High Performance Aqueous Fluids in Deepwater Operation

An exploration drilling in Gambia deepwater with water depth of 965m. well total depth drilled at measured depth 3,457m, the maximum inclination angle 34.6º and the horizontal section depth 1000m. The top-hole section was drilled with seawater and Guar GUM Sweep and the conductor casing set at 1053m. After the 26’’ hole was drilled with seawater and GUAR GUM sweep at TD the well was displaced to pad mud (KCl/polymer Mud) the 20’’ casing run and cemented. The intermediate and landing section was drilled with High Performance Water-based mud which was provide by one of leading servicing provider. This is where it was first deployed in Deepwater operation in West Africa (Gambia) and it shows good cutting and shale inhibitive performance, good hole cleaning, and wellbore stability, it allows the MWD tools to performed at high ROP, the rheological properties were stable with little treatment, the gives good lubrication and good cutting carrying to surface. According to Pearson, J.R.A [1], that the important rheological requirements are that they should have a low an apparent viscosity as possible, consistent with drilled cutting back to the surface during circulation.

In deepwater operation we may encountered some extremely reactive formations that can incur lot of cost, well lost hole pack off and lost of drilling tools (BHA) which will require sidetrack. Also, with the glamour for the clean energy in the world, there are a lot of environmental restriction now and high cost of waste disposal. This high-performance Water based mud is an option to address the above concerns much attractive in drilling operation.

In this study, the rheological preparties of the mud will be compare with Oil based mud to see the way they performed downhole. The hole cleaning ability and the number of cutting waste that will be generated which will translate to the cost of disposal.

This result show that high performance water-based mud is more effective in term of cost, solved environmental concern and performed as oil – based mud that is wildly used in the region.