap by demonstrating how squeezing, in some cases, can have an adverse impact on well productivity and highlight the remedial or preventative methods that have been utilised.A review of the squeeze related, production impairment mechanisms from Statoil operated fields show that they can be related to near wellbore formation, alteration in the reservoir production characteristics or completion design. Physical formation damage mechanisms include a. Squeezing of sensitive reservoirs (fines mobilisation and clay swelling) b. Scaling of production intervals due to incorrect inhibitor placement c. Viscosified inhibitor formation damage d. Damage related to precipitation squeezes e. Increased sand production after squeezing Liquid formation damage mechanisms include a. Squeeze related relative permeability alteration causing increased water cut and reduced oil rates. b. Water blocks and emulsion formation due to squeezing of an aqueous treatment into an oil producing or water sensitive interval. Other examples of squeeze related productivity impairment are screen and gravelpack blockage while an indirect effect are lift problems after squeezing in wells with depleted reservoir pressure. In all instances, the economic costs of lost production can far exceed those of actually performing the squeeze. Case histories will be used to illustrate the productivity impairment mechanisms and methods used to overcome these along with lessons learned.

Benchmarking Project Level Engineering Productivity / Inžinerinės Veiklos Našumo Lyginimas Projektų Lygmeniu

“…Although many approaches have been adopted for performance evaluation in the various industry sectors such as software industry, manufacturing industry, and even the construction industry (Bang et al 2010;Benestad et al 2009; de Aquino, de Lemos Meira 2009;Fleming et al 2010;Issa et al 2009;Niu, Dartnall 2010;Ren 2009;Yang, Paradi 2009), there are limited suitable approaches for the development of a project level engineering productivity metric. The Project-Level Productivity (PLP) index was developed by Ellis and Lee (2006) for monitoring multidiscipline daily labor productivity.…”

Application of Multi-rate Well Tests to Scale Management

“…Well A-19B is another commingled production well at Veslefrikk that has proven to have a severe scaling potential (Fleming et al, 2010). Two MRTs performed in February and July 2008 have been analysed, and are presented below.…”

“…Later coiled tubing milling was performed. The mill got stuck, and the well was shut in for side tracking (Fleming et al, 2010).…”