基于微地震事件点的SRV拟合方法比较研究

Comparative Study of Microseismic Event Location-fitted Stimulated Reservoir Volume Computation Methods

邵媛媛 黄旭日 邢阳

SHAOYuanyuan HUANGXuri XINGYang

“油气藏地质及开发工程”国家重点实验室·西南石油大学, 四川 成都 610500 北京旭日奥油能源技术有限公司, 北京 朝阳 100012

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Sunrise PetroSolutions Tech Inc., Chaoyang, Beijing 100012, China

针对噪声影响下基于微地震事件点的改造体积（SRV）计算不准确的问题，开展了微地震事件SRV拟合算法研究。采用三维水力压裂模型来模拟主裂缝扩展和压裂液由裂缝向基质扩散的过程，依据断裂准则和临界孔隙压力来判断所引发的微地震事件，进而得到水力压裂SRV。基于异常点概念，采用各算法拟合去异常点前、后的微地震事件点集，进而得到相应的SRV，并与水力压裂模拟求得的SRV对比。结果表明，异常点处理可以降低噪声对3种拟合算法计算SRV的影响；面元算法虽然较为保守，但微地震事件SRV与水力压裂SRV相差不大，且具有较好的稳定性和抗噪性；三维狄洛尼三角剖分和最小体积覆盖椭球两种算法所得的微地震事件拟合SRV虽然与水力压裂SRV误差相对较大，但这两种方法不仅从数学领域清楚地划分了微地震活动区域，且提供了更详细、更定量化的SRV几何结构。

The microseismic event location-fitted computation of stimulated reservoir volume (SRV) was studied. The current methods available for computing microseismic event location-based SRV are not accurate because of the impact of noise. A three-dimensional hydraulic fracturing model was employed to simulate the development of principal fractures and the diffusion of fracturing fluids into the matrix. The existence of induced microseismic events was then determined by the existence of fractures and critical pressure in the pore space. Consequently, an SRV value was obtained by the hydraulic fracturing simulation. The SRV was then computed with different algorithms by fitting the point set of microseismic events, both with and without the abnormal points removed, and the resulting SRV values were compared with the SRV value obtained from the hydraulic fracturing simulation. The results showed that the removal of abnormal points reduced the impact of noise on the SRV values computed by all three microseismic event location-fitted algorithms. More specifically, the bin algorithm, although conservative, yielded an SRV value similar to that obtained by the hydraulic fracturing simulation and exhibited good stability and anti-noise characteristics. In contrast, both the three-dimensional Delaunay triangulation algorithm and minimum volume enclosing ellipsoid algorithm yielded SRV values quite different from the SRV value obtained by the hydraulic fracturing simulation; however, these algorithms were capable of clearly identifying the active zone of microseismic events mathematically and providing the geometric structure of SRV in a more detailed and quantifiable manner.

10.11885/j.issn.1674-5086.2017.08.01.01