基于测录井曲线的致密砂岩储层产能评价方法

强烈的非均质性、较差的储层连通性以及复杂的微观孔隙结构是致密砂岩气产能评价难度大和准确率不高的原因，基于此，利用多口井测录井曲线资料，归纳总结典型的曲线形态类型，并采用数学方法对形态进行了定量表征，提出了基于测录井曲线形态的产能评价方法。研究表明：①气测全烃曲线可以分为箱形、半箱形、正三角形、倒三角形、锯齿状和单尖峰状等6种形态，分别与油气层显示程度紧密相关，可以利用幅度、相对质心、相对锯齿、方差及自相关函数的参数值极性量化表征。其中，箱形气测全烃曲线峰形饱满，跨度较大；半箱形，气测全烃峰形跨度明显小于储层厚度；三角形，气测全烃曲线形态呈现正三角形或倒三角形；锯齿状，气测全烃曲线形态呈忽高忽低的趋势，呈现若干尖峰；单尖峰状，气测全烃曲线峰形跨度较小，呈单尖峰状。②6种气测全烃曲线形态与致密砂岩油气储层产能具有较好的对应关系。高、中产层主要为箱形、三角形，低产层主要为（半）箱形、三角形及锯齿状，特低产主要为锯齿状，不产层主要以单尖峰状为主。利用气测曲线形态及产能特征进行权重赋值，建立了解释关系图版。③录井全烃曲线与测井电阻率曲线综合解释可以更加准确判别致密砂岩储层产能。最后，利用定量化模型进行自动解释，通过数据验证发现，产层符合率为80.95%，产能区间符合率为78.05%。实践证明，基于测录井曲线形态可以较好地评价预测致密砂岩储层产气能力。

Evaluation of production capacity to tight sandstone reservoir based on logging and mud logging curve

Strong heterogeneity，poor reservoir connectivity and complex micro-pore structure are the reasons for the high difficulty and low accuracy in evaluating the productivity of tight sandstone reservoir gas.This paper used various well logging and mud logging curve data，summarizes the typical curve type，and the mathematical method to form is used for quantitative characterization，logging curve evaluation method is proposed based on the test of production capacity.Results show that total hydrocarbon curve can be divided into six types，including box shape，half box shape，positive triangle，inverted triangle，sawtooth shape，single peak，etc.，which are closely related to the level of oil and gas reservoir layer.Six types of total hydrocarbon curve can be quantified by amplitude，relative centroid，relative sawtooth，variance and the parameter value of the autocorrelation function.The box-shaped total hydrocarbon gas logging curve is full and has a large scale.Half box shape total hydrocarbon gas logging curve peak scale is significantly smaller than the reservoir thickness.Triangle shape total hydrocarbon gas logging curve is a positive triangle or an inverted triangle.Sawtooth shape total hydrocarbon gas logging curve has a tendency of high and low，which shows a number of spikes.Single peak shape total hydrocarbon gas logging curve is small，with a single peak.There is a good relationship between the 6 kinds of total hydrocarbon gas logging curves and the gas tight sandstone reservoir production capacity.The high and middle gas pay layers are mainly box shaped and triangular，and the lower production layer is mainly (half) box shape，triangle and zigzag pattern.However，the low gas pay layers is mainly sawtooth pattern，and the non-production layer is mainly single peak shape.The comprehensive interpretation of the total hydrocarbon gas logging curve and log resistivity curve can more accurately distinguish the production capacity of tight sandstone gas reservoirs.Finally，the quantitative model is used for automatic interpretation.Through data verification and analysis，it is found that the coincidence rate of production gas pay layer is 80.95%，and the coincidence rate of production capacity is 78.05%.It is proved by practice that the formation gas capacity of tight sandstone gas reservoir can be predicted based on the shape of logging and mud logging well curve.