潮坪相碳酸盐岩酸压改造油井压力动态特征

Pressure dynamic characteristics of oil wells in the carbonate reservoirs of tidal flat facies reconstructed by acid fracturing

史文洋 姚约东 石志良 程时清 秦佳正 高敏

SHI Wenyang YAO Yuedong SHI Zhiliang CHENG Shiqing QIN Jiazheng GAO Min

中国石油大学(北京)油气资源与探测国家重点实验室 中国石化石油勘探开发研究院 中国石油长庆油田分公司第四采油厂

State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China SINOPEC Exploration & Production Research Institute, Beijing 100083, China No.4 Oil Production Plant, PetroChina Changqing Oilfield Company, Yinchuan 750001, Ningxia, China

潮坪相碳酸盐岩储层具有溶蚀孔洞、天然微裂缝发育的特征，酸压改造形成的酸压缝网能极大改善井周储层物性、改变储层流体流动形态。根据实际酸压油井压力响应早期未显示酸压裂缝渗流特征的现象，基于酸压有效改造的概念建立了潮坪相碳酸盐岩储层酸压改造油井压力动态模型。利用Laplace变换和Stehfest数值反演得到实空间压力解，分析了储层缝洞特征、酸压改造程度、改造范围、储层边界对压力动态的影响。研究结果表明：酸压改造储层与未改造储层之间存在明显的过渡流，改造程度和改造范围共同控制过渡流形态。新模型在潮坪相碳酸盐岩酸压改造油井的应用实例证明了酸压有效改造区假设的可行性，为酸压效果评价工作提供了新思路，对后期酸化解堵、重复酸压等方案措施的制定具有指导意义。

Carbonate reservoirs of tidal flat facies are characterized by the development of dissolution pores and natural micro-fractures. Fracture network induced by acid fracturing can greatly improve the physical properties of the reservoirs around the well and change the flowing regimes of reservoir fluid. The pressure behavior model for the oil well in the carbonate reservoir of tidal flat facies reconstructed by acid fracturing was established based on concept of effective acid fracturing, combined with the phenomenon that no fracture-vug characteristics is reflected in the early pressure response of actual acid fracturing oil well. Then, the pressure solution in the real space was obtained using Laplace transformation and Stehfest numerical inversion. Finally, the effects of and the fracture-vug characteristics, boundaries of reservoir, the reconstruction degree and range of acid fracturing on the pressure behavior were analyzed. It is shown that there is obvious transitional flow between the reservoir reconstructed by acid fracturing and the unreconstructed reservoir, the transitional flow is under the joint control of reconstruction degree and reconstruction range. The application result of the new model to the oil well in the carbonate reservoir of tidal flat facies reconstructed by acid fracturing proves the feasibility of the assumption of effective acid fractured volume, provides a new idea for the evaluation of acid fracturing effect, and guides the preparation of schemes and measures in the late stage, e.g. the acidizing and plugging removal and the repeated acid fracturing.

10.13639/j.odpt.2019.04.022