First Deepwater Well Successfully Drilled in Colombia With a High-Performance Water-Based Fluid

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 120768, "First Deepwater Well Successfully Drilled in Colombia With a High-Performance Water-Based Fluid," by J. Marin, SPE, F. Shah, SPE, M. Serrano, SPE, A. Jaramillo, and C. Marin, Halliburton, and W. Arevalo and G. Priandi, Petrobras, originally prepared for the 2009 SPE Latin American and Caribbean Petroleum Engineering Conference, Cartagena, Colombia, 31 May-3 June. The paper has not been peer reviewed. Deepwater drilling presents significant issues and uncertainties, especially when there is no prior drilling experience in the area. Uncertainties about the drilling conditions create additional risk to operators and can cause project budget overruns. Innovative technologies often are implemented to help ensure that the well is drilled efficiently and safely. Drilling-fluid selection was a key decision to the success of the project. Introduction Deepwater exploration activity in the oil and gas industry continues to present new hurdles requiring innovative technical solutions. These difficult wells can increase the risk factor and result in potentially higher operational costs. In most cases, an oil-based drilling fluid is selected as the first option because of the high daily costs associated with a deepwater operation and the advantages gained in wellbore stability and rate of penetration (ROP) compared to conventional water-based systems. However, tightening environmental regulations and high costs associated with cuttings and oily fluid disposal are sufficient reasons to seek viable water-based fluid alternatives that could provide an oil-based-drilling-fluid performance. Water-based drilling fluids that simulate the performance of oil-based drilling fluids, commonly are referred to as high-performance water-based fluids (HPWBFs). The main benefits of these systems are reduced environmental footprint and lower costs associated with cuttings and fluids disposal. Petrobras Colombia undertook the challenge of drilling the first deep-water well in Colombia in 1,840-ft water depth in the Tayrona Block in the Caribbean Sea north of Colombia. Because of environmental restrictions, uncertainties about formations that would be encountered, and the need to protect the target zone from damage, an HPWBF was selected to drill the well. HPWBF System Fluid selection presented several challenges related to drilling the exploratory well. The operator rejected the option of using an oil-based fluid because of environmental restrictions and cuttings and fluids-disposal complications. The HPWBF used met the required criteria and was designed for maximum shale inhibition in highly reactive formations and provided wellbore stability, high ROPs, and acceptable rheological properties over a wide range of temperatures. It had been run successfully in the Gulf of Mexico in shelf and deepwater operations.