各向异性地层多探头电缆地层测试解释模型

Research on interpretation model for multi-probe WFT in anisotropy formation

由于地层具有纵向非均质性,在执行多探头电缆地层测试时,将无法使用基于地层纵向均质假设建立的多探头电缆地层测试解释模型。针对这一问题,从仪器探头组合结构与地层纵向非均质之间的适应性入手,重新设计多探头电缆地层测试器的探头组合结构,并基于Carslaw和Jaeger提出的各向异性介质中温度场分布公式,给出了相应的测试解释模型。改进后的测试仪器和相应的解释模型能够适应纵向非均质地层的测试参数解释,同时能够将原来可以解释的参数—水平渗透率kh和垂直渗透率kz进一步解释为在x方向、y方向和z方向上的渗透率分量kx、ky和kz。数值模拟测试解释结果表明,新的仪器探头组合结构和相应的解释模型有较高的测试解释精度,通过电缆地层测试能够更充分地认识地层,拓展了电缆地层测试的功能。

The current multi-probe wireline formation testers （WFT） and the corresponding interpretation models have to rely on the assumption of homogeneous vertical permeability, which makes multi-probe wireline formation tester unsuitable for vertically heterogeneous formation case. But in fact, most actual formations are vertically heterogeneous in terms of permeability. To solve the big conflict above, in the paper the probe locations of a multi-probe wireline formation tester is redesigned based on its prototype, and an interpretation model of the new multi-probe wireline formation tester is developed based on the temperature distribution formula proposed by Carslaw and Jaege. Therefore, the new multi-probe wireline formation tester and interpretation model do not have to be confined to the assumption of vertically homogeneous condition, and can be applied in testing heterogeneous formation. What is more, the formation permeability in all x, y and z directions could be interpreted through the new method, which fatherly expands the functions of wireline formation tester.