Phil Smart - Geodetic Consultant - Survey and Positioning QC

	Contract advice
	I can help you produce a good survey contract, or provide one for your use. It is important that the contract is right at the start. I have seen many problems that stem from an inadequate contract and you can guarantee that the contractor will take advantage of any loopholes.
	Seismic crew survey supervision
	Ensure that proper survey procedures are being followed and HSE requirements are being met. Without adequate supervision certain contractors take short cuts which can lead to inaccurate or even mis-placed surveys.
	Technical advice
	Most surveys are carried out with GPS these days and I have several years experience in this field. GPS appears to be the answer to everyone's positioning dreams but it brings with it certain problems which can cause large survey errors. This is especially true when it comes to relating the GPS system to a local datum. This is not a widely understood subject and I can ensure that your parameters accurately model the local situation. I can also make sure that the contractual positioning tolerances are met. There are many GPS techniques, each with it's own accuracy and limitations, and it's important that the contractor utilises the right method for the job.
	Analysis of old seismic positioning data
	GPS has shown us that much of the seismic surveys carried out by conventional means may be mis-positioned by in some cases, several kilometres. Many surveys were based on inadequate control and often carried out with compass theodolites (T0). Having been in the seismic survey business since the mid-seventies I well remember how little emphasis was placed on the survey aspects of a land seismic survey. It is therefore not surprising that many of the surveys exhibit large and often non-linear errors. This has now become important as exploration chases smaller pockets of oil and gas. Unfortunately the only way to be sure that your old seismic is where you think it is, is to carry out a re-survey using GPS. This is only possible if there remains evidence on the ground, and permanent markers become important monuments. I have much experience in this field in such places as Algeria, Oman, Khazakhstan, and you do have to be some sort of detective to figure out what's going on. Experience counts for a lot under these circumstances.
	Control survey management and supervision
	Any seismic survey must be tied to a good control network. In many cases it's necessary for the contractor to establish control, but this may not be an area in which he has adequate experience. It's very important that the initial control is correct. I believe that the control survey should be carried out ahead of the seismic survey so that the network can be analysed and adjusted in advance. I've seen many problems where the control and seismic have started at the same time and lines have resulted out of position and a re-survey required. The limited range of RTK inevitably means more control.
	GPS processing and ties to the International Terrestrial Reference Frame
	As well as supervising and checking the GPS processing carried out by the contractor, I also process GPS data. One problem that can, and does quite frequently, occur is that there is no, or an inadequate WGS84 origin in the area of operations. Starting with inaccurate WGS84 values will lead to small errors in the survey if working in a local system but more importantly large discrepancies can result if working directly in WGS84. It is not sufficient in most cases to use a stand-alone point position as origin and this is not recommended. It is far better if there is any doubt about the origin to carry out an ITRF tie. This will involve collecting dual frequency GPS data for a 2 day period. The data is then processed using the precise ephemeris and Rinex data collected at various stations around the world used to calculate baseline vectors to your point. The baselines are then used in a least squares network adjustment to provide final 3D co-ordinates to about 20cm. The data is downloaded from the internet.
	Well positioning QC
	I can ensure that your wells are drilled in the right place.
	Conditions of service
	A few minor conditions: 1. Travel between the field of operation and my home will be client chargeable. All flights will be in business class although in these difficult times Premium Economy might be acceptable. 2. Travel will be charged by the day. 3. Following the agreed contract start time, any period spent on "standby" is fully chargeable. This includes, but is not limited to, any time awaiting a visa, or time wasted due to failed travel arrangements. 4. All accommodation in the field will be provided by the client, and be of a single nature. Adequate office facilities must also be provided. 5. The client must have in place an internationally recognised evacuation plan, in case of medical or other emergency. 6. All invoices must be paid within one month.