CONTENTS
SR.NO
DESCRIPTION
Page No.
1
Work over Work over Operations
2
2
Preparation of of drill drill site
4
3
Repair of Approach Approach road
11
4
Requirement of Shed Requirement of Shed at at DTYS DTYS for the storage of of Heavy Heavy equipment
12
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Work over operations WORKOVER
The term
work over is
used to refer to any kind of oil well intervention
involving invasive techniques, such as wire line, coiled tubing or snubbing. More specifically though it will refer to the expensive process of performing major maintenance or remedial treatments on an oil or gas well. In many cases, workover implies the removal and replacement of the production tubing string after the well has been killed and a workover rig has been placed on location. Through-tubing work over operations, using coiled tubing, snubbing or slick line equipment, are routinely conducted to complete treatments or well service activities that avoid a full workover where the tubing is removed. This operation saves considerable time and expense.
Oil discovered 40 years ago is the basis of current oil production. The search for oil continues but projected oil discoveries will contribute little to projected oil production in 2030. The declining rate of oil discoveries makes it painfully obvious--most of the oil has already been discovered. The technology for finding oil has improved greatly since the major discoveries, yet little oil has been found in recent years. The heyday of oil discovery was from 1950 to 1980. It is difficult to avoid the conclusion that most of the oil has been found. World oil production is running flat out
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So in order to meet the growing demand we need to take care of what we have in hand i.e. our oil & gas wells for getting optimum output from them they need to be serviced time to time so that proper reservoir pressure is maintained and optimum oil recovery can be achieved from the known reservoir from here onwards role of work over operations start and this is need of the Hour. In current scenario no Economy can afford to avoid these operations where every drop of oil count
R eas on to perfor m a work over Work over’s rank among the most complex, difficult and expensive types of well work there is. They are only performed if the completion of a well is terminally unsuitable for the job at hand. The production tubing may have become damaged due to operational factors like corrosion to the point where well integrity is threatened. Down hole components such as tubing retrievable down hole safety valves or electrical submersible pumps may have malfunctioned, needing replacement. ROLE OF CIVIL ENGINEER IN WORKOVER OPERATIONS:Before carrying out various workover operations at the well site it has to be cleared and prepared for Rig deployment it comprises of various operations i.e. a) Clearing approach road to the well site for rig movement b) Jungle clearing in area of 70 x 40 m area for placing Activation tank, Generators, Bunk Houses etc. c) Cleaning of cellar pit d) Levelling of the ground for rig and Men movement. e) Fencing of Cluster well or SRP if either is present at well site. f) Supplying local sand for cleaning oil sludge present at site Page | 3
WORK OVER RIG IN OPERATION AT SITE
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Name of work: - Preparation of drill site for LM-150 STEPS IN DRILL SITE PREPARATION: Stacking : -
term referred
for
joint Visit of
Civil, LAQ, SST, Reservoir
personnel for location of well to be drilled with the help of a GPS receiver, with the help of GPS receiver exact latitudes and longitudes of the well are located on the land
and With reference to the well
location required land(i.e. 110 x 110 m in most cases) is acquired with the help of LAQ department . And approach road to the drill site is finalized along with Transportation Deptt. Subsequently. After Stacking of the well on land few landmarks are made on the JM sheet with reference to the well so that it would be easy for Civil personnel to locate exact position of the well to be spudded. PROPOSAL FOR LAND ACUISITION: -
Once this process of stacking is complete a proposal for Acquiring land is produced by civil personnel for rig deployment and approach road for movement of Vehicles and this proposal is handed over to LAQ deptt by the concerned Competent Authority Land Acquisition
After getting proposal for the required land LAQ personnel will contact the concerned farmer to get his land for lease to produce oil from that field Normally it is for 20 yrs. Page | 5
Detailed Estimate
Once the land is acquired a detailed estimate is made for the drill site depending on the Area required and Drilling Rig to be established on the land for drilling purpose . All the item rates are based on the PWD SOR for making detailed estimate of the drill site then this Detailed estimate is sent to Technical cell for checking Technical feasibility and quantity and rate verification PR Creation: -
After making detailed estimate and getting it checked by Technical Cell a PR is created and sent for AA& ES once getting approval a tender is invited and then tender committee will evaluate tender documents and work is awarded to
L1 bidding agency and Letter of Acceptance & Work
order is handed over to the concerned agency to start the civil work Civil works : HARDENING
Hardening at the drill site area is done to assist in easy movement of the heavy machinery involved in the process of drilling process i.e. trailers generators diesel tanks Carrier as most of the land used is farm land which have soft soil strata so proper hardening is required in order to attain a considerable bearing capacity to accommodate vehicle movement without any hindrance It is done in 3 layers firstly a layer of 10 cm of sand is laid to achieve a uniform level over this a 180 mm deep layer of metal of size 90-25 mm is laid in between sand is laid over this layer to fill up the void , this sand also helps in bonding of the metal this layer is properly Page | 6
compacted with application of water and rolling over this layer 91mm thick
layer
of 40-63 mm WBM . Blindage is spread over WBM layer.
Rolling and watering is done on this layer too. Total area under hardening is 3800 Sqm.
Rolling: -
Immediately following at spreading of the coarse aggregate, it shall be compacted to the full width by rolling with either the three-wheel-power-roller of 8 to 10 tonnes capacity or an equivalent vibratory roller. Initially, light rolling is to be done, which shall be discontinued when the aggregate is partially compacted with sufficient void space in them to permit application of screenings. The rolling shall begin from the edges with the roller running forward and backward and adding the Screenings simultaneously until the edges have been firmly compacted. The roller shall then progress gradually from the edges to the centre, parallel to the centre line of the road and overlapping Page | 7
uniformly each preceding rear wheel track by one half width and shall continue until the entire area of the course has been rolled by the rear wheel. Rolling shall continue until the road metal is thoroughly keyed with no creeping of metal ahead of the roller. Only slight sprinkling of water may be done during rolling, if required. On super elevated curves, the rolling shall proceed from the lower edge and progress gradually continuing towards the upper edge of the pavement.
Ap pli ca ti on of Bin di ng Ma te ria l
After the application of screenings and rolling, a suitable binding material shall be applied at a uniform and slow rate in two or more successive thin layers. After each application of binding material, the surface shall be copiously sprinkled with water and the resulting slurry swept in with hand brooms or mechanical brooms or both so as to fill the voids properly. The surface shall then be rolled by a 8-10 tonne roller, water being applied to the wheels in order to wash down the binding material that may get stuck to the wheels. The spreading of binding material, sprinkling of water, sweeping with brooms and rolling shall continue until the slurry that is formed will, after filling the voids form a wave ahead of wheels of the moving roller. FOUNDATION
Size of foundation varies from Rig to rig depth It consist of three parts 1) Carrier Strip 2) Cellar pit 3) Area around cellar pit
Strips for diesel tank, Mud tank, Compressor, Mud pump etc. Page | 8
Barite room
Barite room is constructed to store Barite at the drill site and other costly chemical Fire tank
Fire tank is constructed at the drill site as a safety measure for handling 1.5 lakh litre of water for fire fighting and storing water for other uses. Utilities
Bathroom and water closet are constructed for Rig employees for maintaining Sanitation at the site
Waste pit
Waste pit is constructed to collect all the drilling waste fluid. it is hazardous for the environment so in order to save environment and in compliance Page | 9
with environment ministry we have to prevent this waste from entering the sub strata so that it can’t pollute the ground water and nearby soil Capacity of Waste pit is 1.5 times depth of Well. Waste pit is lined with geotextile “silpaulin” of 200
gsm
to
prevent leaching of Hazardous
chemical into the nearby Earth strata placing in position in finished size and shape (ready to place with necessary eyelets/holes) jointed as per manufacturers specifications at Factory, multi-layered cross laminated UV stabilised plastic sheet of 200 GSM (SILPAULIN manufactured by Supreme Industries Limited) or equivalent, blue coloured conforming to BIS 146111998 Fencing
The drill site area is fenced with barbed wire fencing for restricting entry of unauthorised persons/stray cattle in the drilling area and to protect land from encroachment and security reasons Specifications for Fencing with barbed wire: RCC post:- All posts and struts shall be of standard size, the length of posts
being 1.8 m or as specified and that of struts being minimum of 2.0 m. These shall be cast in cement concrete 1:1 ½ :3 (1 cement : 1 ½ coarse sand : 3 graded stone aggregate 12.5 mm nominal size) reinforced with 10 mm diameter tor steel bars as directed and finished smooth with cement mortar 1:2 (1 cement: 2 fine sand). The specifications for R.C.C. work shall apply. The posts and struts shall be free from cracks, twists and such other defects. G.I. staples on wooden plugs or 6 mm bar nibs will be provided as directed by Engineer-in-Charge while casting the posts. Quantity of RCC post, struts, Rails and Pales to be measured in cubic content. Spacing of Posts and Struts Page | 10
The spacing of posts shall be three metres centre to centre, unless otherwise specified, or as directed by the Engineer-in-Charge to suit the dimensions of the area to be fenced. Every 15th, last but one end post and corner posts shall be strutted on both sides and end posts on one side only.
Fixing of Posts and Struts
Pits 45 x 45 cm and 75 cm deep or as directed shall first be excavated true to line and level to receive the posts. In the case of struts, pits 70 x 45 x 75 cm deep or as directed shall be excavated to suit the inclination of the strut so that it is surrounded by concrete by not less than 15 cm at any point. The pits shall be filled with a layer of 15 cm thick cement concrete 1:3:6 (1 cement: 3 fine sand: 6 graded stone aggregate 40 nominal size). The posts and struts shall then be placed in the pits, the posts projecting 1.2 m or to the specified height above ground, true to line and position. The cement concrete 1:3:6 shall be filled in upto 15 cm for posts and 25 cm for struts below ground level at the base of the concrete so that the posts are embedded in the cement concrete block of size 45 x 45 x 60 cm and strut in block of size 70 x 45 x 50 cm. The concrete in foundations shall be watered for at least 7 days to ensure proper curing. The remaining portions of pits shall be filled up with excavated earth and the surplus earth disposed off as directed by the Engineer-in-Charge and site cleared.
Fixing G.I. Barbed Wire
The barbed wire shall be stretched and fixed in specified number of rows and two diagonals. The bottom row shall be 14 cm above ground and the rest at 12.5 cm centre to centre. The diagonals shall be stretched between Page | 11
adjacent posts from top wire of one post to the bottom wire of the second post. The diagonal wires will be interwoven with horizontal wires by fixing the oddrows of wires first , then the diagonal cross wires and lastly the even rows of wires. The barbed wire shall be held to the R.C.C. posts by means of G.I. staples fixed to wooden plugs or G.I. binding wire tied to 6 mm barnibs fixed while casting the posts. Turn buckles and straining bolts shall be used at the end posts, if so specified.
Name of work : - Repair of approach road from main road to Base gate at WSS Sertha Kalol in Area –I Estimated Cost for this work was ` 294850 workorder for this work was awarded to Vishwakarma constructions after following the procedure of tendering Nature of work
From the main road to Base gate it was 56 meter long WBM road but due to movement of heavy vehicles of WSS there were lots of pot holes and road was of uneven surface so as per the demand of the user group a 10 cm thick RCC road is constructed over the existing WBM road is laid Over the existing wbm road a 10 cm thick layer of Cement concrete 1:4:8 (1 cement :4 Coarse sand :8 hand broken stone aggregate 40 mm nominal size ) is laid after proper watering and rolling of the surface . Over this layer steel reinforcement is provided along the length and Page | 12
breadth of the road at 300mm spacing centre to centre
after laying
reinforcement and checking the spacing between the Re-bars 1:2:4 Cement concrete (1 cement :2 Coarse sand :4 Graded stone aggregate 20 mm nominal size ) is laid and
proper camber is provided for easy
passage of water from the surface of the road Curing: - the RCC work is cured for next7 days after laying RCC
Name of work: - Requirement of Shed at DTYS for the storage of Heavy equipment Work requirement: -there was a requirement of a shed for storage of heavy equipment
used in
drilling
process
with EOT crane of
load
handling capacity of 10 ton along with a building to accommodate senior officers and a conference room for holding
surface team’s
meeting plinth area of the building was 21 x 6m Nature of work
Preparing estimate based on the plinth area rates as provided in the CPWD plinth (applicable
area
rate
schedule 2007
for Ahmedabad) for
calculation
with of
cost
index
of 22%
plinth
area
rate the
building was designed as office building RCC framed Structure of floor height 3.5 m extra provisions were made for making building earthquake resistant as Gujarat lies under high Risk prone zone After making preliminary estimate on the basis of plinth area rates and getting AA&ES for the plinth area a detailed estimate was made using CPWD DSOR Page | 13
