SX火山岩油藏氮气吞吐选井方法

WELL SELECTING METHOD FOR THE NITROGEN HUFF AND PUFF IN SX VOLCANIC-ROCK OIL RESERVOIR

为解决火山岩油藏因孔隙度低、非均质性而导致的后期含水率高的问题,根据SX石炭系油藏地质开发特征以及油藏火山岩的特点,研究氮气吞吐影响因素。通过剩余油分布、阁楼油位置、定容体位置、底水能量以及单井潜力分析,选择出具有氮气吞吐潜力的井。以典型井为例,进行氮气吞吐数值模拟,预测增油情况。最终确定选井方法为选择剩余可采储量大于0.5×10~4t、构造高部、避免储集体顶部、反"Z"型含水率曲线为主、油井初期产量大于20 t/d的区块部署氮气吞吐井。该方法对解决火山岩油藏水侵问题有参考价值。

In order to solve the problem of the high watercut in the late period caused by the low porosity and heterogeneity in volcanic rock oil reservoirs,according to the geologic and development characteristics of SX Carboniferous oil reservoir and the features of the volcanic rock oil reservoir,the influencing factors of the nitrogen huff and puff were researched. With the help of the following analyses i. e. the remained oil distribution,the attic/loft oil location,the constant-volume body location,the bottom water energy,the single well potential,the wells with a certain nitrogen huff-and-puff potentials were selected. Taking the typical well as the example, the numerical simulation was conducted for the nitrogen huff and puff to predict the oil incremental condition. Finally the well selecting method in a block shows as follows： the remained recoverable reserves is more than 0. 5×10^4 t,the top of the structure,avoiding the reservoir peak,taking the reversed ＂Z＂type watercut curve as the main form,the initial production of the oil well is up to 20 t/d. The method possesses a certain reference value for solving the problem of the water invasion in the volcanic rock oil reservoir.