Optimizing geological design of J-shaped deviation oil & gas well by deepening kickoff point

Abstract

In the geological design of 2-D J-shaped deviated oil and gas wells, once the coordinates of wellhead and production layer target are determined (restricted by specific ground conditions and underground understanding, respectively), the position of the kickoff point (KOP) becomes very sensitive. By deepening the kickoff point (KOP) based on the current conventional fixed upper position and the dog leg severity (DLS) remaining unchanged within the penetrated range, a smaller drill axis and an angle between the production layer and axis can be obtained at the same designated target point to extend the section of penetrated oil-bearing layers, expand the oil drainage area, increase proven reserves, and ultimately enhance the oil production and recovery during the contract period. In addition, after optimization, it is expected to save 1-2% of well drilling costs by reducing drilling time. With the help of drilling engineering and production engineering, drilling KOP can be achieved easily in deeper and harder rock formations, which is able to improve the efficiency of the electric submersible pump (ESP) and to avoid eccentric wear of the ESP, resulting in extension of the service life of the ESP. This optimized design also runs in parallel with various well stimulation programs and projects without any confliction of each other. This design can be either used for comparison of the parameters of the completed inclined wells with assumed ones of deepening KOP design to show how the deepening KOP can be used to differentiate the increased thickness of the penetrated target layers and the drainage area of target zones, or it can be utilized to compare any pair of parameters between inclined production wells within a range. In the same drilling field, any random increase of 1° inclination angle in a stable inclination section can lead to a corresponding increase in the thickness of the penetrated oil-bearing layer and production. Our research results quantitatively indicate that in the geological design of J-shaped deviation oil and gas wells, the KOP can be re-set from a shallower fixed position along the current conventional trajectory to a reasonable position as deep as possible, which shall be suitable for most situations of optimizing well performance, especially for some restricted complex surface conditions and energy-deficient reservoirs, which assign the KOP a new geological significance in line with the business strategy of rapid oil recovery