A Study On Gas Capping Formation Of H Oil Layer In The South Of Daqing Placanticline

In order to clear the regular pattern of natural gas accumulation and distribution of Heidimiao oil layer in the southern part of Daqing Placanticline, this article studys the characteristics of development and distribution and the capacity of the capillary closure making use of existing drilling, well logging, seismic and analysis data, the results show that the Heidimiao oil layer which lie in the southern part of Daqing Placanticline has more than one sets of mudstone caprock, in which H14,H15 and H16 are the three sets of most developed mudstone caprock,which are the main capping layer of Heidimiao gas. Through the comparison of southern Daqing Placanticline's cap thickness and the relative size of source fault amplitude, the three sets of the regional distribution mudstone caprock were staggered mostly, formed multiple oven windows, natural gas was only saved under the three sets of unstaggered mudstone caprock, H14,H15 and H16. If the trap develops, natural gas can accumulation in Heidimiao oil layer; otherwise natural gas will continue to loss along the oven window migration. Through studying the relationship between measured displacement pressure and the magnitude difference of natural potential, the displacement pressure of caprocks in the south of Daqing Placanticline Heidimiao oil layer, from H11 to H24, increases gradually. The displacement pressure is more than 1MPa under the cover H15. This paper evaluates Heidimiao oil layer of the southern Daqing Placanticline through the thickness of cap rock, the proportion of mudstone and layer, destructiveness of cap rock caused by fault and displacement pressure, the results show that cap rock closure property H11 to H24 increase gradually. Through the research of natural gas wells and the relationship of cover between the temporal and spatial distribution, the control role of the cover to natural gas gathering and distribution is mainly manifested in the following two aspects:â‘ The spatial distribution of three sets of the regional distribution mudstone caprock controls natural gas gathering layer and the plane distribution parts.â‘¡The formation period match nen one, two passage air discharge period finely, in favor of natural gas accumulating in the Heidimiao oil layer.