Loading...
HomeMy WebLinkAbout7 Exhibit 6A( EXHIBIT j b-d Bore Piping Plan and Explanation SUMMARY Ursa Resources will be drilling wells for the production of Oil & Gas in the Battlement Mesa area and needs to design a transportation method for movement of the fluids produced. In addition to the normal pipeline system designed for this process, a few instances will require bore piping to go under roads, waterways, sewer systems, etc. This presentation will be looking at connecting the BMC "B Pad" to the BMC "D Pad" as show below in an overview map. With the bore pipe in place, liquid and gas will flow from the "B Pad" to the "D Pad" and then onto a point of sale downstream of the "D Pad." Ursa is planning on boring between these two pads and connecting them with a 16" casing containing an 8" carrier pipe for water parallel to a separate 12" gas line. Boring is a very commonly used method to transmit gas under many surfaces that create obstacles for traditional pipeline methods. It is done by all utilities and is how we receive water, electricity, sewer service, etc. in our communities. We have chosen to use a bore method for this pipe due to the steep hillside and the road crossing involved in connecting these pads. Alternative methods were researched, but due to the surrounding housing development and power lines, boring proved to be the best and safest method. ( ( r ( ENGINEERING DETAIL FRICTION Before considering bore pipe installation many core samples are taken from the ground to see what the soil composition will be in the path of the bore. From these samples, one can put together a profile of what the bore path will look like. Once a profile is defined we can then figure out how much friction we can expect between the pipe and the soil around it. The soil samples taken in this area are composed of mostly silt and clay with a few very large boulders. This is an ideal profile for the bore path planned because friction in clay and boulders help keep the pipe in place. Once the pipe is pulled and at rest static friction helps hold the pipe in place. This is relatively easy to calculate and can be done as follows: Where: Ff is the friction force µis the friction factor (usually a number between 0 and 1) N is the normal force of gravity on an object Using this formula and some basic numbers, we can come up with the force that it would take to move this pipe. To start this calculation, we need the weight of the pipe: 16" pipe with 0 .500" wall thickness weighs 82 .771bs/ft. This pipe will be approximately 1500 feet long which is 124,1551bs of pipe . Looking at the elevations on the map on the previous page, we are gaining roughly 150 feet of elevation over the 1500 foot length. This gives us an average elevation angle of roughly 6". To calculate the normal force of an object on a slope, the formula is: N=mg"cos{) where mg is the weight of the object and {)is the angle of the object to horizontal. Using this, we find that N is equal to 123,4751bs. The next factor to look at is the friction factor. To figure out this number previous data Is referred to, such as the amount of force it takes to pull one pound of steel on another pound of steel. A ratio is then developed, usually between O and 1, which can then be applied to this formula. From looking at many published research papers, it can be concluded that an average friction factor for steel pipe against a clay surface is 0.6. It has been show that the normal force value (N) is 123,4751bs in this case and the friction factor is 0.6. That would mean that the force it takes to move this object is at least 123,475•0.6 = 74,0851bs . This is equivalent to 37 tons of force to move this pipe from its static location. This is also assuming that just the bottom of the pipe is touching the surface of the bore hole which will not be the case. Most of the surface of the pipe will be in contact with the soil around it which will only result in a higher friction factor (closer to 0.8). For information, using a friction factor of 0.8, it would take 98, 780 pounds of force to move the empty pipe. Anything inside the pipe would only increase the weight and thus the friction factor, so the most conservative approach is to look at an empty pipe. These same numbers and formulas can be applied to the 12" gas pipe, but for the sake of simplicity only the 16" pipe has been shown to emphasize the effect of friction forces between pipe and soil. In addition to the values shown above, Ursa Resources will be installing a thrust block at the top of the pipe for an extra safety factor. A thrust block is basically a large cast in place block of concrete placed around the top of the pipe to prevent any possible movement due to lateral forces imposed on the pipe by mechanical or geological events. The combination of friction and the thrust block makes the bore method the best and safest method for this application.