Coiled Tubing Sand Clean Outs Utilizing BHA Technology and Simulation Software in Demanding Wellbore Geometries

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAlthough efforts are made to reduce or eliminate sand production in a producing well, sometimes sand fill is an unavoidable by-product of well conditions and the need for a cleanout intervention is necessary. Various cleanout methods have been utilized in the past, including the use of coiled tubing. Removing sand fill from a well using coiled tubing is one of the earliest applications for CT and continues to be an important service to the industry today.Historically, coiled tubing cleanouts have incorporated high circulation rates, exotic/costly fluids and reverse circulation to remove solids. Many of these conventional sand cleanout methods often apply excess hydrostatic pressure on the formation, resulting in lost circulation in low formation pressure reservoirs. Incorporating large liner geometries with smaller completion restrictions magnifies the task at hand as the annular velocities are drastically reduced even with higher coiled tubing circulation rates.Using a specially developed cleanout tool and a computer simulator for solids transport provides an opportunity to optimize the operation for the removal of solids to near 100% efficiency, with all fluidized solids being removed. Simplified operational procedures allow for making a more qualitative decision about the cleanout efficiency. This paper will show cost effective solutions utilized in Saudi Arabia from 2007 to present by providing an overview of all field cases and job optimization. The main focus of the paper will be to highlight and compare the coiled tubing cleanout job design process, operational procedures, results, and lessons learned from two case studies; the first case study being a successful cleanout, while in the second case study the cleanout objective was not achieved.

Optimization of coiled tubing nozzle for sand removal from wellbore

“…But in many cases, the nozzle and the jetting tool were sandwiched between two layers of sand, as the broken sand accumulates just behind the jetting tool. As a result, cleanout performed by slow continuous penetration into the fill followed by a stationary circulation followed by a moving of the CT upwards over the previous penetration interval, and continuous circulation while running back in the hole is used and found to be very efficient (Li and Green 2011). The wellbore cleaning process depends on several variables, including fluid properties, flow velocities, well geometry, deviation, particle properties, penetration rate and so on.…”

Effect of Different Qualities of Foam on Fill Particle Transport in Horizontal Well Cleanup Operation Using Coiled Tubing

“…Removing wellbore fill is one of the most frequently use and yet challenging issue in coil tubing unit for wellbore cleanup. It forms (50%) of coil tubing services [1]. Coil Tubing has two modes of fluid circulation inside wellbore to remove fine particles downhole, namely the forward and reverse circulation mode.…”

Factors affecting fill removal from horizontal well during colied tubing cleanout operation

“…Therefore ,well cleaning operation is required to enhance the oil/gas production. Currently, fill removal is the largest CT application with approximately 50% of all CT operations industry wide [1]. Coil Tubing has two circulation modes to remove solid particles, namely the forward and reverse circulation modes.…”