油气井不稳定产能评价方法

在对低渗透和非均质油气藏进行试油试采时，许多深层气井、间歇生产油井和因地层受启动压力梯度影响具有非达西流动特征的油井，不能采用常规的油气井产能评价理论进行产能分析。为了能对这类井的产能进行科学准确的认识，以油气井不稳定渗流理论为基础，根据油气井生产特点，对其产能评价方法进行了研究攻关。建立了适用于连续生产油气井的不稳定IPR曲线产能评价、适用于间歇生产井的间采产能评价、适用于有启动压力梯度的低速非达西油井产能评价方法。应用4口试油试采井对其进行实践检验，结果表明这些方法充分考虑了储层、井筒及生产方式等因素，产能评价结果与实际情况完全相符。该方法在气井产能评价工作中具有合理性和准确性，可设计间歇定产或定压生产井的产量，实现了对开发井低渗透储层中长期产能的准确预测，为描述油气层的产能变化规律提供了有效保障，解决了以往低渗透油气层不能准确评价产能的难题，有利于得到油气井稳定产能，最大限度地提高经济效益，对指导开发生产具有重要意义。

气井表皮系数分解法

近井地带的表皮系数,是评价油气井产能和完井效率的重要参数。然而,利用压力恢复曲线确定的表皮系数,是一个总表皮系数。它应包括:打开程度表皮系数、射孔密度表皮系数、高速湍流表皮系数和泥浆污染表皮系数。综合有关的成果(参考文献[1]、[2]、[3]、[4]、[5]、[6]),提出了气井表皮系数的分解方法。通过实例应用表明,提供的方法是有效的。

Pore structure effect on reservoir electrical properties and well logging evaluation

The reservoir pore structure controls the reservoir quality and resistivity response of hydrocarbon-bearing zones and thus, critically affects logging interpretation. We use petrophysical data in three types of reservoir with different pore structure characteristics to show that the complexity of pore structure had a significant effect on the effective porosity and permeability regardless of geological factors responsible for the formation of pore structure. Moreover,, the distribution and content of conductive fluids in the reservoir varies dramatically owing to pore structure differences, which also induces resistivity variations in reservoir rocks. Hence, the origin of low-resistivity hydrocarbon-bearing zones, except for those with conductive matrix and mud filtrate invasion, is attributed to the complexity of the pore structures. Consequently, reservoir-specific evaluation models, parameters, and criteria should be chosen for resistivity log interpretation to make a reliable evaluation of reservoir quality and fluids.