Evaluation On Efficient Source Rock Of Qingshankou Formation In Northern Songliao Basin, China

This article was expected to qualify the distribution of effective source rock, thecharacteristics of hydrocarbon expulsion and the hydrocarbon potential of source rockin the Qingshankou formation, north of Songliao Basin. The result was expected toadvance the further exploration theoretically in this area. The study was based onlarge data sets of geochemistry available on database and studies by formerresearchers. The research has established the evaluation standards for effective sourcerock and corresponding evaluation plot. According to the proposal, the study hascovered subjects including:1) the effective source rock distribution in detail,2) theheterogeneousness and geochemical characteristics of source rock,3) the mass ofhydrocarbon generation and expulsion. Additionally, the study has established a seriesof methods to predict trap prospects based on geochemical technology, which hasbeen adopted by explorationists and has received some positive feedback. The mainconclusions can be summarized as follows.1. By applying new technology of source rock evaluation, source rocks inGulong depression, Sanzhao depression, south of Changyuan plateau and Wangfudepression are classified as effective source rock and part of source rock in Heiyupaodepression is also the effective source rock.2. During the deposit of Qingshankou formation, there may be two depocenterswhich are divided by the NE-SW belt in the mid of Sanzhao depression. The effectivesource rocks of Qingshankou1stmember are mainly deposited in Qijia-Gulongdepression, the south of Sanzhao depression, the south of Changyuan plateau, Wangfudepression and the south of Heiyupao depression. And in Qingshankou2nd-3rdmembers, the effective source rocks are mainly distributed in the south of Qijiadepression, Gulong depression and then in the mid of Sanzhao depression and Andasyncline. The effective source rock distribution in Wangfu depression is small in thesemembers.9. The total mass of oil expulsed form Qingshankou formation is expected at251×108tons,80%of which are from Qingshankou1stmember and only20%arefrom Qingshankou2nd~3rdmembers. The total oil potential by Qingshankouformation is expected at126~151×108tons, most of which are from Gulong and Sanzhao depression.10. With the predicting technology by geochemistry,3out of7proposed wellshave seen oil shows in Anda syncline. In the north of Qijia depression,2out of4wells proposed have seen oil shows. The geochemistry prediction technology has alsobeen applied to determine the preferred oil migration path and trap prospects inChaochang area and the result has been used as a proof in the exploration strategy.