Challenges Associated with an Unconventional Tight Sand Exploration Program in Central Saudi Arabia
The Kingdom of Saudi Arabia may have a tremendous expanse of unconventional hydrocarbon trapped in very thick sections of tight rock over very large areas adjacent to some of the world's largest oil and gas fields. Capturing this resource requires modern technologies and multidisciplinary teams to overcome some of the existing challenges. These challenges include: 1) very large exploration area; 2) multiple, thick, stacked tight Paleozoic gas sands; 3) liquids rich gas causing multiphase production issues; 4) high temperature and significant measured depths; 5) low flowing pressures and 6) conventional well completions. Leveraging numerous legacy exploration wells over the expansive area by compiling a complete list of uneconomic gas shows and tests, along with detailed analysis of logs and core, allowed us to initiate our drilling program without spending years doing basin and seismic analysis, which would delay the initiation of the program. The very thick column of multiple stacked tight gas sands are being evaluated by horizontal appraisal wells in previously known sands with gas shows, while new vertical wells appraise previously untested zones. Condensate rich gases have the propensity to liquid load the wellbore and cause blockage in the formation if draw down is too high and below the dew point. Small choke sizes and velocity strings help with acquiring proper flow tests. High reservoir temperatures force the use of special logging tool selections along with proper frac fluid chemistry to ensure the breaker was activated at the desired time. Deep measured depths require well completions to be designed for high treating pressures. New low pressure infrastructure had to be designed to allow for long-term production in resource plays that produce at rates and at pressures below the current gas infrastructure. Smaller frac designs and friction reducing techniques allowed for stimulations in legacy exploration wells not designed to be frac'd. Throughout the tight gas exploration phase, Saudi Aramco has utilized modern technologies and multidisciplinary teams to overcome the numerous technical challenges, which could significantly delay the full cycle development of the Kingdom's unconventional resources.
AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014