青海涩北气田出砂规律实验研究

涩北气田储层为第四系粉砂岩和泥质粉砂岩，埋深浅，成岩性差，胶结疏松，气藏开采时气井出砂严重，所出砂为细粉砂（粒径0.04~0.07 mm），防砂难度较大。开展气井出砂规律和机理研究是形成涩北气田有效防砂技术、提高单井产能的主要基础工作，为此，设计了一套实验装置，模拟气层在开采过程中出砂量的变化以及影响出砂量的主要因素。通过实验研究，发现出砂量和储层渗透率、采气压差、气体流速以及出水量有明显指数正相关性，并利用数理统计方法建立了出砂量和上述４个参数之间的综合数学方程，利用该数学方程计算的出砂量与实验结果相比，较为一致，表明该数学模型具有相当高的精度，能指导气井开采中出砂量的计算以及为防砂技术措施的设计提供了基础数据。

AN EXPERIMENTAL STUDY ON SANDING MECHANISM IN SEBEI GAS FIELD, QINGHAI

Reservoir beds of Sebei gas field belong to Quaternary siltstone and argillaceous siltstone, having shallow burial depth, bad diagenetic grade, and loose consolidation. Therefore, sanding is a severe problem during field development, and the sand prevention becomes difficult due to the fine siltstone whose grain diameter is only 0.04—0.07 mm. Aiming at developing effective sand prevention technology, this paper carried out a study on the sanding mechanism and designed a set of experiment equipment to model changes of sand volume during the development of gas reservoir and find out principal factors affecting sanding volume. According to the study results, the sanding volume was in obvious exponential proportion to reservoir permeability, production drawdown, gas velocity and water cut. In addition, correlation equations between sanding volume and those parameters were set up by statistics. The calculation results matched the practical sanding volume very well, which could secure application of this mathematic model.