The research of array holdup tools response characteristic for oil-water two-phase in near horizontal well

Stratified flow can be observed in typical flow pattern of oil-water two-phase in near horizontal well, which results in measure response using a conventional single probe centered measurement instruments cannot truly reflect the state of the fluid flow, inaccurate information taken from holdup measurements. Therefore, it is necessary to do the research on measuring holdup effect of Capacitance Array Tool (CAT) and Resistance Array Tool (RAT) in entire covering cross section of wellbore. In this paper, based on simulation experiment of multi-probe measurement instruments (CAT, RAT) in the large diameter flow loop, firstly, we have obtained the flow pattern characteristics in case of different proportion, made the charts of instrument response, for example, water holdup - flow rate (water cut) relationship, slip velocity - flow rate (water cut) relationship and inclination - water holdup (water cut) relationship, and so on. Secondly, using compiled data processing module, Surfer software and radial basis function, we have achieved fluid flow simulation for multi-probe measurement instruments (CAT, RAT), compared CAT with RAT measurement result, and obtained the assignment principle for holdup calculation with the weight optimization. Finally, the results can be used to judge oil-water two-phase flow conditions in near horizontal well and calculate each phase's holdup under different conditions.