Optimization of Reinjection Fluids of Oil-Based Drilling Cuttings

Abstract

ABSTRACT: Oil-based drilling fluid will produce a large amount of oil-based drilling cuttings with complex composition and pollution factors. Cuttings reinjection technology, as an effective method to treat oilfield wastes, has gradually become a preferential choice for the treatment of oil-based drilling wastes in offshore oilfields. In order to increase the efficiency of cuttings reinjection, an oil-based drilling cutting slurry system was developed through a series of experimental studies. The final optimized cutting slurry has a formula of drilling cuttings content of 15%-35%, guar gum and Xanthan gum compounded in a ratio of 4:3 as the main additives, with 0.33% filter loss agent and 0.23% defoamer. The experimental results show that the viscosity of the cuttings slurry system is 55 mPa·s, the viscosity of the Marsh funnel is 93 s, and the suspension stabilization time can reach 24 h. The sedimentation density difference is 0.137 g/cm3. At a temperature of 70 °C, The overall performance of the optimized cutting slurry satisfies the requirement of the operator, and can overcome the issues of perforation hole blockage, cuttings bed accumulation, fracture tip deposition, commonly caused by the insufficient suspension ability of the injection slurry. 1. INTRODUCTION Oil-based drill cuttings contain organic compounds such as diesel (white oil), polycyclic aromatic hydrocarbons, chemical additives, etc., which are complex in composition, many pollution factors, and difficult to handle. Any carelessness will affect the ecological environment such as soil, water quality, the environmental protection of oil-based drill cuttings has become one of the important tasks in the oil and gas drilling industry (Mckay et al. 1991). Solidification, bioremediation, incineration or different chemical and mechanical treatments were used in the treatment of drilling waste, but this requires a lot of storage space, a large site. It will greatly increase the costs. Therefore, there is an urgent need for an economic and sustainable treatment of oilfield waste (Arfie et al. 2005, Reed et al. 2002).