Neutron logging technology can identify gas reservoirs by detecting thermal neutron or secondary gamma information, which is of great significance for real-time reservoir evaluation in the logging while drilling (LWD). Compared to other methods, the method using inelastic gamma information is more promising in the gas-layer identification, because the inelastic gamma information overcomes the shortcoming that thermal neutron and capture gamma information are easily affected by the content of elements with the high capture cross-section. However, it is still influenced by formation density, especially in the more complex LWD environments. To solve this problem, a new LWD gas-reservoir recognition method based on inelastic gamma information of drill collar is proposed. Based on Monte Carlo method, a set of LWD instrument-formation models of controllable source neutron logging is built to simulate the inelastic gamma information. Through the analysis of the inelastic gamma spectrum in the LWD, the inelastic gamma information of drill collar is extracted to conduct gas-reservoir recognition, and the influence of environment factors on the new method is studied. The study shows that the drill collar inelastic gamma is linearly related with the fast neutron, which means the drill collar inelastic gamma inherits the advantages of the fast neutron and has higher detection efficiency. Compared with the total inelastic gamma, the inelastic gamma of drill collar is less affected by formation density decay and has higher sensitivity. In terms of environmental factors, the drill collar inelastic gamma is related with formation lithology, wellbore fluid, wellbore size, and it is not affected by formation water salinity basically. Ferrous shale formations can increase the inelastic gamma yield of drill collar and affect the recognition result. In general, this gas reservoir recognition method has high sensitivity and is less affected by environmental factors, and has broad application prospects in LWD.
虽然在稠油蒸汽吞吐时常用栲胶、碱木素等作为成胶剂制备封汽窜用高温冻胶,但这些物质在高温下成胶时间短,难以满足蒸汽驱过程中大剂量注入的要求,为此本文尝试以磺化酚醛树脂来制备成胶时间长、热稳定的封汽窜用冻胶.研究结果表明,选择磺化酚醛树脂为成胶剂、以六亚甲基四胺为交联剂,可以制备出在200℃成胶时间达12h以上、200℃热处理90d脱水率低于20%的冻胶.成胶剂磺化酚醛树脂含量变化对磺化酚醛树脂冻胶的成胶时间、冻胶强度和稳定性影响较大,而交联剂六亚甲基四胺含量变化对上述参数影响较小;另外,成胶液中盐含量增加会提高冻胶强度和稳定性.物理模拟实验评价表明,在渗透率 5～30 μm2 的填砂管中磺化酚醛树脂堵剂的突破压力梯度可以达到0.5～1.7 MPa/m,注汽100 PV封堵率保持75%以上,表现出较强的封堵能力.
为明确川西雷口坡组四段上亚段储层特征及成因机理,基于野外露头、岩心、测井和地震等资料,结合实验分析数据,对其进行了系统分析.研究表明:川西雷口坡组四段上亚段储层岩性以微粉晶白云岩和藻纹层白云岩最为有利.平均孔隙度3.7%,平均渗透率9.31×10-3 μm2,下储层段物性明显好于上储层段.主要储集空间为成岩组构溶蚀孔洞.白云化及组构选择性溶蚀等建设性成岩作用主要发生于沉积-成岩早期.(藻)云坪是优质储层发育的沉积基础.准同生白云石化和溶蚀作用是优质储层发育的关键.优质储层多发育在向上变浅高频旋回中上部藻纹层中.储层发育有利区平面上在川西中部,呈北东—南西向展布.
原油集输系统是油气生产和碳排放的重要环节,其碳排放核算与评价的研究越发重要.针对原油集输系统碳排放源,建立碳排放核算模型,确定碳排放强度;并对集输系统生产过程中的主要碳排设备,确立集输系统节能减排评价基准,预测油田企业节能减排潜力.以碳排放量、碳排放强度、节能减排潜力作为原油集输系统碳排放评价指标,通过对某双管掺水集油作业区进行碳排放情况核算与评价,识别井口、接转站及联合站各子系统的高碳排节点,评价了作业区块碳排放情况,并预测出该作业区块节能潜力可达到14486.98～49816.18 MJ、CO2 减排潜力可达到2022.03～5879.21 kg.
水平井分段多簇压裂能够对非常规储层形成密切割改造,同时降低压裂成本.然而,段内簇间非均衡进液严重制约了该技术的现场应用.段内暂堵利用暂堵剂封堵优势进液孔眼,迫使液流转向,从而获得均衡改造.明确加砂冲蚀孔眼封堵规律是提高段内暂堵效果,获得均衡改造的关键.本文建立了高承压孔眼封堵模拟系统,制备了5 种不同形状的孔眼模型,研究了暂堵球直径、架桥颗粒浓度、填充颗粒浓度、泵注排量和孔眼形状对孔眼的封堵规律.研究结果表明,圆形孔眼封堵难度小,异形孔眼封堵难度大,需要大粒径颗粒架桥封堵孔眼边部空隙;提高颗粒浓度和泵注排量能够显著提高孔眼封堵速度;封堵孔眼时,应先泵注暂堵球封堵孔眼主通道,再泵注颗粒+纤维,如若改变泵注顺序,难以达到理想封堵效果.本文研究成果有助于提高非常规油气水平井分段多簇压裂效果.
