Study Of Vector Well Pattern For Sandstone Oil Reservoir With Bottom-water

Development of Modern Detailed Reservoir Description technology has enabled us to understand the reservoir better. The traditional arrangements of well patterns have changed with the application of complex wells technology. The traditional well pattern theory is not suitable for development of modern oil field exploitation technology. For this reason Liu-Dehua and others proposed the concept of vector pattern of well-net in 2004 which is based on reservoir description, the premise of maximum control of reserves, and is for the purpose of improving single oil well production. Vector well pattern is an integrated well spacing method based on the geological vector, of which purpose is to determine reasonable development mode in consideration with various factors. With the wide use of horizontal wells for oil and gas development, the study of vector well pattern for horizontal wells have become more and more important. When the concept of vector well pattern was firstly introduced, the horizontal well and the geological situation ought to be both considered about. But the logical extension of horizontal direction in horizontal wells, best direction of horizontal wells row and the combination of the various geological factors in specific reservoirs are problems that need to be answered.Coordination of well vector and geological vector is the basic principles of vectorial well design. For sandstone oil reservoir with bottom-water, the deployment of vector wells should be based on reservoir structure and morphology, sediment source direction in the process and reservoir heterogeneity, the direction of horizontal-section well and horizontal wells arrangement should be reasonably designed, and the best standoff of horizontal wells should been carefully considered as well as the rational choice for different types of wells in reservoir be made. In this paper on the basis of detailed reservoir description and in combined with the actual geological conditions of 1st Block of Tahe Oilfield, an ideal model is established considering with various factors, quantitative discussions of the different factors affecting the direction of horizontal-section well and horizontal well array are made, and the best direction of horizontal-section well and horizontal well array of vectorial wells are determined.In the actual development of sandstone oil reservoir with bottom-water standoff, the height of water avoidance is one of the important factors to affect the velocity of bottom water coning and water-free production period. According to the calculation of ideal geological model with different bottom water energy, the result shows that the horizontal well should be as close as possible to the upper reservoir. The reasonable selection of well-type is conducive to reduce reservoir development investment under the circumstances of obtaining equal economic benefits. Through a comparative analysis on production performance of horizontal and vertical wells in 1st Block of Tahe oilfield with similar reservoir geology situation, it is believed that reasonable well-type selection should be considered with the actual construction of 1st Block of Tahe Oilfield.The quantified research and related discussions are made about factors that need to be considered in vectorial well arrangement and their impacts on well-net, and the conclusions need to be verified by specific reservoirs. Through design of vector well-net and contrast between existing well-net and vector well-net in 1st Block of Tahe Oilfield, we have found that under the same investment conditions, vector well-net helps to control water-content rise and increase recovery percent, that is, vector wells enhance economic performance better than the existing well-net in 1st Block of Tahe Oilfield. Now control degree of well-net in 1st Block of Tahe Oilfield is not sufficient, so in the next step well-net arrangement should be conducted with vectorial well arrangement methods. In this paper integrated the principle of vectorial well arrangement, a next-step well-net adjustment program is designed. According to numerical simulation prediction results, it is believed that the use of Vector Well-net helps to achieve better beneficial results in next-step well-net adjustment.