低渗透难动用储量压裂专家系统的研究及应用

针对国内低渗透油田储量难动用的特点,提出了经济有效开发的压裂专家系统.该系统包括基于网络功能的数据库、区块经济评价的蒙特-卡洛风险性分析、不规则井网与裂缝系统的快速评价、基于遗传算法的压裂方案优化及压后排液和求产的优化等.在此基础上,以降低成本和提高单井产量为目标,进行了现场新技术的试验,包括考虑地应力的井网优化、低粘度压裂液及多种支撑剂组合注入、分层压裂、大型压裂、水力压裂及超前注水等.在3个油田进行了现场应用,取得了显著的效果.吉林油田前48区块提高产量34%,降低成本37%;在克拉玛依油田3口井进行了低聚合物压裂和分层压裂试验,压裂后原油产量提高2倍以上;在董志油田的超前注水也见到了实际效果.

Hydraulic fracturing expert system for low-permeability and undeveloped oil-bearing reservoirs

A hydraulic fracturing expert system for the low-permeability and undeveloped oil-bearing reservoirs is developed according to the characteristics and development difficulty of reservoirs. The system contains database of undeveloped oil-bearing reservoirs, economic risk analysis of overall hydraulic fracturing using Monte-Carlo method, quick evaluation of irregular well pattern and fitted fracture system, automatic optimization of fracturing design plan based on the theory of genetic algorithm, optimization of flowing back of fracturing fluid and bottom-hole flowing pressure. The field pilot tests were performed, in order to decrease fracturing cost and improve the production rate of single well. The new techniques include optimization of well pattern considering in-situ stress orientation, combined pumping technique using various low-viscosity and low-damage fracturing fluid and various types of proppant, layering fracturing, large proppant weight fracturing combined with water flooding at early time, water fracturing technique as well. Above techniques were put into field applications in Qian-48 Block of Jilin Oilfield, Keramay Oilfield of Xinjiang area and Dongzhi Oilfield of Changqing area. The post-fracturing effects were all satisfied. The production rate of single well increased by 34 percent, while the fracturing cost decreased by 37 percent in Jilin Oilfield. Again in Keramay Oilfield, the average post-fracturing rate was twice as large as before. The early water flooding in Dongzhi Oilfield also shows an ideal result.