Effects of Single and / or Combined Application of Water and Oil Based Drill Cuttings in a Tropical Agricultural Soil Located in Jusepin Oil Field (Monagas State, Venezuela)

Abstract

Effects of Single and / or Combined Application of Water and Oil Based Drill Cuttings in a Tropical Agricultural Soil Located in Jusepin Oil Field (Monagas State, Venezuela). Abstract At eastern Venezuela, the oil developments are established mainly in areas with agricultural and cattle arising activities. This compel to an effective and environmentally safe treatment for water (WB) and oil-based (OB) drill cuttings (DC), according to the Venezuelan regulations. In order to determine the effects of individual and combined applications of WS and OB in an acid soil (Ultisol), it was designed and installed on January 1997 a field test in the Jusepin Oil Field (Monagas State). In 9 plots of 0.7 ha. each one, were applied the following treatments (equivalent doses in m3/ha.): WB: 0,125, 250, 500; WB/OB: 90/72, 180/140, 360/280; and OB: 100, 200, 400. Then were applied an adjusted fertilization (N, P, S), complementary amendments and periodical tillage, to stimulate the hydrocarbons biodegradation (TPH). After a 87 days period, the TPH percentage in OB treatments (45.9 %) was smaller than WB/OB (53.3%). Due to the use of CaO at the output of solids control equipment as dryer for DC, sorne soils plots showed high Ca++ and pH, mainly at high DC doses (an over liming effect). Other soil and leacheates parameters (electric conductivity, Cl TPH and heavy metals), were found under the established limits by ad hoc environmental regulation (actually being reviewed). The 500 WB treatment shown both high soil fertility and grasses growth. The results show that is feasible the WB/OB application, being reduced the treatment area for the safe disposal of more than 2000 m3 DC by well.