Исследование течения флюида к горизонтальной скважине

Abstract

Recently, it is necessary to note the presence of negative dynamics in the deterioration of the reserves structure for newly discovered fields, and most of the them are classified as hard-to-recover, confined to deposits with a complex geological structure, low permeability, high oil viscosity, complicated by the presence of faults, active bottom waters and gas caps. Hard-to-recover reserves are drilled with horizontal wells. This is primarily because horizontal wells make it possible to multiply the area of fluid filtration due to the increase in the drainage area, due to the extensive contact of the horizontal well section with the rock, allowing to increase the well flow rate many times over. Summarizing the above, horizontal wells are used to develop fields with the following parameters: fields with a thin oilsaturated rim (up to 15 m), with a gas cap and bottom water; fields of heavy oil, with a viscosity of more than 30 mPa·s; fields with low reservoir permeability (less than 0.002 μm2). Under these conditions, linear Darcy’s law cannot describe fluid filtration. Under the conditions of high-viscosity oil and lowpermeability reservoir existence, a certain initial pressure gradient is determined, due to the rheological properties of the filtering fluid and high values of the surface friction coefficient. Under conditions of a thin oil rim and an increased gas factor, the limiting filtration rates due to the dissolved gas regime are observed, and a nonlinear law describes the fluid inflow. One of the main parameters in the preparation of the technical and economic assessment of the reservoir is the flow rate of each individual horizontal well. Analytical methods for calculating the horizontal well flow rate show a high error. It is proposed to take a fresh look at the problem of determining the predicted flow rate of a horizontal well, using well-known approaches for solving this issue. It is rather difficult to reliably predict the parameters of reservoir operation: the horizontal wells productivity obtained with the help of modern hydrodynamic stimulators turns out to be unreliable, which leads to the formation of an insufficiently rational development system. And the arising complications during operation in field conditions have to be eliminated due to significant volumes of material and labor resources. Thus, the development of methods that contribute to obtaining a reliable calculation of production is an urgent task for the oil industry.