Meeting the Ultrahigh-Temperature/Ultrahigh-Pressure Fluid Challenge

Abstract

Ultrahigh-temperature/ultrahigh-pressure (uHT/uHP) conditions have a different definition, depending on the region, the operator, and the service company. In this paper, the definition used for uHT/uHP fluid performance is that the fluid be able to perform above 500 F and 30,000 psi. This paper describes the development of innovative drilling fluids that are specific to these well conditions.When bottomhole temperatures exceed 400 F, the design and engineering of drilling fluids can be challenging. Drilling fluids that destabilize can cause a variety of fluid-control problems that could lead to drilling and completion issues. With invert-emulsion fluids, the major challenges encountered with these conditions are related to the thermal degradation of the emulsifier and wetting package that can lead to gelation and syneresis. Another challenge is fluid loss that is related to the emulsion stability and to the degradation of the fluid-loss-control additives. Finally, efficient control of the rheological properties-critical to the success of any well-also can be challenging when effects from emulsion instability, filtration-control degradation, and rheology-control-additive degradation are coupled with increases in drilled solids, rapidly leading to rheological instability. This can manifest itself as high-fluctuating rheologies and gelation or the loss of rheological properties that can give rise to sag of weight material, both potentially leading to associated well-control problems.The paper describes the development of the new fluid system designed for such uHT/uHP environments (highlighting the chemical differences) and compares the test data of the system with more-conventional high-temperature/high-pressure (HT/HP) invert-emulsion fluids. Data are presented that show the stability and performance of the new fluid with extended exposure to temperature >500 F, demonstrating a tolerance to various contaminations and showing the rheological behavior and stability to 600 F and 40,000 psi.

Rheological Behavior of Drilling Fluids Containing Hydrophobically Modified Starch for Filtrate Reduction

“…Among the main parameters that affect the rheological properties are viscosity of the continuous phase, overall viscosity, volumetric fraction, average size and size distribution of particles in the dispersed phase, the nature and concentration of the emulsifier and the size and shape of the dispersed solids [23]. Careful selection of additives that are suitable for wells being drilled under severe environmental conditions is fundamental to control the rheological and filtration properties of the fluid [24].…”

Nanomaterial-Based Drilling Fluids for Exploitation of Unconventional Reservoirs: A Review

“…Stefano et al [118] have stated that emulsifiers which have been used in HPHT application at up to 478 K are from a class of chemicals distinguished by functional groups with bipolarity such as fatty acids, fatty alcohols, and amine. Nicora et al [119] focused on polyamides for synthesis of primary emulsifiers of the Kristin Development Project, as this chemical class shows the best stability at high temperature.…”

Study on Rheological Property Control Method of “Three High” Water Based Drilling Fluid

“…Applied "three high" water-based drilling fluid technology, to a certain extent, it solves the complex problems in the drilling process. But its rheological property control exists high temperature, high salinity, high density, and weighting difficulties, etc unresolved issues [5][6][7][8][9][10]. Boul synthesized a highperformance salt water tackifier which was based on the multi-molecular structure unit.…”