Surface and interfacial properties of 1,3-dialkyl glyceryl ether hydroxypropyl sulfonates as surfactants for enhanced oil recovery

2021

In foam flooding, foams stabilized by conventional surfactants are usually unstable in contacting with crude oil, which behaves as a strong defoaming agent. In this article, synergistic effects between different surfactants were utilized to improve foam stability against crude oil. Targeted to reservoir conditions of Daqing crude oil field, China (45 C, salinity of 6778 mg L −1 , pH = 8-9), foams stabilized by typical anionic surfactants fatty alcohol polyoxyethylene ether sulfate (AES) and sodium dodecyl sulfate (SDS) show low composite foam index (200-500 L s) and low oil tolerance index (0.1-0.2). However, the foam stability can be significantly improved by mixing the anionic surfactant with a sulfobetaine surfactant, which behaves as a foam stabilizer increasing the half-life of foams, and those with longer alkyl chain behave better. As an example, by mixing AES and SDS with hexadecyl dimethyl hydroxypropyl sulfobetaine (C 16 HSB) at a molar fraction of 0.2 (referring to total surfactant, not including water), the maximum composite foaming index and oil tolerance index can be increased to 3000/5000 L s and 1.0/4.0, respectively, at a total concentration between 3 and 5 mM. The attractive interaction between the different surfactants in a mixed monolayer as reflected by the negative β s parameter is responsible for the enhancement of the foam stabilization, which resulted in lower interfacial tensions and therefore negative enter (E), spreading (S), and bridging (B) coefficients of the oil. The oil is then emulsified as tiny droplets dispersed in lamellae, giving very stable pseudoemulsion films inhibiting rupture of the bubble films. This made it possible to utilize typical conventional anionic surfactants as foaming agents in foam flooding.

Section: Resultsmentioning

confidence: 92%

Synergistic Effects between Anionic and Sulfobetaine Surfactants for Stabilization of Foams Tolerant to Crude Oil in Foam Flooding

Liu

2021

“…In our previous articles (Yan et al, ; Yan et al, ), the resistance against adsorption by Daqing sandstone ( A s = 3.5 m 2 g −1 ) (Cui et al, ) of the double‐chain single‐head surfactants has been evaluated by measuring the total adsorption time, of a surfactant or an optimum formulation (usually binary mixture), until ultralow IFT can no longer be achieved. With a solid/liquid weight fraction ratio of 0.1/0.9 and starting at a total concentration of 10 mM, the total adsorption can be as high as 11 times and 8 times, respectively, for formulations dominated with anionic surfactants (1,3‐dialkyl glyceryl hydroxypropyl sulfonates, containing 0.5 wt.% Na 2 CO 3 ) (Yan et al, ) and nonionic surfactants (1,3‐dialkyl glyceryl ether ethoxylates, free of alkali), respectively (Yan et al, ). Using a similar method, maximum five times adsorption is obtained for the diC 8 GE‐HSB/C 16 HSB (0.90/0.10) binary mixture (free of alkali) starting at a total concentration of 7.5 mM, as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…A good approach for solving these problems is to design surfactants with a double‐chain single‐head structure, which have improved aqueous solubility and larger interaction with oil when adsorbed at the oil/water interface than those with a single‐chain of similar total chain length (Adkins et al, ; Rosen et al, ). Using this principle, we have recently synthesized a series of double‐chain single‐head surfactants and evaluated their performances for SP flooding, including anionic surfactants like dodecyllauroylbenzene sulfonate (Cui et al, ) and 1,3‐dialkyl glyceryl hydroxypropyl sulfonates (Yan et al, ), zwitterionic surfactants such as dialkyl methyl carboxylbetaines (Cui et al, ) and dialkyl methyl sulfobetaines (Li et al, ) as well as nonionic surfactants such as 1,3‐dialkyl glyceryl ethoxylates and Guerbet alcohol ethoxylates (Yan et al, , , ). It has been found that the performances of these double‐chain single‐head surfactants depend strongly on their hydrophilic head group.…”

Section: Introductionmentioning

confidence: 99%

“…It has been found that the performances of these double‐chain single‐head surfactants depend strongly on their hydrophilic head group. The anionic surfactants are still not effective in the absence of alkali, but effective in the presence of gentle alkali (Yan et al, ; Cui et al, ). The nonionic surfactants can not be used as hydrophobic surfactants, but those with a long EO chain can be used as hydrophilic components to mix with other highly hydrophobic surfactants in the absence of alkali (Yan et al, , , ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A New Series of Double‐Chain Single‐Head Sulfobetaine Surfactants Derived from 1,3‐Dialkyl Glyceryl Ether for Reducing Crude Oil/Water Interfacial Tension

Yan

et al. 2018

Self Cite

A new series of sulfobetaine surfactants with double‐chain single‐head structure were derived from 1,3‐dialkyl glyceryl ethers and their performances in reducing Daqing crude oil/connate water interfacial tension (IFT) in the absence of alkali were studied. With a large hydrophilic head group and double hydrophobic chains, these surfactants are efficient at reducing crude oil/connate water IFT. Those with didecyl and dioctyl are good hydrophobic surfactants that can reduce Daqing crude oil/connate water to ultra‐low IFT by mixing with a small molar fraction of various conventional single‐chain hydrophilic surfactants, such as α‐olefin sulfonates, dodecyl polyoxyethylene (10) ether, and cetyl dimethyl hydroxypropyl sulfobetaine. The asymmetric double‐chain sulfobetaine derived from 1‐decyl‐3‐hexyl glyceryl ether can reduce Daqing crude oil/connate water IFT to ultra‐low solely over a wide concentration range (0.03–10 mM or 0.0017–0.58 wt.%), which allows for use of an individual surfactant instead of mixed surfactants to avoid chromatographic separation in the reservoir. In addition, formulations rich in sulfobetaine surfactants show low adsorption on sandstone, keeping the negatively charged solid surface water‐wet, and forming crude oil‐in‐water emulsions. These new sulfobetaine surfactants are, therefore, good candidates for surfactant‐polymer flooding free of alkali.

“…For surfactants with conventional structure, or single alkyl chain and single head, the enhancement of lipophilicity is mostly realized by increasing hydrocarbon chain length, which however is limited by the raw materials supplied (≤C 18 generally) (Li et al, 2020), and a long single alkyl chain makes surfactant to crystallize easily from water reducing aqueous solubility. In contrast, surfactants with dialkyls and single head are easy to achieve a higher lipophilicity and thereby higher alkyl chain density at oil/water interface (Yan et al, 2017a, b, 2018), which is beneficial for achieving ultralow IFT. Moreover, the double chain‐single head surfactants have larger aqueous solubility than those with a single chain of equal total carbon number (Cui et al, 2012; Li et al, 2016a), similar to surfactants with branched chains (Rosen and Kunjappu, 2012).…”

Section: Introductionmentioning

confidence: 99%

Dialkyl Sulfobetaine Surfactants Derived from Guerbet Alcohol Polyoxypropylene–Polyoxyethylene Ethers for SP Flooding of High Temperature and High Salinity Reservoirs

Liu

2021

Dialkyl hydroxypropyl sulfobetaine (HSB) surfactants, C 16 GA-(PO) 5 -(EO) 3 -HSB and C 24 GA-(PO) 10 -(EO) 10 -HSB, were synthesized from Guerbet alcohols (GA) polyoxypropylene-polyoxyethylene (PO-EO) ethers and their behaviors in surfactant-polymer (SP) flooding of high temperature and high salinity reservoirs were examined and compared with their anionic hydroxypropyl sulfonate (HS) counterparts, C 16 GA-(PO) 5 -(EO) 3 -HS and C 24 GA-(PO) 10 -(EO) 10 -HS. The PO-EO chain embedded improves their aqueous solubility, and the sulfobetaines show better salt resistance than sulfonates. For a reservoir condition of total salinity 19,640 mg L −1 and 60-80 C, C 16 GA-(PO) 5 -(EO) 3 -HSB alone can reduce crude oil/connate water interfacial tension (IFT) to ultralow at 0.25-5 mM, which can be further widened to 0.1-5 mM by mixing with dodecylhexyl (C 12+6 ) glyceryl ether hydroxypropyl sulfobetaine (C 12+6 GE-HSB), a slightly hydrophobic surfactant. C 24 GA-(PO) 10 -(EO) 10 -HSB is more hydrophobic for the specified reservoir condition, however, by mixing with hexadecyl dimethyl hydroxypropyl sulfobetaine (C 16 HSB), a hydrophilic surfactant, ultralow IFT can also be achieved at a total concentration of 0.25-5 mM. The anionic counterparts can also reduce IFT to ultralow by mixing with C 12+6 GE-HSB and C 16 HSB, respectively. Moreover, the optimum binary mixture, C 16 GA-(PO) 5 -(EO) 3 -HSB/C 12+6 GE-HSB at a molar fraction ratio of 0.6/0.4, can keep the negatively charged solid surface water-wet (θ w = 12-23 ) in a wide concentration range, and can still achieve ultralow IFT after stored at 90 C for 90 days (initially 5 mM), which overall are favor of improving oil displacement efficiency at high temperature and high salinity reservoir conditions. Keywords Sulfobetaines Á Guerbet alcohols Á Alkyoxylated Á Ultralow interfacial tension Á Harsh reservoir conditions