低滲透裂縫性油藏弱凝膠調剖實驗研究
發(fā)布時間：2018-08-20 12:48
【摘要】：低滲透裂縫性油藏由于儲層物性差、裂縫發(fā)育,具有基質-裂縫雙重介質特征,需進行壓裂改造才能獲得較理想的產量和經濟效益。而裂縫的存在使得水驅開發(fā)過程中,油井含水上升快、無效注水嚴重,甚至出現暴性水淹,水驅開發(fā)矛盾突出、油藏采出程度低。XF油田油層平均溫度60℃、地層水礦化度60345 mg/L;儲層裂縫發(fā)育,最大開啟寬度達到2 mm,多在0.2~1.0 mm,導致油井含水上升快,出現暴性水淹現象。目前,XF油田現場已開展了大規(guī)模的弱凝膠調剖增產措施,并取得了重要成果,部分油井出水問題有所緩解。此外,還有部分層段水淹狀況仍未得到明顯改善,調剖效果較差。目前室內實驗對調剖劑的評價模型,多采用多孔介質物理模型,或是簡單人造裂縫模型。這樣,模型模擬油藏的相似程度較低、裂縫參數量化困難、基質-裂縫雙重介質模型調剖改善后效果不能充分體現等問題。為此,本文針對油田實際,首先對現場使用的弱凝膠調剖體系性能效果進行評價,包括剪切作用、礦化度、老化作用以及溶脹作用對弱凝膠性能影響;然后重點開展了以油藏相似性準則為基礎的物理模型設計與研究,利用自主研發(fā)能夠實現裂縫參數可調、裂縫與基質分流、模擬程度高、模型可重復利用、操作簡便的低滲透裂縫性油藏調剖物理模型,研究了包括裂縫寬度、裂縫面積以及裂縫形狀等裂縫參數對弱凝膠封堵性能影響;并通過驅油試驗給出影響裂縫性油藏水驅采出程度低的主要原因和相應的改善途徑。弱凝膠體系性能評價結果表明,弱凝膠體系中聚合物HPAM分子受到剪切作用后相對分子質量及視黏度均隨聚合物質量濃度的增加減小幅度降低;未剪切弱凝膠體系老化180 d后視黏度仍高于28000 mPa·s,剪切后和礦化度高的弱凝膠在老化25 d后出現脫水現象,弱凝膠強度和穩(wěn)定性下降;溶脹作用使膠體膨脹吸水,弱凝膠強度下降。弱凝膠在裂縫物理模型中的驅替試驗結果表明,弱凝膠封堵強度隨裂縫寬度的增大而減小,根據其封堵作用強弱,臨界裂縫寬度為0.69 mm;弱凝膠在不同裂縫寬度條件下封堵機理不同,當裂縫寬度小于臨界寬度0.69 mm時,弱凝膠封堵裂縫能力在自身黏性較大的基礎上,主要是弱凝膠體系的彈性作用,提高了體系的封堵強度;而大于臨界寬度時,弱凝膠封堵裂縫主要依靠自身黏性或弱凝膠內摩擦力來增加后續(xù)水流動阻力,從而提高注水壓力,但壓力提高幅度不大;裂縫寬度為0.43 mm時,弱凝膠封堵能力與裂縫面積呈正相關關系,單位裂縫面積內的封堵壓力相同;在形狀不同的裂縫中,弱凝膠對直縫的封堵能力最差,而隨著裂縫形狀的復雜化,弱凝膠與裂縫間的受力關系復雜化,弱凝膠封堵裂縫強度是其與裂縫間的附著力和彈力的綜合表現;靜態(tài)條件下有利于聚合物吸附于介質表面,形成的弱凝膠附著力高、封堵強度高,而無附著力時弱凝膠的封堵能力下降幅度高達35倍;隨著裂縫寬度的增加,弱凝膠的封堵能力降低、基質中的分液量降低,同時后續(xù)注入水發(fā)生繞而流形成的死油區(qū)增大,后續(xù)注入水的波及效率由100%降低至67.84%,綜合采收率由43.91%下降至29.28%,弱凝膠封堵較寬裂縫的強度低是后續(xù)注入水發(fā)生繞流導致波及效率降低的原因;弱凝膠在0.43 mm裂縫中的封堵強度較高,隨著基質滲透率的增加,基質吸水量增加,巖心波及效率高接近100%,而驅油效率不同導致了滲透率為0.1~1.0×10-3μm2綜合采收率不同;弱凝膠-預凝膠顆粒復合體系能夠有效提高弱凝膠對較寬裂縫的封堵能力,降低了后續(xù)水發(fā)生繞流的可能性,使得裂縫寬度為0.98 mm時,綜合采收率由29.28%上升至42.35%。
[Abstract]:The low permeability fractured reservoir is characterized by poor reservoir physical property, well developed fractures and dual media of matrix and fracture, so it is necessary to carry out fracturing transformation to obtain ideal production and economic benefits. The average reservoir temperature in XF oilfield is 60 C and the salinity of formation water is 60345 mg/L. The maximum opening width is 2 mm, mostly from 0.2 mm to 1.0 mm, which leads to rapid increase of water cut and sudden flooding. As a result, the water production problem of some oil wells has been alleviated. In addition, the water flooding condition of some sections has not been improved obviously, and the profile control effect is poor. For this reason, in view of the actual situation in the oilfield, this paper firstly evaluates the performance of the weak gel profile control system used in the field, including shearing, salinity, aging and swelling effects on the weak gel properties; and then focuses on the development of the weak gel properties. Physical model design and research based on reservoir similarity criterion can realize adjustable fracture parameters, fracture and matrix splitting, high degree of simulation, model reusable, easy to operate low permeability fractured reservoir profile control physical model, including fracture width, fracture area and fracture shape and other fracture parameters. The results show that the relative molecular mass and apparent viscosity of polymer HPAM in weak gel system depend on the polymer mass concentration after shearing. The apparent viscosity of the unshared weak gel system is still higher than 28000 mPa.s after 180 days of aging, and the weak gel after shearing and high salinity dehydrates after 25 days of aging, and the strength and stability of the weak gel decrease; swelling makes the gel swell and absorb water, and the strength of the weak gel decreases. The results show that the sealing strength of weak gel decreases with the increase of fracture width, and the critical fracture width is 0.69 mm according to its sealing effect. The sealing mechanism of weak gel is different under different fracture width conditions. It is mainly due to the elastic effect of weak gel system, which improves the plugging strength of the system; when the width of the fracture is larger than the critical width, weak gel plugging cracks mainly rely on its own viscosity or weak gel internal friction to increase the flow resistance of subsequent water, thus increasing the injection pressure, but the pressure increases little; when the width of the fracture is 0.43 mm, weak gel plugging capacity and Fracture area is positively correlated, and the sealing pressure is the same in the unit fracture area; among the cracks with different shapes, weak gel has the worst sealing ability to the straight crack. With the complication of fracture shape, the force relationship between weak gel and crack is complicated, and the strength of weak gel sealing crack is the combination of adhesion and elasticity between weak gel and crack. The results show that under static conditions, the weak gel formed by polymer adsorbing on the surface of the medium has high adhesion and sealing strength, but without adhesion, the sealing ability of the weak gel decreases as much as 35 times; with the increase of crack width, the sealing ability of the weak gel decreases, the amount of liquid separation in the matrix decreases, and the subsequent injection water flows around and flows. With the increase of dead zone, sweep efficiency of subsequent injection water decreased from 100% to 67.84%, and comprehensive recovery decreased from 43.91% to 29.28%. The low strength of weak gel plugging wider fractures is the reason of sweep efficiency reduction caused by flow around subsequent injection water; the sealing strength of weak gel in 0.43 mm fracture is higher, with the increase of matrix permeability. Additionally, the matrix water absorption increases, and the core sweep efficiency is nearly 100%. The different displacement efficiency results in the different comprehensive recovery of 0.1-1.0 *10-3 micron 2. Weak gel-pre-gel particle composite system can effectively improve the sealing ability of weak gel to wider fractures, reduce the possibility of subsequent water flow around, and make the fracture width 0.1-1.0 *10-3 micron 2. .98 mm, the comprehensive recovery increased from 29.28% to 42.35%.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE348
本文編號：2193657
[Abstract]:The low permeability fractured reservoir is characterized by poor reservoir physical property, well developed fractures and dual media of matrix and fracture, so it is necessary to carry out fracturing transformation to obtain ideal production and economic benefits. The average reservoir temperature in XF oilfield is 60 C and the salinity of formation water is 60345 mg/L. The maximum opening width is 2 mm, mostly from 0.2 mm to 1.0 mm, which leads to rapid increase of water cut and sudden flooding. As a result, the water production problem of some oil wells has been alleviated. In addition, the water flooding condition of some sections has not been improved obviously, and the profile control effect is poor. For this reason, in view of the actual situation in the oilfield, this paper firstly evaluates the performance of the weak gel profile control system used in the field, including shearing, salinity, aging and swelling effects on the weak gel properties; and then focuses on the development of the weak gel properties. Physical model design and research based on reservoir similarity criterion can realize adjustable fracture parameters, fracture and matrix splitting, high degree of simulation, model reusable, easy to operate low permeability fractured reservoir profile control physical model, including fracture width, fracture area and fracture shape and other fracture parameters. The results show that the relative molecular mass and apparent viscosity of polymer HPAM in weak gel system depend on the polymer mass concentration after shearing. The apparent viscosity of the unshared weak gel system is still higher than 28000 mPa.s after 180 days of aging, and the weak gel after shearing and high salinity dehydrates after 25 days of aging, and the strength and stability of the weak gel decrease; swelling makes the gel swell and absorb water, and the strength of the weak gel decreases. The results show that the sealing strength of weak gel decreases with the increase of fracture width, and the critical fracture width is 0.69 mm according to its sealing effect. The sealing mechanism of weak gel is different under different fracture width conditions. It is mainly due to the elastic effect of weak gel system, which improves the plugging strength of the system; when the width of the fracture is larger than the critical width, weak gel plugging cracks mainly rely on its own viscosity or weak gel internal friction to increase the flow resistance of subsequent water, thus increasing the injection pressure, but the pressure increases little; when the width of the fracture is 0.43 mm, weak gel plugging capacity and Fracture area is positively correlated, and the sealing pressure is the same in the unit fracture area; among the cracks with different shapes, weak gel has the worst sealing ability to the straight crack. With the complication of fracture shape, the force relationship between weak gel and crack is complicated, and the strength of weak gel sealing crack is the combination of adhesion and elasticity between weak gel and crack. The results show that under static conditions, the weak gel formed by polymer adsorbing on the surface of the medium has high adhesion and sealing strength, but without adhesion, the sealing ability of the weak gel decreases as much as 35 times; with the increase of crack width, the sealing ability of the weak gel decreases, the amount of liquid separation in the matrix decreases, and the subsequent injection water flows around and flows. With the increase of dead zone, sweep efficiency of subsequent injection water decreased from 100% to 67.84%, and comprehensive recovery decreased from 43.91% to 29.28%. The low strength of weak gel plugging wider fractures is the reason of sweep efficiency reduction caused by flow around subsequent injection water; the sealing strength of weak gel in 0.43 mm fracture is higher, with the increase of matrix permeability. Additionally, the matrix water absorption increases, and the core sweep efficiency is nearly 100%. The different displacement efficiency results in the different comprehensive recovery of 0.1-1.0 *10-3 micron 2. Weak gel-pre-gel particle composite system can effectively improve the sealing ability of weak gel to wider fractures, reduce the possibility of subsequent water flow around, and make the fracture width 0.1-1.0 *10-3 micron 2. .98 mm, the comprehensive recovery increased from 29.28% to 42.35%.
【學位授予單位】：成都理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE348
【參考文獻】
相關期刊論文 前4條
1 周新桂;張林炎;黃臣軍;萬曉龍;;華慶地區(qū)長6~3儲層裂縫分布模型與裂縫有效性[J];吉林大學學報(地球科學版);2012年03期
2 王俊魁,孟憲君,魯建中;裂縫性油藏水驅油機理與注水開發(fā)方法[J];大慶石油地質與開發(fā);1997年01期
3 李華斌,羅平亞,鄭焰,郭擁軍,王健,廖廣志,楊振宇;大慶油田締合聚合物/堿/表面活性劑三元復合驅油提高采收率研究[J];四川大學學報(工程科學版);2001年04期
4 王成勝;黃波;易飛;陳士佳;朱洪慶;孫艷萍;;渤海SZ36-1油田締合聚合物黏度損失研究[J];石油鉆采工藝;2010年05期
相關博士學位論文 前3條
1 劉德華;油田開發(fā)中后期綜合治理技術研究[D];西南石油學院;2005年
2 馮金德;裂縫性低滲透油藏滲流理論及油藏工程應用研究[D];中國石油大學（北京）;2007年
3 李志賢;西部油氣資源型城市（鎮(zhèn)）可持續(xù)發(fā)展研究[D];蘭州大學;2014年
相關碩士學位論文 前1條
1 孫秀芝;注聚過程中HPAM水溶液剪切穩(wěn)定性研究[D];中國石油大學;2009年
，本文編號：2193657
本文鏈接：http://sikaile.net/kejilunwen/shiyounenyuanlunwen/2193657.html
教材專著
