Shale Gas Play Definition using Controlled Source Electro-Magnetic Geophysics

GSTDTAP

项目编号	NE/N004752/1
	Shale Gas Play Definition using Controlled Source Electro-Magnetic Geophysics
	[unavailable]
主持机构	University of Edinburgh
项目开始年	2015
	2015-05-01
项目结束日期	2016-10-31
资助机构	UK-NERC
项目类别	Research Grant
国家	英国
语种	英语
英文摘要	INTRODUCTION. This project aims to show that the presence of subsurface hydrocarbons, especially shale gas, may be detected before drilling by performing a controlled-source electromagnetic (CSEM) survey on the earth's surface above the target. The application of CSEM for shale gas detection has never been done before. We plan to do this over an existing seismic line in Scotland. Hydrocarbons are electrically resistive. So the objective is to map subsurface resistivity variations using the surface CSEM survey data. There are two goals: (1) to acquire good quality transient CSEM data; and (2) to recover the resistivities from the data. CSEM DATA ACQUISITION USING THE MTEM METHOD. Using a field layout similar to that used in seismic reflection, the method has a current source that injects current (~40A) into the Earth via a pair of source electrodes, and a line of electric field receivers, each of which measures the voltage response of the earth between a pair of receiver electrodes. The recorded data are processed to recover the impulse response of the earth for each source-receiver pair. EQUIPMENT. The equipment we will use was developed initially in the University of Edinburgh and later in MTEM Limited and Petroleum Geo-Services (PGS). In 2009 PGS ceased to perform land surveys. In April 2014 PGS donated the MTEM land system to the University of Edinburgh for research purposes. This system, valued at £500k, forms a key part of this project. There are more components than are required for the survey, providing redundancy, and minimising the risk of downtime due to equipment failure. MTEM FIELD SURVEY. The MTEM survey will be conducted over a shale gas prospect at the Deerdykes site in the Midland Valley of Scotland near Cumbernauld, where shale gas/oil plays are suspected to be present at depths ranging to 3000 m below the ground surface. Previous land MTEM surveys have acquired data for targets down to 2000 m. The Petroleum Exploration and Development License (PED) for the site is held by ReachCSG (project Partner), who already have significant geological and geophysical information relating to the site, including historic 2-D seismic reflection data that will be made available to the project. The survey line will pass through a location where Reach have extant planning permission to drill a shale gas exploration borehole. THE DATA. The data will be obtained with the most up-to-date commercial grade equipment and are expected to be of excellent quality. This will be the first CSEM data set ever recorded over a shale gas prospect. RECOVERING THE RESISTIVITIES FROM THE DATA. We will recover resistivities from the MTEM data using forward modelling routines to compute synthetic impulse response data that would be obtained over the model for all the sourcereceiver configurations used in the survey. The resistivity model will be adjusted to minimise the error between the synthetic and real data, this is a process known as inversion. The data will be inverted in two ways: first, without any a priori information or constraints; second, using sub-surface rock layer interfaces obtained from the existing seismic reflection data, which will be re-processed by project partner ReachCSG.
来源学科分类	Natural Environment Research
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/85572
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	[unavailable].Shale Gas Play Definition using Controlled Source Electro-Magnetic Geophysics.2015.