Challenges for Coiled Tubing in Horizontal Well Intervention

Abstract

Most coiled tubing (CT) interventions are performed in a Rigless environment. Infact, this is one of the important drivers for the widespread acceptance and continued growth of the technique for well servicing. Now a days in most of the reservoirs with high water-cut wells are drilled horizontally. But its maintenance and work over jobs are challenging and needs the most advanced and precise technology. As a result CT units are employed to do the interventions in horizontal wells. But it faces the following problems during its operation Fill material can rapidly accumulate on the low side of the wellbore during production and during conventional removal operations. In some cases, the fluid velocity can carry fill along horizontal sections, but cannot lift it through the build angle into the vertical wellbore. Gravity causes the particles to accumulate and slide down the low side of the wellbore, especially at inclinations of 300 to 600. Once the fill has settled, it is difficult to re-establish particle transport. Turbulent flow significantly improves hole cleaning in a horizontal wellbore. However, in many cases, turbulent flow is not possible, due to the flow and pressure restrictions imposed by the CT work string, or the relative size of the completion tubular. This paper describes the solutions to the above mentioned problems along with the description of the new tool used. which leads to the better functioning of the unit and stability of borehole.

Evolution of Coiled Tubing Electric Line Plug and Perf Technology for Multistage Hydraulic Fracturing in Pakistan

“…As the interest in multistage hydraulic fracturing technology in horizontal wells increases rapidly, the scope of work for coiled tubing has become much wider (Rohilla, 2010). Operators have drilled horizontal wells to access tight gas reservoirs with the intent of carrying out multistage hydraulic fracturing.…”