Drilling and Completion Technology

Combining enhanced drilling, geosteering and reservoir planning successfully develops thin sand reservoir. In the Niger Delta, new geosteering techniques and formation evaluation technologies, combined with reservoir management techniques, enabled a 1,200-ft horizontal well to be placed within a thin hydrocarbon sand having structural dip and stratigraphic uncertainty. This made it feasible to develop and produce reserves that had been previously unattainable. Authors from ChevronTexaco and Schlumberger tell the story of how it was done.

Understanding how downhole vibration is created and transmitted. Identification of drillstring vibration transmission, attenuation, and interaction was important in several wells for ChevronTexaco, where vibrations had damaged several MWD and BHA components at two offshore rigs in the Gulf of Thailand. This article presents a study on the investigation of vibration transmission, attenuation and interactions based on data obtained from dual, downhole vibration sensors. Authors from Halliburton Sperry-Sun, Global Santa-Fe and ChevronTexaco discuss the results of the study, which have been effective in reducing harmful vibrations and in improving the performance of BHA components.

 Exploration/Reservoir

How to integrate time-picking uncertainties in gross rock volume calculations using geostatistics. Authors from Geovariances and Shell Italia E&P describe this key issue in hydrocarbon resource evaluations across the exploration- appraisal- development cycle. Geostatistics provide various techniques for deriving velocity models by combining well information with, for instance, more densely sampled stacking velocity data. This article presents an innovative approach to quantify two-way traveltime uncertainty, and shows how it was successfully applied to a complex hydrocarbon field. The impact of two-way traveltime uncertainty on gross rock volume is quantified and discussed.

A new type of surface logging. Similar to CSEM (controlled source electromagnetics), this new method has some significant differences, but nevertheless relies on EM waves for measuring resistance from the surface. Although too new to feature a bona fide case study, the technology a product of research from the University of Edinburgh has been tested on known reservoirs, and is now going commercial.

 Production Technology

VOC control system for field gas dehydration unit solves regulatory problem. This case study involves a mature Wyoming oil and gas field that draws gas from 17 wells that are served by two central compressor stations. Before 2003, 14 well-site dehydration units were employed within the field, but excessive operations and maintenance costs dictated shutting down the field units and installing a centralized dehydration unit at each compressor station. Regulations required that the new dehydration units must comply with Best Available Control Technology (BACT) and achieve a minimum 95% reduction in Volatile Organic Compound (VOC) and Hazardous Air Pollutant (HAP) emissions from the dehydrator re-boiler vent stack. The author from TOCA Services LLC describes how it was accomplished in a very cost-effective manner.

 Petroleum Technology Digest

World Oil's regular monthly feature is published in association with the Petroleum Technology Transfer Council. This month features a case study about enhancing production, told from the operator's view.

 Drilling, Completion and Workover Fluids

World Oil's exclusive annual reference comprises about 21 pages that show trade names, generic descriptions, recommended usage and suppliers of nearly 2,400 fluid systems/additives for drilling, completion and workover.