东营凹陷深部异常高压与岩性油气藏的形成

The Deep Abnormal Pressure and the Formation of Lithologic Reservoir in Dongying Sag

研究了东营凹陷深洼陷内超高压与岩性油气藏成藏的关系。研究表明,深洼陷内砂体的油气充注程度与超高压呈正相关,超高压为其油气向深洼陷内岩性圈闭充注的主要动力;超高压降低了储集层含油藏物性下限,因此,在深洼陷强超压带内,储集层物性条件不是制约油气成藏的主要因素;强超高压的发育有利于超高压裂缝的形成,为油气运移提供有利输导条件;随超高压裂缝的间歇性开启和闭合,油气流体呈混相涌流方式间歇向岩性圈闭充注,圈闭内水则持续缓慢渗出。据此认为,由于强成藏动力的存在,东营凹陷深洼陷内岩性油气藏具有良好的勘探前景。

The relationship between the deep overpressure and the lithologic hydrocarbon accumulation in Dongying sag is presented. The study shows that the oil-gas containing degree in the deep sand body is positive correlation to the overpressure which could be the main dynamic force for lithologic trapping and filling, lowering the cutoff value of PVT in such a reservoir. Therefore, the petrophysical conditions could not be as the main factors to constrain hydrocarbon accumulation in the overpressure belt rather than the fractures formed by overpressure. With the overpressure fractures＂ intermittent opening and close, oil-gas fluid could fill intermittently into the lithologic trap in the form of mix phase, while the water within the trap could flow out continuously and slowly. It is concluded that the existence of strong dynamic force allows the deep lithologic reservoir in Dongying sag to be of bright exploration potentials.