普光气田碳酸盐岩储层暂堵转向酸压技术

Temporary plugging, diverting and acid fracturing technology used in carbonate reservoirs of Puguang Gasfield

陈灿 王栋 扈殿奇 魏美涛 石恒毅 崔梦瑄

CHEN Can WANG Dong HU Dianqi WEI Meitao SHI Hengyi CUI Mengxuan

中国石化中原油田分公司石油工程技术研究院 中国石油华北油田分公司第二采油厂

Research Institute of Petroleum Engineering Technology, SINOPEC Zhongyuan Oilfield Company, Puyang 457001, Henan, China NO. 2 Oil Production Plant, Huabei Oilfield Company, Bazhou 065703, Hebei, China

普光气田主体气藏属超深层、高含硫、中孔、低渗透构造-岩性气藏，主要含气层为三叠系飞仙关组、二叠系长兴组，产出剖面显示部分层段未动用或动用率低。暂堵转向酸压技术可改善产气剖面，提高储层动用程度，普光气田拟采用该技术。目前微地震监测技术虽对暂堵压裂裂缝转向及其扩展规律进行了定量分析，但受信号干扰误差较大。本文应用真三轴模拟实验装置，采用与储层物性类似的露头岩心，加载与实际储层对应的三向应力，采用自主研发的可降解酸压暂堵剂和高温清洁转向酸体系进行酸压暂堵转向实验。由露头暂堵酸压实验可知，转向酸作为压裂液明显有利于复杂裂缝的形成，加入暂堵剂后，起裂压力增加了5~10 MPa，且明显有新裂缝出现，表明暂堵剂暂堵效果显著。由暂堵酸压现场试验可知：在暂堵剂进入储层阶段，暂堵剂最高暂堵压力为66.13 MPa，比未注入暂堵剂的最高施工压力高了近20 MPa，表明暂堵剂在不断压实并封堵高渗层；在转向酸进入储层阶段，施工压力波动明显，表明转向酸向低渗层转移并不断开启新裂缝，与前期露头岩心暂堵酸压实验结果类似，验证了暂堵转向酸压技术的可靠性。

The principal gas reservoir of Puguang Gasfield is an ultra deep structural-lithological gas reservoir of high sulfur content, moderate porosity and low permeability, and its main gas bearing layers are the Triassic Feixianguan Formation and the Permian Changxing Formation. Production profiles show that some intervals are not produced or less produced. Temporary plugging, diverting and acid fracturing technology can improve the gas production profile and increase the reservoir producing degree. And Puguang Gasfield tends to adopt this technology. At present, microseismic monitoring technology can be used to analyze quantitatively the diverting and propagation laws of fractures created by temporary plugging fracturing, but its error is larger due to the signal interference. Experiments on temporary plugging, diverting and acid fracturing were conducted by using the independently developed degradable temporary plugging agent for acid fracturing and high-temperature clean diverting acid system. In the experiments, the true triaxial simulation experiment device was used to apply the triaxial stress corresponding to the actual reservoir, and the outcrop cores whose physical property is similar to that of the reservoir were adopted. The temporary plugging and acid fracturing experiment on the outcrops shows that the diverting acid, acting as the fracturing fluid, is obviously favorable for the formation of complex fractures. And after the temporary plugging agent is added, the fracture initiation pressure is increased by 5−10 MPa and new fractures emerge obviously, indicting remarkable effect of temporary plugging. The on-site temporary plugging and acid fracturing experiment reveals that when the temporary plugging agent moves into the reservoir, its maximum temporary plugging pressure is 66.13 MPa, which is nearly 20 MPa higher than the maximum construction pressure without temporary plugging agent, indicating that the temporary plugging agent is compacting and sealing the high-permeability layers continuously. And when the diverting acid moves into the reservoir, the construction pressure fluctuates greatly, indicating that the diverting acid is transferring to the low-permeability layers and initiating new fractures continuously. The on-site experimental results are similar to the experimental results of outcrop cores, verifying the reliability of the temporary plugging, diverting and acid fracturing technology.

10.13639/j.odpt.2019.02.017