MDT测试资料确定气水界面的方法研究

通过对MDT测压资料的分析,发现了造成测试点压力值存在误差的主要原因有两个方面：一方面是由于部分测压点储层物性差,测试探针抽吸地层流体后储层压力恢复需要的时间较长,然而由于实际原因测试压力恢复无法等待足够的测试时间;另一方面是由于部分物性较差储层较难形成好的泥饼,以至于受到比较严重的泥浆侵入使得测试点产生超压现象,测试得到的地层压力和实际压力相比偏大.同时分析发现物性较好的储层往往能够得到相对可靠的测试压力.合理的气水界面对于计算探明地质储量有着很重要的意义,尤其是高温高压气田,气水过渡带往往较大,可能会达到30m左右,这种情况下无法仅从钻遇情况分析气水界面,此时可以结合MDT测压资料分析气水界面,从而确定合理的地质储量.通过分析实际MDT测压资料,对不同测压点进行了误差分析并在此基础上提出了压力数据点的筛选原则.通过实际检验认为新的回归方法确定出的气水界面科学合理.

Study on the Method for Determination of GWC with MDT Test Data

Through analysis of the MDT pressure data, it is revealed that there are two main reasons for errors in testing pressure value. On one hand, the reservoir physical property at the pressure testing points are very poor, and it takes a long time for reservoir pressure recovery after suction fluid with testing probe. However, due to practical reasons, there is not enough time to wait for pressure recovery. On the other hand, it is difficult to form mud cake in partial reservoirs with poor quality, and serious mud invasion occurred, resulting in overpressure phenomenon at the testing points, and great difference the formation pressure is compared with the actual partial pressure. At the same time analysis showed that the physical property of reservoir better tend to be relatively reliable test pressure. The gas/water contact and reasonable has important significance for the calculation of reserves, especially in high tem- perature and high pressure gas field, gas/water transition zone are often large, may reach about 30 m, this situation not only from the analysis of the gas/water contact drilling situations, this can be combined with MDT measurement data of gas/water contact, so as to determine the geological reserves of reasonable. Through the analysis of actual pressure data of MDT, analyses the error of different measuring points is put forward based on the principle of data points selection pressure. Through the actual test that a new regression method to determine the gas/water contact of scientific and reasonable!