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为了在发育异常高压沉积盆地的中深层进行有效的油气勘探,综合运用薄片、岩心常规、粒度分析、SEM等分析化验资料,探讨了渤中凹陷西北次凹储层压实作用和胶结作用的压力响应特征。得到了异常高压对机械压实具有抑制作用的有力证据。证实了不同胶结物类型有不同的压力响应特征。研究认为,每超静水压力7 MPa的异常高压可保存约2.0%原生孔隙。胶结强度的压力响应特征呈斜坡状:1陡坡段,远离高压界面的常压带→高压界面外280 m,胶结强度迅速增强,以弱胶结为特征,胶结物以自生黏土矿物为主,约占总胶结物的85%;2缓坡段,高压界面外280 m→异常高压带,胶结强度缓慢增大,以强—中胶结为特征,胶结物以碳酸盐为主,约占总胶结物的75%以上。在高压界面附近的常压带,碳酸盐胶结作用的压力响应厚度比自生黏土矿物的响应厚度小,前者约280 m,后者>430 m。研究区原生孔隙与渗透率具有较好相关性,相关系数可达0.77,表明原生孔隙发育的砂岩是优质储层。研究结果可为在异常高压发育的盆地中深层寻找优质储层提供理论依据。
In order to carry out effective oil and gas exploration in the middle and deep layers of the developing anomaly high-pressure sedimentary basin, the pressure of compaction and cementation of the Northwest sub-depression in the Bozhong sag was discussed through comprehensive analysis of thin-section, core-scale, particle size analysis and SEM analysis. Response characteristics. Obtained strong evidence of abnormal high pressure on mechanical compaction has inhibitory effect. It was confirmed that different cement types have different pressure response characteristics. According to the study, an abnormal high pressure of 7 MPa per hydrostatic pressure can save about 2.0% of primary porosity. The pressure response characteristics of cementation strength is slope: 1 steep slope, 280m away from the normal pressure zone → high pressure interface far away from the high pressure interface, the cementation strength increases rapidly and is characterized by weak cementation. The cements are 85% of the total cements; 2 Gentle slope, 280 m → high pressure outside the high pressure interface, the cementation strength increases slowly and is characterized by strong-middle cementation. The cements are mainly carbonate, accounting for about the total cements More than 75%. In the normal pressure zone near the high pressure interface, the pressure response of carbonate cementation is smaller than that of the authigenic clay minerals, the former is about 280 m and the latter is> 430 m. The correlation between primary porosity and permeability is good, and the correlation coefficient is up to 0.77, indicating that the sandstone with primary porosity is a good reservoir. The results can provide a theoretical basis for searching for high-quality reservoirs in the deep-developed basins of abnormally high pressure.