Wpływ resztkowego nasycenia wodą na wielkość strefy przemytej piaskowców wodonośnych
Abstract
INFLUENCE OF RESIDUAL SATURATION WITH WATER UPON THE RESISTANCE OF A WASHED-OUT ZONE OF WATER-BEARING SANDS
Summary
It has been shown experimentally (5), that about 5-10 per cent and sometimes more of the original connate water is not replaced by the mud filtrate in the invaded zone. It may lead to errors during quantitative interpretation of the results of the well log measurements. In the case, when this error caused by the presence of the original connate water in the invaded zone is not taken into consideration the determining value of the resistivity ρsp of the invaded zone for low mineralization is higher than the negative sing points to the fact, that the true value is lower (zone of negative errors shown in Fig. 2. The negative sing points to thef act, that the true value is higher than the apparent one). It leads to serious errors in computations of the coefficients of porosity and water saturation basing on the parameters of the invaded zone. The value of the error which was made by appointing ρsp is almost independent from the resistivity formation factor Pp. It depends only on the presence of the original connate water in the invaded zone and on the ratio ρf/ρwz. The coefficient of residual water saturation in the invaded zone can be calculated from the formula (10).
Summary
It has been shown experimentally (5), that about 5-10 per cent and sometimes more of the original connate water is not replaced by the mud filtrate in the invaded zone. It may lead to errors during quantitative interpretation of the results of the well log measurements. In the case, when this error caused by the presence of the original connate water in the invaded zone is not taken into consideration the determining value of the resistivity ρsp of the invaded zone for low mineralization is higher than the negative sing points to the fact, that the true value is lower (zone of negative errors shown in Fig. 2. The negative sing points to thef act, that the true value is higher than the apparent one). It leads to serious errors in computations of the coefficients of porosity and water saturation basing on the parameters of the invaded zone. The value of the error which was made by appointing ρsp is almost independent from the resistivity formation factor Pp. It depends only on the presence of the original connate water in the invaded zone and on the ratio ρf/ρwz. The coefficient of residual water saturation in the invaded zone can be calculated from the formula (10).