The wireline formation tester is very important for formation evaluation, such as calculating formation pressure and permeability, identifying fluid type, and judging the interface between oil and water. But in the formation with low porosity and low permeability, the pressure boost effect exists as the mudcake has poor seal ability, and the mudcake can not isolate the hydrostatic pressure of the formation around the borehole and the mud seepage into the formations, the pressure measure is not real formation pressure. At the same time the tool is easily grappled in the low porosity and low permeability formations because of the long waiting and testing time. We present a method for determining the minimum testing time of the wireline formation tester in the paper. The pressure distribution of the mucake and the formation were respectively calculated with the finite-element method, the radius of influence of the mud pressure was also calculated, and the minimum testing time in low porosity and low permeability formation can be determined. The ranges of the minimum testing time of the formation with different permeability were also obtained. The minimum testing time determination can guarantee to get the true data of the formation and avoid the accident caused by the long waiting and testing time. It gives a theoretical support for wide development and application of the wireline formation tester in low porosity and low permeability formations.
The Minimum Testing Time Determination For Wireline Formation Tester Applying To Low Porosity/Low Permeability Formation
Falong, Hu, Lizhi, Xiao, and Zhang Yuanzhong. "The Minimum Testing Time Determination For Wireline Formation Tester Applying To Low Porosity/Low Permeability Formation." Paper presented at the SPWLA 46th Annual Logging Symposium, New Orleans, Louisiana, June 2005.
Download citation file: