识别油气井径向流选层

识别油气井径向流选层提高老井重复压裂措施效果对油田的可持续发展变得尤为重要。

基础井网压裂井数比例达86.76%，压裂厚度达74.5%；压裂投产后油气井的生产特征一般分为3个阶段。

Improve the effect of old well repeated fracturing measures for the sustainable development of the oilfield is particularly important. Basic well pattern fracturing well number proportion reaches 86.76%, the thickness of the fracturing was 74.5%; Fracturing of oil and gas well production characteristics after the production of general is divided into three stages.（1）线型流阶段。

此阶段原油从支撑裂缝前缘流向井筒，为压后高产阶段，不过产量下降较快。

(1) linear flow phase. At this stage of crude oil is flowing from support crack front shaft, for high yield after pressure stage, but the decline in output quickly.（2）拟径向流阶段。

此阶段原油一方面从支撑裂缝前缘流向井筒，另一方面也从裂缝两侧基岩流入井筒。

此时产量已低于第一阶段产量，但生产能力仍高于油层未经过压裂改造前的产量，此阶段产量较稳定。

(2) the phase of quasi radial flow. This stage of crude oil is flowing from support crack front shaft on one hand, on the other hand also on both sides of the bedrock from the cracks into the wellbore. Production at this point is below the first stage of production, but production capacity is still higher than before after fracturing oil layer of the production, the output of this stage is relatively stable.（3）径向流阶段。

此阶段支撑裂缝已失去了高导流能力，生产能力已恢复到压前水平。

压裂井经过线型流、拟径向流直至径向流，增产期即告结束，此时，原油处于经济生产下限，应考虑重复压裂。

(3) the radial flow stage. This stage to supportcracks has lost high flow conductivity, production capacity has been restored to the front of the pressure level. Fracturing Wells after linear flow, quasi radial flow and radial flow, production period is come to an end, at this point, the crude oil in the economic limit production, repeated fracturing should be considered.支撑剂镶嵌到裂缝壁面，减小了裂缝宽度，使导流能力下降，其影响达到20%以上；同时对裂缝壁面产生压实作用，加大了地层流体进入裂缝的渗流阻力；以往原缝重复层压裂措施有效率为40%左右，有效井压后初期平均单井日增油仅为平均压裂井增油效果的1/3，平均有效期只有3个月。

Proppant inlaid into the cracks in the wall, decrease the crack width, the diversion ability drops, its influence to over 20%; Compaction on the cracks in the wall at the same time, increased the formation fluid into the fracture seepage resistance; Before the original seam duplicate layer fracturing measures effective rate was 40%,3 / 8effective after the initial growing on average single well oil well pressure was only about one third of the average increment of oil fracturing well, mean is only valid for 3 months.压裂选井选层不合理。

对井层认识不准，压裂层段物性差、地层能量低或注采不完善导致压后低效和高含水；二是压裂时机选择不当。

酿酒设备改造时间相对超前，上次增产改造未得到充分发挥，改造时间滞后，不能及时接替产量，造成增油量的损失；三是施工规模和砂量不够。

Layer fracturing Wells picked is not reasonable. Understanding of the well layer, poor physical properties of the fracturing zone and low formation energy or imperfect injection-production pressure after inefficiency and high water cut; The second is improper fracturing timing. Modification time is relatively advanced, the last production stimulation is not fully play, modification time lag, cannot replace in time production, thereby causing loss to the increasedamount of oil; Three is the construction scale and sand quantity is not enough.化学结垢和沉积引起堵塞。

此外，胶质、沥青等重质烃组分沉积也将堵塞裂缝及附近地层。

由于重复压裂裂缝长度、砂量不足，原裂缝未能得到有效扩展，裂缝导流能力变化不大，原裂缝内石英砂破碎产生的堵塞不能得到解除；油井必须具有足够的剩余储量和地层能量。

一般油井静压应在7MPa以上。

Fouling and chemical vapor deposition (cause blockage. Moreover, colloid, asphalt and other heavy hydrocarbon component deposition will jam, fissure and nearby. Caused by a lack of repeated fracturing fracture length, amount of sand, the fracture failure to effectively extend fracture diverting capacity change is not big, the original cracks in quartz sand and broken the plug cannot be lifted; The well must have enough remaining reserves and strata energy. General oil well static pressure should be more than 7 mpa.5 / 8优先选择前次压裂由于施工原因造成施工失败（如早期脱砂）井；前次改造规模不够的压裂井；前次改造对裂缝支撑不够的井；改造后支撑剂破碎的井。

有足够的地层系数。

地层系数过低，地层供油能力弱，必须加大施工规模，增加裂缝长度；喷灌设备地层系数过大，必须有很高的裂缝导流能力，宜采用端部脱砂压裂技术。

一般要求ｋｈ0.5×10-3μm2。

选井要注意井况，应选择套管状况及强度具备条件，最好距边底水、气顶有一定距离，有较好遮挡层的井层。

Prefer the previous fracturing due to construction caused the failure (e.g., early sand-out) well; Previous transform diseconomies of fracturing Wells; The previous modification of propping fracture well enough; After transforming proppant broken well. Have enough formation coefficient. Stratigraphic coefficient is low, oil supply ability is weak, must strengthen the construction scale and increase the crack length; Formation coefficient is too big, must have high fracture diverting capacity, appropriate USES end to take off the sand fracturing technology. General requirements kh0.5x 10-3 mu m2. Selecting well pay attention to the well conditions, should choose casing condition and strength requirements, the best is apart from the edge of bottom water and gas cap has a certain distance, have a good shade of well layers.用模糊识别原理进行定量选井选层。