Surgil ESIA Report - Volume III - EKN

“Management of Ustyurt GCC infrastructure objects
and Surgil GCF construction” UE »
ening/neutralization by their mechanical mixing in open tank is 32% addition of Portland
cement or 9 % addition of hardener ECO-2.
8.6.5. Reagent choice (Portland cement or hardener ECO-2) as drilling cuttings hardener for each
concrete case remains a prerogative of the customer – “Ustyurtgaz” USE, and will start from
economic reasonability as, in spite of exceeding efficiency of ECO-2 hardener effect over
Portland cement, its cost also exceeds cement cost.
8.6.6. As practice shows, after well drilling works termination there is remain fixed part of thickened
leaving at the bottom of cuttings storage barn (25-30%), over (45-50%) – moving part
of thickened leaving, and more over fluid semi-fluid and liquid phase. It is also possible the
lenses presence in moving part of thickened leaving consisting of fluid semi-fluid and liquid
phases. Layout view of drilling cuttings content (waste drilling mud + drilling rock + drilling
sewage waters) in cuttings storage barn after drilling works termination is resulted in the
figure 8.1.
8.6.7. Considering climatic conditions of drilling area, execution of work on drilling cuttings hardening
and disposal in cuttings barn, with a glance of allowed period of drilling wastes temporary
placement in cuttings barns, is recommended to begin in May. It is caused by the following factors;
According to Decision of Cabinet of Ministers № 199 from May, 1, 2003 “On improvement
of payments system for environmental pollution and drilling wastes placement in the Republic
of Uzbekistan territory” it is allowed, in certain conditions, temporary storage of production
wastes (up to six months) without compensatory payments.
According to long-term meteorological observations, the days with minus temperature in this
region exceeds 100, i.e. December, January, February and the beginning of March, and average
depth of seasonal frost penetration in the region reaches 0.7m (peak - 115sm), that
does not possible drilling cutting mixing process with binding substances in the open area.
Practice shows, that after drilling works termination, there is collects in cuttings storage barn
liquid phase layer above drilling cuttings (formation, drilling and storm sewage waters) by
thickness to 35-40sm and execution of drilling cuttings hardening in the open area in time
when the peak annual amount of precipitations is in the April, can lead to considerable exbarn
walls
insulating layer
semi-liquid phase of drilling cuttings and DSW
lens from semi-liquid
and liquid phases
drilling cuttings non-fluid,
semi-solid layer
drilling rock hard phase
Figure 8.1 – Drilling cuttings layer-by-layer incision in cuttings storage barn after drilling
works termination
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