高压充填重复防砂对产能的影响及解决方案

高压充填防砂技术的应用效果较好，目前已被广泛应用于出砂严重的油气井，对油田的防砂稳产起着重要的作用．但防砂失效后．管外将会存在一个较厚的砾砂混合区，其在重复防砂作业时很难被清理，这一砾砂混合区域对提高单井产能十分不利，并且，随重复防砂次数增多，混合区的厚度也随之增大，这种不利影响也将不断加剧。文中针对这一问题对高压充填防砂井管外充填区进行了分析，提出了3种可供选择的解决方案，包括压裂充填防砂技术、管外砾石充填区酸洗工艺及高压变粒径充填技术．并对各个方案和技术进行了简要的说明和分析，提出并阐述了管外砾石充填区酸洗技术主要技术思路和要点，即清除砾石层中的细砂．改善砾石层的渗透，同时还在传统高压充填工艺的基础上提出了高压变粒径充填，并根据Saucier方法和拱桥理论，对变粒径砾石充填中的砾石尺寸进行了分析，得出了其设计的基本原则：Ⅱ层砾石粒径大于或等于Ⅰ层砾石粒径的3倍，Ⅰ层砾石尺寸设计采用Saucier方法．

Influence of high pressure pack repeat sand control on productivity and solution

High pressure pack sand control technique has a good application effect. The technique is widely used for the oil and gas wells of severe sand production at present and it plays an important part in sand control and production maintenance in oilfield. But there will be a thicker mixing gravel-sand zone outside of casing, which is hard to clean up in the process of the repeat sand control operation, after sand control failure. The mixing gravel-sand area is unfavorable for improving the single well productivity. With the increasing of repeat sand contrnl times, the mixing zone will be thicker and thicker. The effect will continue to increase. This article analyzes the outside packing area of high pressure pack sand control well and puts forward three solutions： fracturing pack, acid pickling of outside gravel packing area and high pressure variable grain diameter pack techniques. And every solution has been briefly illustrated and analyzed. The paper proposes the acid pickling of outside gravel packing area and describes the main technical thinking and feature in order to clean up the fine sand within gravel bed and to improve the permeability of gravel bed. At the same time, based on the traditional high pressure pack technique, high pressure variable grain diameter packing is presented. According to Saucier method and arch bridge theory., the gravel size of variable grain diameter packing is analyzed, which derives the basic design principles that the grain diameter of Layer Ⅱ gravel is greater than or equals to 3 times of Layer Ⅰ gravel size and that the Saucier method is adopted for the design of Layer I gravel size.