摘要
异常高压裂缝性低渗油气藏具有岩石孔隙体积压缩系数大且易变化的特点。为了准确计算异常高压裂缝性低渗油气藏的探测半径，利用油气藏压力变化引起的孔隙体积压缩系数、孔隙度和渗透率变化的机理，建立了孔隙体积压缩系数、孔隙度和渗透率计算模型，提出了适合异常高压裂缝性低渗油气藏的探测半径计算新方法。研究发现：对于异常高压裂缝性低渗油气藏，孔隙体积压缩系数在生产过程中随着孔隙压力降低先快速降低，后逐渐平缓。在计算探测半径时，孔隙体积压缩系数、孔隙度和渗透率三者的变化机理均不可忽略，通常会考虑孔隙度和渗透率的应力敏感效应，但如果忽略孔隙体积压缩系数的变化，会严重低估此类油气藏压力传播距离，且产量越大，低估程度越大。研究成果对异常高压裂缝性低渗油气藏试井设计和合理井距确定具有指导意义。
Abstract
Abnormally high?鄄pressure fractured low?鄄permeability reservoirs have the characteristics of large rock pore volume compressibility and easy to change. In order to accurately calculate the detection radius in abnormally high?鄄pressure fractured low?鄄permeability oil and gas reservoirs, based on the mechanism of the change of pore volume compressibility, porosity and permeability caused by the change in oil and gas reservoir pressure, the calculation model of pore volume compressibility, porosity and permeability is established, and a new calculation method for calculating the detection radius suitable for abnormally high?鄄pressure fractured low?鄄permeability oil and gas reservoirs is proposed. It is found that for abnormally high?鄄pressure fractured low?鄄permeability oil and gas reservoirs, the pore volume compressibility first decreases rapidly and then gradually flattens with the decrease of pore pressure in the production process. When calculating the detection radius, the change mechanism of pore volume compressibility, porosity and permeability cannot be all ignored. The stress sensitive effect of porosity and permeability is usually considered. However, if the change of pore volume compressibility is ignored, the pressure propagation distance of such oil and gas reservoirs will be seriously underestimated, and the greater the production, the greater the degree of underestimate. The research results have guiding significance for well test design and reasonable well spacing determination in abnormally high?鄄pressure fractured low?鄄permeability oil and gas reservoirs.
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