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Research On Low Porosity And Low Permeability Reservoir Protection Technology In Middle East And Central Asia

Posted on:2012-11-17Degree:MasterType:Thesis
Country:ChinaCandidate:Q S MengFull Text:PDF
GTID:2120330338493221Subject:Oil and Natural Gas Engineering
Abstract/Summary:PDF Full Text Request
The formations in Middle East blocks of SinoPec are low porous and low permeability, and are damaged seriously in drilling process. There is good show of oil and gas but poor testing results. It's urgent for reservoir protection. Focused on Saudi B block, the characteristic of reservoir and its damage mechanism in drilling and completion process are analyzed to develop reservoir protection technology fitting for the reservoir with low porosity, low permeability and high temperature in this block, which contributes to qualified and effective progressive development in Middle East and Middle Asia oil and gas province production, and makes qualified drilling technology and reservoir protection technology reaching the advanced level.First, the data of the block were collected.The physical characteristics and structure and minerals of reservior rocks were researched. The potential damage types and level were analyzed. Results indicated that, there are mainly point throats, followed by tubular throats and a small amount of laminar and curved lamellar throats.Shale content in reservior surpasses 6.5%. The minerals are mainly composed with illite, chlorite and andreattite, a little of kaolinite. The content of silk illite is more than 40%. The average porosity is 7.6% and average permeability is 0.465×10-3μm~2, which indicateds that the reservior is a typical formation with low porosity and low permeability. Sensitivity tests demonstrated that there is medium weak velocity sensitivity, water sensitivity and salt sensitivity, weak acid sensitivity and alkali sensitivity and medium stress sensitivity. Water lock and flowing back test indicated polyol can prevent water lock eccfectively. Oil lock by condensate oil and kerosene will reduce formation's permeability serverly, with only 15%~20% peremability. A cumulative damage effect existed when formation contacts with drilling fluid, cementing fluid and perforating fluid in succession. The damage mechanism of low porosity and low permeability formation was proposed and responding strategies were determined.According to the properties of the low porosity and low permeability for this formation, experiments to evaluate low porosity and low permeability formation protected by drilling fluid were performed. After adding 0.3% polyol and 0.2% SPAN-80 to drilling fluid currently used, the permeability recovery rate increased from 68.0%~75.0% (the average is 72.25%) to 81.2%~84.7% (the average is 82.7%) by 8~15%. The optimized drilling fluid and completion fluid were fitted for protecting the formations in Saudi B block. There are good show of C1 in Unayzah formation and Sarah formation in Well MTLH-0001 drilling .Test data indicated that the fitting K of permeability is 0.0044mD, and surface factor is -3.5. There is no damage caused by drilling fluid in the operation.
Keywords/Search Tags:Saudi Arabia B block, physical parameter, sensitivity test, drilling fluid for protecting reservoir, application
PDF Full Text Request
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