Research on Reasonable Vertical Well Injection Mode in Horizontal Well Area

Abstract

AbstractHorizontal wells and vertical wells are used to jointly develop low permeability thin and poor oil layers, increasing the drainage area of horizontal wells to improve the initial production of single well, flexibly adopting different methods such as vertical well water injection and vertical well oil production to improve the degree of reserve control and production, and to realize the effective production of low permeability and difficult to recover reserves. However, due to the imperfect injection production relationship and insufficient formation energy supply in horizontal well area, the stable production period of horizontal well is short and the production decline is large, which affects the possibility of further enhancing oil recovery by joint development of horizontal well and vertical well. Combined with the characteristics of long horizontal section when drilling horizontal wells in a single oil layer plane and multiple oil layers when drilling conventional vertical wells vertically, the new concepts of connectivity ratio of both sides of horizontal section and connectivity coefficient of horizontal section length are proposed, and the corresponding relationship between injection and production and the degree of formation energy conservation in the combined development area of horizontal and vertical wells are systematically evaluated. Taking the horizontal well as the center, according to the position relationship between the horizontal well and the surrounding water injection wells (vertical wells), three kinds of injection production corresponding modes, namely symmetrical, triangular and quadrilateral, are innovatively defined. The numerical simulation method is applied to calculate the difference of formation pressure maintaining level and ultimate recovery factor of different injection production corresponding modes in Zhiping joint development well area under different reserves control degree, so as to optimize the mode of transferring vertical wells to injection, reasonably supplement formation energy, improve the formation pressure maintaining level, control the production decline rate of horizontal wells, and improve the recovery factor.KeywordsHorizontal wellVertical well to injectionSupplement formation energyDifferent injection production corresponding waysEnhanced oil recovery