Evaluation of Centrifugal Drying for Recovery of Synthetic-Based Drilling Fluids

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractLoss of synthetic-based mud (SBM) on drilled cuttings discharged offshore can add considerably to the drilling fluid cost. In addition, offshore environmental regulations are becoming increasingly strict, causing discharge of SBM to be severely curtailed. To reduce the loss and discharge of SBM, a new mud recovery technology -Centrifugal Drying -was tested as an enhancement to conventional solids control technology on four development wells in the Gulf of Mexico.Centrifugal Dryers, sometimes called rotating shakers, remove fluid from the cuttings by use of a spinning, screened basket arrangement which imparts a Centrifugal force on the order of 100 G on the cuttings. Cuttings discharged from the shakers are transferred to the Dryer's inlet pipe and are fed by gravity to the distribution cone and support disc. The cone removes the cuttings from the pipe and accelerates and spreads them evenly over the inner surface of the conical screen. Cuttings are held to the screen by Centrifugal force and moved to the exit port via vibratory motion or a sweeper, while the drilling fluid is forced through the screen and recovered.In the field tests, the conventional solids control equipment left a residue of synthetic fluid on the cuttings (SOC) of 10 to 15% by weight, whereas the Centrifugal Dryer was generally found to reduce SOC to less than 5% by weight (Fig. 1). Furthermore, the cuttings discharged from the unit dispersed readily and produced no visible sheen when released into the sea water under the cuttings discharge line. By reducing the volume of synthetic discharged, a savings of about $100,000 in mud cost was realized over the life of the project (4 wells).

A Comparative Study of Lost Circulation Materials

“…Bradford et al (1999) also noted that an LCM pill and the cement plugs must be chosen for their dissolvability by later acid treatment.…”

Parametric study of the remediation efficiency of oil-drilling cuttings by ozonation

“…For the decontamination of ODC fluids before their disposal, several technologies have been used in order to achieve the levels which have been established by the environmental legislation. These are thermal desorption [1] thermo mechanical desorption [2], centrifugal dryer [3] and microwave desorption [4]). The solid waste of ODC is heavily contaminated by non-aqueous phase liquids (NAPL) and is fully saturated with salty water.…”