南疆沙漠区超深层高密度地震采集方法

Ultra deep and high-density seismic acquisition method in desert area of South Xinjiang

中国新疆南部沙漠区奥陶系油气储量丰富,是西部地区重要的油气勘探开发领域。该区地质目标勘探存在三方面难点,包括目的层埋藏深(一般超过7000 m)、地质目标是小尺度断溶体、地表为巨厚沙漠,常规地震采集资料的分辨率难以满足油气开发需求。高密度地震采集技术是目前业界公认的解决隐蔽油气藏开发的重要技术,在中国东部地区已取得显著效果。将高密度地震采集技术引入南疆沙漠区进行试验研究,形成了针对南疆沙漠超深目标的小组合+高密度采集技术,其中25 m×25 m面元、约400次覆盖、330万/km2炮道密度、横纵比0.7是适用于该区的观测系统参数,两串小组合+适中的井深药量对拓宽高频效果显著。最终断溶体成像精度得到显著提高,表明上述地震采集技术组合适用于南疆沙漠超深层目标成像。

The Ordovician oil and gas reserves are abundant in the desert area of southern Xinjiang,China,which is an important oil and gas exploration and development field in the western region.There are three difficulties in the geological target exploration in this area,including the burial depth of the target layer(generally more than 7000 m),the geological target is a small-scale fault solution,and the surface is a huge thick desert.The data resolution of conventional seismic acquisition is difficult to meet the needs of oil and gas development.High density seismic acquisition technology is recognized by the industry as an important technology to solve the development of subtle oil and gas reservoirs,and has achieved remarkable results in the east.The high-density seismic acquisition technology was introduced to the desert area of South Xinjiang for test,and small combination+high-density acquisition technology suitable for ultra deep targets in the desert area of South Xinjiang was obtained in the test,including 25 m×25 m bin,400 times of coverage,3.3 million shot path density and horizontal to vertical ratio of 0.7 are suitable observation system parameters for SHB area in southern Xinjiang.Two string small combinations+moderate well depth charge are effective for widening high frequency.Finally,the imaging accuracy of fault solution has been significantly improved,indicating that high-density seismic acquisition technology has a good effect on the imaging of ultra deep targets in the desert of South Xinjiang.