BANGLADESH POWER DEVELOPMENT BOARD TENDER ... - BPDB

A written record of the drilling information which is called a Well Log shall be keptby the drillers and shall be available for examination by the Board at any timeduring the work and a complete typewritten copy of the well log shall besubmitted to the Board within ten (10) days after completion of the work. Thewell log shall show amongst other things the type of materials encountered,colour of the return water, depth at which circulation as lost, manner of drilling,length of casings installed, and other pertinent drilling data.(4) Well Completion and DevelopmentThe Contractor shall undertake all operations pertaining to the completion anddevelopment of the well which shall consist of the installation of casings, installingwell screen within a sand and gravel formation, developing the water-bearingformation, grout filling of the upper section of the well casing (from collar to atleast 6m deep), surging and back-washing.The well casings to be installed shall be carbon steel, ASTM A-53, seamless,Grade B or equivalent. Openings of the well screens shall be so designated toprevent clogging and shall be free from jagged edges and irregularities so as toavoid clogging and corrosion.(5) Pumping Test for Yield and Draw-downPumping tests shall be performed to determine the deep-well capacity and otherhydraulic characteristics of the water-bearing strata.The Contractor shall furnish and operate a pump for this purpose that is capableof continuous operation at a sustained delivery of 380 lit/mm or more in aduration of at least five (5) hours of pumping test operation. Measurements of thevolume of water pumped per minute, the depth of static water level beforepumping started, the depth of the pumping level at one or more constant rates ofpumpage, the rate of recovery of the water level after pumping test stopped andthe length of pumping time of each pumping rate shall be made by the Contractorin the presence of the Board & Engineer. The Contractor shall construct any otherstructures necessary to conduct water away from the deep-well.For a comprehensive test of the well, the pump shall be operated continuously atabout 1/3 of its capacity until pumping level is attained. After making thenecessary measurements, the pump rate is adjusted to about 2/3 of the pumpcapacity and measurements are repeated when the pumping level becomesconstant. By increasing the rate of pumpage to produce maximum draw-down; orincreasing it to the full capacity of the pump and making measurements a thirdtime when the pumping level becomes stable.All the necessary equipment the measuring devices for testing the deep-well shallbe calibrated and provided by the Contractor at his own expense.After developing and testing operations are completed to the satisfaction of theBoard, the Contractor shall measure the depth of the well and record the totalopen depth of the casing. Sterilisation of the well is done by pouring a solution of450 grams of high test Calcium Hypochlorite (HTH) in 45 litters of water.Upon completion of the drilling, the Contractor shall submit to the Board theGhorasal 200 MW to 300 MW Gas Turbine Peaking Power Plant Project (Vol-2 of 3)184