Following excessive sand production from the HB-1 Well in the Bekapai Field, the oil production from the central panel of the main zone was stopped. A cost-effective sand control solution was needed to reproduce that zone since Bekapai field is a mature field with mediocre gain expected. This solution will have to overcome several challenges which are: 1. Through tubing operation with an old completion (more than 20 years old) with a very small ID. 2. Dual annulus configuration: sand control solution to be applied in a concentric configuration of 5"1/2 blank pipe inside a 9"5/8 casing. 3. Small tripod platform: lifting and handling operation directly from crane barge due to limited working space. The solution chosen was to utilize a Vent screen combined with a high rate water pack. This method is a compromise between an expensive frac-pack operation and a low productivity classic gravel pack operation. The Vent Screen method uses two screen assemblies separated by blank pipe (Figure 2). Proppant is packed around the lower screen and most of the blank pipe. The differential pressure created on the screen annulus will create a unique flow path. The high rate water pack is aiming to by-pass only the damaging zone in the near wellbore to maximize productivity. The job design objective was to optimize productivity through the vent screen by an enhanced design of the perforation and pumping method. Prior to starting the job, a tubing wash and a sand cleaning were performed. Dual wire wrapped screens were deployed with a Coil Tubing Unit and set on top of the plug covered by cement. A high rate water pack treatment was performed by pumping the proppant using VES (Visco Elastic Surfactant) carrier fluid. After Nitrogen off-load, the well was able to produce oil at the same production rate as before shut in and without any sand trace or proppant flow back indication on surface. The break even point was reached after less than 5 months. This paper will discuss the design method, job execution and lessons learned from this operation.
展开▼
