Advances in Hostile Formation Testing: A Case Study from Gulf of Thailand
Banerjee, Somnath¹; Puttanarakul, Rassamee²; Osman, Kamal³; Rongsayamanon, Nopphon³; Muangsuwan, Atip³
¹Halliburton, Kuala Lumpur, Malaysia.
²Halliburton, Bangkok, Thailand.
³Chevron, Bangkok, Thailand.
Globally, exploration and development wells are being drilled in increasingly deeper, hotter, and more hostile reservoirs. Successfully obtaining pressure and fluid sample information requires a new generation of hostile formation tester tools. This paper discusses the field trial results of a major service provider's second-generation hostile sequential formation testing tool that can operate in environments with temperatures up to 450°F and pressures up to 30,000 psi.
The first generation tool, introduced in 2002, provided a wealth of experience in collecting pressure measurements and samples in formations of approximately 400°F. In the Gulf of Thailand (GOT), these hostile wells are typically slim-hole and highly deviated, which increases the risk for tools to become stuck. The southern fields of GOT are the most challenging, with higher geothermal gradients, relatively deeper burial depths, higher mud weights, reversal in pore-pressure profile, lower permeability, and depleted zones. Previous tool statistics showed that many pressure tests failed to obtain an effective pad seal because of the adverse borehole environment.
The new tool, with its dual pads and independent deployment configuration, can run two different probe pads that are designed specifically for different scenarios based on well conditions. Increased pad life enables the same tool to be run for an extended range of pressure test programs.
This case study reviews examples and job profiles to illustrate the best practices for HTHP testing. Success rates are tracked to demonstrate how the improvements have led to successful testing in progressively more hostile conditions. As of 2011, more than 40 jobs were completed successfully. Conclusions are presented regarding the future of hostile formation testing and how the new technologies that are anticipated for these tools will continue to extend their capabilities.
AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012