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Oct 16, 2018

SWELL (II) JIP

Core Flooding JIP

Scaled Solutions Ltd undertakes a number of Joint Industry Projects, collaborating with industry including operators, suppliers and manufacturers to investigate industry-wide issues. The Core Analysis team have contributed to recent investigations into test protocols for inhibitor return testing.
 
Core flood experiments are an integral part of the selection and optimisation of scale inhibitor treatments, providing information on formation damage, inhibitor return profiles and dynamic retention isotherms. However, significant discrepancies can arise between core and field due to test methodology. The current SWELL (II) JIP directly addresses the procedures involved in core flooding and recommends approaches and test protocols which allow more appropriate product ranking and allow improved simulation from core to field.

Squeeze Design


The complex nature of most oil and gas wells can make it difficult to intuitively assess the placement challenges present in the field.  Typically, placement of bullhead squeeze treatments can be affected by a large number of parameters including permeability differences, pressure contrasts, fluid mobility effects, fluid viscosities, wellbore geometry, frictional pressure losses, the presence of fractures, injection rates and the nature of the treatment chemicals.  As part of a long-running multi-sponsor
Joint Industry Project (JIP), Scaled Solutions has developed the Place-iT™ near-wellbore chemical placement simulator, which will consider all these parameters when simulating the chemical placement and subsequent chemical returns for a well.  The Place-iT™ model has been used to help improve the design of a number of successful scale inhibitor squeeze treatments in challenging wells throughout the world.


Analytical Development

Part of the SWELL II JIP focus is on developing new analytical techniques for residual scale inhibitor concentrations which provide accurate, repeatable and reliable results. These methodologies focus both on automated HPLC-based and solid phase extraction techniques. The objective of these methodologies is to analyse for the “active” scale inhibitor as opposed to some analysable moiety.
 
 
High Performance Liquid Chromatography (HPLC)
 
From the project, a number of methodologies have been developed which include the use of Gel Permeation, Reversed Phase and Ion Chromatography as well as utilising a number of different detection techniques including Evaporative Light Scattering (ELSD), Charged Aerosol Detector (CAD), UV/Vis and Conductivity. 
 
The project also involves extensive screening of HPLC columns for their applicability to retain a series of generic scale inhibitor species. Sponsors have found it beneficial to have a selection of columns screened, under a number of experimental conditions using a series of generic scale inhibitor species to gain knowledge to feedback to their own laboratories.

Solid Phase Extraction (SPE)
 
Residual scale inhibitor analysis in produced waters, particularly for the sulphonated co-polymers is recognised as an ongoing challenge for many offshore production environments. Although methods have been well documented, there are a number of known difficulties when assaying residual ppm and sub ppm levels of sulphonated polymers where separation of the inhibitor from the brine phase can be a time consuming, labour intensive and often difficult operation.
 
The SWELL II JIP also involves the development of appropriate solid phase extraction (SPE) techniques which demonstrate near 100% retention of sulphonated polymers from brines of different salinities and therefore negate the requirement for dialysis. Present advances made in the separation and assay of these and other polymeric species including the ability to obtain reliable separation and, when required, concentration using SPE methods as well as the utility of a variety of different detection systems. Extensive validation tests in a range of high salinity brines demonstrates the limits of detection and repeatability at ppm and sub ppm level for a variety of different polymers including PVS, VS-Co and more conventional polyacrylate as well as phosphorous containing polymers.