High inclination wells (above 70°) and specially horizontal wells have specific difficulties for obtaining accurate surveys. Two main problems arise with high inclination surveying: getting wireline survey tools down; vertical position uncertainty. Another application with horizontal wells where surveying is a problem is with dual horizontal wells. With dual horizontal wells, two closely spaced parallel … Horizontal well surveying

Since the mid eighties there has been an interest in drilling wells with smaller hole sizes, typically 4-1/8″, 4-3/4″ or 5-7/8″ hole sizes, with the smaller holes taking a 3-1/2″ liner. 1. Slim hole surveying There are a number of gyro survey tools and steering tools that have an OD of 1.75″ and are used … Slim hole, coiled tubing and under-balanced drilling surveying

Conventional magnetic survey tools consist of a mechanical inclinometer, i.e. a pendulum and a compass to determine azimuth. They are used as magnetic single-shot (MSS) and magnetic multi-shot (MMS). Conventional magnetic survey tools are cheap to run but less accurate than magnetic solid state tools. They should be run in a full length of NMDC. … Conventional magnetic survey tools

Pre-survey checklist & Running procedures for conventional magnetic single-shot survey tools: MSS tools are normally run by the Driller. The pre-survey checklist and running procedures are given below. Check that the instrument box is complete and that the angle units have been checked in the workshop before delivery to the wellsite. Check that no angle … Conventional magnetic single-shot survey tools: Pre-survey checklist and Running procedures

This article presents a pre-survey checklist & running procedure for conventional multi-shots magnetic survey tools: Pre-survey Checklist MMSs are normally run by a Survey Engineer. The pre-survey checklist for MMS instruments is similar to the pre-survey checklist of MSS. In addition to the MSS pre-survey checklist, it should be ensured that the Survey Engineer has … Conventional multi-shots magnetic survey tools: Pre-survey checklist & Running procedure

This article presents pre-survey checklist and running procedure for conventional gyro survey. Pre-wellbore survey checklist Before starting to drill a new well and before every new wellbore survey, ensure that there is a foresight (directional reference) and that the direction from the wellhead has been determined by the Topographic Department. Ensure that the wellbore survey … Conventional gyro: pre-survey checklist and running procedure

The heart of a conventional gyroscope is the gyro wheel, which spins at high speed symmetrically about an axis. A perfect gyro wheel will maintain its orientation in inertial space for as long as no external forces act on it to alter the direction of the spin axis. In conventional gyro directional survey tools this … Conventional Gyroscopic Survey Tools

Desription of typical North Seeking gyro:  Seeker (Baker Hughes Inteq), Wellbore surveyor (gyro/data), Finder (SDI), GCT (Schlumberger ), G2 (Sperry-Sun) Seeker (Baker Hughes Inteq) 1 directional drilling survey tool description The Seeker from Baker Hughes Inteq is a single axis gyro tool, i.e. the gyro has one sensing axis in the cross-borehole plane. As stated … North Seeking gyro – Common tools description

North Seeking gyro directional drilling survey tools provide substantially more accurate survey data than conventional gyro tools. In the conventional gyroscopic survey tool, the gyro is oriented to a known reference direction or foresight. A North Seeking gyro directional drilling survey tool uses a gyro to reference itself to True North, eliminating the need for … North seeking gyro survey tools