不同倾角煤层气井的水力压裂微震监测

在2017和2018两年中,我们对新疆18口煤层气井的水力压裂,应用微地震向量扫描技术,实施了微震监测.这批井的特点是,除3口井煤层的倾角小于30°外,余均为高倾角,其中6口井的倾角大于70°,近乎直立.由于煤层在强度上较常规油气储层显著得低,因而压裂设计预期裂缝沿煤层延展.然而,经反复校核,尽管多数井的裂缝带满足预期...     

深圳地区的微震监测与研究

在深圳地区设置微震台网,于1985—1986年进行了两期监测。以台网记录结果并结合历年地震资料,研究分析了区内现代地震活动与现今构造应力场。得出:深圳市附近的现代地震活动均属微震范畴,频度不高,震源深度较浅,为5—10Km;研究区内现今构造应力场以水平作用为主,主压应力的优势方位为北西—南东向。     

NC区块页岩气水平井压裂微震实时监测

页岩气储层压裂时微震微小、对其地面监测的记录数据信噪比(S/N)很低,常常<10%.且这些微震多为剪破裂,在不同地点的记录波动具有很强的正负极性.因此,在数据采集过程中需要躲避噪声源、进而有效去噪,以提高剪切破裂的S/N.为了提高微震监测成果在压裂过程中的实用性,需要对整个压裂过程采用实时监测的裂缝描述,为压裂泵注程序优化及时提供参考数据和指导.中国石化重庆页岩气有限公司在2020年5月应用微破裂向量扫描技术对NC区块的三口水平井的压裂进行了地面微震实时监测.三口井埋深3452～3667 m,共压裂和监测了56段.因满足了安静点观测及去噪的应用微破裂向量扫描的必要条件,输出结果可靠.实时观察了每段缝网的发展,有显著的间歇性和跳跃性.每段缝网均由多条交叉子破裂带组成,平均的主走向NE110°、全长470 m、宽度为长度的一半弱,井组地域平均最大主压应力方向应在NE110°～140°之间.由于实时监测,根据缝网当前形态,及时采取了变换排量和砂比等参数,辅以暂堵、改变液性、和停泵转向等手段,实现了更大的改造体积.     

微破裂向量扫描在丰探15井压裂微震实时监测中的应用

浙江油田苏北采油厂于2017-07-28～29对丰探15井近4 km深的泰二段第三段进行了水力压裂,分成试压和主压.我们同时应用微破裂向量扫描(Vector Scanning,VS)实施了地面微震实时监测,目的是评估监测质量、实时监测的可行性、与压裂效果.我们严格执行了安静处布台和有效去噪等应用VS的必要条件,最大限度地提高了信噪比,平均的最小信噪比为2.35%;输出结果可靠.为今后更有效地设计和控制压裂,通过电信网和互联网,我们实施了野外采集数据的实时传输和遥控数据处理解释,观察了每分钟裂缝带的发展;实时监测系统可行.主压的最终X型破裂明显是在试压裂缝的基础上,由试压的300 m长,扩展到400～500 m,并加密了缝网;井域最大主压应力方位被限制在NE(50～80)±5°.本次压裂微震活动有明显的间歇性,较大微震群发生前积累能量所需时间,由初期的10 min内,逐渐延长到最后的百分钟.微震活动由压裂点扩展到远处的顺序清晰,这可能同此井附近的介质较为完整有关.每分钟的压裂微震活动状态一般在5～15 min内可报告给压裂施工团队.通过这次典型的水力压裂微震实时监测,我们验证了:VS的原...     

双树复小波变换在时移微重力监测上的应用——以辽河油田SAGD区为例

SAGD开发会引起地下介质密度产生较大的变化,进而引起地表重力值的变化.时移微重力监测技术通过测量地表重力值的变化来监测SAGD开发过程中蒸汽腔的形态变化,从而获得油藏开发动态变化信息.针对微重力监测技术的重力异常提取对于描述储层变化至关重要.本文利用双树复小波变换将微重力数据分解为不同尺度小波系数,结合软硬阈值折中法...     

微震监测系统标定信号的应用

徐州矿务集团有限公司三河尖煤矿建立了覆盖全矿井的KZ-1型微震监测系统,通过地面监测主机向井下各测站发时间同步校时信号,用GPS秒号起始去同步各个测站下位机时钟,保证了各测站之间相对时间精确度.KZ-1型微震监测系统的拾震器设置了双换能器,且各有一个独立的磁回路,通过地面监测主机向拾震器标定换能器发标定指令信号,信号检测换能器再将输出信号上传至监测主机,实现了即时定量标定.标定信号的应用使KZ-1型微震监测系统具备整个系统检测功能,包括灵敏度、频响特征以及各测站的时间同步误差.     

闽南漳州沙建温泉区的微震观测

1982年9—12月,在漳州温泉区布设了台网进行微震观测。结果表明,在漳州及其以北的沙建温泉区一带均有微震与小震群活动,震级为Ms=-1～1级,震源为3—14km。用震源的分布、震源机制解和微震综合断层面解的结果,研究了地质断裂的现今活动性及其与温泉的关系。认为区内东西向与北东向断裂是控制温泉分布的主要构造,而北西向断裂则是温泉的涌水构造。经探明,在有浅层热储的漳州市以及地质断裂发育的沙建地区,地震波速与介质泊松系数均低于正常值。此外,台网尚观测记录到一些异常的振动现象。根据地震的综合信息,探讨了研究区微震活动与水热活动的关系。     

微震技术与应用研究综述

微震,是指微小的震动.在不同应用领域微震大小的尺度划分也各不相同.对于这种微小的地震信号在许多领域都有广泛的应用,例如金属矿山、油田、火山和地震预报等.随着近年来信息技术高速发展,微震监测技术被广泛应用到地下工程当中,如油田开发、矿山的安全生产、隧道的施工建设、水库大坝的选址等诸多方面,并逐渐工程化、系统化,形成实时监测微震的可视化系统.此外,利用自然界大量的微震现象,可以通过震源定位、速度和衰减成像等方法研究大断裂、火山活动、地震的发生发展趋势以及震源机制等.本文总结了各类微震技术与方法,并分析各种方法的优点和存在的问题.另外分类整理了微震在各个领域的应用,分析其不同应用领域下的微震时频率域特征和研究方法.最后得出结论微震技术无论是在科学研究还是工程生产中都起着非常重要的作用.     

稠油蒸汽热采区声波资料异常现象的物理解释及应用

针对稠油蒸汽热采区常见的声波资料异常现象, 根据双相多孔介质声波传播理论及相关实验结果,对于这一特殊的声波测井响应特征进行了解释,认为注入蒸汽的影响导致了纵波速度的低异常及幅度的强衰减, 而使声波测井资料显现出异常高时差值或出现“跳变”现象.据此总结了利用声波资料评价蒸汽波及范围与蒸汽前缘的解释方法,并进行了多井评价实验, 取得了满意结果.同时,也为利用孔隙介质弹性波动理论评价地下蒸汽分布范围的适用性提供了新的现场实际例证.     

Microseismic monitoring of columnar jointed basalt fracture activity: a trial at the Baihetan Hydropower Station,China

Severe stress release has occurred to the surrounding rocks of the typically columnar jointed basalt after excavation at the Baihetan Hydropower Station, Jinsha River, China, where cracking, collapse, and other types of failure may take place occasionally due to relaxation fracture. In order to understand the relaxation fracture characteristics of the columnar jointed basalt in the entire excavation process at the diversion tunnel of the Baihetan Hydropower Station, real-time microseismic monitoring tests were performed. First, the applicability of a geophone and accelerometer was analyzed in the columnar jointed basalt tunnel, and the results show that the accelerometer was more applicable to the cracking monitoring of the columnar jointed basalt. Next, the waveform characteristics of the microseismic signals were analyzed, and the microseismic signals were identified as follows: rock fracture signal, drilling signal, electrical signal, heavy vehicle passing signal, and blast signal. Then, the attenuation characteristics of the microseismic signals in the columnar jointed basalt tunnel were studied, as well as the types and characteristics of the columnar jointed basalt fracture. Finally, location analysis was conducted on the strong rock fracture events, in which four or more sensors were triggered, to obtain the temporal and spatial evolution characteristics and laws of the columnar jointed basalt relaxation fracture after excavation. The test results are not only of important reference value to the excavation and support of diversion tunnel at the Baihetan Hydropower Station, but also of great referential significance and value to the conduction of similar tests.     

Microseismic feasibility studies – assessing the probability of success of monitoring projects

In this paper we present a workflow for microseismic feasibility studies that allows a thorough assessment of the probability of success of the monitoring project to be made. The workflow includes the following elements: assessment of the value of information to establish the business case; identification of hardware options to investigate deployment options; survey of analogue cases to confirm the do‐ability of the project; modelling of event location errors and detectability to establish the most favourable array geometry; generation of full waveform synthetics to anticipate undesired seismic features. A study comprising all these elements provides the reference frame for discussions with service companies, limiting misunderstandings and avoiding missed opportunities.     

Microseismic field affected by local geological heterogeneities and microseismic sounding of the medium

Experiments and numerical model studies have shown that heterogeneities of the Earth’s crust distort the spectrum of the low frequency microseismic field, decreasing spectral amplitudes of a specific frequency f at the Earth’s surface over high velocity heterogeneities and increasing them above low velocity heterogeneities. The frequency f is connected with the depth of a heterogeneity H and the velocity of the fundamental mode of Rayleigh waves V _R (f) through the relation H = 0.5 V _R (f)/f. The low frequency microseismic field is considered as the superposition of trains of Rayleigh fundamental modes with different frequency spectra. The paper proposes an experimentally tested technology enabling the determination of the deep structure of complex geological objects using data on the microseismic background field.     

东营凹陷王庄--宁海地区馆陶组储层预测

在研究地质资料、测井资料的基础上,针对胜利油田王庄宁海地区馆陶组地层的变化特征规律,制定了新的储层预测技术方法.（1）精细构造技术研究：利用原始地震资料、地震道积分资料及小波分解资料,结合地质平面层序地层单元分析方法,划分出地质单元边界.（2）反演测井声波时差技术研究：利用地震小波变换属性、测井声波时差资料,采用稳健回归方法直接反演声波时差,进而计算孔隙度.该方法,可提高反演的分辨率,增加了反演结果的可靠性.结合研究区地质资料,把这种研究技术方法应用到王庄宁海地区馆陶组储层的预测研究,取得了良好的效果.     

Using numerical modeling for assessing the recoverable reserves of a geothermal steam field: The Pauzhetka geothermal field

A conceptual hydrogeological model has been created and a corresponding 3D numerical, thermal hydrodynamic model developed for the Pauzhetka geothermal field; the model covers an area of 13.6 km² and includes three layers: a basement with conduits that supply the heat carrier, a hydrothermal reservoir, and an upper aquifer with percolation “windows.” Inversion is handled by the iTOUGH2 program; the model was calibrated using the 1960-2006 data on the natural state and extraction at 13675 calibration points. The inversion simulation has made it possible to identify and evaluate the key parameters of the model and to identify the sources that generate the recoverable reserves. Forecasting modeling for the period from 2007 to 2032 shows a sustainable extraction of 29 kg/s steam, provided five additional wells have been put into operation, which will provide 6.8 MWs of production by the geothermal power plant. The results of forecasting modeling, in combination with observations on long-term operation, allow an evaluation of the recoverable reserves in the industrial categories.     

A rapid field method for detecting oil in sediments

A rapid thin-layer chromatographic technique for estimating the relative concentration of crude oil in sediments has been developed. The limit of detection on the chromatogram is 2 μg of Empire Mix or Saudi Arabian crude oil. The technique has been tested on 335 sediment samples collected from 67 stations in the Gulf of Mexico and has been utilized in assessing the location of oil entering the sediments from the Argo Merchant spill incident.