Surgil ESIA Report - Volume III - EKN

“Management of Ustyurt GCC infrastructure objects
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Appendix 5
DRILLING CUTTINGS (CUTTINGS BARNS) NEUTRALIZATION TECHNOLOGY
CONTAINING OILY SOILS (GROUNDS)
Introduction. There is formed drilling cutting during oil-well drilling, containing oil products.
This cutting is stored in cuttings barns and after filling should be neutralized, i.e. is transferred
into leaving of IV danger class that will give the possibility to execute of works on its disposal.
There occur stratifying drilling cuttings during its storage. Most heavy clay fraction collects at the
bottom, and on the surface there is formed the layer consisting of oil products and clay mix.
Drilling cuttings humidity and oil products content depends, in particular, on clay type and
composition in each separate field which define its sorption property to oil products absorption and
to moisture emission.
Analysis of cuttings barns surface layer composition in Surgil field has shown that during
oil-well drilling there is formed drilling cuttings of the following composition:
humidity - 65%;
inorganic part (clay of the waste drilling mud, sand, etc.) - 5.2%;
oil products - 29.8 %.
There is film of free oil products on cuttings surface.
Characteristic of the processes taken as a principle of neutralization technology. Basic
method of oil-containing cuttings neutralization is conversion of petroleum- and oil products to insoluble
calcium salts and their capsulation.
Basically, such compounds as lime, gypsum, alabaster are used for this purpose. Use of
quicklime provides exoteric heating-up that improves efficiency of formation calcium soaps of oil
products. Introduction of gypsum (alabaster) promotes acceleration of hardening of neutralized oil
cuttings at the expense of moisture binding.
The important condition of maintenance of efficiency of oil-containing cuttings neutralization
is calculation of required and enough water amount with a glance of free and binding water in
cuttings. Water volume should provide liming and generation of paste-like mass with the minimum
free water content that promotes reduction of hardening time.
For prevention of the following washing-out of the binding oil products from leaving there is
used introduction of silicates in the form of liquid glass or modifiers in which capacity there use
such compounds as triglyceride, synthetic surface-active substances or flocculants.
Method of researches carrying out. Laboratory researches on development of drilling cuttings
neutralization method were carried out with use of cuttings sample, presented by “VOL-
GOURALINGENERING - CENTRALNAYA AZIYA” Co. Ltd., in laboratory TAHITI
"SUVGEO".
For components mixing there was used "Dzhar-test" unit supplied with arm mixers. Optimum
rate of stirring - 30 r.p.m. Researches were carried out in cylindrical tanks from Plexiglas by
capacity of 0.5l. Cuttings characteristics are defined by the following method:
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