Yatay Kuyularda Perforasyonlardan Kaynaklanan Basınç Kayıplarının Analizi

Abstract

Yatay kuyuların petrol endüstrisindeki öneminin artmasıyla birlikte yatay kuyu uygulamaları üzerindeki araştırmalar da yoğunlaşmıştır. Yatay kuyularda akış davranışı ve basınç kayıplarının analizi, üretime olan etkisi nedeniyle araştırılan konuların başında gelmektedir. Bu Yüksek Lisans Tez Çalışmasında yatay kuyularda perforasyonlardan kuyu içine akışa bağlı basınç kayıpları deneysel olarak araştırılmış, deney sonuçlan matematiksel olarak yorumlanmıştır. Bu çalışmada kullanılan donanım uygun şekilde tasarlanmış olan plastik boru, pompalar, basınç ölçüm panosu ve su tankından oluşmaktadır. Bu donanım üzerine iki farklı çapta (4 mm ve 8 mm) perforasyon açılmış ve her bir perforasyondan değişik debilerde enjeksiyon yapılarak basınç ölçüm noktalan ile basınç ölçümleri gerçekleştirilmiştir. Farklı enjeksiyon/ana hat debi oranlarında gerçekleştirilen bu çalışmanın sonucunda elde edilen deney verileri değerlendirilerek yeni bir sürtünme faktörü korelasyonu geliştirilmiştir. Yeni korelasyon ile hesaplanan perforasyon sürtünme faktörü değerleri bu çalışmada ve benzer çalışmalardaki deney sonuçlarıyla karşılaştırılmıştır. Çalışma sonuçlan yatay kuyularda perforasyonun etkisinin düşünülenden farklı olduğunu ve perforasyondan akışın kuyu akış davranışım bulundukları bölgede değiştirdiğini, bu değişimin kuyu toplam akış debisine bağlı olarak belli bir uzaklıkta (yaklaşık olarak 8dm) kaybolduğunu, sürtünme faktörünün perforasyon/ana hat akış debisi oranının. ve perforasyon/boru çapı oranının fonksiyonu olduğu göstermiştir.

Horizontal wells have become attractive in many applications over the last 20 years. Increasing demand for the use. of horizontal wells have pushed the petroleum industry to work on the application problems of horizontal wells. One of the problems arising from the production of the well is the change of the flow behavior in the welfare. In a horizontal well depending upon the completion method, fluid may enter the welfare at different locations along the well. One of the locations where fluid can enter is the perforations. The influx along the wellbore through" perforations effects the flow behavior in a horizontal well. This behavior change effects the production of the well. Causing important changes on the production of the well. The objective of this study is to investigate the effect of influx from perforations on the flow behavior of horizontal wells. For this purpose a new experimental test facility is designed and constructed to simulate the well and the flow from perforation. Two different diameter perforations (4 mm and 8 mm) are used on these experiments. Experimental Section Figure S.l shows the schematic description of the test facility. Experimental test facility is composed of two parts: Fluid handling system and test section. Fluid handling system is composed of two major sections, main flow and the perforation (injection) flow. In the main flow section, flow in a horizontal well is simulated. Water flows through the test facility and is then circulated back to the water tank. Two different rate centrifugal pumps are used to maintain flow in high (>30 1/min.) and low (30 l/min.<) rates. Both pumps are connected by a by-pass line in order to vary flow rates. In the injection section, flow through perforations into the well is simulated by injecting fluid through perforations. A low rate centrifugal pump with a by-pass line is used to inject fluid through perforations. Water is used as the test fluid. Injection and main flow rates are measured by weighing method. Test section is created to measure the pressure during both injection and no injection cases. Test section is 2.8 meters and located on the fully developed flow region of the test facility which is estimated to start 20 m away from the pipe inlet. As shown in Figure S.2 test section has 14 pressure ports which are composed of 4 mm tubing connected to 9 mm glass manometer tubes to measure the pressure visually in means of water column. Two different diameters (4 mm and 8 mm) perforations are also located in this section. First perforation (4 mm) is located XI in between the measurement ports 2 and 3 and the second one is after the pressure port number 7. Figure S.3 shows the locations of perforations on the test section. Results and Discussion A total of 474 experiments were conducted for 4 mm and 8 mm perforations in various main flow and injection rates. Data were acquired for no fluid and fluid injection cases. Data taken from the pressure measurement ports 1 and 2 is used to find the roughness of the pipe. A good agreement is seen in the comparison with the Moody chart for smooth pipes using the Blasius formula. Blasius formula is as follows 0.316 iNRe In the above equation f is the friction factor and NRe stands for the Reynolds number. Data taken during the "no injection" and "injection cases" from pressure measurement ports 2-3 and 7-9 are used to calculate the apparent wall friction factor and perforation friction factor for 4 mm and 8 mm perforation. Friction factor for no injection and injection cases are calculated by the Moody Equation from developed for pressure losses in pipes. f =. T Ax ^ (S.2) 4R In this equation pi and p2 are inlet and outlet pressures respectively, Ax is the distance, p is the density of the fluids, u is the mean velocity of the pipe flow and R is the radius of the pipe. Two correlations are developed to model the apparent wall friction factor of 4 mm and 8 mm perforations by using the no fluid injection case data. The correlations are as follows; f0 = 98.52NRe~0,926 ; d. = 4 mm (S.3) XII f = 57 22N ı0 D/.z.zı\Re -0.888 d. =8mm (S.4) In this study the total friction factor is considered to be the sum of the wall friction and the friction caused by the inflow through the perforation of the perforated area. f=fo + fP (S.5) Therefore data taken from injection case are considered to be the total apparent friction factor. Wall friction factor is subtracted from the total friction factor to find the apparent friction factor for the perforations (fp). Value's fp is evaluated using different parameters and a new correlation is developed. On figure S.4 the new correlation is shown. As it can be noticed from the Figure the data shows three different trends for both 4 mm and 8 mm cases. The new correlation is as follows; For 0.0932505 MS- <-^-< 0.1 838207 MS- d j qt "V d; 'C v di j m Ax 0.0454444-1.14567x10" \ di j Ut> -2 (S.6) For 0.0129099 MS- < -5i- < 0.0932505 M2- 9t -0.592321 ( \ ii 1.184642 \*\) For 0.0073195 MS. <^_ (0.0 129099 MS- dj qt \\ d; (S.7) 0.0198886- 0.001927 In 'C \ ui J r ^-2 H) (S.8) XIll In these equations dj and dm are the perforation and the pipe diameters respectively, q; is the injection and qt is the total flow rate and Ax stands for the range. As a result of this experimental and analytical study following conclusions are made: The flow behavior through a perforated pipe is different from the flow behavior through a normal pipe. The flow behavior in the perforated section changes while apparent roughness change. It is concluded that the flow disturbance due to flow from perforation, comes its effect in 8 dm distance from the perforation. XIV o.4-* CO Q..c Ü CO CM T" CO XV PERFORATION (4 mm) 17.66 cm.2.54 ci m\ 20.2 cm PERFORA ION (8 mm) l 14.0 cm i 3.0 cm ı 2.4cmti 19.4 cm Figure S.3 Locations of the perforations XVI fi o 'M U o o fi.2 ü £ o o *§ PL, C/3 S Kxvrpj/tojfp/p)