Application Research On Directional Well Seepage Law And Well Test Interpretation Method

In recent years, with growing energy demand, the underground condition limited oil and gas resources more and more attention by people. Directional well has been widely used in the oil and gas field exploration and development because it can increase oil and gas seepage section, drill wear multilayer reservoirs, enhance productivity of oil. It was found that there are few studies of the seepage rule and theoretical methods and there is no well test analysis mode for description of composite reservoir of directional well. The existing flow modeling of directional well has problems that the type curves affected by negative Skin are oscillatory, and the theoretical are rare. For directional well percolation theory research lag behind the pace of technology application, forcing most oil fields in our country adopt the method of vertical wells to analysis the test data in the process of oil and gas well test. So the analysis results can not reflect dynamic characteristics of the reservoir. This text aims at these problems, based on the basic seepage theory of directional well and refer to the vertical wells negative skin template curves oscillation theory, redefine the dimensionless mathematical model that represent the seepage flow characteristic of the directional well and put forward a new way to use integral transform, point source function, characteristic function and the characteristic value of modern mathematics theory to solve the well test mathematical model of directional well. Based on these methods and give full consideration to the actual reservoir characteristics, set up and solve six well test mathematical model of directional well, which includes:(1) Taking effective radius model and outer boundary conditions for infinite and rectangular closed and rectangular directional, three mathematic models of directional well for the homogeneous reservoir that top and bottom is sealing are established. (2) Taking effective radius model and outer boundary conditions for infinite and banded closed and banded directional, three mathematic models of directional well for two regions of linear composite reservoir that top and bottom is sealing are established. Programming to draw a new directional well pressure dynamic characteristic curve and the parameter of transformation and well parameters is preseted to analysis the sensitivity of the pressure dynamic characteristic curves. By analyzing the curves, the one found is directional well model compared with vertical well, there will be appear a horizontal line which represents the early radial flow in the pressure derivative curve of directional well and with the deviation angle increase there will be appear anther horizontal line in middle transition phase. Compared with horizontal well, the ERF phase become shorter and the TRF will be appear in the transition flow, rather than a linear flow. The anther one found is the curve shapes that directional well under the influence of k, h, S and kh/kv. In the end, a set of practical method of transient well testing analysis is formed, and then 22 example directional wells match interpretation of wuerhe reservoirs are made, and many useful reservoir parameters are gained. Through the comparison of the interpretation results of the test datas between directional well model analysis and vertical well model analysis, the relationship between deviation angle and Skin, permeability and pressure. The research achieve- ments are already solved the oscillation problem that the type curves affected by negative Skin and enriched the analysis model of directional well, and the research achievements can also provide reference and service for the development of oil field.