高精度重力探测油气藏的可能性

Possihility of hydrocarbon accumulation discovery using high-accurate gravimetric survey

在国外已经正式发表了多种类型油气田与重力负效应相对应的实例。重力理论研究表明；岩石中饱和石油和水之间的密度差可达-0．3×103～-0．1×103kg／m3；饱含油气储集层与其围岩之间的密度差为-0．6×103～0．2×103kg／m3。据此，采用高精度重力观测，有可能发现重力负效应对应的油气藏。文中列举了泌阳凹陷下二门油田和安棚油田两个地区进行高精度重力观测的实例。通过重力定量解释，进一步证实下二门油田与重力负效应相对应，而安棚油田由于油层少而薄，埋藏又比较深，所获得的重力负效应极小值要远大于该区油气藏的理论值。这种差异，有可能指示新的低密度体存在。

Foreign geophysicists have offered some examples of various oil and gas fieldswhich are related to negative gravity effect- Theoretical gravity research shows thatthe density difference between saturated oil and water in rock may be -0. 3 × 103^- 0. 1 × 103 kg/m3, and that the density difference between hydrocarbon reservoirand country rock may be - 0. 6 × 103~ - 0. 2 × 103 kg/m3. Hence, the high-accurategravimetric survey may lead to the discovery of the hydrocarbon accumulationswhich are related to negative gravity effect. Two examples are given of performinghigh-accurate gravimetric survey in Xiaermen and Anpeng oil-field areas in Miyangdepression- The quantitative gravimetric data interpretation confirms that Xiaermenoil field coincides with negative gravity effect while the minimum negative gravityeffect observed in Anpeng oil field is much higher than the theoretical value corre-sponding to the oil reservoir because the oil reservoir is small,thin and deep. Suchdeviation indicates that there may be other low density bodies in the area.