关键词: 密闭取心井, 饱和度损失, 校正模型, 降压脱气校正, 钻井液侵入校正, 油藏

Abstract:

It’s the most directand effective method to analyze oil and water saturation by using sealed coring data. However,the total saturationof oil and water is only 75%-85% due to the increasingpore volume caused by the processes of raising cores, degasification by release of pressure and mud invading. There are many losses in oil and water saturation during the process. Oil and water saturation should be corrected for exact data. This paper provides experiments of volatilization process and raising cores process. The process of degassing is the main factor that causes the loss of oil and water saturation. It’s very difficult to simulate this process really. Based on the split-flow principle, the correction model of degassing caused by pressure drop is made. Pressure dropping can cause the abundant porosity of the core, as can be accurately tested in the overburden pressure experiment and can provide the basic for oil and water saturation correcting. The precision of this correction model is similar with the result of the sealed coring pressure. And the influence caused by mud invading should be considered in coring of unconsolidated sand. Oil and water saturation should be corrected for complete invading specimen and high invading specimen, and the result is less than 2%.

Key words: sealing core well, saturation loss, correction model, degassing correction, mud invading correction, petroleum deposits