1. SPE 154455
A Successful Remoaval Inorganic Hard Scale Deposits in an Offshore
Pipeline in Gemsa Oil field, Egypt: Field Study
M.Bakr, A. Abdel Hay, SAPESCO; E.Hamdy, GEMPETCO
Copyright 2012, Society of Petroleum Engineers
This paper was prepared for presentation at the SPE International Conference and Exhibition on Oilfield Scale held in Aberdeen, UK, 30–31 May 2012.
This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been
reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its
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Abstract
Water flooding is the hinge pin for Gemsa Oil Field. Water injection is supplied from shallow water supply wells.
Compatibility tests had indicated probable deposition of calcium sulphate scale on surface and subsurface production
equipment. Calcium sulphate scale has been recognized to be a major operational problem. The bad consequences of scale
formation comprised the contribution to flow restriction thus resulting in oil and gas production decrease. The nature of
calcium sulphate scale is very hard and can’t be dissolved with known dissolver. Sister companies that has similar problem
were always going to the mechanical remover options.
Extensive lab and field work was conducted to determine the suitable chemicals to dissolve calcium sulphate scale.
This paper describes the development and field application of chemical treatment to remove scale in an offshore 8” production
line in Gemsa oil field. Continuous precipitation of calcium sulphate scale caused partial plugging of the pipeline. This partial
plugging created a back pressure on production wells which decreased the productivity. The field production has been
decreased to almost one tenth of the normal field production level(1)
.
A thorough investigation was conducted to identify the composition and location of the scale, in order to recommend a suitable
chemical to remove the scale, and to assess the effectiveness of the treatment method in the field.
Based on extensive lab studies, SAG-01 was tested and applied in production line to remove the scale efficiently, the program
was designed taking into consideration the nature of the scale.
The treatment program included three - staged process:
1. The use of an organic solvent
2. The main treatment (SAG-01).
3. The post flush stage (injection water),
The job results were outstanding, where as
1- Production increased by about 2,000 BOPD
2- Launcher pressure dropped by about 350 psi.
3- Decrease the back pressure on our producing wells.
4- Additional producing wells into production.
5- Efficient cost /Bbl.