高压裂缝性致密砂岩气藏出砂影响因素及防治

迪那2气藏为高压裂缝性致密砂岩凝析气藏，采用衰竭式开发。单井普遍、持续出砂，堵塞井筒，严重影响气田正常生产。根据经验出砂指标判断基质出砂可能性小，单纯的基质因素很难造成当前的出砂现状。结合迪那地质条件、实际开发情况，从岩石力学角度出发，寻找岩石抗压强度相对薄弱区和有效上覆压力相对高值区，获取出砂影响因素。结果表明:导致岩石抗压强度降低的主要原因有砾岩和含砾岩层抗压强度薄弱带，断层、裂缝抗压强度薄弱带，射孔、酸化抗压强度薄弱带；导致有效上覆压力增加的主要原因为地层压力下降引起的有效上覆压力整体上升，越靠近射孔底部岩石受到的有效上覆压力越大，污染、集流、应力敏感等引起的附加表皮加大生产压差，生产压差越大，近井带受到的有效上覆压力越大。通过Hoek-Brown强度准则判断部分岩石在以上因素综合影响下可达到破坏条件。通过以上认识，提出防治措施，如优化射孔层段和射孔方位、加大孔密和穿深、采用清洁完井工艺，指出防治方向如井位优化、陶瓷防砂等。

Influence factors and control of sand production in high-pressure fractured tight sandstone gas reservoirs: A case study on Dina 2 gas reservoir in the Tarim Basin

Dina 2 gas reservoir is a high-pressure fractured tight sandstone condensate gas reservoir, which is developed in the depletion mode. Continuous sand production is common in individual wells, which blocks wellbores and has severe impact on the normal production of the gas field. It is judged from the empirical sand production indicators that the possibility of sand production from matrix is low, and the current situation of sand production can be hardly resulted from the single factor of matrix. In this paper, the zones with lower rock compressive strength or higher effective overburden pressure were searched for from the point of rock mechanics, combined with the geological conditions and actual development situations in Dina. And accordingly, the factors influencing sand production were determined. It is indicated that the reduction of rock compressive strength is mainly caused by the low strength zones of conglomerate and conglomerate bearing layers, the weak zones of fault and fracture strength and the weak zones of perforation and acidification strength. The main reason for the increase of effective overburden pressure is the reduction of formation pressure. The closer it is to the bottom of perforation, the higher the effective overburden pressure of the rock is. The additional skin induced by contamination, afflux and stress sensitivity leads to the increase of production pressure difference. The larger the production pressure difference, the higher the effective overburden pressure near the wellbore is. It is discriminated according to Hoek-Brown strength criterion that some rocks can reach the breaking conditions under the joint effect of above factors. Finally, based on the cognitions, some sand control measures were proposed, such as optimizing perforation interval and orientation, increasing perforation density and penetration depth and adopting clean well completion technology. In addition, the sand control directions were pointed out, e.g. well location optimization and ceramic sand control.